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COMMENTS ON THE SPACE PROGRAM


	The   manned  space  program  should  be  continued  for  the
following reasons:

	1. Its value for science.  This is a minor  reason  and  only
justifies  (say)  $100,000,000 per year of its cost.  This is because
manned space travel is very expensive, and more science per buck  can
be  obtained  in other ways.  Nevertheless, that fraction of the cost
of the space program that contributes to science should  be  able  to
charge  to  science its scientific value.  This estimate might change
if something very interesting turned up.  In fact, the probability of
this is worth (say) an additional $50,000,000 per year.

	2. Technological progress applicable to other fields.  15% of
the cost of the program.  The reasoning is similar to the above.

	3. Direct applications.  The smaller of $150,000,000 per year
and 50% of the cost.

	4.     Satisfying  mankind's  collective  curiousity.    This
collective curiousity provides part of the justification for science,
but  science is not its only component.  In my opinion, this is worth
about $3,000,000,000 per year.

	5. To provide freedom to emigrate from the earth  for  groups
that  don't like any of the existing governments.  As the world fills
up, the restrictions on individuals grow.  This freedom will  benefit
not  only  those who actually exercise it but will reduce feelings of
claustrophobia by others who consider themselves potential emigrants.
This is worth $2,000,000,000 per year.

	Adding up these numbers, we get about $6,000,000,000 per year
for the manned component of the space program which would pay  for  a
program  considerably  more  ambitious  than  Apollo.  What kind of a
program should this be?

	1. Technologically,  the  first  thing  is  to  complete  the
Shuttle  and  provide it with a re-usable booster so as to reduce the
cost per pound to orbit as much as possible.

	2. A low thrust rocket capable of making  arbitrary  journeys
within  the  solar system in a matter of months.  Probably this would
be a nuclear electric rocket.

	3. A permanent space station.

	4. Facilities at the space station  for  assembling  vehicles
and payloads.

	2. Missions.

		2.1.  Exploration  of  the  moon  and  planets.  This
should be done much more boldly than previously.  It  should  consist
mainly  of  one  way  missions with the explorers committed to remain
until retirement or even for  the  rest  of  their  lives  and  earth
committed to supply them. Thus, if Apollo had been conducted as a one
way with resupply program, we estimate that four explorers could have
made  a  permanent  base  on  the moon and been provided with 200,000
pounds of supplies.  This would include 75,000  pounds  of  food  and
oxygen  to  last  them for five years and 125,000 pounds of equipment
including a shelter, material for  extending  it,  tools,  excavating
equipment, a couple of vehicles, and a nuclear or solar power source.
The scientific return would have been  much  greater,  and  a  ground
survey of a substantial part of the moon would be possible.

	Of  course,  such  a  mission  would  have substantial risks.
There might be an irrepairable failure  of  some  part  of  the  life
support  system. One or more men might lose there lives in landslides
or from falls or other accidents of the kind that explorers suffer on
earth.   There  might  have been some uncompensable effect of the low
gravity.  Nevertheless, the risks might well be less than that of the
Apollo  program  as  operated  since  the  return parts of the Apollo
missions also have important risks. In  any  case,  the  risks  would
almost  certainly  be less than those that explorers have suffered in
the past.

	Qualified candidates would certainly  have  been  found,  but
they would have to be a different kind of person than the test pilots
of Apollo who are prepared to take great risks but expect to be  able
to  return  to  their  families  after  short  periods.  The explorer
mentality also exists in adequate numbers.

	One way missions of this type should be planned for the moon,
Mars,  probably  one  of  the moons of Mars, a large asteroid, a moon
each of Jupiter and  Saturn,  and  Pluto.   If  the  temperature  and
pressure  problems  can  be  solved,  then Mercury and Venus are also
candidates. Actually, it will be  relatively  easy  to  retrieve  the
crews  from  the  moons  of Mars, the asteroids, and Mercury, because
they will not be deep in a gravitational field.

	2. The problem of permanent living  in  interplanetary  space
needs  to  be  solved  so that emigration will be possible.  Once the
shuttle and low thrust rockets have been developed, the  problem  may
be  solved  by emigrants rather than by earth governments.  I see the
problem as follows:

	The best place to live in the solar system off the  earth  is
interplanetary   space.    The  other  planets  are  all  worse  than
Antarctica. The advantage of interplanetary space is that solar power
is  easily collected since the collectors can be permanently oriented
to the sun and will never be occluded.  A second  advantage  is  that
the  lack  of gravity makes the construction of structures easy.  The
disadvantage is that matter has to be obtained elsewhere.   The  best
sources  of  matter  are  the  asteroids  since  if we imagine a good
low-thrust high specific  impulse  technology,  they  can  be  easily
visited  without  the need to enter a deep gravitational well.  It is
not clear that all the elements  necessary  for  human  life  can  be
obtained  from  them.  Some may have to be obtained from the moons of
Jupiter or even from Earth.  Perhaps structural  materials  will  be
obtainable in Space and biological materials will have to be obtained
from Earth.  Only material for expansion will be required since there
must be a technology for complete recycling of biological wastes into
food, drinking water and breathable air.  I imagine  that  groups  as
small as twenty will be viable, but hundreds will be more normal.