essay on life in space

Living in space

Like every other living creature we know of, humans evolved at the bottom of a gravity well. We take the Earth's tug for granted, and so do our bodies. So it's not surprising that our bodies behave oddly in orbit. What is surprising is that humans turn out to adapt remarkably well to zero-g (more precisely, microgravity). After all, back in 1961, Soviet scientists were genuinely worried that any prolonged period of weightless might even be fatal - which is why they limited Yuri Gagarin's first space flight to just 108 minutes and a single orbit.

Since then, scientists around the world have had the benefit of years of data on the effects of long-term space living. (The record for a long-duration mission is still held by Russian cosmonaut Valeri Polyakov, who completed a 438-day tour of duty aboard the Mir space station in 1995.) The crews of the ISS are already making full use of that experience, and will certainly add to it.

Weightlessness itself is the most important and the most obvious influence on life in space. Most astronauts find their freedom from gravity exhilarating, especially as they adapt to their new environment. But weightlessness enormously complicates the business of daily life, from eating to sleeping. And space adaptation involves some very complex changes in the human body, both short-term and long-term. These changes can cause health problems both in space and on return to Earth.

There are other factors, too. Outside the protective shield of the Earth's atmosphere, astronauts have to contend with high radiation levels. Mostly, these have minor and long-term effects: a slight increase in the risk of cancer in later life, for example. But during occasional solar flares, the sleet of radiation from the Sun can be immediately life-threatening.

Human psychology plays an important part in the story, too. Life in space also means living with a distinct lack of space. The ISS is vastly larger than any previous space structure, but even so it is no mansion. Astronauts can enjoy the finest views imaginable, with the whole planet stretched out before them amid the starry immensity of the universe. But their living quarters are pretty cramped, and they must share them with their fellow crew members for months at a time.

Still, there is no shortage of applicants for astronaut positions. And virtually everyone who has had the chance to live in space is keen to return. Besides, as our knowledge increases, and space medicine develops throughout the 21st century, the men and women in orbit - and hopefully beyond - should have a more comfortable time in future.

Microgravity affects just about everything in the human body, and usually for the worst. Fortunately, the effects are seldom more than temporarily disabling: humans are very good at adapting. And when astronauts return to Earth, they normally re-adapt very quickly to the customary, gravity-bound environment.

The vestibulary system and "Space Adaptation Syndrome"

We take our ability to stand upright just as much for granted as we do the force of gravity that holds us to the Earth. In fact, the human sense of balance depends on an extremely sophisticated sensor system that provides a constant stream of information to the brain. The key motion sensors are the subtle organs of the vestibulary system inside the inner ear. These function as super-sensitive accelerometers feeding the brain with a steady stream of signals that indicate motion and direction. There are also pressure receptors in the skin and in muscles and joints. Our senses of sight and hearing complete the data stream. Without having to think about it, we usually know everything we need about our body's posture and state of balance.

In the absence of gravity, signals from the vestibulary system and the pressure receptors are wildly misleading. The effect usually leads to immediate disorientation: many astronauts suddenly feel themselves upside-down, for example, or even have difficulty in sensing the location of their own arms and legs.

This disorientation is the main cause of the so-called Space Adaptation Syndrome, which one astronaut wryly described as "a fancy term for throwing up". Half or more of all space travellers suffer from space sickness, which brings with it headaches and poor concentration as well as nausea and vomiting. Usually, though, the problems disappear within a few days as astronauts adapt.

It is their brains, not their stomachs, that do most of the adapting. The confusing signals from the inner ear are largely ignored and vision becomes the prime source of "balance" information. In space, "down" is where your feet happen to be.

When they return to Earth, astronauts have to re-adapt just as painfully. Back at the bottom of the gravity well, most have difficulty maintaining balance - and if they close their eyes, they are very likely to fall over. Because of the effects of weightlessness on bones and muscles, they may have difficulty standing at all. But disorientation itself usually only lasts a few days, and there seem to be no long-term effects.

There is one re-adaptation that can take somewhat longer to accomplish, although the consequences are more likely to be amusing than crippling. Several long-duration Russian cosmonauts have reported that months after their flight, they still occasionally let go of a cup or some other object in mid-air - and are quite disconcerted when it crashes to the floor.

Heart, circulation and body fluids

Almost two-thirds of the average body weight is made up of water, in the form of intercellular fluid, blood plasma and the interstitial fluid between blood vessels and surrounding tissue. On Earth, all this liquid tends to settle downward in the body. Blood pressure at our feet, for example, is about 100mm of mercury higher than blood pressure in our chests. And the need to pump blood against the force of gravity requires the muscles of a big, powerful heart.

In space, there is nothing to pull body fluids down: there is no "down" to pull them to. The first effects are almost immediate. Without the restraint of gravity, fluids migrate from the legs to the head. Inside a day, legs shrink by up to a litre in volume and faces puff up correspondingly. The extra fluid in the head also leads to blocked sinuses and noses - the "space sniffles" that astronauts generally have to live with throughout their mission.

Other effects are more serious. Blood plasma drops by about 20% and the red blood cell count falls similarly: returning astronauts usually suffer from a temporary anaemia. Without gravity to contend with, the heart has to do far less pumping work. Heartbeat slows down. Since the body no longer needs to maintain the powerful heart muscles needed on Earth, heart tissue begins to shrink.

Exercise is not enough to reverse the process, but it helps to minimise it and the exertion also provides some relief from the "sniffles". Whenever possible, astronauts spend several hours a day on a treadmill or similar apparatus: the more exercise they can do in space, the less time it will take to recover on their return.

Bones and muscle

Bones are the scaffolding that holds the body against gravity. Our powerful skeletal muscles support that scaffolding - and of course move it around as required. Without gravity, bone and muscle alike lost their prime function. After even a short time in orbit, some strange things begin to happen.

The first seems like good news: without the compressive force of gravity, your spinal column expands and you grow taller, usually by between 5 and 8 cm. Unfortunately, the extra height can bring complications, which may include backache and nerve problems. More worrying than height gain, though, is the loss of bone and muscle tissue that becomes apparent from the first few days of a space mission.

Bone is a living, dynamic tissue. In normal life, new bone cells are constantly being made while worn bone is destroyed and its materials recycled. Bone regeneration is governed by a complex system, regulated by hormones and vitamins as well as physical stress on various parts of the skeleton. In microgravity, the body has no need to maintain its skeletal structure to Earth-bound standards. So bone tissue is absorbed and not replaced: astronauts can lose up to 1% of their bone mass each month. The missing bone shows up as high calcium levels elsewhere in the body, which itself can lead to health problems - kidney stones, for example.

Microgravity bone loss stops soon after astronauts return to Earth, but so far, no one is sure whether the lost bone fully regenerates. The life science experiments planned for the ISS should help scientists learn much more precisely how bone loss comes about, and perhaps how to cure it. Since the problem is very similar to osteoporosis, a bone-wasting disease especially common among elderly women on Earth, astronauts will not be the only people to benefit from the research.

Exercise seems to have little effect on bone loss, but it does reduce muscle shrinkage and generally improves an astronaut's sense of well-being. It may also be essential to a mission: astronauts can move around inside the ISS with very little effort, but spacewalks - or even installing heavy equipment within the station - involve heavy work.

Most astronauts, at least once they get over any space sickness, report an initial exhilaration at their freedom from weight. They are all disciplined, highly trained people, too, who share a sense of being part of an elite team with important work ahead of them. So it is not surprising that psychological problems are unusual on short-duration space missions.

Sooner or later, though, despite the marvellous views and the sense of mission, astronauts do feel the pressure of confinement in what amounts to a few small rooms. One Russian cosmonaut wryly remarked, "All the conditions necessary for murder are met if you shut two men in a cabin measuring 5 metres by 6 and leave them together for two months."

Fortunately, no astronaut has ever come nearer murder than a little ill-temper. But Russian psychologists - with almost 90,000 flying hours aboard the old Mir station to provide their data - have learned a good deal about the psychology of long-term space flight. Generally, they observed their cosmonauts go through three distinct phases. During the first, which usually lasted about two months, people were busy adapting, usually successfully, to their new environment. In the second phase, their were clear signs of fatigue and low motivation. And in the final phase, cosmonauts could become hypersensitive, nervous and irritable - a group of symptoms the Russians called "asthenia".

Other than a return to Earth, there seems to be no instant cure. But an easier workload, coupled with frequent opportunities for private communication with families back home, are important morale boosters. ISS operations managers have learned a great deal from the Russian experience, which is one reason why duty tours aboard the station will normally be limited to six months.

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Life on Other Planets: What is Life and What Does It Need?

One day, perhaps in the not-too-distant future, a faraway planet could yield hints that it might host some form of life – but surrender its secrets reluctantly.

Our space telescopes might detect a mixture of gases in its atmosphere that resembles our own. Computer models would offer predictions about the planet’s life-bearing potential. Experts would debate whether the evidence made a strong case for the presence of life, or try to find still more evidence to support such a groundbreaking interpretation.

“We are in the beginning of a golden era right now,” said Ravi Kopparapu, a scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, who studies habitable planets. “For the first time in the history of civilization we might be able to answer the question: Is there life beyond Earth?”

For exoplanets – planets around other stars – that era opens with NASA’s James Webb Space Telescope. Instruments aboard the spacecraft are detecting the composition of atmospheres on exoplanets. As the power of telescopes increases in the years ahead, future advanced instruments could capture possible signs of life – “biosignatures” – from a planet light-years away.

Within our solar system, the Perseverance rover on Mars is gathering rock samples for eventual return to Earth, so scientists can probe them for signs of life. And the coming Europa Clipper mission will visit an icy moon of Jupiter. Its goal: to determine whether conditions on that moon would allow life to thrive in its global ocean, buried beneath a global ice shell.

But any hints of life beyond Earth would come with another big question: How certain could any scientific conclusions really be?

“The challenge is deciding what is life – when to say, ‘I found it,’” said Laurie Barge of the Origins and Habitability Lab at NASA’s Jet Propulsion Laboratory in Southern California.

With so much unknown about what even constitutes a “sign of life,” astrobiologists are working on a new framework to understand the strength of the evidence. A sample framework, proposed in 2021, includes a scale ranging from 1 to 7, with hints of other life at level 1, to increasingly substantial evidence, all the way to certainty of life elsewhere at level 7. This framework, which is being discussed and revised, acknowledges that scientific exploration in the search for life is a twisted, winding road, rather than a straightforward path.

And identifying definitive signs remains difficult enough for “life as we know it.” Even more uncertain would be finding evidence of life as we don’t know it, made of unfamiliar molecular combinations or based on a solvent other than water.

Still, as the search for life begins in earnest, among the planets in our own solar system as well as far distant systems known only by their light, NASA scientists and their partners around the world have some ideas that serve as starting points.

Life That Evolves

First, there’s NASA’s less-than-formal, non-binding but still helpful working definition of life: “A self-sustaining chemical system capable of Darwinian evolution.” Charles Darwin famously described evolution by natural selection, with characteristics preserved across generations leading to changes in organisms over time.

Derived in the 1990s by a NASA exobiology working group, the definition is not used to design missions or research projects. It does help to set expectations, and to focus debate on the critical issues around another thorny question: When does non-life become life?

“Biology is chemistry with history,” says Gerald Joyce, one of the members of the working group that helped create the NASA definition and now a research professor at the Salk Institute in La Jolla, California.

That means history recorded by the chemistry itself – in our case, inscribed in our DNA, which encodes genetic data that can be translated into the structures and physical processes that make up our bodies.

The DNA record must be robust, complex, self-replicating and open-ended, Joyce suggests, to endure and adapt over billions of years.

“That would be a smoking gun: evidence for information having been recorded in molecules,” Joyce said.

Such a molecule from another world in our solar system, whether DNA, RNA or something else, might turn up in a sample from Mars, say from the Mars sample-return mission now being planned by NASA.

Or it might be found among the “ocean worlds” in the outer solar system – Jupiter’s moon, Europa, Saturn’s Enceladus or one of the other moons of gas giants that hide vast oceans beneath shells of ice.

We can’t obtain samples of such information-bearing molecules from planets beyond our solar system, since they are so far away that it would take tens of thousands of years to travel there even in the fastest spaceships ever built. Instead, we’ll have to rely on remote detection of potential biosignatures, measuring the types and quantities of gases in exoplanet atmospheres to try to determine whether they were generated by life-forms. That likely will require deeper knowledge of what life needs to get its start – and to persist long enough to be detected.

A Place Where Life Emerges

There is no true consensus on a list of requirements for life, whether in our solar system or the stars beyond. But Joyce, who researches life’s origin and development, suggests a few likely “must-haves.”

Topping the list is liquid water. Despite a broad spectrum of environmental conditions inhabited by living things on Earth, all life on the planet seems to require it. Liquid water provides a medium for the chemical components of life to persist over time and come together for reactions, in a way that air or the surface of a rock don’t do as well.

Also essential: an energy source, both for chemical reactions that produce structures and to create “order” against the universal tendency toward “disorder” – also known as entropy.

An imbalance in atmospheric gases also might offer a tell-tale sign of the presence of life.

“In Earth’s atmosphere, oxygen and methane are highly reactive with each other,” Kopparapu said. Left to themselves, they would quickly cancel each other out.

“They should not be seen together,” he said. “So why are we seeing methane, why are we seeing oxygen? Something must be constantly replenishing these compounds.”

On Earth, that “something” is life, pumping more of each into the atmosphere and keeping it out of balance. Such an imbalance, in these compounds or others, could be detected on a distant exoplanet, suggesting the presence of a living biosphere. But scientists also will have to rule out geological processes like volcanic or hydrothermal activity that could generate molecules that we might otherwise associate with life.

Careful laboratory work and precision modeling of possible exoplanet atmospheres will be needed to tell the difference.

Going Through Changes

Barge also places high on the list the idea of “gradients,” or changes that occur over time and distance, like wet to dry, hot to cold, and many other possible environments. Gradients create places for energy to go, changing along the way and generating molecules or chemical systems that later might be incorporated into life-forms.

Plate tectonics on Earth, and the cycling of gases like carbon dioxide – buried beneath Earth’s crust by subduction, perhaps, or released back into the atmosphere by volcanoes – represent one kind of gradient.

Barge’s specialty, the chemistry of hydrothermal vents on the ocean floor billions of years ago, is another. It’s one possible pathway to have created a kind of primitive metabolism – the translation of organic compounds into energy – as a potential precursor to true life-forms.

“What gradients existed before life?” she asks. “If life depends so much on gradients, could the origin of life also have benefited from these gradients?”

Clearer mapping of possible pathways to life ultimately could inform the design of future space telescopes, tasked with parsing the gases in the atmospheres of potentially habitable exoplanets.

“If we want to be sure it’s coming from biology, we have to not only look for gases; we have to look at how it’s being emitted from the planet, if it’s emitted in the right quantities, in the right way,” Kopparapu said. “With future telescopes, we’ll be more confident because they’ll be designed to look for life on other planets.”

Search for Life

This article is one in a series about how NASA is searching for life in the cosmos.

Beginnings: Life on Our World and Others

The Hunt for Life on Mars – and Elsewhere in the Solar System

'Life' in the Lab

Searching for Signs of Intelligent Life: Technosignatures

Finding Life Beyond Earth: What Comes Next?

Related Terms

• Astrobiology
• Terrestrial Exoplanets
• The Search for Life

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Black Holes

Recapturing a Future for Space Exploration: Life and Physical Sciences Research for a New Era (2011)

Chapter: summary.

SCIENCE AND EXPLORATION

More than four decades have passed since a human first set foot on the Moon. Great strides have been made since in our understanding of what is required to support an enduring human presence in space, as evidenced by progressively more advanced orbiting human outposts, culminating in the current International Space Station (ISS). However, of the more than 500 humans who have so far ventured into space, most have gone only as far as near-Earth orbit, and none have traveled beyond the orbit of the Moon. Achieving humans’ further progress into the solar system has proved far more difficult than imagined in the heady days of the Apollo missions, but the potential rewards remain substantial. Overcoming the challenges posed by risk and cost—and developing the technology and capabilities to make long space voyages feasible—is an achievable goal. Further, the scientific accomplishments required to meet this goal will bring a deeper understanding of the performance of people, animals, plants, microbes, materials, and engineered systems not only in the space environment but also on Earth, providing terrestrial benefits by advancing fundamental knowledge in these areas.

During its more than 50-year history, NASA’s success in human space exploration has depended on the agency’s ability to effectively address a wide range of biomedical, engineering, physical science, and related obstacles—an achievement made possible by NASA’s strong and productive commitments to life and physical sciences research for human space exploration, and by its use of human space exploration infrastructures for scientific discovery. * This partnership of NASA with the research community reflects the original mandate from Congress in 1958 to promote science and technology, an endeavor that requires an active and vibrant research program. The committee acknowledges the many achievements of NASA, which are all the more remarkable given budgetary challenges and changing directions within the agency. In the past decade, however, a consequence of those challenges has been a life and physical sciences research program that was dramatically reduced in both scale and scope, with the result that the agency is poorly positioned to take full advantage of the scientific opportunities offered by the now fully equipped and staffed ISS laboratory, or to effectively pursue the scientific research needed to support the development of advanced human exploration capabilities.

Although its review has left it deeply concerned about the current state of NASA’s life and physical sciences research, the Committee for the Decadal Survey on Biological and Physical Sciences in Space is nevertheless

_____________

* These programs’ accomplishments are described in several National Research Council (NRC) reports—see for example, Assessment of Directions in Microgravity and Physical Sciences Research at NASA (The National Academies Press, Washington, D.C., 2003).

convinced that a focused science and engineering program can achieve successes that will bring the space community, the U.S. public, and policymakers to an understanding that we are ready for the next significant phase of human space exploration. The goal of this report is to lay out steps whereby NASA can reinvigorate its partnership with the life and physical sciences research community and develop a forward-looking portfolio of research that will provide the basis for recapturing the excitement and value of human spaceflight—thereby enabling the U.S. space program to deliver on new exploration initiatives that serve the nation, excite the public, and place the United States again at the forefront of space exploration for the global good. This report examines the fundamental science and technology that underpin developments whose payoffs for human exploration programs will be substantial, as the following examples illustrate:

• An effective countermeasures program to attenuate the adverse effects of the space environment on the health and performance capabilities of astronauts, a development that will make it possible to conduct prolonged human space exploration missions.

• A deeper understanding of the mechanistic role of gravity in the regulation of biological systems (e.g., mechanisms by which microgravity triggers the loss of bone mass or cardiovascular function)—understanding that will provide insights for strategies to optimize biological function during spaceflight as well as on Earth (e.g., slowing the loss of bone or cardiovascular function with aging).

• Game changers, such as architecture-altering systems involving on-orbit depots for cryogenic rocket fuels, an example of a revolutionary advance possible only with the scientific understanding required to make this Apollo-era notion a reality. As an example, for some lunar missions such a depot could produce major cost savings by enabling use of an Ares I type launch system rather than a much larger Ares V type system.

• The critical ability to collect or produce large amounts of water from a source such as the Moon or Mars, which requires a scientific understanding of how to retrieve and refine water-bearing materials from extremely cold, rugged regions under partial-gravity conditions. Once cost-effective production is available, water can be transported to either surface bases or orbit for use in the many exploration functions that require it. Major cost savings will result from using that water in a photovoltaic-powered electrolysis and cryogenics plant to produce liquid oxygen and hydrogen for propulsion.

• Advances stemming from research on fire retardants, fire suppression, fire sensors, and combustion in microgravity that provide the basis for a comprehensive fire-safety system, greatly reducing the likelihood of a catastrophic event.

• Regenerative fuel cells that can provide lunar surface power for the long eclipse period (14 days) at high rates (e.g., greater than tens of kilowatts). Research on low-mass tankage, thermal management, and fluid handling in low gravity is on track to achieve regenerative fuel cells with specific energy greater than two times that of advanced batteries.

In keeping with its charge, the committee developed recommendations for research fitting in either one or both of these two broad categories:

1. Research that enables space exploration: scientific research in the life and physical sciences that is needed to develop advanced exploration technologies and processes, particularly those that are profoundly affected by operation in a space environment.

2. Research enabled by access to space: scientific research in the life and physical sciences that takes advantage of unique aspects of the space environment to significantly advance fundamental scientific understanding.

The key research challenges, and the steps needed to craft a program of research capable of facilitating the progress of human exploration in space, are highlighted below and described in more detail in the body of the report. In the committee’s view, these are steps that NASA will have to take in order to recapture a vision of space exploration that is achievable and that has inspired the country, and humanity, since the founding of NASA.

ESTABLISHING A SPACE LIFE AND PHYSICAL SCIENCES RESEARCH PROGRAM: PROGRAMMATIC ISSUES

Research in the complex environment of space requires a strong, flexible, and supportive programmatic structure. Also essential to a vibrant and ultimately successful life and physical sciences space research program is a partnership between NASA and the scientific community at large. The present program, however, has contracted to below critical mass and is perceived from outside NASA as lacking the stature within the agency and the commitment of resources to attract researchers or to accomplish real advances. For this program to effectively promote research to meet the national space exploration agenda, a number of issues will have to be addressed.

Administrative Oversight of Life and Physical Sciences Research

Currently, life and physical science endeavors have no clear institutional home at NASA. In the context of a programmatic home for an integrated research agenda, program leadership and execution are likely to be productive only if aggregated under a single management structure and housed in a NASA directorate or key organization that understands both the value of science and its potential application in future exploration missions. The committee concluded that:

• Leadership with both true scientific gravitas and a sufficiently high level in the overall organizational structure at NASA is needed to ensure that there will be a “voice at the table” when the agency engages in difficult deliberations about prioritizing resources and engaging in new activities.

• The successful renewal of a life and physical sciences research program will depend on strong leadership with a unique authority over a dedicated and enduring research funding stream.

• It is important that the positioning of leadership within the agency allows the conduct of the necessary research programs as well as interactions, integration, and influence within the mission-planning elements that develop new exploration options.

Elevating the Priority of Life and Physical Sciences Research in Space Exploration

It is of paramount importance that the life and physical sciences research portfolio supported by NASA, both extramurally and intramurally, receives appropriate attention within the agency and that its organizational structure is optimally designed to meet NASA’s needs. The committee concluded that:

• The success of future space exploration depends on life and physical sciences research being central to NASA’s exploration mission and being embraced throughout the agency as an essential translational step in the execution of space exploration missions.

• A successful life and physical sciences program will depend on research being an integral component of spaceflight operations and on astronauts’ participation in these endeavors being viewed as a component of each mission.

• The collection and analysis of a broad array of physiological and psychological data from astronauts before, during, and after a mission are necessary for advancing knowledge of the effects of the space environment on human health and for improving the safety of human space exploration. If there are legal concerns about implementing this approach, they could be addressed by the Department of Health and Human Services Secretary’s Advisory Committee on Human Research Protections.

Establishing a Stable and Sufficient Funding Base

A renewed funding base for fundamental and applied life and physical sciences research is essential for attracting the scientific community needed to meet the prioritized research objectives laid out in this report. Researchers

must have a reasonable level of confidence in the sustainability of research funding if they are expected to focus their laboratories, staff, and students on research issues relevant to space exploration. The committee concluded that:

• In accord with elevating the priority of life and physical sciences research, it is important that the budget to support research be sufficient, sustained, and appropriately balanced between intramural and extramural activities. As a general conclusion regarding the allocation of funds, an extramural budget should support an extramural research program sufficiently robust to ensure a stable community of scientists and engineers who are prepared to lead future space exploration research and train the next generation of scientists and engineers.

• Research productivity and efficiency will be enhanced if the historical collaborations of NASA with other sponsoring agencies, such as the National Institutes of Health, are sustained, strengthened, and expanded to include other agencies.

Improving the Process for Solicitation and Review of High-Quality Research

Familiarity with, and the predictability of, the research solicitation process are critical to enabling researchers to plan and conduct activities in their laboratories that enable them to prepare high-quality research proposals. Regularity in frequency of solicitations, ideally multiple solicitations per year, would help to ensure that the community of investigators remains focused on life and physical science research areas relevant to the agency, thereby creating a sustainable research network. The committee concluded that:

• Regularly issued solicitations for NASA-sponsored life and physical sciences research are necessary to attract investigators to research that enables or is enabled by space exploration. Effective solicitations should include broad research announcements to encourage a wide array of highly innovative applications, targeted research announcements to ensure that high-priority mission-oriented goals are met, and team research announcements that specifically foster multidisciplinary translational research.

• The legitimacy of NASA’s peer-review systems for extramural and intramural research hinges on the assurance that the review process, including the actions taken by NASA as a result of review recommendations, is transparent and incorporates a clear rationale for prioritizing intramural and extramural investigations.

• The quality of NASA-supported research and its interactions with the scientific community would be enhanced by the assembly of a research advisory committee, composed of 10 to 15 independent life and physical scientists, to oversee and endorse the process by which intramural and extramural research projects are selected for support after peer review of their scientific merit. Such a committee would be charged with advising and making recommendations to the leadership of the life and physical sciences program on matters relating to research activities.

Rejuvenating a Strong Pipeline of Intellectual Capital Through Training and Mentoring Programs

A critical number of investigators is required to sustain a healthy and productive scientific community. A strong pipeline of intellectual capital can be developed by modeling a training and mentoring program on other successful programs in the life and physical sciences. Building a program in life and physical sciences would benefit from ensuring that an adequate number of flight- and ground-based investigators are participating in research that will enable future space exploration. The committee concluded that:

• Educational programs and training opportunities effectively expand the pool of graduate students, scientists, and engineers who will be prepared to improve the translational application of fundamental and applied life and physical sciences research to space exploration needs.

Linking Science to Needed Mission Capabilities Through Multidisciplinary Translational Programs

Complex systems problems of the type that human exploration missions will increasingly encounter will need to be solved with integrated teams that are likely to include scientists from a number of disciplines, as well as engineers, mission analysts, and technology developers. The interplay between and among the life and physical sciences and engineering, along with a strong focus on cost-effectiveness, will require multidisciplinary approaches. Multidisciplinary translational programs can link the science to the gaps in mission capabilities through planned and enabled data collection mechanisms. The committee concluded that:

• A long-term strategic plan to maximize team research opportunities and initiatives would accelerate the trajectory of research discoveries and improve the efficiency of translating those discoveries to solutions for the complex problems associated with space exploration.

• Improved central information networks would facilitate data sharing with and analysis by the life and physical science communities and would enhance the science results derived from flight opportunities.

ESTABLISHING A LIFE AND PHYSICAL SCIENCES RESEARCH PROGRAM: AN INTEGRATED MICROGRAVITY RESEARCH PORTFOLIO

Areas of Highest-Priority Research

NASA has a strong and successful track record in human spaceflight made possible by a backbone of science and engineering accomplishments. Decisions regarding future space exploration, however, will require the generation and use of new knowledge in the life and physical sciences for successful implementation of any options chosen. Chapters 4 through 10 in this report identify and prioritize research questions important both to conducting successful space exploration and to increasing the fundamental understanding of physics and biology that is enabled by experimentation in the space environment. These two interconnected concepts—that science is enabled by access to space and that science enables future exploration missions—testify to the powerful complementarity of science and the human spaceflight endeavor. For example, the research recommended in this report addresses unanswered questions related to the health and welfare of humans undertaking extended space missions, to technologies needed to support such missions, and to logistical issues with potential impacts on the health of space travelers, such as ensuring adequate nutrition, protection against exposure to radiation, suitable thermoregulation, appropriate immune function, and attention to stress and behavioral factors. At the same time, progress in answering such questions will find broader applications as well.

It is not possible in this brief summary to describe or even adequately summarize the highest-priority research recommended by the committee. However, the recommendations selected (from a much larger body of discipline suggestions and recommendations) as having the highest overall priority for the coming decade are listed briefly as broad topics below. The committee considered these recommendations to be the minimal set called for in its charge to develop an integrated portfolio of research enabling and enabled by access to space and thus did not attempt to further prioritize among them. In addition, it recognized that further prioritization among these disparate topic areas will be possible only in the context of specific policy directions to be set by NASA and the nation. Nevertheless, the committee has provided tools and metrics that will allow NASA to carry out further prioritization (as summarized below in the section “Research Portfolio Implementation”).

The recommended research portfolio is divided into the five disciplines areas and two integrative translational areas represented by the study panels that the committee directed. The extensive details (such as research time-frames and categorizations as enabling, enabled-by, or both) of the research recommended as having the highest priority are presented in Chapters 4 through 10 of the report, and much of this information is summarized in the research portfolio discussion in Chapter 13 .

Plant and Microbial Biology

Plants and microbes evolved at Earth’s gravity (1 g ), and spaceflight represents a completely novel environment for these organisms. Understanding how they respond to these conditions holds great potential for advancing

knowledge of how life operates on Earth. In addition, plants are important candidates for components of a biologically based life support system for prolonged spaceflight missions, and microbes play complex and essential roles in both positive and negative aspects of human health, in the potential for degradation of the crew environment through fouling of equipment, and in bioprocessing of the wastes of habitation in long-duration missions. The highest-priority research, focusing on these basic and applied aspects of plant and microbial biology, includes:

• Multigenerational studies of International Space Station microbial population dynamics;

• Plant and microbial growth and physiological responses; and

• Roles of microbial and plant systems in long-term life support systems.

Behavior and Mental Health

The unusual environmental, psychological, and social conditions of spaceflight missions limit and define the range of crew activities and trigger mental and behavioral adaptations. The adaptation processes include responses that result in variations in astronauts’ mental and physical health, and strongly stress and affect crew performance, productivity, and well-being. It is important to develop new methods, and to improve current methods, for minimizing psychiatric and sociopsychological costs inherent in spaceflight missions, and to better understand issues related to the selection, training, and in-flight and post-flight support of astronaut crews. The highest-priority research includes:

• Mission-relevant performance measures;

• Long-duration mission simulations;

• Role of genetic, physiological, and psychological factors in resilience to stressors; and

• Team performance factors in isolated autonomous environments.

Animal and Human Biology

Human physiology is altered in both dramatic and subtle ways in the spaceflight environment. Many of these changes profoundly limit the ability of humans to explore space, yet also shed light on fundamental biological mechanisms of medical and scientific interest on Earth. The highest-priority research, focusing on both basic mechanisms and development of countermeasures, includes:

• Studies of bone preservation and bone-loss reversibility factors and countermeasures, including pharmaceutical therapies;

• In-flight animal studies of bone loss and pharmaceutical countermeasures;

• Mechanisms regulating skeletal muscle protein balance and turnover;

• Prototype exercise countermeasures for single and multiple systems;

• Patterns of muscle retrainment following spaceflight;

• Changes in vascular/interstitial pressures during long-duration space missions;

• Effects of prolonged reduced gravity on organism performance, capacity mechanisms, and orthostatic intolerance;

• Screening strategies for subclinical coronary heart disease;

• Aerosol deposition in the lungs of humans and animals in reduced gravity;

• T cell activation and mechanisms of immune system changes during spaceflight;

• Animal studies incorporating immunization challenges in space; and

• Studies of multigenerational functional and structural changes in rodents in space.

Crosscutting Issues for Humans in the Space Environment

Translating knowledge from laboratory discoveries to spaceflight conditions is a two-fold task involving horizontal integration (multidisciplinary and transdisciplinary) and vertical translation (interaction among basic,

preclinical, and clinical scientists to translate fundamental discoveries into improvements in the health and well-being of crew members during and after their missions). To address the cumulative effect of a range of physiological and behavioral changes, an integrated research approach is warranted. The highest-priority crosscutting research issues include:

• Integrative, multisystem mechanisms of post-landing orthostatic intolerance;

• Countermeasure testing of artificial gravity;

• Decompression effects;

• Food, nutrition, and energy balance in astronauts;

• Continued studies of short- and long-term radiation effects in astronauts and animals;

• Cell studies of radiation toxicity endpoints;

• Gender differences in physiological effects of spaceflight; and

• Biophysical principles of thermal balance.

Fundamental Physical Sciences in Space

The fundamental physical sciences research at NASA has two overarching quests: (1) to discover and explore the laws governing matter, space, and time and (2) to discover and understand the organizing principles of complex systems from which structure and dynamics emerge. Space offers unique conditions in which to address important questions about the fundamental laws of nature, and it allows sensitivity in measurements beyond that of ground-based experiments in many areas. Research areas of highest priority are the following:

• Study of complex fluids and soft matter in the microgravity laboratory;

• Precision measurements of the fundamental forces and symmetries;

• Physics and applications of quantum gases (gases at very low temperatures where quantum effects dominate); and

• Behavior of matter near critical phase transition.

Applied Physical Sciences

Applied physical sciences research, especially in fluid physics, combustion, and materials science, is needed to address design challenges for many key exploration technologies. This research will enable new exploration capabilities and yield new insights into a broad range of physical phenomena in space and on Earth, particularly with regard to improved power generation, propulsion, life support, and safety. Applied physical sciences research topics of particular interest are as follows:

• Reduced-gravity multiphase flows, cryogenics, and heat transfer database development and modeling;

• Interfacial flows and phenomena in exploration systems;

• Dynamic granular material behavior and subsurface geotechnics;

• Strategies and methods for dust mitigation;

• Complex fluid physics in a reduced-gravity environment;

• Fire safety research to improve screening of materials in terms of flammability and fire suppression;

• Combustion processes and modeling;

• Materials synthesis and processing to control microstructures and properties;

• Advanced materials design and development for exploration; and

• Research on processes for in situ resource utilization.

Translation to Space Exploration Systems

The translation of research to space exploration systems includes identification of the technologies that enable exploration missions to the Moon, Mars, and elsewhere, as well as the research in life and physical sciences that

is needed to develop these enabling technologies, processes, and capabilities. The highest-priority research areas to support objectives and operational systems in space exploration include:

• Two-phase flow and thermal management;

• Cryogenic fluid management;

• Mobility, rovers, and robotic systems;

• Dust mitigation systems;

• Radiation protection systems;

• Closed-loop life support systems;

• Thermoregulation technologies;

• Fire safety: materials standards and particle detectors;

• Fire suppression and post-fire strategies;

• Regenerative fuel cells;

• Energy conversion technologies;

• Fission surface power;

• Ascent and descent propulsion technologies;

• Space nuclear propulsion;

• Lunar water and oxygen extraction systems; and

• Planning for surface operations, including in situ resource utilization and surface habitats.

For each of the high-priority research areas identified above, the committee classified the research recommendations as enabling for future space exploration options, enabled by the environment of space that exploration missions will encounter, or both.

Research Portfolio Implementation

While the committee believes that any healthy, integrated program of life and physical sciences research will give consideration to the full set of recommended research areas discussed in this report—and will certainly incorporate the recommendations identified as having the highest priority by the committee and its panels—it fully recognizes that further prioritization and decisions on the relative timing of research support in various areas will be determined by future policy decisions. For example, and only as an illustration, a policy decision to send humans to Mars within the next few decades would elevate the priority of enabling research on dust mitigation systems, whereas a policy decision to focus primarily on advancing fundamental knowledge through the use of space would elevate the priority of critical phase transition studies. The committee therefore provided for future flexibility in the implementation of its recommended portfolio by mapping all of the high-priority research areas against the metrics used to select them. These eight overarching metrics, listed below with clarifying criteria (see also Table 13.3 ) added in parentheses, can be used as a basis for policy-related ordering of an integrated research portfolio. Examples of how this might be done are provided in the report.

• The extent to which the results of the research will reduce uncertainty about both the benefits and the risks of space exploration ( Positive Impact on Exploration Efforts, Improved Access to Data or to Samples, Risk Reduction )

• The extent to which the results of the research will reduce the costs of space exploration ( Potential to Enhance Mission Options or to Reduce Mission Costs )

• The extent to which the results of the research may lead to entirely new options for exploration missions ( Positive Impact on Exploration Efforts, Improved Access to Data or to Samples )

• The extent to which the results of the research will fully or partially answer grand science challenges that the space environment provides a unique means to address ( Relative Impact Within Research Field )

• The extent to which the results of the research are uniquely needed by NASA, as opposed to any other agencies ( Needs Unique to NASA Exploration Programs )

• The extent to which the results of the research can be synergistic with other agencies’ needs ( Research Programs That Could Be Dual-Use )

• The extent to which the research must use the space environment to achieve useful knowledge ( Research Value of Using Reduced-Gravity Environment )

• The extent to which the results of the research could lead to either faster or better solutions to terrestrial problems or to terrestrial economic benefit ( Ability to Translate Results to Terrestrial Needs )

Facilities, Platforms, and the International Space Station

Facility and platform requirements are identified for each of the various areas of research discussed in this report. Free-flyers, suborbital spaceflights, parabolic aircraft, and drop towers are all important platforms, each offering unique advantages that might make them the optimal choice for certain experiments. Ground-based laboratory research is critically important in preparing most investigations for eventual flight, and there are some questions that can be addressed primarily through ground research. Eventually, access to lunar and planetary surfaces will make it possible to conduct critical studies in the partial-gravity regime and will enable test bed studies of systems that will have to operate in those environments. These facilities enable studies of the effects of various aspects of the space environment, including reduced gravity, increased radiation, vacuum and planetary atmospheres, and human isolation.

Typically, because of the cost and scarcity of the resource, spaceflight research is part of a continuum of efforts that extend from laboratories and analog environments on the ground, through other low-gravity platforms as needed and available, and eventually into extended-duration flight. Although research on the ISS is only one component of this endeavor, the capabilities provided by the ISS are vital to answering many of the most important research questions detailed in this report. The ISS provides a unique platform for research, and past NRC studies have noted the critical importance of its capabilities to support the goal of long-term human exploration in space. † These include the ability to perform experiments of extended duration, access to human subjects, the ability to continually revise experiment parameters based on previous results, the flexibility in experimental design provided by human operators, and the availability of sophisticated experimental facilities with significant power and data resources. The ISS is the only existing and available platform of its kind, and it is essential that its presence and dedication to research for the life and physical sciences be fully utilized in the decade ahead.

With the retirement of the space shuttle program in 2011, it will also be important for NASA to foster interactions with the commercial sector, particularly commercial flight providers, in a manner that addresses research needs, with attention to such issues as control of intellectual property, technology transfer, conflicts of interest, and data integrity.

Science Impact on Defining Space Exploration

Implicit in this report are integrative visions for the science advances necessary to underpin and enable revolutionary systems and bold exploration architectures for human space exploration. Impediments to revitalizing the U.S. space exploration agenda include costs, past inabilities to predict costs and schedule, and uncertainties about mission and crew risk. Research community leaders recognize their obligations to address those impediments. The starting point of much of space-related life sciences research is the reduction of risks to missions and crews. Thus, the recommended life sciences research portfolio centers on an integrated scientific pursuit to reduce the health hazards facing space explorers, while also advancing fundamental scientific discoveries. Similarly, revolutionary

† See, for example, National Research Council, Review of NASA Plans for the International Space Station , The National Academies Press, Washington, D.C., 2006.

and architecture-changing systems will be developed not simply by addressing technological barriers, but also by unlocking the unknowns of the fundamental physical behaviors and processes on which the development and operation of advanced space technologies will depend. This report is thus much more than a catalog of research recommendations; it specifies the scientific resources and tools to help in defining and developing with greater confidence the future of U.S. space exploration and scientific discovery.

More than four decades have passed since a human first set foot on the Moon. Great strides have been made in our understanding of what is required to support an enduring human presence in space, as evidenced by progressively more advanced orbiting human outposts, culminating in the current International Space Station (ISS). However, of the more than 500 humans who have so far ventured into space, most have gone only as far as near-Earth orbit, and none have traveled beyond the orbit of the Moon. Achieving humans' further progress into the solar system had proved far more difficult than imagined in the heady days of the Apollo missions, but the potential rewards remain substantial.

During its more than 50-year history, NASA's success in human space exploration has depended on the agency's ability to effectively address a wide range of biomedical, engineering, physical science, and related obstacles—an achievement made possible by NASA's strong and productive commitments to life and physical sciences research for human space exploration, and by its use of human space exploration infrastructures for scientific discovery. The Committee for the Decadal Survey of Biological and Physical Sciences acknowledges the many achievements of NASA, which are all the more remarkable given budgetary challenges and changing directions within the agency. In the past decade, however, a consequence of those challenges has been a life and physical sciences research program that was dramatically reduced in both scale and scope, with the result that the agency is poorly positioned to take full advantage of the scientific opportunities offered by the now fully equipped and staffed ISS laboratory, or to effectively pursue the scientific research needed to support the development of advanced human exploration capabilities.

Although its review has left it deeply concerned about the current state of NASA's life and physical sciences research, the Committee for the Decadal Survey on Biological and Physical Sciences in Space is nevertheless convinced that a focused science and engineering program can achieve successes that will bring the space community, the U.S. public, and policymakers to an understanding that we are ready for the next significant phase of human space exploration. The goal of this report is to lay out steps and develop a forward-looking portfolio of research that will provide the basis for recapturing the excitement and value of human spaceflight—thereby enabling the U.S. space program to deliver on new exploration initiatives that serve the nation, excite the public, and place the United States again at the forefront of space exploration for the global good.

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An Astronaut Reveals What Life in Space Is Really Like

There’s no way to anticipate the emotional impact of leaving your home planet. You look down at Earth and realize: You're not on it. It's breathtaking. It's surreal. It's a “we're not in Kansas anymore, Toto” kind of feeling. But I've spent a total of 55 days in space, over the course of five missions for NASA, and I've learned that being out there isn't just a series of breathtaking moments. It's a mix of the transcendently magical and the deeply prosaic. It can be crowded, noisy, and occasionally uncomfortable. Space travel—at least the way we do it today—isn't glamorous. But you can't beat the view!

Everyone imagines that when you're sitting on the launchpad atop 7 million pounds of explosive rocket fuel, you're nervous and worried; but the truth is, there isn't much to do for those two hours after you climb into the shuttle. Many astronauts just take a nap. You're strapped in like a sack of potatoes while the system goes through thousands of prelaunch checks. Occasionally you have to wake up and say “Roger” or “Loud and clear.” But the launch itself is a whole other thing—from the pad to orbit in 8.5 minutes, accelerating the entire time until you reach the orbital velocity of 17,500 mph. That is a ride.

It turns out that once you're actually in orbit, zero-g has some upsides. Without gravity, bodily fluids move toward your head. It's a great face-lift. Your stomach gets flat. You feel long, because you grow an inch or two. (I thought, “Oh cool, I'll be tall,” but of course everybody else was taller too.)

But zero-g also has some disadvantages. As that fluid shifts north, you get an enormous headache. Your body compensates and loses about a liter of fluid in the first couple of days—you essentially pee the headache away. And a lot of people get nauseated. The way to feel better is to “lose up,” to convince your visual system that “up” is wherever you point your head and “down” is where your feet are. When you can do that, and go headfirst or earlobe-first wherever you want, then you're getting adapted to zero-g. On each flight this adaptation happens more quickly—your body remembers having been in space. But it can take a few days before your stomach finally settles down and says, “OK, what's for lunch?”

I didn't eat much on any of my flights. I don't have a big appetite even on Earth, but between the lack of gravity and the shifting fluids, things can taste different in space. I'd bring great chocolate with me and it would taste like wax—it was very disappointing. But you don't go to space for the gourmet dining. There's no way to cook, on the shuttle or on the ISS. Space food is already cooked and then either freeze-dried and vacuum-packed—so you add water and put it in the oven to warm up—or it's thermo-stabilized, like a military MRE. With no refrigerator on board, fresh food won't keep. So on the shuttle we'd have to eat anything fresh—usually fruit like apples, oranges, and grapefruit—early in the mission.

One of the strangest experiences in space is one of the simplest on Earth: sleeping. On the shuttle, you strap your sleeping bag to the wall or the ceiling or the floor, wherever you want, and you get in. It's like camping. The bag has armholes, so you stick your arms through, reaching outside the bag to zip it up. You tighten the Velcro straps around you to make you feel like you're tucked in. Then you strap your head to the pillow—a block of foam—with another Velcro strap, to allow your neck to relax. If you don't tuck your arms into the bag, they drift out in front of you. Sometimes you wake up in the morning to see an arm floating in front of your face and think, “Whoa! What is that?” until you realize it's yours.

On most of my flights, I slept in the airlock, in the middeck of the shuttle. Nobody worked in there when we weren't doing an EVA (extra-vehicular activity), so it was like my own private bedroom. The downside? It was also the coldest part of the shuttle by about 20 degrees. I would tuck my arms into the bag and wear four layers of clothes; sometimes I'd warm up a package of food in the oven and throw it in my sleeping bag like a hot-water bottle. On the last two nights of my final flight, I slept on the flight deck, my sleeping bag strapped beneath the overhead windows. The position of the shuttle put Earth in those windows, so when I woke up the whole world was out there in front of me—in that moment, just for me alone.

The most amazing thing about my spaceflights was how relaxing they were. New astronauts get so worried about fulfilling their duties that they sometimes get hours or days into a mission before stopping to watch the sun rise, even though it happens 16 times a day on orbit. Shuttle flights were always busy—experiments, daily maintenance, EVAs, robotic operations. It was incredibly hard work, stressful in its own way, and scary—if you screwed up, you screwed up with people all over the world watching. But at the same time I found it all very relaxing. When you travel on Earth, you're almost never out of touch. Anyone can reach you if they need to. But going to space, you are really out of reach. You have comm with the ground and email, sure, but there's not much you can do about those everyday worries: Did I pay the bills? Did I feed the dog? I felt like everyday things just stopped at the edge of the atmosphere. I was totally liberated from Earth. But all those earthly concerns reattached as soon as we reentered. By the time I landed, my brain was mapping out a to-do list.

I never got sick going to space, but I never felt great coming home. When you return, your inner ear—which keeps you balanced on Earth and which has been essentially turned off for the duration of your trip—feels a little gravity and becomes unbelievably sensitive. Your balance is off and you have to relearn how to move in a gravity field. If I turned my head, I would fall over. Muscles you haven't used in weeks have to reengage to help you do everyday stuff like walk, stand, and hold things. It can take days or weeks to get your Earth legs back.

It was hard, it was exciting, it was scary, it was indescribable. And yes, I'd go back in a heartbeat.

Essay Curve

Essay on Space Exploration – 10 Lines, 100 to 1500 Words

Essay on Space Exploration: Space exploration has always been a fascinating topic for scientists, researchers, and the general public alike. The idea of venturing beyond our planet and discovering the mysteries of the universe has captured the imagination of generations. In this essay, we will delve into the importance of space exploration, the advancements it has brought to technology and science, and the potential benefits it holds for the future of humanity. Join us on this journey through the cosmos as we explore the wonders of space exploration.

Table of Contents

Space Exploration Essay Writing Tips

1. Start with a strong introduction that grabs the reader’s attention and provides background information on space exploration. You can begin with a quote, statistic, or anecdote to engage the reader.

2. Provide a brief history of space exploration, highlighting key milestones such as the launch of Sputnik, the Apollo moon landings, and the International Space Station. This will give the reader context and show the progression of space exploration over time.

3. Discuss the benefits of space exploration, such as technological advancements, scientific discoveries, and international cooperation. Explain how space exploration has led to innovations in areas such as medicine, communications, and environmental monitoring.

4. Address the challenges and risks associated with space exploration, such as the high cost, technical difficulties, and potential dangers to astronauts. Consider ethical concerns, such as the impact of space debris on Earth’s orbit and the potential for space tourism to exacerbate environmental issues.

5. Explore the future of space exploration, including upcoming missions to Mars, the Moon, and beyond. Discuss the potential for commercial space travel, space mining, and the colonization of other planets.

6. Consider the role of government agencies, such as NASA and the European Space Agency, as well as private companies like SpaceX and Blue Origin, in advancing space exploration. Discuss the importance of international collaboration in achieving common goals in space exploration.

7. Address any counterarguments or criticisms of space exploration, such as the argument that funds could be better spent on solving problems on Earth or concerns about the militarization of space. Provide evidence to support your position and offer a balanced perspective on the issue.

8. Conclude your essay by summarizing the key points and reiterating the importance of space exploration for the future of humanity. Consider ending with a call to action or a thought-provoking question to leave a lasting impression on the reader.

9. Proofread your essay carefully to check for spelling and grammar errors, as well as to ensure that your arguments are clear and well-supported. Consider asking a friend or teacher to review your essay for feedback before submitting it.

Essay on Space Exploration in 10 Lines – Examples

1. Space exploration involves the discovery and exploration of outer space using spacecraft and other technologies. 2. It allows scientists to study planets, moons, stars, and other celestial bodies in our solar system and beyond. 3. Space exploration has led to important discoveries about the origins of the universe and the possibility of extraterrestrial life. 4. It has also provided valuable information about the effects of space travel on the human body. 5. Space exploration has inspired technological advancements in areas such as robotics, materials science, and communication systems. 6. It has also sparked international cooperation and collaboration among countries with space programs. 7. The exploration of space has the potential to lead to new resources and opportunities for economic growth. 8. Space exploration has captured the imagination of people around the world and inspired future generations of scientists and engineers. 9. Challenges in space exploration include the high costs, technical difficulties, and risks associated with sending humans and equipment into space. 10. Despite these challenges, space exploration continues to be a priority for many countries and organizations as we seek to expand our understanding of the universe.

Sample Essay on Space Exploration in 100-180 Words

Space exploration is a fascinating and important endeavor that allows us to learn more about the universe beyond our planet. By sending spacecraft and astronauts into space, we can study other planets, stars, and galaxies, as well as gain a better understanding of our own planet and its place in the cosmos.

Exploring space also has practical benefits, such as developing new technologies and materials that can be used to improve life on Earth. Additionally, space exploration can inspire people to pursue careers in science, technology, engineering, and mathematics, and can foster international cooperation and collaboration.

However, space exploration is not without its challenges and risks, including the high cost of missions, the dangers of space travel, and the ethical implications of potentially contaminating other planets with Earth-based organisms. Despite these challenges, the benefits of space exploration far outweigh the risks, and it is essential that we continue to push the boundaries of our knowledge and understanding of the universe.

Short Essay on Space Exploration in 200-500 Words

Space exploration has always been a topic of fascination for mankind. The idea of venturing into the unknown, discovering new worlds, and unraveling the mysteries of the universe has captivated the minds of scientists, researchers, and the general public alike. Over the years, space exploration has made significant advancements, with numerous missions to the moon, Mars, and beyond.

One of the primary reasons for space exploration is the quest for knowledge. By studying celestial bodies, scientists can gain a better understanding of the universe and its origins. For example, the Mars Rover missions have provided valuable insights into the geology and climate of the red planet, helping scientists piece together its history and potential for supporting life. Similarly, missions to the moon have helped us learn more about the Earth’s satellite and its impact on our planet.

Space exploration also plays a crucial role in technological advancements. Many of the technologies developed for space missions have found applications in everyday life, such as satellite communication, GPS systems, and medical imaging devices. The challenges of space travel have pushed scientists to innovate and develop new technologies that have far-reaching benefits for society.

Furthermore, space exploration has the potential to open up new opportunities for humanity. As resources on Earth become increasingly scarce, the idea of mining asteroids or establishing colonies on other planets has gained traction. By expanding our presence beyond Earth, we can ensure the survival of our species and potentially unlock new avenues for economic growth and development.

Despite the many benefits of space exploration, there are also challenges and ethical considerations to consider. The cost of space missions is often exorbitant, with budgets running into billions of dollars. Additionally, there are environmental concerns associated with space travel, such as space debris and the potential for contamination of other planets.

In conclusion, space exploration is a fascinating and important endeavor that has the potential to expand our knowledge, drive technological advancements, and open up new opportunities for humanity. While there are challenges and ethical considerations to navigate, the benefits of space exploration far outweigh the risks. As we continue to push the boundaries of what is possible in space, we will undoubtedly uncover new discoveries and pave the way for a brighter future for humanity.

Essay on Space Exploration in 1000-1500 Words

Space exploration has always been a fascinating topic for humanity. The idea of venturing into the unknown, discovering new worlds, and expanding our understanding of the universe has captivated the minds of scientists, researchers, and the general public for centuries. In recent years, space exploration has become more prominent with advancements in technology and the increasing interest in exploring beyond our own planet. In this essay, we will explore the importance of space exploration, the benefits it brings to society, and the challenges that come with it.

One of the main reasons why space exploration is important is that it allows us to expand our knowledge of the universe. By sending spacecraft and probes to different planets, moons, and asteroids, scientists can gather valuable data that helps us understand the origins of the universe, the formation of planets, and the possibility of life beyond Earth. For example, the Mars rover missions have provided valuable information about the geology and climate of the red planet, as well as the potential for microbial life to exist there. This knowledge not only enhances our understanding of the universe but also helps us appreciate the complexity and diversity of the cosmos.

Furthermore, space exploration has practical benefits for society. The technologies developed for space missions have led to numerous innovations that have improved our daily lives. For example, satellite technology has revolutionized communication, weather forecasting, and navigation systems. The development of lightweight materials, advanced propulsion systems, and life support systems for astronauts has also led to advancements in various industries, such as healthcare, transportation, and energy. Additionally, space exploration has inspired a new generation of scientists, engineers, and entrepreneurs who are pushing the boundaries of innovation and creating new opportunities for economic growth.

In addition to the scientific and technological benefits, space exploration also has the potential to address some of the pressing challenges facing humanity. For example, the study of asteroids and comets can help us develop strategies to protect Earth from potential impact events. By understanding the composition and trajectory of these celestial bodies, scientists can develop methods to deflect or destroy them before they pose a threat to our planet. Furthermore, space exploration can also help us address environmental issues on Earth by providing new insights into climate change, resource depletion, and pollution. By studying other planets and moons, we can learn more about sustainable practices and technologies that can help us protect our own planet for future generations.

Despite the numerous benefits of space exploration, there are also challenges and risks associated with venturing into space. One of the main challenges is the high cost of space missions. Building and launching spacecraft, maintaining communication networks, and supporting astronauts in space all require significant financial resources. This has led to debates about the allocation of funding for space exploration, especially when there are competing priorities such as healthcare, education, and poverty alleviation. Additionally, the long duration and distance of space missions pose risks to the health and safety of astronauts. Exposure to radiation, microgravity, and isolation can have negative effects on the human body and mind, leading to concerns about the long-term sustainability of human space exploration.

Another challenge of space exploration is the ethical and legal implications of exploring new worlds. As we venture further into space and potentially encounter other forms of life, we must consider how our actions may impact these alien civilizations. Questions about planetary protection, resource exploitation, and cultural preservation arise as we explore new planets and moons. Additionally, the issue of space debris and pollution poses a threat to the sustainability of space exploration. The accumulation of defunct satellites, rocket stages, and other debris in Earth’s orbit can hinder future missions and pose a risk to operational spacecraft.

In conclusion, space exploration is a fascinating and important endeavor that has the potential to expand our knowledge of the universe, benefit society, and address pressing challenges facing humanity. By investing in space missions, developing new technologies, and inspiring future generations, we can continue to explore the cosmos and unlock the mysteries of the universe. However, we must also be mindful of the challenges and risks associated with space exploration, and work together to address them in a responsible and sustainable manner. Only by working together as a global community can we fully realize the potential of space exploration and ensure a bright future for humanity in the cosmos.

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Does life exist outside of the solar system?

Since humans first looked to the cosmos, we have wondered if life exists elsewhere in the Universe. Scientists and engineers at the Center for Astrophysics | Harvard & Smithsonian may soon be able to answer that question.

Scientists and engineers from the Center for Astrophysics aim to achieve the following advances to enable the discovery of life on other planets:

• Understand the Origins of Life: We investigate the conditions of planetary development that made life’s emergence on Earth possible.
• Modeling and Instrumentation: We develop new models for the spectroscopic signatures that identify the composition of planetary atmospheres, and build new instruments to detect them.
• Search and Observation: We identify targeted exoplanet candidates for observation, and continually refine the search process.
• Data Analysis: We use observational data to infer planetary mass, orbit, size, and composition.

How We Search

Exoplanets , or planets in solar systems other than our own, sometimes orbit directly between the Earth and their host star. When the planet orbits in front of its star, it blocks a small amount of light. CfA scientists use the Transiting Exoplanet Survey Satellite (TESS) and the Kepler space telescopes as well as the ground-based robotic telescopes of the MEarth project to look for dips in starlight. This “transit” method of planet hunting has revealed thousands of exoplanets.

During a transit, a small amount of starlight is absorbed by the planet’s atmosphere, yielding clues to the chemical makeup of the atmosphere. A massive, technologically advanced telescope is crucial for detecting the composition of an Earth-like planet’s atmosphere, including the subtle chemical signatures that life is expected to produce.

Thanks to next generation telescopes like the planned Giant Magellan Telescope (GMT) , we are approaching a point in our observational capabilities that may allow us to make previously unthinkable discoveries. One of these breakthroughs is the detection of life on a distant planet, light years away from Earth.

Juliana Garcia-Mejia working on the GMT-Consortium Large Earth Finder (G-CLEF) spectrograph for the Giant Magellan Telescope, in a lab at CfA in Cambridge, MA.

Theory of Life

Institute for Theory and Computation scientists at the CfA work on identifying the exoplanets that are most likely to harbor life. The orbit must lie in the “habitable zone” where the exoplanet’s surface is just the right temperature for liquid water to exist. Every form of life we know requires liquid water, so an exoplanet too close or too far from its host star is less likely to contain life. Additionally, ultraviolet light may be needed to form some necessary prebiotic molecules, but an overactive host star can blast the young planet, stripping away its atmosphere. When searching for extraterrestrial life, finding the perfect star could be as important as finding the perfect exoplanet.

Our Next Tool

The G-CLEF or GMT-Consortium Large Earth Finder, a next-generation spectrometer planned for use on the GMT, is our newest tool for measuring the starlight filtered through the atmosphere of an orbiting exoplanet. Using this instrument, scientists will soon be able to measure the chemical composition of a small rocky exoplanet’s atmosphere. Such an extraordinary feat is like trying to see through and study the antennae of a moth flying in front of a spotlight.

Based on our current understanding of the conditions necessary for life, the detection of biomarkers like oxygen in the atmosphere of a remote world through such observations would hint towards the presence of living organisms.

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When we look at our own planet Earth, we see life that abounds everywhere. Do these same conditions exist elsewhere in the Universe? Remarkably, 21st Century science and engineering may soon answer that question. Dr. Charles Alcock, Director, The Center for Astrophysics

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space exploration , investigation, by means of crewed and uncrewed spacecraft , of the reaches of the universe beyond Earth ’s atmosphere and the use of the information so gained to increase knowledge of the cosmos and benefit humanity. A complete list of all crewed spaceflights, with details on each mission’s accomplishments and crew, is available in the section Chronology of crewed spaceflights .

Humans have always looked at the heavens and wondered about the nature of the objects seen in the night sky. With the development of rockets and the advances in electronics and other technologies in the 20th century, it became possible to send machines and animals and then people above Earth’s atmosphere into outer space . Well before technology made these achievements possible, however, space exploration had already captured the minds of many people, not only aircraft pilots and scientists but also writers and artists. The strong hold that space travel has always had on the imagination may well explain why professional astronauts and laypeople alike consent at their great peril, in the words of Tom Wolfe in The Right Stuff (1979), to sit “on top of an enormous Roman candle, such as a Redstone, Atlas , Titan or Saturn rocket , and wait for someone to light the fuse.” It perhaps also explains why space exploration has been a common and enduring theme in literature and art. As centuries of speculative fiction in books and more recently in films make clear, “one small step for [a] man, one giant leap for mankind” was taken by the human spirit many times and in many ways before Neil Armstrong stamped humankind’s first footprint on the Moon .

Achieving spaceflight enabled humans to begin to explore the solar system and the rest of the universe, to understand the many objects and phenomena that are better observed from a space perspective, and to use for human benefit the resources and attributes of the space environment . All of these activities—discovery, scientific understanding, and the application of that understanding to serve human purposes—are elements of space exploration . (For a general discussion of spacecraft , launch considerations, flight trajectories, and navigation , docking, and recovery procedures, see spaceflight .)

Overview of recent space achievements

Although the possibility of exploring space has long excited people in many walks of life, for most of the latter 20th century and into the early 21st century, only national governments could afford the very high costs of launching people and machines into space. This reality meant that space exploration had to serve very broad interests, and it indeed has done so in a variety of ways. Government space programs have increased knowledge, served as indicators of national prestige and power, enhanced national security and military strength, and provided significant benefits to the general public. In areas where the private sector could profit from activities in space, most notably the use of satellites as telecommunication relays, commercial space activity has flourished without government funding. In the early 21st century, entrepreneurs believed that there were several other areas of commercial potential in space, most notably privately funded space travel.

In the years after World War II , governments assumed a leading role in the support of research that increased fundamental knowledge about nature, a role that earlier had been played by universities, private foundations, and other nongovernmental supporters. This change came for two reasons. First, the need for complex equipment to carry out many scientific experiments and for the large teams of researchers to use that equipment led to costs that only governments could afford. Second, governments were willing to take on this responsibility because of the belief that fundamental research would produce new knowledge essential to the health, the security, and the quality of life of their citizens. Thus, when scientists sought government support for early space experiments, it was forthcoming. Since the start of space efforts in the United States , the Soviet Union , and Europe , national governments have given high priority to the support of science done in and from space. From modest beginnings, space science has expanded under government support to include multibillion-dollar exploratory missions in the solar system. Examples of such efforts include the development of the Curiosity Mars rover, the Cassini-Huygens mission to Saturn and its moons, and the development of major space-based astronomical observatories such as the Hubble Space Telescope .

Soviet leader Nikita Khrushchev in 1957 used the fact that his country had been first to launch a satellite as evidence of the technological power of the Soviet Union and of the superiority of communism . He repeated these claims after Yuri Gagarin ’s orbital flight in 1961. Although U.S. Pres. Dwight D. Eisenhower had decided not to compete for prestige with the Soviet Union in a space race, his successor, John F. Kennedy , had a different view. On April 20, 1961, in the aftermath of the Gagarin flight, he asked his advisers to identify a “space program which promises dramatic results in which we could win.” The response came in a May 8, 1961, memorandum recommending that the United States commit to sending people to the Moon , because “dramatic achievements in space…symbolize the technological power and organizing capacity of a nation” and because the ensuing prestige would be “part of the battle along the fluid front of the cold war.” From 1961 until the collapse of the Soviet Union in 1991, competition between the United States and the Soviet Union was a major influence on the pace and content of their space programs. Other countries also viewed having a successful space program as an important indicator of national strength.

Even before the first satellite was launched, U.S. leaders recognized that the ability to observe military activities around the world from space would be an asset to national security. Following on the success of its photoreconnaissance satellites, which began operation in 1960, the United States built increasingly complex observation and electronic-intercept intelligence satellites. The Soviet Union also quickly developed an array of intelligence satellites, and later a few other countries instituted their own satellite observation programs. Intelligence-gathering satellites have been used to verify arms-control agreements, provide warnings of military threats, and identify targets during military operations, among other uses.

In addition to providing security benefits, satellites offered military forces the potential for improved communications, weather observation, navigation, timing, and position location. This led to significant government funding for military space programs in the United States and the Soviet Union. Although the advantages and disadvantages of stationing force-delivery weapons in space have been debated, as of the early 21st century, such weapons had not been deployed , nor had space-based antisatellite systems—that is, systems that can attack or interfere with orbiting satellites. The stationing of weapons of mass destruction in orbit or on celestial bodies is prohibited by international law .

Governments realized early on that the ability to observe Earth from space could provide significant benefits to the general public apart from security and military uses. The first application to be pursued was the development of satellites for assisting in weather forecasting . A second application involved remote observation of land and sea surfaces to gather imagery and other data of value in crop forecasting, resource management, environmental monitoring, and other applications. The U.S., the Soviet Union, Europe, and China also developed their own satellite-based global positioning systems , originally for military purposes, that could pinpoint a user’s exact location, help in navigating from one point to another, and provide very precise time signals. These satellites quickly found numerous civilian uses in such areas as personal navigation, surveying and cartography, geology, air-traffic control , and the operation of information-transfer networks. They illustrate a reality that has remained constant for a half century—as space capabilities are developed, they often can be used for both military and civilian purposes.

Another space application that began under government sponsorship but quickly moved into the private sector is the relay of voice, video, and data via orbiting satellites. Satellite telecommunications has developed into a multibillion-dollar business and is the one clearly successful area of commercial space activity. A related, but economically much smaller, commercial space business is the provision of launches for private and government satellites. In 2004 a privately financed venture sent a piloted spacecraft, SpaceShipOne , to the lower edge of space for three brief suborbital flights. Although it was technically a much less challenging achievement than carrying humans into orbit, its success was seen as an important step toward opening up space to commercial travel and eventually to tourism . More than 15 years after SpaceShipOne reached space, several firms began to carry out such suborbital flights. Companies have arisen that also use satellite imagery to provide data for business about economic trends . Suggestions have been made that in the future other areas of space activity, including using resources found on the Moon and near-Earth asteroids and the capture of solar energy to provide electric power on Earth , could become successful businesses.

Most space activities have been pursued because they serve some utilitarian purpose, whether increasing knowledge, adding to national power, or making a profit . Nevertheless, there remains a powerful underlying sense that it is important for humans to explore space for its own sake, “to see what is there.” Although the only voyages that humans have made away from the near vicinity of Earth—the Apollo flights to the Moon—were motivated by Cold War competition, there have been recurrent calls for humans to return to the Moon, travel to Mars, and visit other locations in the solar system and beyond. Until humans resume such journeys of exploration, robotic spacecraft will continue to serve in their stead to explore the solar system and probe the mysteries of the universe.

October 1, 2023

14 min read

Why We’ll Never Live in Space

Medical, financial and ethical hurdles stand in the way of the dream to settle in space

By Sarah Scoles

Tavis Coburn

N ASA wants astronaut boots back on the moon a few years from now, and the space agency is investing heavily in its Artemis program to make it happen. It's part of an ambitious and risky plan to establish a more permanent human presence off-world. Companies such as United Launch Alliance and Lockheed Martin are designing infrastructure for lunar habitation. Elon Musk has claimed SpaceX will colonize Mars. But are any of these plans realistic? Just how profoundly difficult would it be to live beyond Earth—especially considering that outer space seems designed to kill us?

Humans evolved for and adapted to conditions on Earth. Move us off our planet, and we start to fail—physically and psychologically. The cancer risk from cosmic rays and the problems that human bodies experience in microgravity could be deal-breakers on their own. Moreover, there may not be a viable economic case for sustaining a presence on another world. Historically, there hasn't been much public support for spending big money on it. Endeavors toward interplanetary colonization also bring up thorny ethical issues that most space optimists haven't fully grappled with.

At the 2023 Analog Astronaut Conference, none of these problems seemed unsolvable. Scientists and space enthusiasts were gathered at Biosphere 2, a miniature Earth near Tucson, Ariz., which researchers had built partly to simulate a space outpost. Amid this crowd, the conclusion seemed foregone: living in space is humans' destiny, an inevitable goal that we must reach toward.

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The conference attendees know it's a big dream. But their general outlook was summed up by Phil Hawes, chief architect for Biosphere 2, who gave the opening talk at the meeting. He recited a toast made by the first team to camp out here decades ago: "Here's to throwing your heart out in front of you and running to catch up with it."

The question remains as to whether we can—and will—ever run fast enough.

In 1991 eight people entered Biosphere 2 and lived inside for two years. This strange facility is a 3.14-acre oasis where scientists have re-created different terrestrial environments—not unlike an overgrown botanical garden. There's an ocean, mangrove wetlands, a tropical rainforest, a savanna grassland and a fog desert, all set apart from the rest of the planet they're mimicking. One goal, alongside learning about ecology and Earth itself, was to learn about how humans might someday live in space, where they would have to create a self-contained and self-sustaining place for themselves. Biosphere 2, located on Biosphere 1 (Earth), was practice. The practice, though, didn't quite work out. The encapsulated environment didn't produce enough oxygen, water or food for the inhabitants—a set of problems that, of course, future moon or Mars dwellers could also encounter. The first mission and a second one a few years later were also disrupted by interpersonal conflicts and psychological problems among the residents.

Today the people who participate in projects like Biosphere 2—simulating some aspect of long-term space travel while remaining firmly on Earth—are called analog astronauts. And although it's a niche pursuit, it's also popular: There are analog astronaut facilities in places such as Utah, Hawaii, Texas and Antarctica. People are building or planning them in Oman, Kenya and Israel. And they all share the goal of learning how to live off Earth while on Earth.

The people who are mingling on Biosphere's patio, where the desert sunset casts a pink light on the habitat's glass exterior, are part of that analog world. Some of them have participated in simulation projects or have built their own analog astronaut facilities; others are just analog-curious. They are astronomers, geologists, former military personnel, mail carriers, medical professionals, FedEx employees, musicians, artists, analysts, lawyers and the owner of the Tetris Company. On this night many have donned Star Wars costumes. As the sun goes down, they watch the rising moon, where many here would like to see humans settle.

Human bodies really can't handle space. Spaceflight damages DNA, changes the microbiome, disrupts circadian rhythms, impairs vision, increases the risk of cancer, causes muscle and bone loss, inhibits the immune system, weakens the heart, and shifts fluids toward the head, which may be pathological for the brain over the long term—among other things.

At the University of California, San Francisco, medical researcher Sonja Schrepfer has dug into two of the conditions that afflict space explorers. Her research, using mice floating within the International Space Station, has revealed that blood vessels leading to the brain get stiffer in microgravity. It's part of why today's astronauts can't simply walk out of their capsules once they return to Earth, and it would play out the same way on Mars—where there's no one to wheel them to their new habitat on arrival. Schrepfer and her colleagues did, however, uncover a molecular pathway that might prevent those cardiovascular changes. "But now the question I try to understand is, 'Do we want that?'" she says. Maybe the vessels' stiffening is a protective mechanism, Schrepfer suggests, and limbering them up might cause other problems.

She also wants to figure out how to help astronauts' faltering immune systems, which look older and have a harder time repairing tissue damage than they should after spending time in space. "The immune system is aging quite fast in microgravity," Schrepfer says. She sends biological samples from young, healthy people on Earth up to orbit on tissue chips and tracks how they degrade.

Vision and bone problems are also among the more serious side effects. When astronauts spend a month or more in space, their eyeballs flatten, one aspect of a condition called spaceflight-associated neuro-ocular syndrome, which can cause long-lasting damage to eyesight. Bones and muscles are built for life on Earth, which involves the ever present pull of gravity. The work the body does against gravity to stay upright and move around keeps muscles from atrophying and stimulates bone growth. In space, without a force to push against, astronauts can experience bone loss that outpaces bone growth, and their muscles shrink. That's why they must do hours of exercise every day, using specialized equipment that helps to simulate some of the forces their anatomy would feel on the ground—and even this training doesn't fully alleviate the loss.

Perhaps the most significant concern about bodies in space, though, is radiation, something that is manageable for today's astronauts flying in low-Earth orbit but would be a bigger deal for people traveling farther and for longer. Some of it comes from the sun, which spews naked protons that can damage DNA, particularly during solar storms. "[That] could make you very, very sick and give you acute radiation syndrome," says Dorit Donoviel, a professor at the Baylor College of Medicine and director of the Translational Research Institute for Space Health (TRISH).

Future astronauts could use water—perhaps pumped into the walls of a shelter—to shield themselves from these protons. But scientists don't always know when the sun will be spitting out lots of particles. "So if, for example, astronauts are exploring the surface of the moon, and there is a solar particle event coming, we probably have the capability of predicting it within about 20 to 30 minutes max," Donoviel says. That means we need better prediction and detection—and we'd need astronauts to stay close to their H2O shield.

If you didn't get to safety in time, the nausea would come first. "You would vomit into your spacesuit," Donoviel says, "which now becomes a life-threatening situation" because the vomit could interfere with life-support systems, or you might breathe it in. Then comes the depletion of cells such as neutrophils and red blood cells, meaning you can't battle germs or give your tissues oxygen effectively. You'll be tired, anemic, unable to fight infection, and throwing up. Maybe you'll die. See why lots of kids want to be astronauts when they grow up?

From September 1991 to September 1993, eight people lived inside the Biosphere 2 research facility in Arizona, helping scientists learn how humans might live in outer space. Credit: Science History Images/Alamy Stock Photo

There's another type of radiation, galactic cosmic rays, that even a lot of water won't block. This radiation is made of fast-moving elements—mostly hydrogen but also every natural substance in the periodic table. The rays burst forth from celestial events such as supernovae and have a lot more energy and mass than a mere proton. "We really cannot fully shield astronauts from them," Donoviel says. And inadequately shielding explorers makes the problem worse: the rays would split when they hit a barrier, making more, smaller particles.

The radiation an astronaut en route to Mars might get from galactic cosmic rays at any one time is a small dose. But if you're on a spaceship or a planetary surface for years, the calculus changes. Imagine, Donoviel says, being in a room with a few mosquitoes. Five or 10 minutes? Fine. Days? Months? You're in for a whole lot more itching—or, in this case, cancer risk.

Because shielding astronauts isn't realistic, Donoviel's TRISH is researching how to help the body repair radiative damage and developing chemical compounds astronauts could take to help fix DNA damage in wounds as they occur. "Everybody's worried about waiting for the cancer to happen and then killing the cancer," Donoviel says. "We're really taking the preventive approach."

Even if most of the body's issues can be fixed, the brain remains a problem. A 2021 review paper in Clinical Neuropsychiatry laid out the psychological risks that astronauts face on their journey, according to existing research on spacefarers and analog astronauts: poor emotional regulation, reduced resilience, increased anxiety and depression, communication problems within the team, sleep disturbances, and decreased cognitive and motor functioning brought on by stress. To imagine why these issues arise, picture yourself in a tin can with a small crew, a deadly environment outside, a monotonous schedule, an unnatural daytime-nighttime cycle and mission controllers constantly on your case.

Physical and mental health problems—though dire—aren't even necessarily the most immediate hurdles to making a space settlement happen. The larger issue is the cost. And who's going to pay for it? Those who think a billionaire space entrepreneur is likely to fund a space colony out of a sense of adventure or altruism (or bad judgment) should think again. Commercial space companies are businesses, and businesses' goals include making money. "What is the business case?" asks Matthew Weinzierl, a professor at Harvard Business School and head of its Economics of Space research efforts.

For the past couple of years Weinzierl and his colleague Brendan Rousseau have been trying to work out what the demand is for space exploration and pursuits beyond Earth. "There's been a ton of increase in supply and cutting of costs of space activity," Weinzierl says, "but who's on the other side?" Space companies have historically been insular: specialists creating things for specialists, not marketing wares or services to the broader world. Even commercial undertakings such as SpaceX are supported mostly by government contracts. Company leaders haven't always thought through the capitalism of their ideas; they're just excited that the rockets and widgets work. "Technical feasibility does not equal a strong business case," Rousseau says.

Today private spaceflight companies target tourists for business when they're not targeting federal contracts. But those tourists aren't protected by the same safety regulations that apply to government astronauts, and an accident could stifle the space tourism industry. Stifling, too, is the fact that only so many people with money are likely to want to live on a place like Mars rather than take a short joyride above the atmosphere, so the vacation business case for permanent space outposts breaks down there as well.

The Biosphere 2 research facility in Arizona houses a greenhouse. Credit: Kike Calvo/Universal Images Group via Getty Images

People tend to liken space exploration to expansion on Earth—pushing the frontier. But on the edge of terrestrial frontiers, people were seeking, say, gold or more farmable land. In space, explorers can't be sure of the value proposition at their destination. "So we have to be a little bit careful about thinking that it will just somehow pay off," Weinzierl points out.

Weinzierl and Rousseau find the idea of a sustained human presence in space inspiring, but they're not sure when or how it will work from a financial perspective. After all, inspiration doesn't pay invoices. "We'd love to see that happening," Rousseau says—he thinks lots of people would. "As long as we're not the ones footing the bill."

Many taxpayers would probably agree. As hard as it is for space fans to believe, most people don't place much value on astronaut adventures. A 2023 Pew poll asked participants to rate the importance of nine of NASA's key missions as "top priority," "important but lower priority," or "not too important/should not be done." Just 12 and 11 percent of people thought sending humans to Mars and to the moon, respectively, should be a top priority. That placed those missions at the bottom of the list in terms of support, behind more popular efforts such as monitoring Earth's climate, watching for dangerous asteroids and doing basic scientific research on space in general.

Similarly, a 2020 poll from Morning Consult found that just 7 to 8 percent of respondents thought that sending humans to the moon or Mars should be a top priority. And although history tends to remember the previous moon exploration era as a time of universal excitement for human spaceflight, polls from the time demonstrate that that wasn't the case: "Consistently throughout the 1960s, a majority of Americans did not believe Apollo was worth the cost, with the one exception to this a poll taken at the time of the Apollo 11 lunar landing in July 1969," wrote historian Roger Launius in a paper for Space Policy . "And consistently throughout the decade 45–60 percent of Americans believed that the government was spending too much on space, indicative of a lack of commitment to the spaceflight agenda."

When space agency officials discuss why people should care about human exploration, they often say it's for the benefit of humanity. Sometimes they cite spin-offs that make their way to citizens as terrestrial technology—such as how telescope-mirror innovations improved laser eye surgery. But that argument doesn't do it for Linda Billings, a consultant who works with NASA. If you were interested in furthering a technology, she suggests, you could invest directly in the private sector instead of obliquely through a space agency, where its development will inevitably take longer, cost more and not be automatically tailored toward earthly use. "I don't see that NASA is producing any evidence that [human settlement of space] will be for the benefit of humanity," she says.

Whether tax dollars should support space travel is an ethical question, at least according to Brian Patrick Green of Santa Clara University. Green became interested in science's ethical issues when he worked in the Marshall Islands as a teacher. The U.S. used to detonate nuclear weapons there, causing lasting environmental and health damage. Now the islands face the threat of sea-level rise, which is likely to inundate much of their infrastructure, erode the coasts and shrink the usable land area. "That got me very interested in the social impacts of technology and what technology does to people and societies," he says.

In space travel, "Why?" is perhaps the most important ethical question. "What's the purpose here? What are we accomplishing?" Green asks. His own answer goes something like this: "It serves the value of knowing that we can do things—if we try really hard, we can actually accomplish our goals. It brings people together." But those somewhat philosophical benefits must be weighed against much more concrete costs, such as which other projects—Earth science research, robotic missions to other planets or, you know, outfitting this planet with affordable housing—aren't happening because money is going to the moon or Mars or Alpha Centauri.

And an even simpler ethical question is, "Should we actually send people on these sorts of things?" Green says. Aside from incurring significant risks of cancer and overall body deterioration, astronauts aiming to settle another world have a sizable chance of losing their lives. Even if they do live, there are issues with what kind of an existence they might have. "It's one thing just to survive," Green says. "But it's another thing to actually enjoy your life. Is Mars going to be the equivalent of torture?"

If people make the attempt, we will also have to acknowledge the risks to celestial bodies—the ones humans want to travel to as well as this one, which they may return to if they haven't purchased a one-way ticket. The moon, Mars or Europa could become contaminated by microscopic Earth life, which NASA has never successfully eradicated from spacecraft, although it tries as part of a "planetary protection" program. And if destination worlds have undetected life, then harmful extraterrestrial microbes could also return with astronauts or equipment—a planetary-protection risk called backward contamination. What obligation do explorers have to keep places as they found them? Setting aside the question of whether we can establish ourselves beyond Earth, we also owe it to ourselves and the universe to consider whether we should.

on this question, science-fiction scholar Gary Westfahl casts doubt on space travel's inherent value. In his vast analyses of sci-fi, he has come to view the logic and drive of the enterprise as faulty. "I inevitably encountered the same argument: space travel represents humanity's destiny," he says of the impetus for writing his essay "The Case against Space." Space explorers are often portrayed as braver and better than those who remain on their home planet: they're the ones pushing civilization forward. "Philosophically, I objected to the proposition that explorers into unknown realms represented the best and brightest of humanity, that progress could be achieved only by boldly venturing into unknown territories," Westfahl says. After all, a lot of smart and productive people (not to mention a lot of happy and stable people) don't spend their lives on the lam. "Clearly, history demonstrates no correlation between travel and virtue," he writes. "The history of our species powerfully suggests that progress will come from continued stable life on Earth, and that a vast new program of travel into space will lead to a new period of human stagnation," he concludes ominously.

Celestial bodies, including our moon, are at risk of contamination by microscopic Earth life. Credit: NASA’s Scientific Visualization Studio

In some ways, the desire for simpler living is part of what motivates space explorers. Astronauts are stuck with just a few people they have to get along with, or else they'll be miserable—a communal way of living that's more common to villages. They must make do with the nearby supplies or create their own, like people did before Walmart and Amazon. Communication with those beyond their immediate sphere is slow and difficult. They have a strict but straightforward and prescribed work schedule. Everything is a struggle; there are no conveniences. Unlike in a modern, digitally connected environment, their attention isn't split in many directions—they are focused on the present. Or at least that's how analog astronaut Ashley Kowalski felt during the SIRIUS 21 endeavor, an eight-month-long joint U.S.-Russia "lunar mission" that took place in a sealed space in Moscow.

Kowalski's talk at the Analog Astronaut Conference at Biosphere 2 was called "Only Eight Months." The goal of those eight months was to study the medical and psychological effects of isolation. She and her teammates regularly provided blood, feces and skin samples so researchers could learn about their stress levels, metabolic function and immunological changes. Researchers also had them take psychological tests, sussing out their perception of time, changes in cognitive abilities and shifts in interpersonal interactions. Inside they had to eat like astronauts would, guzzling tubes of Sicilian pizza gel and burger gel. Kowalski would squeeze them into rehydrated soup to make meals heartier. Via their greenhouse, they got about a bowl of salad between the six of them every three weeks.

Kowalski missed freedom and food and friends, of course. But the real struggle came with her return to the real world once the isolation was over: "reentry, not to the atmosphere but to the planet," she told the conference audience. She didn't remember how to go about having friends, hobbies or a job and had trouble dealing with requests coming from lots of sources instead of just mission control. In the Q&A period after the talk, Tara Sweeney, a geologist in the audience, thanked Kowalski for talking about that part of the experience. Sweeney had just returned from a long stay in Antarctica and also didn't quite know how to reintegrate into life in a more hospitable place. They had both missed "Earth," the real world. But it was hard to come back.

Still, the Analog Astronaut Conference crowd remained optimistic. "Where do we go from here?" conference founder and actual astronaut Sian Proctor asked at one point. On cue, the audience members pointed upward and said, "To the moon!"

Analog-astronaut work can't solve space travel's hardest problems—the intractable medical troubles, the in-red money questions, the touchy ethical quandaries. But while we all wait to see whether we'll ever truly migrate off this planet, and whether we should, these grounded astronauts will continue to escape Earth, for a time at least, without leaving it.

Sarah Scoles is a Colorado-based science journalist, a contributing editor at Scientific American and Popular Science and a senior contributor at Undark. Her newest book is Countdown: The Blinding Future of Nuclear Weapons (Bold Type Books, 2024).

Are we alone? Intelligent aliens may be rare, new study suggests

"The fact that we don't see anything out there means that if they did exist, they vanished long ago and their signatures have decayed away."

The universe should either be crowded with life or harbor hardly any life at all, according to a new study that revamps the Drake equation using probabilistic logic.

A common axiom in the search for extraterrestrial intelligence (SETI) is that if we do detect technologically advanced aliens, there are probably many, many instances of alien life out there rather than there just being two cases (us and the new discovery).

In a new paper, astronomers David Kipping of Columbia University in New York and Geraint Lewis of the University of Sydney describe how this logic works, based on a probability distribution first introduced by the biologist and mathematician J. B. S. Haldane in 1932. Let's imagine a bunch of Earth-like exoplanets , all with similar characteristics. Given their minor differences, we would expect life to arise either on all of them or on none of them; there's no obvious reason why half of these near-identical planets would support life and half wouldn't, for example. 

We can then display the various outcomes in a U-shaped graph, with the probability on the y-axis and the fraction of planets with life on the x-axis. The two prongs of the U-shape correspond to none or very few planets with life, and lots of planets with life. The valley of the U-shape, which corresponds to a low likelihood, represents half the planets having life.

Related: Drake Equation: Estimating the odds of finding E.T.

Now Kipping and Lewis have ascribed Haldane's logic to the famous Drake equation . Developed by astronomer Frank Drake prior to the first-ever SETI conference, at Green Bank Observatory in 1961, as a means of providing the workshop with an agenda, the Drake equation has subsequently taken on a life of its own, being used to estimate the number of technological lifeforms in the Milky Way galaxy . 

The Drake equation is written as N = R* x fp x ne x fl x fi x fc x L, where N is the number of civilizations, R* is the star-formation rate, fp is the fraction of stars that have planets, ne is the number of planets that are potentially habitable, fl is the fraction of those potentially habitable planets that evolve life, fi is the fraction that develop "intelligent" life, fc is the fraction that have communicative life, and L is the average lifetime of civilizations.

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Astronomers know the star-formation rate (less than 10 solar masses per year in our galaxy) and the fraction of stars that have planets (almost every star has planets) very well. The number of potentially habitable planets is less well known, but astronomers are learning more about them every day as they probe exoplanetary atmospheres with the James Webb Space Telescope and characterize those worlds. The values of the other four terms remain a complete mystery, which renders any attempts to use the Drake equation less than satisfactory because so much of it is guesswork.

However, Kipping and Lewis point out that the first six terms in the Drake equation describe the "birth" of what they call extraterrestrial technological instantiations, or ETI. This is how they refer to technological alien life, neatly sidestepping terms such as "civilizations," "species" and "intelligence," which have not only proven problematic (for example, how do we define intelligence?) but may also be inaccurate when describing alien life. Meanwhile, the final term, L, relates to the "death," or otherwise the disappearance, of ETI. 

Splitting the terms of the Drake equation this way has allowed Kipping and Lewis to simplify the formula, to read: The time-averaged number of ETIs in the galaxy equals the birth rate of ETIs multiplied by their death rate. 

"The beauty of our approach is that it is totally general," Kipping told Space.com . This means that there is no need to have to worry about the terms of the Drake equation that we don't know. 

"We are not assuming any particular mechanism or means of birth," added Kipping. "The births could occur via spontaneous emergence, or panspermia seeding, or empire building or whatever else you want — there simply is a birth rate."

Kipping and Lewis assume what they call a steady state Drake equation, where there is a roughly equal level of birth and death rates in an equilibrium that is inevitably reached once enough time has passed. The two astronomers then relate this back to Haldane's prior (a "prior" is the name for a type of probability distribution, such as the U-shaped curve) by way of a characteristic called the occupation fraction, F. In the exoplanet example mentioned earlier in this article, a high value of F — close to 1 — would correspond to every planet having life, and a low value — close to or equal to 0 — would relate to no planets having life.

The problem facing SETI scientists is that, based on observations so far, F probably is not near 1; otherwise, we would have noticed by now that we are not alone, assuming that intelligent aliens are proficient at spreading across the galaxy, building megastructures such as Dyson swarms and beaming out radio signals. This means that, if we really are not alone in the universe, then the occupation fraction must be closer to 0.5, placing it in that unlikely valley of the U-shaped curve. Based on that U-shape, it is likely that we are relatively alone — that technological life elsewhere in the universe is rare. 

"These are instances of life who become obvious, firstly through the signals they produce and then through their colonization where they would be seen through megastructures," Lewis told Space.com. "If such an ETI had arisen in the life of the Milky Way, then they could have colonized the entire galaxy in 10 million to 100 million years, and even after they fall, then their debris would be around for a long time. The fact that we don't see anything out there means that if they did exist, they vanished long ago and their signatures have decayed away and we are back to our original premise — ETIs appear to be rare in time and space."

Related: The search for alien life

— Where are all the intelligent aliens? Maybe they're trapped in buried oceans

— Fermi Paradox: Where are the aliens?  

— SETI & the search for extraterrestrial life  

Yet Kipping and Lewis don't advocate giving up on SETI. If we ignore the lack of evidence for a moment, the steady state Drake equation predicts a crowded universe as being equally likely as one in which we are lonely. For a crowded universe, the occupation fraction must be close to 1, and perhaps this is still possible under certain circumstances. Maybe ETI stays in their own region, and our solar system just happens to be in a region that no one has spread into yet. That would mean the aliens are quite far away, and our strategy of searching for them around stars close by is the wrong one. These inhabited regions might be more clearly detected in other galaxies. "I certainly would advocate for extragalactic SETI," said Kipping.

Or perhaps interstellar travel and megastructure-building are too difficult, or maybe they are not even desired by an ETI living a more frugal, less colonial, existence. And with regards to a lack of a radio or optical signal detection, SETI has hardly had the resources to be particularly comprehensive in its search so far, and we could easily have missed a signal .

It's also possible that there is plenty of complex life, but that the development of technological life is rare.

There's also a chance that the birth and death rates of ETI have not reached a steady state after all, meaning that there would be still time for new ETI to arrive on the scene and increase the occupation fraction. Given the age of the universe and the finite lifespan of an ETI, however, this seems unlikely.

The research is currently available as a pre-print , and has been submitted to the International Journal of Astrobiology for peer-reviewed publication.

Join our Space Forums to keep talking space on the latest missions, night sky and more! And if you have a news tip, correction or comment, let us know at: [email protected].

Keith Cooper is a freelance science journalist and editor in the United Kingdom, and has a degree in physics and astrophysics from the University of Manchester. He's the author of "The Contact Paradox: Challenging Our Assumptions in the Search for Extraterrestrial Intelligence" (Bloomsbury Sigma, 2020) and has written articles on astronomy, space, physics and astrobiology for a multitude of magazines and websites.

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• Unclear Engineer I don't disagree with what is in the article, but I don't think it does much more than update us to what we currently know. At this point, I think we are close to finding out if life originates easily on many planets, or not. If it does, then the search for planets with intelligent life that has the potential to communicate with other planets would need to look for planets that have both water and rocky surfaces, etc. because a bunch of creatures confined to an ocean are not going to start transmitting radio signals, and probably don't understand fire. So, the search for the necessary type of planet would be the next major issue. Only with that information can we deduce whether the product of the probability that a intelligent and technologically communicative society will arise times its length of time in existence is rare or common, given the opportunity. And, we aren't likely to figure out that last pair of parameters separately unless we are able to find dead civilizations on other planets. So, the existential question for humans on Earth is whether we can keep finding our way through the problems we create for ourselves, or not. Even if we do survive as a technological society for the next few billion years, there is still the possibility that it is simply not possible for us (or any other technological society) to "spread across the galaxy" due to the limits imposed by physical reality of distance and speed limits. So, we can't use the apparent fact that no technological society has "spread across the galaxy" as evidence that there are no other technological societies in existence in the galaxy with very long periods of existence ("L" in Drake's Equation). Reply
• ChrisA THere is an easier way to figure this out. It also agrees with what we observe. If we assume that Earth is not rare or unique and that there are millions of Earthlike planets in the galaxy then if this were true what should we expect? How can we calculate what we would see. Not "guess" but "calculate" Lets build a simulated galaxy populated with exact copies of Earth but the key is each copy of Earth is made on a different year over the 4 billion years of Earth's existence. So our simulated galaxy has 4 billion earth-like planets and they all have different ages. What would we see? Out of the 4 billion Earths 1) about 100 of them would be humans who know how to build radios. So radio technology would be very rare. with one 2) most of them would have only microscopic life 3) A fair fraction would have multi-cellular life 4) one in a million planets would have mammals, like mice and monkeys and such Earth is the only data point we have but Earth has existed for 4 billion years, we can look at Earth one each of those billion years and get 4,000,000,000 data points This is actually VERY disappointing from a SETI perspective because it means that even of something like 1 in 25 plants has an exact copy of Earth we can expect only 100 planets with radio and perhaps zero that can transmit a radio signal over interstellar distances. So, bacteria-like life might be common, multi-cellular life would be rare, intelligent life would be a one-in-a-billion level rare and advanced technological life would be exactly zero (as we are not there yet.) I think this is the ONLY method of prediction that does not use extrapolation or guessing. It makes an impossibly optimistic assumption and then concludes that we should expect to hear and see nothing even in a galaxy teaming with "life". In other words, this theory predicts what to observe. If you want a theory that predicts that we will find ETs then you have to introduce guess and extrapolations like 1) High-tech societies do not destroy themselves be war or global warming or advanced AI. 2) As societies age they continue to care about the universe around them. We don't know. Perhaps they only play video games and live in simulations. 3) perhaps the biological people are peacefully replaced by some kind of hybrid AI and therefore required very small amount of resource for trillions of them to live and expansion is possible by simply building a one meter cube server room We have no idea about 1,2 or 3 and any answer is a guess. But if you assume only what we 100% know, we should expect a silent galaxy that is filled with simple life. Reply
• Unclear Engineer At this time, I don't think we really have the data to tell us even that we should not be able to detect a signal from another technological species on another inhabited world even within the range of detection that we currently have. We really don't know what planets are out there around relatively nearby stars. because we need transits or big planets close-in creating wobbles in their host stars. There are certainly more planets that remain undetected by us than the number we have detected so far. And, we really just have a lot of speculation about what it takes to have indigenous lifeforms, and more importantly, why intelligence develops. Do we really need a star similar to the Sun, with a guide planet similar to Jupiter, and an Earth-like planet with plate tectonics, a strong magnetic field, a large moon, an amount of water that creates oceans and dry lands, and a series of cataclysmic events that favor the development of intelligence over specialization to fixed environmental parameters? If all of that set of conditions is necessary, then life at the technology level we have already created could be quite rare in the galaxy. IF so, then the lifetime of such technological civilizations could be quite long, and we might still never detect one. The place where such speculation seems to go off-the-rails of logical scientific conjecture is when it is supposed that an intelligent species will eventually develop the capability to travel throughout the galaxy if not killed off while doing that development. We have no logical or scientific basis for assuming that we or any other technological society will ever be able to develop even interstellar travel, much less trans-galactic travel. There could be a sizeable population of planets inhabited by disillusioned beings who have realized that they are never going to reach the stars that they can see. But, they could certainly send signals farther than they, themselves, could ever travel. Reply

Admin said: A new interpretation of the famous Drake equation finds little reason to be optimistic about the search for extraterrestrial intelligence. Are we alone? Intelligent aliens may be rare, new study suggests : Read more

• billslugg In essence, the Drake Equation tells us the number of intelligent civilizations is equal to the number of planets there are times the percentage that have intelligent civilizations. It seems circular to me. Reply
• Unclear Engineer Agree, except that Drake did not intend his equation to be predictive. He introduced it to try to create some structure in the speculation about what it would take for there to be life that we can communicate with elsewhere in the galaxy. Frankly, unless the planet is within a few dozen light years of Earth, it seems unlikely that we could hold a useful interstellar conversation, just due to signal transit times. So, even finding a more advanced life form on another planet might not be useful to us for learning anything other than that we are not alone. Or, at least we weren't alone when they last transmitted. If their existence is as precarious as some of the pessimists on Earth say our own is, they might be gone before we get their last message. Reply
• Classical Motion If we ever find convincing evidence or even strong suspicion, it won’t matter. We will never be able to confirm it. And will always be in contention if it’s really evidence. Especially if we only find ONE. Reply
• Unclear Engineer And then there is the "theory" that the reason we can't detect 95% of the matter and energy in the universe is that the Klingons have it cloaked. ;) But, seriously, good point about lasers as communication systems that we would not detect. An advanced civilization might need to actually want to be detected in order for them to emit something that we can readily detect. Reply
• Manix The problem here is us. Humans have this ego of they're the pinnacle of existance. There could be many millions or even billions of intelligent species out there whom have advenced passe dour primitive radio signals. They could also "mask" or cloak their planet from detection, to hide them from being observed. We might just be starting out, trying to discover other intelligent life forms out there, but it is possible several scenarios exist A: the don't to be detected; either because like Hawkins said they believe it could be dangerous to them; or they have already had that encounter and it didn't turn out well and now out of self preservation are hiding themselves even in plane sight. Or B: they are so far advanced that they simply see us, but we are so primitive they truly don't want to communicate with us. Their technology maybe so advanced we simply cannot detect it with our own primitive equipment as advanced as we think it is. Until we start thinking out of the box, I feel we're going to keep seeing the same results over and over again with no real conclusion. Reply
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The Kepler telescope was designed to discover exoplanets, stellar flares, star spots, and dusty planetary rings. Exoplanets cannot be seen directly—instead, Kepler detects slight dips in the light of a star; an exoplanet orbiting around a sun makes its light dim, creating a lightcurve. This lightcurve allows us to figure out a planet’s approximate size and even shape. Obviously, planets possess a round shape, due to the basic physical laws that dictate that a planetary body is governed by hydrostatic equilibrium and which, to cut the long story short, causes its round shape (Discovery).

But what Kepler has discovered recently is far more exciting. The star which it observed recently— KIC 8462852 —displays a dramatic and strange dimming of its starlight. Normally, stars with exoplanets revolving around them manifest a 1-2% drop in their light; however, KIC’s light dims by approximately 20%. What is more fascinating is that these drops are not periodical, as one would expect from an orbiting astronomical object, but seem to occur randomly; at least, during the 1600 days of Kepler’s observations of the star, these intervals were irregular: approximately after 800 days of observation, KIC’s light dropped by 15%, and on the day 1500, the dimming reached 20% of the starlight. Such a dramatic drop of brightness could occur if only the object passing in front of the star was at least half of its size. This object is unlikely to be a planet though: one of the largest-known planets, Jupiter, is only 1/10th of the size of our sun, and KIC is 1.5 times larger than our sun (The Guardian).

Most likely, based on what the strange light pattern “tells” scientists, there is a whole mess of objects circling KIC 8462852. These objects seem to be organized in a sort of formation, and are in general big enough to block a significant amount of KIC’s light. Researchers Yale Postdoc and Tabetha Boyajian wrote that, “KIC 8462852 was observed to undergo irregularly shaped, aperiodic dips in flux down to below the 20% level. The dipping activity can last for between 5 and 80 days […] We determine that KIC 8462852 is a main-sequence F3 V/IV star, with a rotation period ~0.88 d, that exhibits no significant IR excess.“ They have also added that this mess of objects is neither a comet field nor asteroid remnants. Jason Wright, an astronomer from Penn State University, suggested that the objects could be an industrial object, a megastructure constructed by aliens. “Aliens should always be the very last hypothesis you consider, but this looked like something you would expect an alien civilization to build,” Wright admitted.

Although it is too early to make unequivocal conclusions, the phenomenon of KIC challenges everything astronomers know about exoplanets and the stars around which they revolve. Too big for a planet, unlikely to be a field of asteroid remnants of comets, the mysterious object near the star can be the first evidence of the existence of intelligent extraterrestrial life.

“Has Kepler Discovered an Alien Megastructure?” Discovery. N.p., n.d. Web. 02 Nov. 2015. <http://news.discovery.com/space/alien-life-exoplanets/has-kepler-discovered-an-alien-megastructure-151014.htm>

“‘Alien Megastructure’ Could Explain Mysterious New Kepler Results.” The Guardian. N.p., n.d. Web. 2 Nov. 2015. <http://www.theguardian.com/science/across-the-universe/2015/oct/16/alien-megastructure-could-explain-mysterious-new-kepler-results>

“Has NASA Found an Alien Civilization? Kepler Discovers Star Orbited By Mess Of Mysterious Objects.” Tech Times. N.p., 15 Oct. 2015. Web. 02 Nov. 2015. <http://www.techtimes.com/articles/95399/20151015/has-nasa-found-an-alien-civilization-kepler-discovers-star-orbited-by-mess-of-mysterious-objects.htm>

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The human body in space.

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Space radiation, isolation and confinement, distance from earth, gravity fields, hostile/closed environments.

For more than 50 years, NASA’s  Human Research Program (HRP) has studied what happens to the human body in space. Researchers are using what they learn to design procedures, devices, and strategies to keep astronauts safe and healthy throughout their missions.

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The simple answer is: No. NASA is researching risks for Mars missions which are grouped into five human spaceflight hazards related to the stressors they place on the body. These can be summarized with the acronym “ RIDGE ,” short for Space  R adiation,  I solation and Confinement,  D istance from Earth,  G ravity fields, and Hostile/Closed  E nvironments .

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Studies of radiation-exposed human cohorts are also being conducted to estimate the health risks in populations relevant to astronauts.

Expedition crews selected for a stay onboard the space station are carefully chosen, trained, and supported to ensure they will be able to work effectively as a team for the duration of their six to 12-month missions. Crews for a Moon or Mars mission will undergo even more careful assessment, selection, and preparation since they will travel farther and potentially for longer than previous humans in an isolated and confined environment, with only a few other people. Additionally, crews will likely be international and multi-cultural, making cross-cultural sensitivity and team dynamics paramount to mission success.

Ensuring astronauts get quality sleep is also important; otherwise, their internal biological clocks, or  circadian rhythm , might be altered by factors like different dark and light cycles, a small and noisy environment, the stress of prolonged isolation and confinement, and a 37-minute extended day on Mars.

It is important to prepare for the fatigue astronauts may experience during spaceflight, given that there will be times with heavy workloads and shifting schedules. To prevent crew boredom, NASA considers the kinds of activities in which the astronauts will participate during a multi-year round trip to Mars.

Communication and understanding among crew members are vital to the success of the mission, and changes in morale and motivation are possible as the mission unfolds. This may relate to reduced stimulation, the longing for loved ones, or feeling unable to assist with family emergencies back on Earth, regardless of how long the mission lasts.

Using spaceflight analogs on Earth, NASA’s research has revealed that both the duration and type of confined and isolated experience are important to consider. The more restricted the space, and the less contact with people outside the environment, the more likely humans are to develop behavioral or cognitive conditions or psychiatric disorders.

The Key:  NASA has been studying people in isolated and confined environments for years, and has developed methods and technologies to counteract possible problems.

NASA scientists are using devices, such as actigraphy, that help assess and improve sleep and alertness by recording how much people move and how much ambient light is around them. New lighting, spurred by the development of Light-Emitting Diode (LED) technology, is used on the space station to help align astronaut’s circadian rhythms and to improve sleep, alertness, and performance.

A 10-minute self-test of vigilance and attention assesses the effect of fatigue on performance. Astronauts write in journals as a safe place to vent frustrations and provide researchers a tool to study behavioral issues that are on the minds of crew members who are living and working in isolation and confinement.

Researchers are also looking into using virtual reality to simulate relaxing environments to help improve the mood of crews in isolation. Engaging in relevant, meaningful activities, including learning a language or learning new medical skills, could help ward off depression and boost morale. Crews may even tend to a  space garden , which could have positive behavioral health benefits in addition to providing a fresh source of food and helping to purify the air.

Researchers are using Earth-based analogs to investigate how much   privacy and living space will be needed on longer missions where crew members will be restricted in a relatively small spacecraft together. NASA is also determining strategies to formulate the best  crew  by studying individual and team attributes, composition, and dynamics.

The space station orbits 240 miles above Earth. The Moon is 1,000 times farther from Earth than the space station. In contrast, Mars is on average  140 million miles  from Earth. With a communication delay of up to  20 minutes  one-way while on Mars, astronauts must be able to solve problems and identify solutions as a team without help from NASA’s mission control.

The types of food and medicine to be packed for a multi-year trip without access to a grocery store or pharmacy are also important to consider. Unlike space station crews, which regularly receive supplies from cargo flights from Earth, astronauts going to Mars will have to bring all of the food, equipment, and medical supplies they need.

The Key:  NASA is using its human spaceflight experience on the space station to figure out what types of medical events happen in space over time and what types of skills, procedures, equipment, and supplies are needed so that they will have a good idea of what to pack for future missions to the Moon and Mars.

Space station astronauts already receive medical training before and during space missions that teach them how to respond to health problems as they arise. For example, astronauts learn how to use onboard space station equipment to produce an intravenous (IV) solution from purified water, which can be used for medical administration.

Crew members also perform  ultrasound scans  on each other to monitor organ health. If one crew member becomes sick during the mission, crews are ready to perform laboratory testing to help make the right diagnosis and guide treatment.

NASA is working on developing a medical data architecture for spacecraft that enables the capabilities of  clinical decision support tools , which could use artificial intelligence and machine learning to further help diagnose and treat various illnesses. Researchers are also looking into the role that virtual assistants could play to help crews identify and respond to spaceflight anomalies quickly for more distant missions.

Additionally, the agency is studying and improving  food formulation , processing, packaging, and preservation systems to ensure the nutrients remain stable and the food remains acceptable for years. Space-resilient medications and packaging systems that preserve the integrity of pharmaceuticals for long-duration missions are another significant part of NASA’s research.  

Astronauts will encounter three different gravity fields on a Mars mission. On the six-month trek between the planets, crews will be weightless. While living and working on Mars, crews will be in approximately one-third of Earth’s gravity. Finally upon returning home, crews will have to readapt to Earth’s gravity.

Transitioning from one gravity field to another is trickier than it sounds. It affects spatial orientation, head-eye and hand-eye coordination, balance, and locomotion, with some crew members experiencing space motion sickness.

Landing a spacecraft on Mars could be challenging as astronauts adjust to the gravity field of another celestial body. When shifting from weightlessness to gravity, astronauts may experience post-flight orthostatic intolerance where they are unable to maintain their blood pressure when standing up, which can lead to lightheadedness and fainting.

NASA has learned that without Earth’s gravity affecting the human body, weight-bearing bones lose on average  1% to 1.5%  of mineral density per month during spaceflight. After returning to Earth, bone loss might not be completely corrected by rehabilitation; however, their risk for fracture is not higher. Without the proper diet and exercise routine, astronauts also lose muscle mass in microgravity faster than they would on Earth.

Moreover, the fluids in the body shift upward to the head in microgravity, which may put pressure on the eyes and cause vision problems. If preventive or countermeasures are not implemented, crews may experience an increased risk of developing kidney stones due to dehydration and increased excretion of calcium from their bones.

The Key:  By analyzing how the body changes in weightlessness and after returning to Earth’s gravity, NASA is developing protective measures against these changes for a Mars mission.

Functional task testing is in place to help detect and improve balance control after landing on a gravitational surface.  Fine motor skill testing is done to detect any changes in the ability of astronauts to interact with computer-based devices.

Distribution of the fluids in the body is closely monitored to help evaluate any connection to changes in  vision. Compression cuffs worn on the thighs help keep the blood in the lower extremities to counteract those fluid shifts. A lower-body negative pressure device could help draw fluids from the head into the legs as well.

Back pain, which some astronauts have reported experiencing during spaceflight, is monitored by obtaining  spinal ultrasounds . Muscle size and bone density are assessed for deterioration using MRI and high-resolution imaging techniques, before and after flight. Crew members perform periodic fitness self-evaluations  to help researchers better understand the decline in heart function that can occur during spaceflight.

Medicines that NASA is studying, such as potassium citrate, may help combat the physiological change that could increase the risk of developing kidney stones. Bisphosphonate medications have been shown in NASA studies to be effective in preventing bone loss.

NASA has also designed an efficient way to collect and measure how much urine a crew member produces in space, which is essential to human research since it reveals key information about a person’s health. For example, researchers can analyze different levels of certain substances in an astronaut’s urine to determine whether they are at risk of developing a  kidney stone  in space, and make modifications to the diet, exercise routine, and water intake as preventive measures.

Aerobic and resistive exercise has been shown to keep the heart healthy,  bones and muscles strong , the mind alert, as well as maintain a more positive outlook, and may even help with  balance and coordination . Software-generated workout partners could be used to help motivate astronauts to exercise regularly for longer space missions. NASA has even completed a joint Earth-based bed rest study to determine whether centrifuge artificial gravity  may be an effective way to counter the physiological effects of weightlessness.

NASA has learned that the ecosystem inside the spacecraft plays a big role in everyday astronaut life in space. Microbes can change characteristics in space, and micro-organisms that naturally live on the human body are transferred more easily from person to person in closed habitats, such as the space station. Stress hormone levels are elevated and the immune system is altered, which could lead to increased susceptibility to allergies or other illnesses.

Earth-based analogs do not perfectly simulate the spaceflight environment, making them insufficient for studying on the ground how human immune systems react in space. However, NASA-funded Antarctic analog studies could provide insight into how certain spaceflight stressors may affect the human immune system. What is known is that spaceflight changes the immune system, although crews do not tend to get sick upon returning to Earth. Even though astronauts’ acquired immunity is intact, more research is needed into whether spaceflight induced altered immunity may lead to autoimmune issues, in which the immune system mistakenly attacks the healthy cells, organs, and tissues present in the body.

Beyond the effects of the environment on the immune system, every inch and detail of living and working quarters must be carefully thought-out and designed. No one wants their house to be too hot, too cold, cramped, crowded, loud, or not well lit, and no one would enjoy working and living in such a habitat in space either.

The Key:  NASA is using technology to monitor the air quality of the space station to ensure the atmosphere is safe to breathe and not contaminated with gases, such as formaldehyde, ammonia, and carbon monoxide.  Thermal Control Systems  function to maintain temperatures of the space station and keep astronauts comfortable.

Blood and saliva samples are analyzed to identify changes in the immune system and the reactivation of latent viruses during spaceflight. NASA uses advanced molecular techniques to evaluate the risk of microbes that may cause illness for crew members. Various parts of the body and the space station are swabbed regularly for analysis of the microbial population that inhabits the environment. Crews change out air filters, clean surfaces, and treat the water to prevent illnesses that may result from the accumulation of contaminants.

Astronauts are advised to get a  flu  shot to boost their immunity and are  quarantined  before their missions to avoid catching any sort of illness before launch. During the Twins Study and One-Year Mission, Scott Kelly administered a flu vaccine to himself while his brother received his on Earth. The immunization proved to work as well in space as it does on Earth, which is a good finding for longer missions to the Moon and Mars.

Living quarters and work environments are carefully planned and evaluated to ensure that designs balance comfort and efficiency. Lighting onboard the space station is similar to what would be experienced naturally on Earth, thanks to the new  LED  lighting system.    

NASA is taking action on all of these risks and working to solve the challenges of human spaceflight with some of the most brilliant minds in their fields. The results garnered from laboratories, ground analogs, and space station missions will provide more insight into these adaptations and present a stepping stone for longer missions.

On upcoming Artemis missions to lunar orbit and the surface of the Moon, even more data will be collected as this work continues. On future longer duration missions to the Moon and Mars, astronauts will benefit from years of research that will ensure they will be able not just to survive, but thrive on their spacefaring missions.

Click here for an infographic summarizing the risks of human spaceflight and the safeguards against them .

NASA’s  Human Research Program , or HRP, pursues the best methods and technologies to support safe, productive human space travel. Through science conducted in laboratories, ground-based analogs, and the International Space Station, HRP scrutinizes how spaceflight affects human bodies and behaviors. Such research drives HRP’s  quest  to innovate ways that keep astronauts healthy and mission-ready as space travel expands to the Moon, Mars, and beyond.

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Collection Finding Our Place in the Cosmos: From Galileo to Sagan and Beyond

Messages to and from outer space.

As the 20th century began, interest in the potential of life on Mars and the possible civilizations there lead to a search for signals. Could we communicate with another planet? How might we look for signals and messages from other worlds?

An 1896 newspaper article titled " A Signal from Mars " offered one example of how we might receive communications from the planet. In noting "a luminous projection on the southern edge of the planet", the article suggests that this might be because "the inhabitants of Mars were flashing messages" to Earth. We can find this same idea in a piece of music. The 1901 piece, " A Signal From Mars, March and Two Step " offers music that Martians might be playing for us. From the cover illustration, it would appear that one rather civilized Martian is using a spotlight to communicate the tune while the other watches Earth with a telescope, likely waiting to see if we have the same taste in marches and two steps.  Soon, the development of radio technology would provide a much more powerful way to listen for and send messages to other worlds.

Tesla Promises Radio Communication with Mars

In the late 19th and early 20th centuries the idea and development of wireless telegraphy, sending and receiving electromagnetic waves through the air, offered new method of searching for communications from space. In 1901, engineer Nicola Tesla made the astonishing claim that he was receiving radio communications from Mars. His story was picked up and reported on broadly in the press.

An article from the Richmond Times offered an extensive description and commentary on his alleged discovery. "As he sat beside his instrument on the hillside in Colorado, in the deep silence of that austere, inspiring region, where you plant your feet in gold and your head brushes the constellations — as he sat there one evening, alone, his attention, exquisitely alive at that juncture, was arrested by a faint sound from the receiver — three fairy taps, one after the other, at a fixed interval. What man who has ever lived on this earth would not envy Tesla that moment!" While Tesla's alleged communications with Mars captured media attention, it did not capture much serious interest from scientists.

Hello Earth!

As radio took off, so did stories of communicating with Mars. One such article from 1920, Hello, Earth! Hello! Marconi believes he is receiving signals from the planets provides extensive commentary on similar signals observed by the Italian engineer Guglielmo Marconi. Aside from describing this discovery, the article quotes Thomas Edison as saying Marconi's work offers "good grounds for the theory that inhabitants of other planets are trying to signal to us." As radio developed as a medium for communications in the early 20th century it was also positioned for listening for contact from other worlds. While it would quickly become clear that there weren't signals from Mars, radio would play a critical role in the search for life on worlds outside our solar system.

In the 1930s and 40s radio became an invaluable instrument for observing the heavens. As astronomers began developing radio telescopes they made discoveries of various sources of electromagnetic waves in the heavens and these became useful sources of observational data about the space.

Intergalactic Contact & The Drake Equation

In the 1960s Frank Drake, Carl Sagan and a number of other scientists began searching for signals indicating the existence of intelligent life elsewhere in the universe. As it became increasingly clear that there was no intelligent life on other planets in the solar system, it became possible to detect signals from much further away. The Drake Equation was a way to estimate the number of civilizations out in the galaxy that could be sending out radio signals we could detect.  

The goal of this equation is to define the parameters for figuring out the possible number of civilizations in our galaxy that we might be able to communicate with. Each of the variables after the equals sign are multiplied together to get the result. R is the rate of star formation, fp  is the fraction of those stars that have planets, ne  is the average number of planets that could, in theory, support life, f ℓ would be the fraction of planets that could support life that, at some point, do in fact support life, fi  is the fraction of those planets that actually develop intelligent  life, fc is the fraction of civilizations that develop a technology that releases detectable signs of their existence into space, and L  is an estimate for the length of time for which such civilizations would last for. All together the Drake equation looks like this N = R* • fp • ne • fl • fi • fc • L.

In general, Sagan and Drake were excited about the possibility of contacting intelligent life in the universe because of their own ideas about the progressive value of technology and science. Those civilizations, which possibly could have existed longer than ours, would have, in their minds, likely gotten past petty things like war, violence and conquest.

Voyager's Message "To Future Times & Beings"

What do you say to a super intelligent alien race on behalf of all the inhabitants of Earth? Or at least, how would you sum up humanity to the universe just in case someone was listening?  This was the question posed to Carl Sagan and a team he assembled who developed the content for the Voyager record.

In a letter to Alan Lomax, Carl Sagan called the Voyager Record " a cosmic greeting card. " Both of the Voyager spacecraft, launched in 1977, carry copies of these records. Earlier, Sagan had been involved in crafting a message placed on Pioneer 10 and 11, the first NASA missions that would leave our solar system. The plans for messages to travel with the Voyager missions were set out on a much grander scale.

The records contain sounds and images selected to portray the diversity of life and culture on Earth. To illustrate the diversity of its image content it contains; an X-ray of a human hand, a street scene from Pakistan, an image of a violin next to a music score, images of the planets Mercury and Mars, diagrams of the structure of DNA, and the definitions of a range of units of measure. For audio recordings, each record contains greetings from earth in 55 languages and 90 minutes of music, including recordings as diverse as; "Johnny B. Goode," written and performed by Chuck Berry, a selection from Stravinsky's Rite of Spring, and ethnographic recordings of music from the Solomon Islands, Peru, China and India. After the launch of the Voyager probes, in a birthday message to Chuck Berry , Carl Sagan and Ann Druyan suggest that his music is now "quite literally out of this world." As these images and recordings now leave our solar system they collectively represent the furthest reach of humanity into our universe. 

In selecting audio recordings to include, Carl Sagan found a collaborator in folklorist Alan Lomax . In this letter to Lomax , Sagan describes the Voyager mission and explains that the record has "a probable lifetime of a billion years" noting that "it is unlikely that many other artifacts of humanity will survive for so prodigious a period of time; it is clear, for example, that most of the present continents will be ground down and dissipated by then." In this respect, Sagan suggests, "Inclusion of the musical selections on the Voyager Record ensures for them a kind of immortality which could not be achieved in any other way." It's unlikely that the voyager records now at the edge of our solar system will ever be found by alien life forms. Just like the ideas about life on the moon , intelligent alien life , civilization on Mars and preoccupations with UFOs  the Voyager records tells us a lot about how we see ourselves in a cosmic context. Reflecting on the ideas behind the record offers an opportunity to consider how we have presented ourselves on an artifact Sagan insisted would outlast nearly everything else humanity produces.

At the dawn of the 20th century, many looked to find signals from Mars in patterns in light. The advent of radio greatly expanded that search beyond our solar system. While scientists have yet to find signals from another world they haven't stopped looking.  In fact we took it upon ourselves to reach out first and have tried to compose literally universal messages for the ages.

50, 100, And 300 Words Essay on Space In English

Table of Contents

Introduction

Children are interested in space because it is a fascinating topic. It generates curiosity and interest among us when we hear about space missions or astronauts flying into space. In our minds, there are many questions. 

At takeoff, how intense is the acceleration for astronauts? When you are floating weightlessly in space, how does it feel? What is the sleeping environment like for astronauts? How do they eat? When viewed from space, how does Earth look? In this essay on space, you will find the answers to all of these questions. To gain a deeper understanding of space, students should read it.

50 Words Essay on Space

Space is the area outside the earth. Planets, meteors, stars, and other celestial objects can be found in space. Meteors are objects that fall from the sky. There is a lot of silence in space. If you scream loudly enough in space, no one will hear you.

Air does not exist in space! What a strange experience that would be! Yes, indeed! Basically, it’s just a vacuum. No sound waves can travel in this space and no sunlight can scatter in it. A black blanket can sometimes cover space.

There is some life in space. Stars and planets are separated by a vast distance. Gas and dust fill this gap. Celestial bodies also exist in other constellations. There are many of them, including our planet.

100 Words Essay on Space

The sound of your scream can’t be heard in space. The vacuum in space is caused by the lack of air. Vacuums do not permit the propagation of sound waves.

A 100 km radius around our planet marks the beginning of “outer space.”. Space appears as a black blanket dotted with stars due to the absence of air to scatter sunlight.

There is a common belief that space is empty. However, this is not true. Massive amounts of thinly spread gas and dust fill the vast gaps between stars and planets. A few hundred atoms or molecules per cubic meter can be found even in the most empty parts of space.

Radiation in space can also be dangerous to astronauts in many forms. Solar radiation is a major source of infrared and ultraviolet radiation. A high-energy X-ray, gamma ray, and cosmic ray particle can travel as fast as light if it comes from a distant star system.

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300 Words Essay on Space

Our countrymen have always been fascinated by things related to space. It was only through imagination and stories that man could dream of traveling in space when it was absolutely impossible to do so.

Space Travel is Now Possible

Until the twentieth century, the man had significant success in space research, giving this dream a simple form.

India has grown so much in science in the 21st century that many mysteries of space have been solved by the country. Additionally, visiting the moon has become very easy now, which was the dream of many long ago. As a side note, human spaceflight began in 1957.

First Life in Space

‘Layaka’ was sent into space for the first time via this vehicle to explore how space affects animals.

A spacecraft named Explorer was launched by the United States of America on January 31, 1958, giving another title to the world of space.

An enormous magnetic field above the Earth was to be discovered through this vehicle, along with its effects on Earth as a whole.

First Passenger

Our space research history is remembered for the event of July 20, 1969. Neil Armstrong and Edwin Aldrin became the first Americans to set foot on the moon on this day.

Sitting on a spacecraft named ‘Apollo-11’, he reached the surface of the moon. A third passenger in this spacecraft was Michael Collins.

He said, “Everything is beautiful” when he first landed on the moon. With this, he became the first person in the world to land on the moon.

Conclusion,

It would have been impossible to have imagined that the era of space tourism would also come in the future following the dawn of the space age. The first space tourist in the world was India’s Dennis Tito in 2002.

Long And Short Essay On Water Conservation In English

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Essay on Space

Students are often asked to write an essay on Space in their schools and colleges. And if you’re also looking for the same, we have created 100-word, 250-word, and 500-word essays on the topic.

Let’s take a look…

100 Words Essay on Space

Introduction.

Space is a vast, infinite expanse beyond Earth’s atmosphere. It is where everything, including our planet, is located.

What is Space?

Space is the boundless, three-dimensional area where objects and events occur. It’s a vacuum, meaning it’s almost completely empty.

The Mystery of Space

Space holds many mysteries. Scientists use telescopes and spacecraft to explore and understand it better. However, there’s still much we don’t know.

Space Travel

Humans have been traveling to space since 1961. Astronauts conduct experiments and learn how to live in space.

Space exploration helps us understand our universe. It’s an exciting field with lots to discover.

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250 Words Essay on Space

Introduction to space.

Space, often referred to as the final frontier, is the vast, seemingly infinite expanse that exists beyond the Earth and between celestial bodies. It is a boundless sphere of activity where the laws of physics persistently apply.

Understanding the Universe

Space is a dynamic field of study, with astronomers using advanced technology to delve into its mysteries. It contains all known celestial bodies, including our solar system, galaxies, stars, planets, and even the tiny particles of matter that drift aimlessly. Space is not just a void but a canvas on which the universe unfolds its narrative.

Space Exploration

Human curiosity has led to remarkable advancements in space exploration. From the first manned moon landing to the ongoing Mars Rover missions, our understanding of space has dramatically improved. Space exploration is not only about discovery but also about the survival and future of humanity. It has the potential to provide resources and habitats that could secure the human race’s existence.

Theoretical Perspectives

Theoretical physics offers fascinating perspectives on space. Theories like the Big Bang propose that space and time originated from a singularity. Meanwhile, String Theory suggests that multiple dimensions may exist beyond our perception. These theories challenge our understanding, pushing the boundaries of human knowledge.

Despite the advancements, space remains largely unexplored and mysterious. As we continue to probe its depths, space offers endless possibilities for discovery, innovation, and understanding. The exploration of space not only satisfies our curiosity but also holds the key to our future.

500 Words Essay on Space

The infinite expanse: a journey into space.

Space, the final frontier, is a vast, unending expanse filled with galaxies, stars, and planets. It is a place of infinite possibilities and endless mysteries, a realm that humans have long yearned to explore and understand.

The Fascination with Space

The fascination with space is as old as humanity itself. Ancient civilizations looked up at the night sky and saw patterns in the stars, creating myths and legends to explain the cosmos. Today, our understanding of space has grown exponentially due to advancements in technology. We have sent spacecrafts to distant planets, landed humans on the moon, and even captured images of black holes. Yet, despite these achievements, space remains largely unexplored and misunderstood.

The Importance of Space Exploration

Space exploration is not merely a quest for knowledge. It also has practical implications. For instance, studying other planets can help us understand our own. Mars, in particular, has been a subject of interest because of its similarities to Earth. By studying Mars, we can learn about Earth’s past and future, and possibly about the potential for life on other planets.

The Challenges of Space Exploration

Despite its benefits, space exploration is fraught with challenges. The harsh conditions of space, including zero gravity, extreme temperatures, and radiation, pose significant risks to astronauts. Furthermore, the vast distances involved make space travel incredibly time-consuming and expensive. For instance, even at the speed of light, it would take about four years to reach the nearest star to our solar system.

The Future of Space Exploration

The future of space exploration looks promising. With the advent of private space companies like SpaceX and Blue Origin, space travel is becoming more accessible. These companies are developing reusable rockets, which could significantly reduce the cost of space travel.

Space, with its infinite mysteries and possibilities, continues to captivate our imagination. As we continue to explore this vast frontier, we are not only learning about the universe around us, but also about ourselves. Space exploration challenges us to push the boundaries of what is possible, and in doing so, it brings out the best in humanity: our curiosity, our ingenuity, and our desire to understand the world around us. As we look to the stars, we are reminded of our place in the universe and our responsibility to protect our home planet.

That’s it! I hope the essay helped you.

Happy studying!

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