Satgen308   Satellite Hindsight No7    by GM4IHJ               18 Feb 95
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Possibly the most tragic mode of failure of a satellite, is failure of
concept. The original idea being fatally flawed by design or by politics,
or both, even before the satellite leaves the ground. Two examples stand
out in this field. The first was the ECHO series of reflector satellites.
In theory the idea of a satellite which could be blown up to a very large
size. Thereby providing a superb passive reflector that required no
satellite onboard transponder. Seemed to be a winner. First impressions
were excellent . The satellite launched and expended to a large size once
in space, where it proved to be a very useful radio reflector. But then
the problems started. Keplerian orbit elements useful on one day , could
not locate it the very next day. Indeed the satellite was not following a
regular orbit at all. The trouble was that the enormous size versus the
very light weight of the reflector made it just like a balloon at ground
level. Although the atmosphere at orbit height was very thin, it was more
than enough to stop the satellite nearly dead in its tracks. So its orbit
was never repeatable or predictable, and it entered the lower atmosphere
and burnt up in a matter of weeks.
Quite a different , but double tragedy occured with SARA, a low earth
orbit satellite designed to monitor the natural radio signals generated by
the planet Jupiter and its satellites. The trouble here was that while
Jupiter transmits wideband signals between 3 and 45 MHz, Sara was
restricted to receiving only the lower half of this band. This caused a
problem because Saras orbit near earth meant that it only saw Jupiter
"directly " for about 25% of the time. The rest of the time it was either
not seeing Jupiter at all because it was eclipsed behind the earth, or
nearly as bad, looking at Jupiter through an ionosphere which was blocking
the passage of the lower HF band reception frequencies. Had Sara been
designed to listen up to 45 MHz it might have done better. But Sara had
another problem in that several prominent Amsat noise makers decided to
condemn it as " NOT an Amateur radio satellite" unapproved ( according to
their undemocratic view ) by Amsat. This had the treble result of warning
off radio amateurs from Sara , denying a radio amateur prelauch input to
Sara which might have corrected the receiver problem, and ensuring thereby
that any future project teams of this type will be discouraged from
approaching Amsat for assistance. A very nasty case of "Not invented here"
just when we need a few friends from hobby groups who might associate with
us in useful projects. For, make no bones about it . The stupidity of this
particular piece of Amsat politics was clearly revealed recently. All you
have to do to get the enormity of this tragedy is reflect how much capital
and mileage in the press and media, amateur radio could have made if Sara
had been operational when the fragments of Comet Shoemaker-Levy hit
Jupiter, last July.
It is to be earnestly hoped that Amsat will never again indulge such
narrow minded chauvanism. There will be opportunities in the future for
cooperation with Radio Astronomy groups, Solar sail ventures , Weather and
surface picture projects ,and, propagation experiments. Lets not kick the
proposers in the teeth, next time. 
PS. RS15 appears to have a battery problem whereby it either goes off
completely on going into earth shadow or it sends slow intermittent
telemetry on its beacon, indicating low suply volts. When in sunlight its
operation seems to be OK. 73 de GM4IHJ @ GB7SAN