Path: utzoo!attcan!uunet!samsung!uakari.primate.wisc.edu!caen!umich!dgsi!gregc
From: gregc@cimage.com (Greg Cronau)
Newsgroups: sci.space.shuttle
Subject: Re: apollo 13
Message-ID: <1990Dec14.053652.4228@cimage.com>
Date: 14 Dec 90 05:36:52 GMT
References: <90346.083237TACON019@ysub.ysu.edu>
Reply-To: gregc@dgsi.UUCP (Greg Cronau/10000)
Organization: Cimage Corp, Ann Arbor, MI
Lines: 28

In article <90346.083237TACON019@ysub.ysu.edu> TACON019@ysub.ysu.edu (Fred Ullom) writes:
>I just saw a documentary on the apollo 13 disaster (or success depending
>on how you look at it). They used the LEM for habitation on the return
>trip to earth when the command module was crippled and then jettisoned
>it in earth orbit before re-entry.
>
>I was just curious, is the LEM still orbiting the earth or did the orbit
>decay?

The CSM/LEM never went into earth orbit after return from the moon. They were
targeted for a direct reentry from translunar flight. The SM and LEM separated
and went straight into the atmosphere and burned up. The CM skimmed the upper
atmosphere on a tangental trajectory and then pulled up back out of the upper
atmosphere to shed some of the heat from the heat shield. It then fell back
into the atmosphere at a steeper angle due to the lost velocity from the first
encounter. It was able to pull up through a combination of it's trajectory and
a certain amount of aerodynamic lift provided by it's shape. It is sort of an
aerobraking manuever. I *think* all the returning Apollo moon flights used this
method of reentry. I don't believe there was a need to first attain earth orbit
on return from translunar flight.

>Thanks,
>------------------------------------------------------------------------
>tacon019@ysub.ysu.edu (Fred S. Ullom)
>Youngstown State University
>------------------------------------------------------------------------

gregc@cimage.com