Newsgroups: sci.space.shuttle
Path: utzoo!henry
From: henry@utzoo.uucp (Henry Spencer)
Subject: Re: Where is Challenger?
Message-ID: <1989May3.171521.5821@utzoo.uucp>
Organization: U of Toronto Zoology
References: <11360@well.UUCP> <1989Apr23.000034.7797@utzoo.uucp> <2555@phred.UUCP> <1989Apr26.232428.3073@utzoo.uucp> <2562@phred.UUCP>
Date: Wed, 3 May 89 17:15:21 GMT

In article <2562@phred.UUCP> petej@phred.UUCP (Pete Jarvis) writes:
>>You forgot Mariners 6, 7, and 9, the last of which was particularly important.
>>Ancient history, all of them.
>>
>Ancient history? The pictures the Mariners took 25 years ago are just as
>valuable now as then. Has Mars changed much in the last 25 years, or in
>the case of the highly successful Viking probes, 13 years? I doubt it.

Do you *know*?  I don't.  The surface of Mars does change, in small ways
at least.

>What kind of probe do *you* think we should have sent to Mars in the 1980's?

For starters, we should have followed through on the proposal to fit Viking
3 (now in the Smithsonian) with caterpillar treads rather than footpads and
land it near the north polar cap.

>And what would it have gained us? We have already mapped  a good portion of
>the Mars surface in preparation for future landings.

We have not mapped it with accuracy sufficient for precision landings or
even precision aerobraking, however.  We can measure where the probes are
*relative to Earth* within meters, but we don't know where Mars is, or
where specific Martian features are, to closer than several kilometers.
Atmospheric entry magnifies errors considerably.

>We have analyzed some of its soil and atmosphere.

In two places chosen to be as boring and predictable as possible, in the
middle of desert plains.  What is the edge of the polar cap like?  (There
is liquid water there, probably, in spring.)  There is at least one area
on Mars (Solis Lacus?  don't remember) which radar measurements show to 
have slight surface water at times; what is it like?  We don't even know
*for sure* whether there is life on Mars or not; all we can say with any
assurance is that there probably is no life at the Viking landing sites
and there probably wasn't any there recently.

>... I suspect we will be going back to Mars again in one form or the
>other in the 1990's.

Mars Observer looks pretty solid for 1992 (originally 1990, and before
that it was 1988 for a little while), but there are no follow-on plans
that have been approved.  And M.O., while valuable, is hardly what one
would call an ambitious mission.

>It's pretty obvious the USA has a remarkable success
>story going on the exploration of the solar system including a Neptune
>fly-by this August! ...

The story is not "going on", it is rapidly drawing to a close (or nearly
so).  The Voyagers were launched in the 70s; we are very lucky that they
have survived this long.  (The Apollo seismometer network on the Moon
didn't last that long -- it was shut down, while still working perfectly,
because there wasn't money to keep on receiving the data.  There was at
least one proposal to do the same to the Voyagers.)  Galileo and Magellan,
for all their timeliness now, were conceived in the 70s and have simply
had extremely protracted gestation periods.  Where are the follow-ons?
The US currently has *no* plans for Venus after Magellan, and *no* plans
for Jupiter after Galileo.  Mars Observer is a much more modest bird, and
it may be the first and last of the intended series of such birds, at
this rate.
-- 
Mars in 1980s:  USSR, 2 tries, |     Henry Spencer at U of Toronto Zoology
2 failures; USA, 0 tries.      | uunet!attcan!utzoo!henry henry@zoo.toronto.edu