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From: clj@ksr.com (Chris Jones)
Newsgroups: sci.space.shuttle
Subject: Re: Fuel-line door questions...
Message-ID: <2461@ksr.com>
Date: 5 Mar 91 13:03:43 GMT
References: <1991Feb25.204556.16156@athena.mit.edu> <1991Feb26.112746.11838@pbs.org> <1991Feb26.230611.4715@freedom.msfc.nasa.gov> <2433@ksr.com> <63125@eerie.acsu.Buffalo.EDU>
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Reply-To: clj@ksr.com (Chris Jones)
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In-reply-to: v071pzp4@ubvmsd.cc.buffalo.edu (Craig L Cole)

In article <63125@eerie.acsu.Buffalo.EDU>, v071pzp4@ubvmsd (Craig L Cole) writes:
>
>Okay - how much _can_ the shuttle alter its orbital incliination and
>alitutude?
>

Off the top of my head, the simple answers are that the shuttle would probably
have no trouble matching the apogee and perigee of Mir or a Progress, but you
can't expect the orbits to be in phase, so you'd have to spend more fuel and
time to get the orbits in sync.  It really doesn't matter, though, because the
inclination is a real killer.  I don't know how much delta-v the shuttle
typically has available in its OMS after orbital insertion (it clearly depends
on the OMS specific impulse and the characteristics of the shuttles cargo and
launch profile), but a 20 degree plane change (about what one might expect
given the latitudes of Baikonur and Canaveral) would take about 8700 feet/sec
of delta-v.  I don't think that's within the shuttle's capabilities.

>If landing before consumable had run out was impossible, the astronauts
>would be able to use the fuel planned for deorbiting to change orbits.
>Considering the burns necessary to deorbit the ship, you'd have quite
>a bit of fuel to move around.

It only takes about 300 feet/sec to deorbit the shuttle.  That's pretty
insignificant compared to the inclination- changing requirement.
>
>Of course fixing the doors would be simpler, but the question was,
>what if you _couldn't_?

If you can't do the simpler thing, why does doing the more difficult thing have
any chance of success?
--
Chris Jones    clj@ksr.com    {world,uunet,harvard}!ksr!clj