STARSHIPS i73
the skeletal system, lower production of red blood cells, lower immune
response, and a reduced functioning of the cardiovascular system
seem to be the inevitable consequences of prolonged weightlessness in
space.
Missions to Mars, which may take several months to a year, will
push the very limits of the endurance of our astronauts. For long-term
missions to the nearby stars, this problem could be fatal. The starships
of the future may have to spin, creating an artificial gravity via centrifugal forces in order to sustain human life. This adjustment would
greatly increase the cost and complexity of future spaceships.
Second, the presence of micrometeorites in space traveling at
many tens of thousands of miles per hour may require that spaceships
be equipped with extra shielding. Close examination of the hull of the
Space Shuttle has revealed evidence of several tiny but potentially
deadly impacts from tiny meteorites. In the future, spaceships may
have to contain a special doubly reinforced chamber for the crew.
Radiation levels in deep space are much higher than previously
thought. During the eleven-year sunspot cycle, for example, solar
flares can send enormous quantities of deadly plasma racing toward
Earth. In the past, this phenomenon has forced the astronauts on the
space station to seek special protection against the potentially lethal
barrage of subatomic particles. Space walks during such solar eruptions would be fatal. (Even taking a simple transatlantic trip from L.A.
to New York, for example, exposes us to about a millirem of radiation
per hour of flight. Over the course of our trip we are exposed to almost
a dental X-ray of radiation.) In deep space, where the atmosphere and
magnetic field of the Earth no longer protect us, radiation exposure
could be a serious problem.
SUSPENDED ANIMATION
One consistent criticism of the rocket designs I have presented so far is
that even if we could build such starships, it would take decades to
the skeletal system, lower production of red blood cells, lower immune
response, and a reduced functioning of the cardiovascular system
seem to be the inevitable consequences of prolonged weightlessness in
space.
Missions to Mars, which may take several months to a year, will
push the very limits of the endurance of our astronauts. For long-term
missions to the nearby stars, this problem could be fatal. The starships
of the future may have to spin, creating an artificial gravity via centrifugal forces in order to sustain human life. This adjustment would
greatly increase the cost and complexity of future spaceships.
Second, the presence of micrometeorites in space traveling at
many tens of thousands of miles per hour may require that spaceships
be equipped with extra shielding. Close examination of the hull of the
Space Shuttle has revealed evidence of several tiny but potentially
deadly impacts from tiny meteorites. In the future, spaceships may
have to contain a special doubly reinforced chamber for the crew.
Radiation levels in deep space are much higher than previously
thought. During the eleven-year sunspot cycle, for example, solar
flares can send enormous quantities of deadly plasma racing toward
Earth. In the past, this phenomenon has forced the astronauts on the
space station to seek special protection against the potentially lethal
barrage of subatomic particles. Space walks during such solar eruptions would be fatal. (Even taking a simple transatlantic trip from L.A.
to New York, for example, exposes us to about a millirem of radiation
per hour of flight. Over the course of our trip we are exposed to almost
a dental X-ray of radiation.) In deep space, where the atmosphere and
magnetic field of the Earth no longer protect us, radiation exposure
could be a serious problem.
SUSPENDED ANIMATION
One consistent criticism of the rocket designs I have presented so far is
that even if we could build such starships, it would take decades to