Path: utzoo!attcan!uunet!husc6!bloom-beacon!mit-eddie!rutgers!bellcore!faline!thumper!karn
From: karn@thumper.bellcore.com (Phil R. Karn)
Newsgroups: sci.space.shuttle
Subject: Re: gratuitous anthrophobia (was Re: Shuttle computer reprogramming)
Message-ID: <1348@thumper.bellcore.com>
Date: 10 Oct 88 13:33:35 GMT
References: <6689@nsc.nsc.com> <6980@ihlpl.ATT.COM> <1938@kalliope.rice.edu> <1988Oct8.234146.11950@utzoo.uucp>
Organization: Bell Communications Research, Inc
Lines: 30

Oh, come on Henry, I'm right and you know it. :-)

Just see my previous postings regarding Microsat for evidence of what
you can do for very little money when you don't have human lives riding
on it. Even in the unmanned arena, AMSAT has made significant
contributions to spacecraft technology, usually because we were forced
to by the cost of the existing solutions. For example, the command
system on Oscar-13, although it may be over a decade old in design, is
much more sophisticated than the corresponding system in most existing
geostationary communications satellites. (I understand they still use
audio tones from the ground to fire their motors.) Also take a look at
our Phase 4 (geostationary) design. A three-axis spacecraft that looks
like a spinner (no despun bearing or steered solar arrays, too
expensive). An attitude control system based on fluid momentum loops
(constant use of thrusters is too expensive). An attitude sensor system
likely based on radio interferometry (conventional optical sensors are
too expensive). Extremely high efficiency linear RF amplifiers (extra
solar arrays are too expensive). And so on.

Necessity is often the mother of invention in AMSAT, and more often than
not, the necessity comes from the lack of funds to do things the
"standard" way. But if you combine relatively lavish funding with a "you
cannot fail, human lives and lots of money are on the line" directive,
then you get extremely conservative, and your rate of technological
development slows to a crawl. The perception of the space shuttle as the
ultimate symbol of American high technology is a master stroke of NASA
public relations; a close look at subsystems like the onboard computers
reveals just how out-of-date much of its technology (necessarily) is.

Phil