Construction of the International Space Station scheduled to start later this year marks another milestone in space exploration. Research missions that once lasted only a few weeks, could routinely last many months, even years. But health effects of the space environment observed during short flights raise concerns about the safety and performance of astronauts during longer missions.
Because these detrimental effects could be intensified by extended
missions, NASA should support additional research into the
consequences of space flight on the biology and behavior of humans and
other organisms, says a new report from a committee of the National
Research Council.
The report provides a comprehensive review of the findings to date
from a wide range of life sciences research for space. It also
outlines the areas of research on humans and other organisms that NASA
should pursue if it is to successfully achieve such long-term goals as
operating the International Space Station, colonizing the moon, and
sending humans to Mars.
NASA should mount at least one more Spacelab-type mission to continue
the momentum of life sciences research in space and generate
additional data on the biological and psychological effects of space
travel, the committee said. It recommended specific research
priorities to ensure the safety and optimal performance of crews on
future extended missions.
NASA should concentrate on fully understanding how weightlessness
affects bone and muscle mass, blood pressure, sensory orientation, and
movement, in order to devise effective countermeasures, the committee
said. Losses in bone and muscle mass pose two of the greatest
obstacles to health and safety on long missions. Crew members on the
Russian space station Mir showed an average loss in bone mass density
of up to 1 percent a month in weight-bearing bones, the report notes.
Significant muscle atrophy has been recorded after only five days in
space. In-flight exercise programs proved helpful, but did not fully
prevent deterioration.
Changes in cardiovascular and pulmonary function have not yet been a
hindrance during space flight. However, two-thirds of the astronauts
tested after flights showed an impaired ability to maintain adequate
blood pressure. This condition could have more serious consequences
during docking and landing maneuvers involving rapid transitions
between gravitational force levels.
The agency should use the latest advances in molecular and cellular
biology to explore the underlying processes by which humans respond to
changes in gravity, the report says. Low gravity alters the body's
ability to sense direction and control motion, sometimes impairing
astronauts' ability to walk when they first return to Earth. This
condition could be exacerbated, the committee observed, and could
undermine the crew's abilities to operate the craft or disembark
rapidly in an emergency.
While space-based research will be crucial for advancing knowledge in
these areas, most research funding should be directed to ground-based
experiments — which are less costly to conduct — to answer
fundamental questions and frame hypotheses for testing in outer space.
For example, self-supporting colonies in outer space will require the
cultivation of plants in completely contained environments for food
and an oxygen source. So far this has not been successfully achieved
either on Earth or in space, the report notes.
The report emphasizes the need for more research on the impact of the
space environment's isolating and confining nature on astronauts'
behavior and performance. This is one of the least-studied effects of
space flight, yet the compatibility of crew members and their mental
well-being can greatly influence the ultimate success of a mission.
NASA also should improve its collection of data from astronauts to
answer fundamental questions about the effects of space travel on the
human body and mind. This process thus far has been arbitrary and
often hindered by astronauts' concerns about confidentiality. The
agency should revise its policies and practices to create a more
systematic approach to collecting and disseminating such information,
and encourage full cooperation and compliance from the astronauts.
In addition, NASA should encourage more timely publication of results
of experiments in peer-reviewed journals, and the agency should
provide the funding necessary to analyze and archive data so that it
is readily accessible to the scientific community.
The study was funded by NASA. The National Research Council is the
principal operating agency of the National Academy of Sciences and the
National Academy of Engineering. It is a private, non-profit
institution that provides science advice under a congressional
charter. A committee roster follows.
Copies of A Strategy for Research in Space Biology and Medicine In the
New Century are available from the National Academy Press for $49.00
(prepaid) plus shipping charges of $4.00 for the first copy and $.50
for each additional copy; tel. (202) 334-3313 or 1-800-624-6242.
Reporters may obtain a copy from the Office of News and Public
Information (contacts listed above).
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