Research for a Future in Space: The Role of Life and Physical Sciences ppt

WOLOSCHAK, Northwestern University Feinberg School of Medicine This booklet is based on the Space Studies Board SSB report Recapturing a Future for Space Exploration: Life and Physical S

Research for a Future in Space

The Role of Life and Physical Sciences

Copyright © National Academy of Sciences All rights reserved.

ISBN 978-0-309-26103-6

32 pages

8 1/2 x 11

PAPERBACK (2012)

Committee for the Decadal Survey on Biological and Physical Sciences in

Space;Space Studies Board; National Research Council

The SSB is a unit of the National Research Council of the National Academies, which serve

as independent advisers to the nation on science, engineering, and medicine

Support for this publication was provided by the National Academy of Sciences and the National Aeronautics and Space Administration Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the agency that provided support for the project

The SSB acknowledges Chase Estrin, Sandra Graham, Katie Kline, and Duke Reiber for contributing to the text of this booklet

Booklet design by Katie Kline

Cover image and title page image (right) of the NASA Desert RATS program are courtesy of NASA

Copyright 2012 by the National Academy of Sciences

ELIZABETH R CANTWELL, Lawrence Livermore National Laboratory, Co-chair

WENDY M KOHRT, University of Colorado, Denver, Co-chair

LARS BERGLUND, University of California, Davis

NICHOLAS P BIGELOW, University of Rochester

LEONARD H CAVENY, Independent Consultant, Fort Washington, Maryland

VIJAY K DHIR, University of California, Los Angeles

JOEL E DIMSDALE, University of California, San Diego, School of Medicine

NIKOLAOS A GATSONIS, Worcester Polytechnic Institute

SIMON GILROY, University of Wisconsin-Madison

BENJAMIN D LEVINE, University of Texas Southwestern Medical Center at DallasRODOLFO R LLINAS, New York University Medical Center

KATHRYN V LOGAN, Virginia Polytechnic Institute and State University

PHILIPPA MARRACK, National Jewish Health

GABOR A SOMORJAI, University of California, Berkeley

CHARLES M TIPTON, University of Arizona

JOSE L TORERO, University of Edinburgh, Scotland

ROBERT WEGENG, Pacific Northwest National Laboratory

GAYLE E WOLOSCHAK, Northwestern University Feinberg School of Medicine

This booklet is based on the Space Studies Board (SSB) report Recapturing a Future for Space

Exploration: Life and Physical Sciences Research for a New Era, available for free online at

www.nap.edu Details about obtaining copies of the full report, as well as information on SSB and the Division on Engineering and Physical Sciences activities, can be found online at www.nationalacademies.org/ssb and www.nationalacademies.org/deps, respectively

Recapturing a Future for Space Exploration was authored by the Committee for the Decadal Survey on Biological and Physical Sciences in Space:

Research for a

Future in Space

The Role of Life and Physical Sciences

based on the National Research Council report

Recapturing a Future for Space Exploration

Life and Physical Sciences Research for a New Era

Research for a Future in Space The Issues of Bone Loss & Nutritional Needs in Space

Preventing Bone Loss

Shifts in Astronaut Health During Long Periods in Space

Chronic Sleep Loss in Space

Coping with Confined Space Environments

Monitoring Brain and Behavioral Functions in Astronauts Group Dynamics in an Extreme Environment

The Roles of Plant & Microbial Growth

Up-Rooted: Plant Growth in Space Managing Microbes as Spaceflight Companions

The Risk of Cellular & Genetic Changes in Long-Term Space Travel

Muscle Weakness and Protein Degradation

The Nature of Fluid Physics in Space

Recycling Air and Water in Spacecraft Addressing Other Aspects of Fluid Physics in Space

Issues in Fire Behavior & Safety: Prevention, Detection, Suppression

Combustion and Fire Behavior in Reduced Gravity Fire Safety and Prevention in Space

The Matter of Materials & the Relativity of Time

Weighing the Matter of Materials

Essential Technologies for Space Suits

Engineering a Personal, Portable Atmosphere Exploration Enabled by Space Suit Technology

Living Off the Land: Using In-Situ Materials

Harnessing Non-Terrestrial Resources for Exploration Technologies Space Construction with Earth-Tested Methods

Report Recommendations

About the Report

In May 2009, the NRC Committee for the Decadal Survey on Biological and

Physical Sciences in Space began a series of meetings initiated as a result of the

following language in the explanatory statement accompanying the FY 2008

Omnibus Appropriations Act (P.L 110-161):

Achieving the goals of the Exploration Initiative will require a greater understanding of life and physical sciences phenomena in microgravity

as well as in the partial gravity environments of the Moon and Mars

Therefore, the Administrator is directed to enter into an arrangement with the National Research Council

to conduct a “decadal survey” of life and physical sciences research in microgravity and partial gravity to establish priorities for research for the 2010-2020 decade.

In response to this language, a statement of task for an NRC study was developed in

consultation with members of the life and physical sciences communities, NASA,

and congressional staff The guiding principle of the study was to set an agenda for

research in the next decade that would use the unique characteristics of the space

environment to address complex problems in the life and physical sciences, so as to

deliver both new knowledge and practical benefits for humankind as it embarks on

a new era of space exploration

Recapturing a Future for Space Exploration Life and Physical Sciences Research for a New Era

Contents

Research for a Future in Space

The Issues of Bone Loss & Nutritional Needs in Space

Preventing Bone Loss · Nutrition and Space Foods

Shifts in Astronaut Health During Long Periods in Space

Chronic Sleep Loss in Space · Shifts in Cardiovascular Health

Coping with Confined Space Environments

Monitoring Brain and Behavioral Functions in Astronauts ·

Group Dynamics in an Extreme Environment

The Roles of Plant & Microbial Growth

Up-Rooted: Plant Growth in Space ·

Managing Microbes as Spaceflight Companions

The Risk of Cellular & Genetic Changes in Long-Term Space Travel

Muscle Weakness and Protein Degradation · Radiation During Spaceflight

The Nature of Fluid Physics in Space

Recycling Air and Water in Spacecraft ·

Addressing Other Aspects of Fluid Physics in Space

Issues in Fire Behavior & Safety: Prevention, Detection, Suppression

Combustion and Fire Behavior in Reduced Gravity ·

Fire Safety and Prevention in Space

The Matter of Materials & the Relativity of Time

Weighing the Matter of Materials · Exploring Space and Time

Essential Technologies for Space Suits

Engineering a Personal, Portable Atmosphere ·

Exploration Enabled by Space Suit Technology

Living Off the Land: Using In-Situ Materials

Harnessing Non-Terrestrial Resources for Exploration Technologies ·

Space Construction with Earth-Tested Methods

Report Recommendations

Contents

4-5 6-7 8-9 10-11 12-13

14-15 16-17

18-19 20-21 22-23

24-2 5 26-28

Research for a

Along the way to becoming a space-faring species, humanity has faced enormous challenges Despite these many initial hurdles, however, the United States has contributed to the progress of human spaceflight by delivering the lunar landings, the space shuttle, and, in partnership with other nations, the International Space Station (ISS) NASA’s rich and successful history has been enabled by, and responsible for,

a strong backbone of scientific and engineering research accomplishments These milestones and future developments are made possible through ongoing advances in life and physical sciences research

Looking to the future, significant improvements are needed in spacecraft, life support systems, and space technologies to enhance and enable the human and robotic missions that NASA will conduct under the U.S space exploration policy The missions beyond low Earth orbit, to and back from planetary bodies, and beyond will involve a combination of environmental risk factors such as reduced gravity levels and increased exposure to radiation Human explorers will require advanced life support systems and will be subjected to extended-duration confinement in close quarters For longer missions conducted farther from Earth, for which resupply will not be an option, technologies that are self-sustaining and/or adaptive will be necessary

To prepare the U.S for its future as an enduring and relevant presence in space, both basic and applied research in the life and physical sciences within NASA will need to be reinvigorated Specifically, NASA’s compelling future in space exploration will flow in large part from the implementation of a strong life and physical sciences program The NRC decadal surveyRecapturing a Future for Space Exploration: Life

and imperatives that can be achieved most rapidly and efficiently by establishing a multidisciplinary and integrated research program within NASA itself Such a program

is needed to span the gaps in knowledge that represent the most significant barriers to extended human spaceflight exploration

A successful program will depend in part on the results of research that can only

be performed in the unique environment of space; in other words, the program should draw on research that is enabled by access to space This type of fundamental research addresses questions that exist at the very core of discovery: What factors contribute to flame growth and impact fire behavior in reduced-gravity conditions?

Future in Space

What underlying biological mechanisms are revealed when the fundamental force

of gravity is stripped away? From these questions, new technologies can emerge in seemingly unrelated sectors For instance, discoveries might emerge in the field of medicine from access to data on physiological changes, such as heart muscle atrophy and decreasing bone mass, in astronauts during spaceflight

But discovery is just one component of a comprehensive research program To generate progress in all relevant areas needed for human spaceflight, a program should also yield new insights into the space environment that can be applied to exploration mission needs This enabling research could contribute to innovative technologies that are more reliable, cheaper, safer, and more efficient, making human spaceflight more accessible than was possible in these last few decades More specifically, how could a better understanding of the space environment enable engineers to design technologies that harness the unique conditions of space instead of competing with them? For example, are there techniques or materials yet to be developed that could use reduced gravity to enhance, rather than complicate, the transfer of fuels during spaceflight?

Overcoming these specific challenges, as well as the more general scientific and engineering obstacles that are present in space exploration, will require an understanding of biological and physical processes, as well as their intersections, in the presence of a range of reduced gravity conditions

The examples presented in the following pages illustrate only some of the mechanisms, uncertainties, and unique phenomena that are a part of the space environment These are select areas that could benefit from fundamental research in the life and physical sciences, but they also provide a glimpse into the possible applications for this research both in space and for society as a whole These brief vignettes raise questions—such

as, what discoveries still await humanity in the space environment that would not be possible to make on Earth, and what barriers to human spaceflight still remain?

These examples of enabling research, and descriptions of scientific insights enabled

by access to space, are explored in greater detail in the full NRC report Recapturing a Future for Space Exploration

This publication and the full report are available online at http://www.nap.edu

Nutrition and Space Foods

Nutrition is another method by which scientists have tried to mitigate astronaut bone loss While it is well known that inadequate nutrition disrupts proper functioning of the human body, the extent of these effects in microgravity is not well understood Long periods in space may make astronauts particularly susceptible to bone and muscle loss, compromised immune systems, and neurological changes that can affect cognitive functioning and contribute to sleep deprivation conditions likely exacerbated by suboptimal nutrition

Based on information from previous missions, some common vitamin and mineral deficiencies have been identified in astronauts In particular, several deficiencies or insufficiencies are consistently reported, including inadequate energy intake and a depressed vitamin D and

K status Data from individual Skylab missions show that length of mission is a factor in vitamin D status; the longer the mission, the more depressed the vitamin D status Because astronauts are not exposed to UV light in flight, they require a vitamin D supplement This nutrient, which is the only vitamin routinely supplemented in spaceflight, is required for calcium absorption—an important consideration when bone loss is a clearly documented negative consequence of spaceflight

In order to predict and mitigate any deficits experienced by astronauts, short- or long-term,

it is critical to study any changes to the antioxidant capacity of space foods as a function of processing and space conditions NASA has therefore instituted effective measures to ensure that all food consumption and specific nutritional needs are met NASA’s Johnson Space Center has developed a wide selection of foods for use in space that have been analyzed and well documented for their nutritional content On Earth, preparing and storing foods for long periods can lead to loss or depletion of the foods’ nutritional value; however, there is still insufficient information on the ways in which these same processes affect foods in space, including the effects of space radiation

Osteoporosis is a bone disease marked by the steady decrease of BMD, contributing to an increased risk for fracturing Women are particularly at risk due to the hormonal fluctuations experienced during and after menopause Research enabled by access to space could provide insights on bone loss prevention in astronauts and, back on Earth, contribute to advances in the prevention, diagnosis, and treatment of osteoporosis.

Nutritional Needs in Space

The Issues of Bone Loss &

Over millions of years, the structures of organisms on Earth have

evolved under the constant influence of the planet’s gravity When

living in microgravity, however, organisms attempt to adapt to a

new hierarchy of forces For humans, understanding how bones can

change in space, particularly when that change relates to bone loss,

is crucial to allowing longer missions Much as on Earth, a

nutrition-ally adequate diet in space must be maintained for proper body

func-tion How many calories are needed while in space? What types of

physical activity or exercise can promote bone and muscle growth?

Such questions can be answered only through a better

understand-ing of the effects of reduced gravity on the many and complex

sys-tems of the human body.

Preventing Bone Loss

The skeletal system of animals provides a solid framework for structural support, protection,

and mobility in Earth’s gravity (1 g) It is not surprising, then, that the skeletal system

changes in the absence of gravity Reports show that the rate of bone loss in microgravity

can be roughly 10 times greater than the rate of bone loss that occurs in women after

menopause Bone mineral density (BMD) is the measurement used to determine how

much bone loss has occurred

After being in space for six months, astronauts typically need more than two and a half

years for their BMD to return to pre-flight levels, while the changes in bone structure that

also occur in microgravity can be irreversible and actually mimic many of the changes

associated with advanced aging Such issues are currently a barrier to long periods in space,

so it is important for future research to focus on such issues as whether a partial-gravity

environment—for example, one-third gravity for Mars or one-sixth gravity for the Moon—

will provide some degree of protection from the bone loss that occurs in microgravity

The U.S and Russia have used exercise in space as a loading mechanism to counter the

effects of microgravity, but these activities have not been reliably effective for maintaining

bone mass and there is evidence that previous exercise loading on devices failed to adequately

maintain BMD However, ground-based research that uses long-term bed rest to mimic the

effects of sustained lowered gravity have suggested that bone may be somewhat protected

by certain activities, including exercise time Supine treadmill exercise—that is, running

while suspended horizontally—has shown positive benefits when coupled with imposing

negative pressure to the lower-body during both 30- and 60-day periods of bed rest

Over the past 15 years, drugs like biophosphonate have been developed for the prevention

of osteoporosis, and the ISS provides a unique platform for testing their effectiveness

Research has shown that biophosphonate injections maintained a slightly increased BMD

in the spine and hips of rodents during 90 days of hindlimb unloading, which is also

used as an analog of microgravity One concern is that suppression of resorption—the

breakdown and release of bone minerals to the blood stream—will also suppress bone

formation With such drugs, consequently, further research is needed to ensure that bone

fractures will be able to heal as expected

Nutrition and Space Foods

Nutrition is another method by which scientists have tried to mitigate astronaut bone loss While it is well known that inadequate nutrition disrupts proper functioning of the human body, the extent of these effects in microgravity is not well understood Long periods in space may make astronauts particularly susceptible to bone and muscle loss, compromised immune systems, and neurological changes that can affect cognitive functioning and contribute to sleep deprivation conditions likely exacerbated by suboptimal nutrition

Based on information from previous missions, some common vitamin and mineral deficiencies have been identified in astronauts In particular, several deficiencies or insufficiencies are consistently reported, including inadequate energy intake and a depressed vitamin D and

K status Data from individual Skylab missions show that length of mission is a factor in vitamin D status; the longer the mission, the more depressed the vitamin D status Because astronauts are not exposed to UV light in flight, they require a vitamin D supplement This nutrient, which is the only vitamin routinely supplemented in spaceflight, is required for calcium absorption—an important consideration when bone loss is a clearly documented negative consequence of spaceflight

In order to predict and mitigate any deficits experienced by astronauts, short- or long-term,

it is critical to study any changes to the antioxidant capacity of space foods as a function of processing and space conditions NASA has therefore instituted effective measures to ensure that all food consumption and specific nutritional needs are met NASA’s Johnson Space Center has developed a wide selection of foods for use in space that have been analyzed and well documented for their nutritional content On Earth, preparing and storing foods for long periods can lead to loss or depletion of the foods’ nutritional value; however, there is still insufficient information on the ways in which these same processes affect foods in space, including the effects of space radiation

Physiological interactions with gravity conditions are largely unpre- dictable, including our understanding

micro-of the effects on vitamin levels Dietary supplements and nutritionally evalu- ated space foods are approaches to combating deficiencies and ensuring the health of astronauts.

Osteoporosis is a bone disease marked by the steady decrease of BMD, contributing to an increased risk for fracturing Women are particularly at risk due to the hormonal fluctuations experienced during and after menopause Research enabled by access to space could provide insights on bone loss prevention in astronauts and, back on Earth, contribute to advances in the prevention, diagnosis, and treatment of osteoporosis.

The skeletal system of animals provides a solid framework for structural support, protection,

) It is not surprising, then, that the skeletal system changes in the absence of gravity Reports show that the rate of bone loss in microgravity

can be roughly 10 times greater than the rate of bone loss that occurs in women after

menopause Bone mineral density (BMD) is the measurement used to determine how

After being in space for six months, astronauts typically need more than two and a half

years for their BMD to return to pre-flight levels, while the changes in bone structure that

also occur in microgravity can be irreversible and actually mimic many of the changes

associated with advanced aging Such issues are currently a barrier to long periods in space,

so it is important for future research to focus on such issues as whether a partial-gravity

environment—for example, one-third gravity for Mars or one-sixth gravity for the Moon—

The U.S and Russia have used exercise in space as a loading mechanism to counter the

effects of microgravity, but these activities have not been reliably effective for maintaining

bone mass and there is evidence that previous exercise loading on devices failed to adequately

maintain BMD However, ground-based research that uses long-term bed rest to mimic the

effects of sustained lowered gravity have suggested that bone may be somewhat protected

by certain activities, including exercise time Supine treadmill exercise—that is, running

while suspended horizontally—has shown positive benefits when coupled with imposing

Over the past 15 years, drugs like biophosphonate have been developed for the prevention

of osteoporosis, and the ISS provides a unique platform for testing their effectiveness

Research has shown that biophosphonate injections maintained a slightly increased BMD

in the spine and hips of rodents during 90 days of hindlimb unloading, which is also

used as an analog of microgravity One concern is that suppression of resorption—the

breakdown and release of bone minerals to the blood stream—will also suppress bone

formation With such drugs, consequently, further research is needed to ensure that bone

Shifts in Astronaut Health

Adequate sleep—obtained on a regular schedule reflecting the

brain’s natural (circadian) sleep/wake rhythm—is necessary for

maintaining optimal health, alertness, and performance

Cardio-vascular functioning depends on the delivery of blood to all organs

at optimal perfusion pressure In space, however, factors that

de-termine various physiological rhythms and efficiencies, such as

gravity and exposure to the Earth’s light/dark cycle, are altered

or absent A thorough understanding of the interactions between

human physiology and long-term exposure to non-terrestrial

condi-tions will be critical to the success of extended missions in space.

Chronic Sleep Loss in Space

Historically, NASA has recognized the importance of sleep and circadian rhythms for

sustaining cognitive functioning in space and, accordingly, has supported related research

efforts Such studies have generally revealed that sleep is disrupted during space missions,

with reductions in time spent asleep and disturbances of the circadian sleep/wake rhythm

These detrimental effects typically become more severe after 90 days in orbit, leading to

greater fatigue Although it is difficult to specify the extent to which sleep loss and fatigue

have contributed to actual errors or accidents during space missions, these issues have

been recognized as factors that likely contributed to specific incidents, such as the Mir–

Progress collision on June 25, 1997

Scientific evidence is mounting that the effects of chronic sleep loss are not limited

to impaired brain function (such as, alertness, psychomotor performance, situational

awareness, and problem solving) For example, it is now thought that chronic sleep loss

exacerbates unhealthy weight gain by altering leptin and ghrelin levels, which are hormones

that mediate hunger and metabolism Also of particular interest is the possibility that

chronic sleep loss in space could lower psychological resilience and increase the incidence

of stressor-induced symptoms and illness

Shifts in Cardiovascular Health

Developed over millions of years in the constant presence of gravity, the cardiovascular

system is used to dealing with rapid shifts in gravitational gradients: lying down, standing

up, and exercising all change the influence of gravity on the blood and circulation One

such response is the shift in blood volume from the lower extremities to the head and neck

because, in space, the circulatory system is no longer “fighting against” Earth’s gravity

More precisely, fluids shift away from the lower extremities and migrate toward the head,

causing the astronaut’s appearance of thin “bird legs” and a puffy face The heart initially

becomes quite full, and the blood vessels of the head and neck become distended Within

the first few days, the body attempts to get rid of this fluid and there is a decrease in total

blood volume in the astronaut In-flight plasma volume can decrease by 10%-17%, and the

circulation seems to adjust to a level about half-way between lying down and standing up

of cardiac electrophysiological properties—will be necessary to determine the magnitude and significance of these observations

Astronauts could also carry heart problems with them into space During a prolonged mission to Mars, astronauts would not have access to comprehensive healthcare services for two to three years at a time, aside from assigned crew expertise Although astronauts are now carefully screened prior to selection, they often must wait a decade or longer

to fly select missions The resulting age range—the average age of astronauts is 46—puts them at greater risk for developing life-threatening cardiac issues NASA invests considerable resources in training astronauts, so the NRC has recommended that screening and monitoring strategies be implemented to follow astronauts from selection

to flight as a method of identifying individuals whose short term (two- to three-year) risk for a cardiovascular event may have increased It will also be important to develop pharmacological or physiological risk mitigation strategies that will effectively and sufficiently reduce the risk of cardiovascular events prior to and during spaceflight

With little gravity resistance for the heart to pump against, significant atrophy can occur just

as it would with other muscles For example, one study of four astronauts found a 7%-10% atrophy in cardiac muscle following just 10 days in space Actual microgravity conditions can not be simulated for extended periods of time on Earth, but bed rest studies can provide some insights into the effects of a long period of “reduced resistance” on the heart.

During Long Periods in Space

Shifts in Astronaut Health

Shifts in Astronaut Health

Historically, NASA has recognized the importance of sleep and circadian rhythms for

sustaining cognitive functioning in space and, accordingly, has supported related research

efforts Such studies have generally revealed that sleep is disrupted during space missions,

with reductions in time spent asleep and disturbances of the circadian sleep/wake rhythm

These detrimental effects typically become more severe after 90 days in orbit, leading to

greater fatigue Although it is difficult to specify the extent to which sleep loss and fatigue

have contributed to actual errors or accidents during space missions, these issues have

been recognized as factors that likely contributed to specific incidents, such as the Mir–

Scientific evidence is mounting that the effects of chronic sleep loss are not limited

to impaired brain function (such as, alertness, psychomotor performance, situational

awareness, and problem solving) For example, it is now thought that chronic sleep loss

exacerbates unhealthy weight gain by altering leptin and ghrelin levels, which are hormones

that mediate hunger and metabolism Also of particular interest is the possibility that

chronic sleep loss in space could lower psychological resilience and increase the incidence

Developed over millions of years in the constant presence of gravity, the cardiovascular

system is used to dealing with rapid shifts in gravitational gradients: lying down, standing

up, and exercising all change the influence of gravity on the blood and circulation One

such response is the shift in blood volume from the lower extremities to the head and neck

because, in space, the circulatory system is no longer “fighting against” Earth’s gravity

More precisely, fluids shift away from the lower extremities and migrate toward the head,

causing the astronaut’s appearance of thin “bird legs” and a puffy face The heart initially

becomes quite full, and the blood vessels of the head and neck become distended Within

the first few days, the body attempts to get rid of this fluid and there is a decrease in total

blood volume in the astronaut In-flight plasma volume can decrease by 10%-17%, and the

circulation seems to adjust to a level about half-way between lying down and standing up

of cardiac electrophysiological properties—will be necessary to determine the magnitude and significance of these observations

Astronauts could also carry heart problems with them into space During a prolonged mission to Mars, astronauts would not have access to comprehensive healthcare services for two to three years at a time, aside from assigned crew expertise Although astronauts are now carefully screened prior to selection, they often must wait a decade or longer

to fly select missions The resulting age range—the average age of astronauts is 46—puts them at greater risk for developing life-threatening cardiac issues NASA invests considerable resources in training astronauts, so the NRC has recommended that screening and monitoring strategies be implemented to follow astronauts from selection

to flight as a method of identifying individuals whose short term (two- to three-year) risk for a cardiovascular event may have increased It will also be important to develop pharmacological or physiological risk mitigation strategies that will effectively and sufficiently reduce the risk of cardiovascular events prior to and during spaceflight

Astronauts in space experience a ety of sleep difficulties that can be as- sessed by tracking their brain waves during each phase of sleep Electroen- cephalograph machines monitor and measure electrical impulses from the brain, muscles, eyes, and heart; dur- ing spaceflight, a cap of electrodes is secured to the astronaut’s head to re- cord electrical activity as brain waves.

vari-With little gravity resistance for the heart to pump against, significant atrophy can occur just

as it would with other muscles For example, one study of four astronauts found a 7%-10% atrophy in cardiac muscle following just 10 days in space Actual microgravity conditions can- not be simulated for extended periods of time on Earth, but bed rest studies can provide some insights into the effects of a long period of “reduced resistance” on the heart.

During Long Periods in Space

Shifts in Astronaut Health

Monitoring Brain and Behavioral Functions in Astronauts

Long-duration space missions require a crew to perform at peak health in every respect,

overcoming obstacles that may arise from living in a confined, isolated environment Even

small errors in judgment or coordination can have profoundly adverse consequences in

the unforgiving environment of space While research on Earth continues to expand

the use of functional magnetic resonance imaging (fMRI) procedures for mapping the

physiological basis for behavioral and cognitive functioning, currently the only way to

determine cognitive performance capacity for astronauts is to administer cognitive tests

During astronaut selection, candidates submit to a series of tests that go beyond the

bounds of physical performance measures In general, these include self-report personality

inventories and formal psychiatric interviews In addition, NASA’s cognitive performance

tests are only administered for the purpose of informing the astronaut selection process

and then providing meaningful data for detecting trends in the astronauts’ status during

actual missions This process includes a projection of their capacity to perform

mission-related tasks as well as their temporary sense of well-being

Astronauts selected and trained for spaceflight produce a baseline of health data against

which testing performed in space can later be compared Certain environmental conditions

could have an impact on cognitive processes that are critical to coping with issues in a

spacecraft For example, a decline in executive functioning, perhaps as a result of sleep

loss, could impair an astronaut’s reaction time, memory retrieval, problem-solving abilities,

general alertness, and judgment Measures of cognitive resilience should be identified or

developed to assess astronauts’ capacity for sustaining performance in the face of significant

stressors, particularly in the context of challenging situations such as docking

Space Environments

Group Dynamics in an Extreme Environment

Analog studies that involve simulating some of the most salient aspects of the space environment, and surveys of astronaut personnel, have contributed to our understanding of factors that affect social compatibility Some of these include goal orientation, kindness, and

a lack of hostility Crews of future long-duration missions will likely include a diverse mix

of national, organizational, and professional cultures, all of which produce characteristics that have been found to affect group functioning in space

Leadership is always an important predictor of team functioning and may be especially important during space missions Additional research is required to determine how leadership styles across different nationalities will affect crew tension Similarly, evidence-based methods for preventing a breakdown in communication, or the identification of methods for promoting group cohesion, will be important Rigorously designed experimental simulations—mirroring actual mission parameters like isolation, confinement, and workload—are needed to provide further insights into group dynamics and cooperation

On Apollo 13, the carbon dioxide removal system malfunctioned and, with the help of ground crew specialists, the crew was able to devise a replacement unit that brought the system back online This worked to save the astronauts and also strengthen the community supporting the mission In addition to everyday stressors, the extreme conditions of the space environment can pose life-threatening risks Astronauts should be able to rely on both their own unimpaired judgments and the support of the crew when resolving these issues

One of the many challenges faced by astronauts in space is confinement in close quarters with

their crew, coupled with limited contact with friends and family This type of confinement is not

unique to space, but research exploring the group dynamics experienced by current astronauts

could benefit our understanding of fundamental behavioral and cognitive processes Future

studies could help to guide practices regarding the optimum number of crew members needed

to foster healthy group dynamics during long-duration missions Using ISS experience, data on

behavioral and neurological changes resulting from stress factors—such as exposure to

radia-tion or a lack of privacy/personal space—could also contribute to research on physiological

and cognitive responses to traumatic events on longer missions In addition to possible

impli-cations on Earth, these inquiries could guide healthy group dynamics and individual well-being

Long-duration space missions require a crew to perform at peak health in every respect,

overcoming obstacles that may arise from living in a confined, isolated environment Even

small errors in judgment or coordination can have profoundly adverse consequences in

the unforgiving environment of space While research on Earth continues to expand

the use of functional magnetic resonance imaging (fMRI) procedures for mapping the

physiological basis for behavioral and cognitive functioning, currently the only way to

determine cognitive performance capacity for astronauts is to administer cognitive tests

During astronaut selection, candidates submit to a series of tests that go beyond the

bounds of physical performance measures In general, these include self-report personality

inventories and formal psychiatric interviews In addition, NASA’s cognitive performance

tests are only administered for the purpose of informing the astronaut selection process

and then providing meaningful data for detecting trends in the astronauts’ status during

actual missions This process includes a projection of their capacity to perform

mission-Astronauts selected and trained for spaceflight produce a baseline of health data against

which testing performed in space can later be compared Certain environmental conditions

could have an impact on cognitive processes that are critical to coping with issues in a

spacecraft For example, a decline in executive functioning, perhaps as a result of sleep

loss, could impair an astronaut’s reaction time, memory retrieval, problem-solving abilities,

general alertness, and judgment Measures of cognitive resilience should be identified or

developed to assess astronauts’ capacity for sustaining performance in the face of significant

Space Environments

Group Dynamics in an Extreme Environment

Analog studies that involve simulating some of the most salient aspects of the space environment, and surveys of astronaut personnel, have contributed to our understanding of factors that affect social compatibility Some of these include goal orientation, kindness, and

a lack of hostility Crews of future long-duration missions will likely include a diverse mix

of national, organizational, and professional cultures, all of which produce characteristics that have been found to affect group functioning in space

Leadership is always an important predictor of team functioning and may be especially important during space missions Additional research is required to determine how leadership styles across different nationalities will affect crew tension Similarly, evidence-based methods for preventing a breakdown in communication, or the identification of methods for promoting group cohesion, will be important Rigorously designed experimental simulations—mirroring actual mission parameters like isolation, confinement, and workload—are needed to provide further insights into group dynamics and cooperation

On Apollo 13, the carbon dioxide removal system malfunctioned and, with the help of ground crew specialists, the crew was able to devise a replacement unit that brought the system back online This worked to save the astronauts and also strengthen the community supporting the mission In addition to everyday stressors, the extreme conditions of the space environment can pose life-threatening risks Astronauts should be able to rely on both their own unimpaired judgments and the support of the crew when resolving these issues

One of the many challenges faced by astronauts in space is confinement in close quarters with

their crew, coupled with limited contact with friends and family This type of confinement is not

unique to space, but research exploring the group dynamics experienced by current astronauts

could benefit our understanding of fundamental behavioral and cognitive processes Future

studies could help to guide practices regarding the optimum number of crew members needed

to foster healthy group dynamics during long-duration missions Using ISS experience, data on

behavioral and neurological changes resulting from stress factors—such as exposure to

radia-tion or a lack of privacy/personal space—could also contribute to research on physiological

and cognitive responses to traumatic events on longer missions In addition to possible

impli-cations on Earth, these inquiries could guide healthy group dynamics and individual well-being

It has taken eons for Earth to develop its current physical state, and its biosphere’s

characteris-tics are intrinsically connected with terrestrial life These factors are tied with other processes

that are critical for supporting all terrestrial organisms For example, on Earth, the phenomenon

called gravity-driven buoyancy causes the settling and separation of fluids of different densities

and is responsible for natural convection: the movement of molecules en masse within liquids

and gases This phenomenon is involved in such diverse processes as the formation and

move-ment of ocean waves and molecular signaling in bacteria The pervasive force of gravity has

had profound and myriad effects on the evolution and development of terrestrial organisms, but

what happens when these organisms are removed from the gravitational environment in which

they evolved? Since plants can sense changes in gravity, do they grow differently during

space-flight? Can microbes survive and thrive far from Earth? In addition to addressing topics that are

fundamental to all biological processes, research on these questions will be central to having

plants and microbes as useful partners to support humans on long-term space missions as part

of a biologically-based, regenerative life support system.

Up-Rooted: Plant Growth in Space

As plants have evolved in a constant 1 g environment, they have adapted to detect gravity and

respond accordingly by adjusting directional—or gravitropic—growth This allows the plant

to maintain the correct orientation of its organs and, in turn, helps to define the structure

of the root and shoot systems This mechanism, along with other physiological functions, is

driven by forces and processes that are constant on Earth

Space environments, however, present factors other than microgravity that could potentially

alter these specialized functions Components of the spaceflight environment are complex and

dynamic; they range from intrinsic and natural (radiation and gravity) to highly engineered

factors developed for and in the spacecraft habitat itself (atmospheric composition, pressure,

variations in light spectrum, noise, and vibrations)

Pressure is one consideration in the spaceflight environment While Earth’s atmosphere is

approximately 100 kPa (14.5 pounds per square inch), the lower limit of pressure used to

maintain human comfort during routine activities is about 34 kPa (5 psi) Plants, on the other

hand, can tolerate much lower pressures—well below 25 kPa (3.6 psi), depending on the

plant and its stage of growth This suggests that plants could potentially be grown in low

pressure habitats, and even in plant habitats with filtered and compressed CO2 (the principal

component of the martian atmosphere), thereby reducing the high demand of consumable

resources needed to maintain human-accommodating atmosphere and pressure in spacecraft

or plant farming facilities on Mars Research is needed to confirm minimums that can be

sustained for long periods or perhaps perpetually while in space or on other planets

Controlled crop cultivation in this capacity could provide insights into optimizing plant growth

conditions and responses, potentially benefiting human life and health on Earth as well For

example, research into plant responses to gravity could contribute to innovations in crop recovery

after lodging—damage done when weather has bent a crop down flat to the ground

Managing Microbes as Spaceflight Companions

Microbes are a unique component of the spaceflight environment Attempts to broadly eradicate bacteria in spacecraft would not only be extremely difficult, they would also eliminate microbiota essential for human health There are more bacterial cells in and on the human body than there are human cells As a result, it would be all but impossible

to prevent crew members from continually reintroducing microbes into their spacecraft

or habitat

The human microbiome is beneficial for important physiological functions, such as food digestion by humans When antibiotics alter bacteria in the gut, these helpful microbial communities need to repopulate the intestine in order to restore and sustain its function

In the isolated spacecraft environment, it is unclear how this repopulation would occur

if the environment was continually subjected to antibiotic decontamination

However, some amount of microbial decontamination is necessary since the presence of certain microbes in a closed environment can pose a threat to human health Bacterial pathogens can be particularly dangerous, especially for astronauts on long-duration flights in which evacuation may not be an option Research has indicated that bacteria such as E coli can form protective biofilms in microgravity conditions just as they do

on Earth

Research on the effects of the spaceflight environment on microbes is limited The gap

in knowledge is partly due to a lack of isolation technology, such as alternative platforms called free-flyers, that could isolate pathogens from ISS astronauts while allowing research on bacterial virulence to be conducted safely in space Discoveries in this area could potentially contribute to innovations in how best to focus preventative measures

on particularly resilient bacterial pathogens known on Earth

It has taken eons for Earth to develop its current physical state, and its biosphere’s

characteris-tics are intrinsically connected with terrestrial life These factors are tied with other processes

that are critical for supporting all terrestrial organisms For example, on Earth, the phenomenon

called gravity-driven buoyancy causes the settling and separation of fluids of different densities

and is responsible for natural convection: the movement of molecules en masse within liquids

and gases This phenomenon is involved in such diverse processes as the formation and

move-ment of ocean waves and molecular signaling in bacteria The pervasive force of gravity has

had profound and myriad effects on the evolution and development of terrestrial organisms, but

what happens when these organisms are removed from the gravitational environment in which

they evolved? Since plants can sense changes in gravity, do they grow differently during

space-flight? Can microbes survive and thrive far from Earth? In addition to addressing topics that are

fundamental to all biological processes, research on these questions will be central to having

plants and microbes as useful partners to support humans on long-term space missions as part

environment, they have adapted to detect gravity and respond accordingly by adjusting directional—or gravitropic—growth This allows the plant

to maintain the correct orientation of its organs and, in turn, helps to define the structure

of the root and shoot systems This mechanism, along with other physiological functions, is

Space environments, however, present factors other than microgravity that could potentially

alter these specialized functions Components of the spaceflight environment are complex and

dynamic; they range from intrinsic and natural (radiation and gravity) to highly engineered

factors developed for and in the spacecraft habitat itself (atmospheric composition, pressure,

Pressure is one consideration in the spaceflight environment While Earth’s atmosphere is

approximately 100 kPa (14.5 pounds per square inch), the lower limit of pressure used to

maintain human comfort during routine activities is about 34 kPa (5 psi) Plants, on the other

hand, can tolerate much lower pressures—well below 25 kPa (3.6 psi), depending on the

plant and its stage of growth This suggests that plants could potentially be grown in low

(the principal component of the martian atmosphere), thereby reducing the high demand of consumable

resources needed to maintain human-accommodating atmosphere and pressure in spacecraft

or plant farming facilities on Mars Research is needed to confirm minimums that can be

Controlled crop cultivation in this capacity could provide insights into optimizing plant growth

conditions and responses, potentially benefiting human life and health on Earth as well For

example, research into plant responses to gravity could contribute to innovations in crop recovery

Managing Microbes as Spaceflight Companions

Microbes are a unique component of the spaceflight environment Attempts to broadly eradicate bacteria in spacecraft would not only be extremely difficult, they would also eliminate microbiota essential for human health There are more bacterial cells in and on the human body than there are human cells As a result, it would be all but impossible

to prevent crew members from continually reintroducing microbes into their spacecraft

or habitat

The human microbiome is beneficial for important physiological functions, such as food digestion by humans When antibiotics alter bacteria in the gut, these helpful microbial communities need to repopulate the intestine in order to restore and sustain its function

In the isolated spacecraft environment, it is unclear how this repopulation would occur

if the environment was continually subjected to antibiotic decontamination

However, some amount of microbial decontamination is necessary since the presence of certain microbes in a closed environment can pose a threat to human health Bacterial pathogens can be particularly dangerous, especially for astronauts on long-duration flights in which evacuation may not be an option Research has indicated that bacteria such as E coli can form protective biofilms in microgravity conditions just as they do

on Earth

Research on the effects of the spaceflight environment on microbes is limited The gap

in knowledge is partly due to a lack of isolation technology, such as alternative platforms called free-flyers, that could isolate pathogens from ISS astronauts while allowing research on bacterial virulence to be conducted safely in space Discoveries in this area could potentially contribute to innovations in how best to focus preventative measures

on particularly resilient bacterial pathogens known on Earth

Space travel will likely require strategies for ciency as the duration and distance of missions increase

self-suffi-In those instances, disposing of waste would no longer remain cost-effective, and resupplying crew members with oxygen, water, and food from Earth would no longer

be feasible One of the main requirements for sustaining life in space, such as on the lunar surface or on Mars, and as a strategy for long-duration flights, is the devel- opment of bioregenerative life support systems A self- sustaining system could utilize plants and microbes to recycle waste and supply food, oxygen, and water to crew members.