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From: eder@ssc-vax.UUCP (Dani Eder)
Newsgroups: net.movies,net.sf-lovers
Subject: Re: 2010 review review
Message-ID: <262@ssc-vax.UUCP>
Date: Tue, 11-Dec-84 20:19:48 EST
Article-I.D.: ssc-vax.262
Posted: Tue Dec 11 20:19:48 1984
Date-Received: Thu, 13-Dec-84 00:55:16 EST
References: <263@umd5.UUCP>
Distribution: net
Organization: Boeing Aerospace Co., Seattle, WA
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Xref: watmath net.movies:5188 net.sf-lovers:5366

>   Much of the science of "2010" is questionable in the face of what we
> knew, know and are learning.  A new star appears in the solar system and
> the earth escapes without a tremor.  The Leonov embarks without enough
> fuel to either return or slow down.  They do "air braking" (without air)
> to slow Leonov as she whips around the planet and into a new orbit.
> How's that for science friction.
> 
> missed.  The Leonov doesn't depart without enough fuel.  The early departure
> from Jupiter is makes the kludge with Discovery necessary.  And "air braking"
> is not science fiction made up for the movie, it was even featured on the
> cover of Popular Science a year or so ago.
> 
     First of all, the term is 'aerobraking'.  Yes it is possible (we are
studying it here at Boeing.  In fact, Dr. Dana Andrews, who does aero-
propulsion design, has a patent on the concept and was a technical
consultant for 2010.) No, it was not accurately portrayed in the film.
A one-half orbit around Jupiter at cloud top level takes 88.6 minutes.
In the film it is portrayed as taking 1-2 minutes.  The aerobrake trail
would be too small to see on the scale of Jupiter as a whole.

     Credit goes to the filmmakers for getting a reasonable design
for the aerobrake, a multiple-ballute type.  They got the color right,
it would be dark so as to radiate the absorbed heat flux.  You would
probably jettison them as in the film.

     While on the subject of technical mistakes, the Discovery is found
rotating endwise.  Initially, the carousel stopping would leave it 
spinning around its' long axis.  This is unstable and would decay into
the end-for-end rotation.  But, when you spin up the carousel again, it
wouldn't stop rotating end-for-end, it would be a combination motion.
The spinning Discovery would also be pulling about 5 g's at the command
center.

     The apparent motion of the clouds on Jupiter works out to more
than escape velocity (good stiff breeze).  Your hair floats in zero-
gravity (see any shuttle tapes).  They probably knew about this one
but passed because of cost.  They did know that stars are not visible
in space when the sun or a planet is out, but felt the audience would
accept it better with stars.

     When they are escaping from Jupiter, it implodes just as they 
burn out the Leonov's engines.  Surface escape from Jupiter is 67
kilometers/second (151,000 mph)  in the few minutes since they
started to escape, their distance would have changed insignificantly.
If Jupiter is as bright at Europa as the Sun is at Earth, then
Jupiter as seen from the Earth would be as bright as a first-quarter
moon.  In the daytime you would have a hard time finding it.

Dani Eder / Boeing Aerospace Company /  ssc-vax!eder / (206)773-4545

p.s. The aerobrake flight demonstration is scheduled (Congress willing)
for 1988. It won't be 'untried'.