From: higgins@fnala.fnal.gov (Bill Higgins-- Beam Jockey)
Newsgroups: sci.space
Subject: Magellan successors? (was Re: Support Lunar Resource Mapper Too!)
Date: 22 Jul 92 10:13:20 GMT
Organization: Fermi National Accelerator Laboratory

In article <phfrom.204@nyx.uni-konstanz.de>, phfrom@nyx.uni-konstanz.de (Hartmut Frommert) writes:
> seds%cspar@Fedex.Msfc.Nasa.Gov writes:
>>Support Lunar Resource Mapper as well [...]
>>Do you know that after Mars Observer's mission is over, that we will 
>>know more about Mars and Venus than about the Moon! That is tragic and
>>must be corrected.

> On the other hand, that our knowledge on the Moon needs improvement, and,
> therefore, LRM, should in *NO* way mislead anybody to think that we know 
> *ALL* interesting things (or even too much) on Mars and/or Venus. So also a 
> successor of Magellan, as well as Mars Observer (and LRM) should be taken 
> into consideration. 

I asked Dr. Gordon Pettengill this question last year: "Is there a
successor to Magellan?"  The answer is no.  Magellan is giving such a
stupefying quantity of radar mapping data that it will take decades to
sort it out, and no system giving, say, higher spatial resolution is
currently planned.

Venus orbiters and landers have given a pretty good view of the
planet.  I suppose having an orbiter in place to give long-term
information about the atmosphere and magnetosphere would be a good
idea-- Pioneer Venus Orbiter is about to die.   The U.S. program is
not ready to build landers, and the Russian program has put the planet
on the back burner in favor of long-neglected Mars. A Venus rover
would be neat, but a rather tough engineering challenge.  Maybe more
balloons?  Anyway, I think you're going to see a long hiatus in Venus
exploration.

Flying a Magellan-type mission to Mars or the Moon would be neat, too,
but synthetic-aperture radar demands a heavy committment of
tracking-network resources.  It was the *only* way to get maps of the
Venerian surface; since optical methods work well on other bodies,
it's much less urgent to try SAR.  Titan is an obvious choice, and
indeed Cassini-- which will orbit Saturn, but encounter Titan multiple
times during its mission-- is intended to carry SAR which will map a
handful of narrow strips of Titan as it swoops by.

I think Mars Observer and Mars 94 are appropriate, but I'm really
unhappy about the lack of priority given to studies of small bodies. 
CRAF is dead, Vesta doesn't look too healthy, and Rosetta seems
awfully far away.  Maybe there is hope in the new smaller, faster,
allegedly-cheaper probes like SDIO's Clementine or the one APL is
supposed to be cooking up for NASA (LEAP, was it?).

The Moon definitely needs a going-over with Nineties instrumentation. 
But you've heard me say that for years-- even *before* I met Dennis
Wingo. (-:

"Do you know the asteroids, Mr.Kemp?...    Bill Higgins
Hundreds of thousands of them.  All        
wandering around the Sun in strange        Fermilab
orbits.  Some never named, never
charted.  The orphans of the Solar         higgins@fnal.fnal.gov
System, Mr. Kemp."
                                           higgins@fnal.bitnet
"And you want to become a father."
  --*Moon Zero Two*                        SPAN/Hepnet: 43011::HIGGINS