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From: dep@k.cs.cmu.edu (David Pugh)
Newsgroups: net.space
Subject: Manned vs. Unmanned
Message-ID: <740@k.cs.cmu.edu>
Date: Sun, 2-Feb-86 21:39:26 EST
Article-I.D.: k.740
Posted: Sun Feb  2 21:39:26 1986
Date-Received: Wed, 5-Feb-86 02:22:08 EST
Organization: Carnegie-Mellon University, CS/RI
Lines: 82

<>

    The Challenger disaster has raised the manned vs. unmanned debate to
new heights. More people than ever are beginning to wonder whether we really 
should be sending men and women into space. Perhaps, they wonder, we should
wait until it is safer. After all, Voyager shows that people don't really need 
to send people into space. Right?

				WRONG!

    Voyager didn't prove anything. All it had to do was sit and watch the 
greatest show in the solar system. People have done and will be (hopefully!)
doing  far more difficult jobs (repairing satellites, producing new medicines,
etc.).

    Now, and for the forseeable future, people are needed in space to repair 
satellites and to conduct 'shotgun' research (conducting a wide variety of
experiments where the astronaut is responsible for setting the experiments
up). The technology to have waldos (mechanical arms which are controlled
from the ground) do any but the simplest of these jobs simply isn't there.
Consider:
    o	The best waldos available today have little, if any, feedback. This
	means that jobs which are easy to do by hand are difficult, if not 
	impossible to do with a waldo.

    o	The best mechanical 'hands' available today are crude, not having
	anywhere near the flexibility of a human hand (even one encased in a
	heavy glove).

    o	Any waldo used in space will have to be controlled by a radio link. 
	But, NASA no longer has world-wide radio coverage. This means that
	either:
		The waldo is used for only the 15-30 minutes out of each
		orbit it is in radio contact.

		The commands to the waldo are relayed through a satellite
		in geosynchronous orbit. This may not be practical, since
		it means that there will be a 1/2 second delay due to
		speed of light lag.

    Using robots to do repair work is even farther in the future than using
waldos. With the technology available today, it is considered a major
accomplishment to just have a robot pick the right tool up, much less use
it correctly.

    'Shotgun' research is just as, if not more, valuable than repairing 
satellites.  Consider how expensive it would be to send design a payload that 
will take a picture of Halley's comet. It was much less expensive to simply 
hand a camera to one of the astronaughts and ask him or her to take the picture.
A lot of important research that has been done on the space shuttle would
have simply been too expensive to do before we began routinely sending
people into orbit.

    Cost has always been the bottom line. Having people in orbit has allowed
us to recover two satellites, repair two satellites and perform an incredible
amount of research. Without people in orbit, these missions would either have 
been impossible, or far more expensive. In the long run, because of their 
ability to perform research cheaply and their to fix things when they go wrong 
(Columbia, the satellite you just launched isn't working. Could someone go out
and kick it? :-), manned launches will be cheaper than unmanned ones.

    As for waiting until space travel is safer...space travel will never
be perfectly safe (but, neither will driving to work). Obviously we should
try to make it as safe as possible. But when is it safe enough? A reasonable
answer would be: that it is safe enough when there are people willing to do
it. Even following the Challenger disaster, there is no shortage of people
willing to work in space. I say: let's give them the chance.

[I realize I may be preaching to the converted...but I'm planning to send 
a similar letter to Ronnie and would like all the feedback I can get]

							--David Pugh
							  dep@k.cs.cmu.edu

BTW: For those who haven't written to the President yet, here's his
address:
		President Ronald Reagan
		White House
		1600 Pennsylvania Ave.
		Washington, D.C. 20500

Now you have no excuse...start writting!