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9
Human Presence in Space
SPACE AGE SCIENCE
It is difficult to deterrn~ne which of the scientific projects
contemplated in this study, other than those in space medicine,
compel the presence of humans in space. ~ fact, there may be
no others. With sufficient resources, we might devise automated
systems that could substitute for people, performing all of the nec-
essary functions usually associated with humans. People would,
in turn, control the machines from Earth. On the other hand,
it appears that under certain circumstances people are able to
function productively ~ space and perform tasks In support of sci-
entific investigations. At present, we lack enough "formation to
judge where the balance between manned and unmanned missions
should lie.
Some space science rn~ssions at the beginning of the twenty-
first century may be ~ntencled to pave the way for the expansion
of humanity into deep space. For many reasons, not all scien-
tific, human activities may extend into an increasing arena of
space. With the advent of space stations, plans are already being
made by a number of national space agencies for the continuous
presence of men and women in low earth orbit, beginning in the
76
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77
l990s. Such activities ~ the next century may extend to geosyn-
chronous orbit, and possibly to the regions of the I,4 and L5 points.
The National Commission on Space has also expressed interest in
establishing inhabited stations on the Moon and Mars. Space
science practiced at the frontier requires a wide variety of inno-
vations in observational and control capabilities, instrumentation,
and propulsion methods. Thus, the pursuit of space science and
its supporting functions should be a powerful driver of advanced
technology, extending the capabilities of unmanned spacecraft.
Advances In the technology of sensors, robotics, artificial mtelli-
gence, and parallel computation may enable the development of a
new generation of autonomous decision-making machines that will
extend exploration ant] intensive study into remote parts of the
solar system and eventually beyond without a human presence.
Earth orbit can become a proving ground for the deployment of
robots, automated observatories, and advanced data management
systems.
TEE SCOPE OF HUMAN PRESENCE IN SPACE
The space stations of the United States and the Soviet Union
are the first steps toward a sustained human presence in space.
It is impossible now to predict either the pace or the ultimate
extent of this expansion into space. The human-inhabited sphere
may never extend beyond low earth orbit. Whether its boundaries
are near Earth, on the surface of Mars, or somewhere else, this
human-inhabited sphere wiD be the base from which many fu-
ture space science investigations are conducted. Conversely, these
investigations will provide the foundation needed for continued
expansion of this sphere, if caned for. Space science experiments,
tended in space by human beings, may provide the most important
rationale for the staging, assembly, maintenance, repair, and oper-
ation of major space facilities (e.g., space astronomical telescopes,
earth science experunent payloads/platforms, launch vehicles for
planetary missions).
The steering group expects that the sphere of human presence
in space will have relatively distinct boundaries. Within this sphere
human presence unit be pervasive and well-supported. Many scien-
ti~c investigations Urals be carried; out under direct human supervi-
sion, much as they are on the ground; others will be conducted in
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a largely automatic mode, with general superv'mon from scientists
on Earth or perhaps elsewhere within the inhabited sphere.
This confinement of human activities to regions where they
can draw upon a host of well-established facilities Is advisable for
two reasons. First, the capability of humans to make judgments
is optimized when there ~ an opportunity for adaptation, over
a long period of tune, to the new environment. Second, human
manipulative and observational skills can rarely be used electively
without the support of a large array of sophisticated instruments,
ma~hir es, and facilities. Neither of these two conditions is gener-
aDy met by brief forays of human beings into regions far from the
facilities that support their sustained presence. This applies to
manned excursions to Mars, for example, if the human-inhabited
sphere ~ restricted to space near the Earth.
Further, it is important to recognize that the limitations on
human survival in space are not weld known. At present, we are
not certain that mission times can be extended greatly beyond
those already experienced, even with considerable technological
progress. Low gravity leads to loss of bone mass and other phyla
ical effects. High-energy, heavy ion radiation causes irreversible
damage to cells, including brain cells. Human relationships in a
small, isolated group can badly deteriorate arch lead to the loss of
functional capabilities. We have not demonstrated the feasibility
of a closed ecological system yet, and resupply at a great distance
for a long period could be formidable. We must address these
issues before we can reach a final decision about the nature and
extent of human involvement in expanding the frontier of space.
Representative terms from entire chapter:
space science
