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Subject: SPACE Digest V11 #27

SPACE Digest                                      Volume 11 : Issue 27

Today's Topics:
        Galileo Update - 02/09/90 (Forwarded)
               Re: Recreation in Space
             Re: More Info On SSX
          Re: Galileo Update - 02/06/90 (Forwarded)
         Re: furlongs per fortnight in space
               Re: SPACE Digest V11 #18
            Journal of Law and Technology
             Re: More Info On SSX
             Re: Radio Astronomy
         Re: furlongs per fortnight in space
----------------------------------------------------------------------

Date: 9 Feb 90 16:59:50 GMT
From: zaphod.mps.ohio-state.edu!usc!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov![e-mail]  (Ron Baalke)
Subject: Galileo Update - 02/09/90 (Forwarded)

NEW YORK TIMES, FEB. 9

"A GRAVITY BOOST TO GOAL:  JUPITER '95"  John Noble Wilford

"Completing the first leg of a long interplanetary journey, the
Galileo spacecraft will swing by Venus early tomorrow in a
maneuver using the planet's gravity to get a boost in velocity
and a change in trajectory so it can reach its ultimate target,
Jupiter, in 1995."

The TIMES reports controllers at the Jet Propulsion Laboratory
said the spacecraft was on course to pass within 10,000 miles of
Venus's cloud tops about 1 a.m. EST.  The spacecraft will
approach the planet from the night side and pass across the day
side, taking photographs and gathering remote-sensing data in the
hours before and the days after the encounter.

"The spacecraft is in excellent shape," Richard Spehalski, the
project manager, said Wednesday.  "We're on target and everything
looks good."

The paper reports scientists said Galileo's instruments could
acquire important new data about lightning in the Vensuian
atmosphere, the dynamics of the upper cloud layers, the distri-
bution of water vapor at high altitudes and "holes" in the upper
atmosphere through which it may be possible to examine clouds
close to the planet's hot surface.

The TIMES reports the pictures and scientific data collected as
the spacecraft flies by will be stored on the craft's tape
recorder until October.  By that time Galileo will be close
enough to Earth to play them back over its less powerful
antenna.  The craft's more powerful antenna will not be deployed
until it is safely beyond the inner solar system's higher
temperatures.

 Ron Baalke                       |    [e-mail]
 Jet Propulsion Lab  M/S 301-355  |    [e-mail]
 4800 Oak Grove Dr.               |
 Pasadena, CA 91109               |

------------------------------

Date: 9 Feb 90 19:12:54 GMT
From: cs.utexas.edu!jarvis.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Recreation in Space

In article <[e-mail]> [e-mail] (WATMOST Groups 9) writes:
>First, what are current NASA policies regarding recreation for astronauts?
>How many hours per day are allocated?  ...

NASA policy, historically, has been "they're up there to work, not to relax".
This has been moderated somewhat in recent times, particularly for long
missions, but I think the shuttle crews are generally kept pretty busy.
Given the long tours of duty, the station crews are probably going to
have to move more towards a traditional work week, with significant
periods of relaxation every day and regular days off.  Crews won't put
up with being worked to exhaustion for long periods, as witness the way the
third Skylab crew went on strike for a day when Mission Control tried to
just keep piling it on.

>Second, do astronauts work in shifts on the shuttle, and will they do so
>on the Space Station?  ...

The shuttle crews normally sleep more or less at the same time, since the
shuttle is not large and it's difficult to sleep while others are working.
I'd suspect the station will follow a similar policy unless there are
compelling reasons to do otherwise.  Things like routine monitoring that
have to be done 24 hours a day are normally done from the ground.

>Finally, do what would YOU like to do if you were a crewman on the Space
>Station?  Could zero gravity itself be entertaining enough...

The Skylab crews had quite a bit of recreational gear along, and most of
it went unused most of the time.  They did have some fun with free fall,
but by far their favorite recreation was looking out the window.

I'd suggest trying to dig up Henry Cooper's "A House In Space", by far the
best book on the non-technical side of Skylab.  The Skylab experience is
probably the best guide to how things will be done on the space station.
--
SVR4:  every feature you ever |     Henry Spencer at U of Toronto Zoology
wanted, and plenty you didn't.| uunet!attcan!utzoo!henry [e-mail]

------------------------------

Date: 10 Feb 90 04:37:21 GMT
From: rochester![e-mail]  (Paul Dietz)
Subject: Re: More Info On SSX

I asked:
> What's the density of propane at 90 K?

Ok, the density of propane at -180 C is .723 g/cc.  I get that the
density of stoichiometric LOX + subcooled propane is a few percent
*higher* than LOX + RP-1 (RP-1 at 289 K, density .807 g/cc).

    Paul F. Dietz
    [e-mail]

------------------------------

Date: 8 Feb 90 05:00:09 GMT
From: pacific.mps.ohio-state.edu!zaphod.mps.ohio-state.edu!samsung!umich!mailrus!jarvis.csri.toronto.edu!helios.physics.utoronto.ca!physics.utoronto.ca![e-mail]  (Christopher Neufeld)
Subject: Re: Galileo Update - 02/06/90 (Forwarded)

In article <764@crabcake> [e-mail] (Kenneth Arromdee) writes:
>Out of curiosity (and which I asked before): Is Galileo, when it reaches Earth,
>going to take any pictures?  (Maybe they can discover life :-))
>
   Don't laugh. Last I heard that was the plan. Take pictures, and see if
the probe can discover life on Earth. I may be mixing this up with another
probe, but I doubt it. How many probes come backhere on the way to where
they're going anyway? Anyway, I seem to recall that Carl Sagan was a
proponent of this test of the probe's abilities.

>Kenneth Arromdee (UUCP: ....!jhunix!arromdee; BITNET: arromdee@jhuvm;
>     INTERNET: [e-mail])


--
 Christopher Neufeld....Just a graduate student  | "Give me ten men like
 [e-mail]              | Clouseau and I could
 [e-mail]                    | destroy the world."
 "Don't edit reality for the sake of simplicity" |

------------------------------

Date: 7 Feb 90 19:38:51 GMT
From: att!mcdchg!ddsw1!corpane![e-mail]  (John Sparks)
Subject: Re: furlongs per fortnight in space

[e-mail] (Dan Tilque) writes:

>P.S. The switch to measuring engine cylinder displacements in liters
>came about, in part, because of the large number of foreign cars we
>import.  Maybe we should try importing some kilometers.

Hey and let's not forget the insidious trick of labeling the large
jugs of softdrinks in liters!

You can't find quart sizes anymore, all you see are 2 and 3 liter jugs.


--
John Sparks  | D.I.S.K. 24hrs 1200bps. Accessable via Starlink (Louisville KY)
[e-mail] <><><><><><><><><><><> D.I.S.K. ph:502/968-5401 thru -5406
I'm the person your mother warned you about.

------------------------------

Date: 9 Feb 90 15:25:40 GMT
From: cs.utexas.edu!jarvis.csri.toronto.edu!helios.physics.utoronto.ca!physics.utoronto.ca![e-mail]  (Christopher Neufeld)
Subject: Re: SPACE Digest V11 #18

In article <[e-mail]> [e-mail] writes:
>
>  The manoeuver is often referred to as a
>gravitational slingshot effect, for good reason.  When a craft approaches
>the trailing edge of a planet, it accelerates towards the planet for a longer
>period of time that it decelerates away.  This provides the velocity boost
>required.
>
   No it doesn't. In the stationary reference frame of the planet the
probe's orbit is symmetrical. At a distance "r" from the planet it has the
same speed whether it's inbound or outbound. From this it follows
immediately that the outbound journey is exactly as long as the inbound
journey. From one million kilometres out to closest approach takes exactly
as long as the trip from closest approach to one million kilometres out.
   The space probe always leaves the planet with exactly the same relative
speed as it came in. However, since the planet off which the bounce is
being done is moving with respect to all the other interesting things in
the solar system, an observer in another frame (such as the target planet
of the probe) will see a considerable change in speed relative to himself.

>  It is such a manouever that (I believe)
>Galileo will use on approach to Jupiter so it is captured by the planet rather
>than continue on its journey as the Voyagers did.
>
   No, this can't be done. There is no trajectory for a point mass which
approaches another point mass from infinity and becomes a closed orbit. The
mechanics become much more complicated with the sun and Jupiter's
satellites in the picture, but my understanding of classical gravitation
suggests that Galileo will have to slow down off a moon of Jupiter, thereby
putting it into orbit around Jupiter. If Jupiter had no satellites, I don't
believe an orbital insertion would be possible without expenditure of
thrust (braking rockets, not maneovering rockets).

>               Dan


--
 Christopher Neufeld....Just a graduate student  |
 [e-mail]              | "Vulcan has no moon."
 [e-mail]                    | "I'm not surprised!"
 "Don't edit reality for the sake of simplicity" |

------------------------------

Date: 10 Feb 90 01:16:58 GMT
From: intercon![e-mail]  (Mikki Barry)
Subject: Journal of Law and Technology


Those of you interested in the interface between legal dweebdom and
technology may be surprised to find that there is a law journal devoted
to topics like space law, biotech, various computer issues (such as
viruses, slander/libel on bboards, privacy, etc.) and other such type
stuff.  It is called the Journal of Law and Technology, and it is in
dire need of subscribers since its funding has been cut by Georgetown
Law.

I wouldn't be posting this except that it would be a serious shame if
we lost one of the only journals that addresses law and technology.
And yes, I am one of the students involved in staffing the journal,
so I am quite biased toward this "cause".

Besides this bald faced money grubbing, the Journal is interested in
soliciting papers on any topic concerning law and technology.  If you
are interested in submitting papers, please write to the address below.

The current issue concerns the Berne Copyright Convention and what it
means to US copyright laws.  The next issue is the proceedings of the
First Annual Symposium on the Law and Outer Space.  Subsequent issues
will contain various technology related stories.

If you wish to subscribe and/or order single issues, please print out
the following order blank and mail to:

Celeste H. Yousoof
Business Editor
The Journal of Law And Technology
Georgetown University Law Center
600 New Jersey Avenue, N.W.
Washington, DC  20001

We are also looking for corporate sponsorship, and have limited space
available for advertising (sort of like PBS ads).  Write Celeste or
e-mail me for more information.

------------------------------

_____ Proceedings of the First Annual Symposium on the Law and Outer Space
    $20.00

_____ Annual subscription to the Journal of Law and Tehcnology
    $30.00

_____ SPECIAL OFFER:  Proceedings of the Space Law Symposium plus annual
    subscription to the Journal of Law and Technology
    $45.00


Name:       _________________________________________


Address:    _________________________________________


        _________________________________________

------------------------------

Date: 9 Feb 90 18:20:51 GMT
From: shlump.nac.dec.com!quik07.enet.dec.com![e-mail]  (Ben Burch)
Subject: Re: More Info On SSX

In article <[e-mail]>, [e-mail] (John McKernan)
writes:
> I remember the previous posting on the SSX said that it was to use an
> "aerospike" design for its rocket motor. I believe the Centaur engine
> does not use such a design. Does that mean that the "aerospike" design
> has been abandoned for the first version of the SSX, or that the
> Centaur is going to be modified to use the "aerospike" nozzel design?
>

Not Necessarily;  The book "Frontiers of Space" by Bono and Bono (I
lost the book in a divorce, and don't have the authors full names)
depicts several plug nozzle aerospike variants.  They range from
a plug surrounded by "standard" small rocket motors to a plug
surrounded by "flattened" nozzle motors ( "(" shaped ) to a single
torodal combustion chamber surrounding a plug.  The effect of the
plug is to provide much of the efficiency of having a huge bell
nozzle on your engine without paying the penalties involved in
weight and in flow separation at sea-level pressures.  The plug
nozzle configuration automatically compensates for altitude.

So, the RL-10 engines could be clustered in the SSX.

-Ben Burch

------------------------------

Date: 9 Feb 90 19:32:22 GMT
From: phoenix!puppsr![e-mail]  (Marty Ryba)
Subject: Re: Radio Astronomy

In article <9002082140.0.UUL1.3#[e-mail]> [e-mail] (Thomas Lapp) writes:
>The article also goes on to talk about other radio observatories in the
>world.  The only problem I have is the glaring omission of the Green
>Bank Radio Observatory located in Green Bank, West Virginia.  Green Bank
>is operated by the NRAO (who also built the VLA in New Mexico.  Green
>Bank had (until it collapsed last year) a 300 ft. diameter dish which
>was steerable in one axis.  It also has three 85-foot dishes, one which
>is permanent and two which can move along a one mile-long track.  The
>three 85-foot dishes are used for interferometry, which as the article
>describes, is a method of making several small telescopes "look" like
>one large one.
>Disclaimer: Yeah, I *did* grow up in West Virginia, so I *do* know
>            what I'm talking about.  I've even been there three
>            times to visit, so there.
>                         - tom

How then, could you forget the 140-ft?!  With Arecibo in a month-long shutdown
(they found some cracks in the supports and don't want it to collapse too),
the 140-ft is currently the largest single-dish telescope in operation in the
US.  Built at the same time as the 300-ft (RIP), the 140-ft is the last large
telescope to use an equatorial mount.  The largest roller bearing in existence
is part of the structure.  While it was being built they realized how damnably
hard an equatorial mount is; fueling the interest in alt-az.  It is still a very
useful instrument, with feeds up to 24 GHz.  It is often used in conjunction
with the VLA, Effelsburg (FRG), and Arecibo for VLBI.

Marty Ryba (slave physics grad student)
They don't care if I exist, let alone what my opinions are!
[e-mail]
Asbestos gloves always on when reading mail

------------------------------

Date: 9 Feb 90 12:16:50 GMT
From: mcsun!ukc!edcastle!hwcs!hwee![e-mail]  (I. Sutherland)
Subject: Re: furlongs per fortnight in space

In article <[e-mail]> [e-mail] ("Eric Pepke") writes:
   [Pointing out that measurements are given in both standards]
>
>Although the official dictum is that England uses the metric system,
>nearly all of the most common units are still the same old traditional
>ones.  Traditional units of measurement will not go away just because you

  It is true that both standards tend to be given, but it's necessary given
that there is still a large number of the population who grew up with the
Imperial system measurements. I am 23 this year and all through the education
system I have experienced nothing but the metric system of measurement, for
the most part Imperial values are meaningless to me.
  I know what a pint is because milk and other beverages come in that size, but
a pint is about the only unit (other than miles) which I'm regulary exposed to.
I can judge a distance to a nearby point quite well in meters, but ask me to
do it in feet, or even worse yards and I can only take a shot in the dark.
  Traditional units will go away because to people of my age it's just the way
it used to be done.
  I predict though that the mile has a long, secure future since it's well
established on our roadsigns, but for petrol (gasoline) gallons gave way to
litres, despite much fuss, so maybe it's just a matter of time.

--
Iain A. Sutherland             JANET:[e-mail]
B.Eng. Elec.Eng. IV             ARPA:[e-mail]
                               ...!mcvax!hwcs!hwee!sutherla

------------------------------

End of SPACE Digest V11 #27
*******************