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From: lmg@cbnewsh.ATT.COM (lawrence.m.geary)
Newsgroups: sci.space,sci.space.shuttle,sci.astro
Subject: Re: Future Space Missions
Message-ID: <5569@cbnewsh.ATT.COM>
Date: 8 Nov 89 14:16:09 GMT
References: <2086@jato.Jpl.Nasa.Gov>
Reply-To: lmg@cbnewsh.ATT.COM (lawrence.m.geary,ho,)
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In article <2086@jato.Jpl.Nasa.Gov> baalke@mars.jpl.nasa.gov (Ron Baalke) writes:
>                         Future Space Missions
> 
>   o Cassini
>       Possible launch in 1996, orbiter would spend 4 years studying Saturn and
>       send an atmospheric probe into the moon Titan.
> 
>   o Fire and Ice
>       Possible launch in 2001, will use a gravity assist flyby of Earth in
>       2003, and use a final gravity assist from Jupiter in 2005, where the
>       probe will split into its Fire and Ice components:  The Fire probe
>       will journey into the Sun, taking measurements of our star's upper
>       atmosphere until it is vaporized by the intense heat.  The Ice probe
>       will head out towards Pluto, reaching the tiny world for study by 2016.

I have heard that Cassini will also use an Earth flyby to gain speed.
I assume this means that these probes are using underpowered boosters
and launching from the shuttle, as was the case with Galileo. This was
done with Galileo because it was too late - or would cost too much, or
the probe was too heavy - to refit the probe for launch on an ELV with
a Centaur upper stage. But WHY in heavens name is JPL sticking to this
method for probes planned for far in the future? Galileo will take six?
years to reach Jupiter this way; it should have taken two. The other 
probes will likewise take years longer to reach their destinations by
using this technique. Why aren't there plans to use appropriate boosters?

--Larry
-- 

     lmg@hoqax.att.com    Think globally ... Post locally    att!hoqax!lmg