∂AIL Dr.  Richard Goody↓American  Academy of  Arts and  Sciences ↓165
Allandale Street↓Jamaica Plain Station↓Boston MA 02130∞

Dear Dr. Goody:

        The  following  remarks  are  suggested  by  your  memorandum
together with Michael McElroy  and Philip Morrison.  I would  like to
be informed of  future developments towards  an Academy study  of the
issues and might like to take part.

        Looked at from the point  of view of the future  of humanity,
space exploration and colonization has two important aspects:

        1.  The  dispersion   of  humanity  will  help   prevent  its
extermination by catastrophe - whether this catastrophe be  a nuclear
war, some kind of environmental disaster, or a natural disaster.

        2. It will  also help prevent  the domination of  humanity by
any single ideology - whether this ideology be  communism, capitalism
or environmentalism.

        From the point  of view of  individuals or groups,  there are
other considerations:

        1. Some,  who hope  to reform humanity,  look with  horror on
people with bad ideas escaping control.  The Soviet position on space
treaties seems to  express such an attitude  and many who  propose to
confine  mankind  to  the  earth  until  we  can  be  sure  we  won't
contaminate the universe have a similar point of view - no doubt with
somewhat different ideas about  what shouldn't be permitted to  get a
foothold in space.  I can't be sure of your own position; it seems to
be  predicated  on  centralized control  of  mankind's  activities in
space, but this may  only be a reflection  of the fact that  the most
substantial  activities  of  the very  near  future  require  so much
government support.

        My own position  is to encourage  diversity to the  extent of
permitting secession of government sponsored colonies  and permitting
the  formation  of  new  colonies  that  owe  no  allegiance  to  any
government on the earth or to the U.N. or any successor to it.

        2. Those who fear disaster on earth - natural, environmental,
war, or political - will want a means of escape.  True  escape, given
the power  of weapons  based on present  science, may  require multi-
generation  expeditions  leaving  the solar  system.   It  seems that
present  science  would  support a  technology  for  such expeditions
leaving  as  early  as  the  end  of  the  present  century, although
postponed expeditions would arrive at their destinations sooner.



        I have written a manuscript about this deriving a formula

        %2t = 2 s↑(2/3) p↑(-1/3)%1

where %2s%1 is  the distance to  a goal, ⊗t  is the time  required to
reach it, and ⊗p is the figure of merit of the power system  in watts
per  kilogram.   The  system  uses a  power  source  (e.g.  a fission
reactor) to expel a working fluid (e.g. in the form of ions  or other
charged  particles)  at  an exhaust  velocity  that  varies optimally
during the journey.  Nearby stars are reached in the low thousands of
years,  and  because  of  the  factor  %2p↑(-1/3)%1,   improving  the
technology doesn't change the answers qualitatively.

        Of course, interstellar escape in the next few  hundred years
unless there is an advance in science, will be of interest only  if a
group feels rather desperate, but there may be such groups if mankind
evolves towards ideological monopoly.

        Anyhow,  most  of  our attention  should  be  devoted  to the
exploration and colonization of our own solar system.

        I am somewhat  surprised that your memorandum  didn't mention
the   controversies   surrounding  the   proposed   moon   treaty  as
prototypical of issues that will arise.

        Your  remarks   about  self-reproducing   artificial  systems
suggest the comment that such a system can be regarded as  a limiting
case of  increased flexible automation.   A system  that manufactures
new components for itself according to computer programs  written and
controlled by humans only needs  a new top-level program to  become a
self-reproducing  machine.   However,   there  seems  to   be  little
advantage to us in making the system entirely independent,  and there
is especially little advantage in having it split up into independent
self-controlled units.

        Let  me  re-iterate my  interest  in taking  part  in Academy
discussions.  You will find me an advocate of the idea  that humanism
requires  tolerating  and  encouraging  diversity  in   solar  system
exploration and exploitation.