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Subject: SPACE Digest V11 #358

SPACE Digest                                     Volume 11 : Issue 358

Today's Topics:
Re: Giant crawler transporter to pass 1000 miles on STS-35 rollout (Fo
            'Weather' in the VAB ?
             Re: Manned mission to Venus
                   Request
            Re: Project Solar Sail
             Request for HST info
        Re: (How to get rid of) space garbage
        Re: (How to get rid of) space garbage
              Niven's spacecraft drives
      Re: Soviet VENERA Landers on the Surface of Venus.
             Re: Manned mission to Venus
----------------------------------------------------------------------

Date:     Fri,  4 May 90 10:54 CDT
From: Bill Higgins-- Beam Jockey <[e-mail]>
Subject:  Re: Giant crawler transporter to pass 1000 miles on STS-35 rollout (Fo
Apparently-To: <[e-mail]>

rwarded)
To:       [e-mail]
Original_To:  SPACE

There's been some discussion of the Shuttle/Saturn crawlers, but I haven't seen
anybody mention the definitive source of information.

Kids, you want to go find a copy of *Road & Track*, I'm pretty sure it's the
April 1985 issue, page 192.  (If I messed up, look at other issues that year.)
Every once in a while, as a sort of April Fool's thing, *R&T* would run a
deadpan road test of some exotic vehicle like the Goodyear Blimp or the Gresley
A3 Pacific Locomotive.  Well, in 1985 Ted West, Engineering Editor, reported on
"The KSC 554,756 Hardtop: Longer, Lower and Weirder for 1985."

If you have any interest in the crawlers, you *must* read this.  West has lots
of tongue-in-cheek fun with it, but I've never seen more technical information
on the vehicles.  There's lots in the article, and even more figures in long
tables accompanying it, in the manner of auto-magazine tech evaluations.   Some
quotes to get you galvanized and headed down to the library:

"If you're looking for traditional, massive American *horsepower*, the KSC
554,756 is yer kinda car.  Its raucous 554,756 cc are packaged in no less than
six different containers.  And 350,342 of them are enclosed in a pair of
2750-bhp 16-cylinder Alco diesels.  An additional 180,070 cc come wrapped in
two 1075-bhp 8-cylinder White diesels.  Finally, 24,344 cc reside in a pair of
very pedestrian 6-cylinder Cummins truck diesels.   There is also a paltry
7.5-bhp Onan compressor-drive-- but the less said about that little wimp the
better."

"...Speaking of steering, we found the KSC's just a trifle, dare we say it,
heavy.  However, directional stability was exemplary, we felt no buffeting
whatever in stron sidewinds and thought nothing whatever of hands-off steering
for long periods while running flat out.  More top marks."

"There was a great *Cluuunk!* and not quite a *lunge*.  We said we'd bet our
left shoe the thing would be geared too tall, but, to our great surprise, the
554,756 got off the line smartly and was up to cruising speed in just under no
time, leaving our left shoe behind at a steady, smooth 1.0 mph. The 554,756 is
said to be capable of a brisk 2.0 mph flat-out-- `and maybe more'-- but we were
told that, somewhat like the *Queen Mary's*, the 554,756's true top speed is
known only to God and a certain electrical engineer (`poor soul') living in
seclusion for the past 20 years in a small auto court outside Marion, Ohio."

                      ______meson   Bill Higgins
                   _-~
     ____________-~______neutrino   Fermi National Accelerator Laboratory
   -   -         ~-_
 /       \          ~----- proton   Bitnet: [e-mail]
 |       |
 \       /                          SPAN/Hepnet/Physnet: 43011::HIGGINS
   -   -
     ~                              Internet: [e-mail]
 _______________
|   Coming      \      The centennial of Herman Hollerith's
|   soon...     |      little card from the 1890 Census
|_______________|

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

Date: Fri, 4 May 90 11:29:53 +0200
From: [e-mail] (Daniel Fischer)
Subject: 'Weather' in the VAB ?
Cc: [e-mail]

This monday a strange guy gave a talk here in Oberpleis (guess you all know
where that is?). He claimed a) that he flew NASA chase planes in the 1960's
that accompanied returning Gemini capsules, and b) that he'll be a key manager
of Germany's new space agency DARA in charge of space transportation systems.
   This talk, entitled "From Mercury to the Space Shuttle", was the greatest
collection of space nonsense I've ever heard. His slides were excellent; but
unfortunately in most cases he hadn't an idea what they showed. E.g. he claimed
that Solar Max and LDEF were the same(!) ESA-NASA (!!) earth-observation
satellite (!!!) or that the SSME are turned off during the first 2 minutes of
a shuttle launch. This went on for 2 hrs, but now and then he told a story that
was *so* strange that I wonder whether it might be true. The point I wonder
about most is this: ] The Vehicle Assembly Building at the KSC is so big
          ] (isn't it the largest room ever built?) that inside they have
          ] 'local weather'. So while the sun is shining over Florida, if
          ] humidity is high enough, big clouds form under the ceiling.
True or false? Theoretical considerations/First-hand knowledge welcome!    Dan

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

Date: 4 May 90 16:01:07 GMT
From: swrinde!cs.utexas.edu!uwm.edu!ogicse!blake![e-mail]  (Gregory Milligan)
Subject: Re: Manned mission to Venus


    Just because the mission to Venus is manned doesn't mean that
the crew has to actually land on the surface.  I think it would be bet-
ter to send a manned orbiter with a garage full of robot landers.  The
crew could control landings, pilot RPVs, drive crawlers, etc.  The ad-
vantage of having the crew in orbit is that it allows real-time control
of the experiments without that annoying 2-way radio time delay (other
than a few seconds, of course), and it eliminates the need to develop
mobile experiments that can think for themselves.

Greg

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

Date: Fri, 4 May 90 12:36:11 EST
From: [e-mail] (Jay Giurleo)
Subject: Request


I will not be in contact with my mainframe over the summer, so I was wondering
if I could cancel my subscription for space digest.  Thanks.

  [e-mail]

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

Date: 4 May 90 18:12:27 GMT
From: well![e-mail]  (Hank Roberts)
Subject: Re: Project Solar Sail



Project Solar Sail is a nice collection of new and old fiction, with a
fundraising offer in the back ($50 t-shirts). Does anyone have email contact
with any of the people working on the World Space Foundation solar sail
project? It sounds like fun.

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

Date: 3 May 90 02:34:33 GMT
From: hpcc01!hpcea!hpldsla![e-mail]  (Thomas J Merritt)
Subject: Request for HST info

Can anyone tell me when, if, or where, images from the HST will be available?
Actually more interestingly, does anyone know what the schedule for HST
activities is?

Please reply via email as I do not read this group regularly.
Thanks,

TJ Merritt
[e-mail]

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

Date: 3 May 90 14:36:36 GMT
From: usc!zaphod.mps.ohio-state.edu!swrinde!cs.utexas.edu!news-server.csri.toronto.edu!helios.physics.utoronto.ca!physics.utoronto.ca![e-mail]  (Christopher Neufeld)
Subject: Re: (How to get rid of) space garbage

In article <[e-mail]> [e-mail] (Brian L. McCormick) writes:
>In article <[e-mail]>, [e-mail] (Christopher Neufeld) writes:
>[stuff deleted]
>> ... My proposal was to have a 300km diameter mirror out
>> around 80000km from the Earth, balanced off the solar radiation pressure
>> and the Earth's gravitational pull. Essentially, it is a solar sail which
>> can't quite get away from the Earth's pull when it's 80000km out. The
>> existing solar sail technology seems to indicate it should work.
>[more stuff chopped]
>> Because of the way it is positioned, it has a 100% duty cycle. It does not
>> orbit the Earth, but floats ahead of it in orbit around the Sun.
>[remainder zapped]
>
>I am not particularly inclined towards the mathematics of this sort of
>calculation, but it seems to me that this proposal ignores the gravitational
>effect of the moon on an object "floating" in the vicinity of the Earth.
>[...] Any thoughts on whether or not such an orbit is actually possible?
>
   Well, I chose 80000km because it seemed the furthest I could go and
still compensate for the Moon's influence. This was when I thought the
thing would need station-keeping thrusters, so it had to be as far as
possible from the Earth in order to allow for the bulk of cold gas
reaction jets.
   Since those original calculations, though, I've heard that solar
sails can be built with surprisingly (to me) good control properties.
Apparently the transmissivity of an aluminum sail can be altered
considerably by small changes in temperature in the temperature regime
expected for such an object in orbit near the Earth. This allows the
sail to adjust the direction and amount of thrust. The solar sail people
would know better than I do what variation can be expected on a
structure 300km in diameter, but I'd be surprised if they couldn't
manage a 1% change in thrust, which would be quite sufficient.
   You're right, though, that the orbit is not stable. It's not stable
even without the moon. It lies on a point of 2/3 stability, like the L1,
L2, and L3 points. It is unstable about perturbations in the Earth-sail
direction, but stable about perturbations in the two perpendicular
directions. Anyway, the design would require some sort of active station
keeping, so including the Moon in the calculations doesn't change the
design any, other than to put a limit on how far you can put the sail
from the Earth.
   Closer orbits may very well be possible. I don't suppose anybody
would care to provide some numbers for the minimum distance from the
Earth at which a reflecting solar sail could balance off the Earth's pull
for current technology, assuming that the light hits the sail at about
five degrees from the normal to the sail (required by the geometry of
the situation).

>(|||)  Brian McCormick     a.k.a.     [e-mail]  (|||)


--
 Christopher Neufeld....Just a graduate student  |  "Spock, comment?"
 [e-mail]              |  "Very bad poetry
 [e-mail]          Ad astra! | captain."
 "Don't edit reality for the sake of simplicity" |

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

Date: 4 May 90 16:07:38 GMT
From: usc!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: (How to get rid of) space garbage

In article <[e-mail]> [e-mail] (Doug Mohney) writes:
>... What is the feasiblity and possibility of
>working a shuttle rendezvous to pick up a satellite which has been
>in orbit for quite a while? ...

Nothing fundamentally impossible about it, as witness the LDEF retrieval.
However, you need a *big* interest in retrieving your bird, given the cost
of shuttle missions and the lineup for mission slots, and it has to be
qualified to ride in the shuttle cargo bay.  That last is not trivial,
given that most satellites built for expendable launches don't have to
be able to take a 9G crash load -- at right angles to the launch thrust
direction! -- without coming apart.

>ALSO, what would be be possibility of "flying back" an old space probe
>into LEO, rather than letting them drift around for years and years. You'd
>need some propellant leftover and some communications capabilities to
>tell it what to do, but I'm amazed as to what one can do with a couple
>of large planets for assistance....

Unfortunately, said large planets have to be in *just* the right places,
and trajectories to exploit such opportunities are generally very time-
consuming.

It could be done, by being sufficiently devious, for a probe in near-Earth
orbit.  There aren't very many of those, though, since most of the more
sophisticated missions went somewhere else.
--
If OSI is the answer, what is |     Henry Spencer at U of Toronto Zoology
the question?? -Rolf Nordhagen| uunet!attcan!utzoo!henry [e-mail]

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

Date: Fri, 4 May 90 15:50:58 EDT
From: John Roberts <[e-mail]>
Disclaimer: Opinions expressed are those of the sender
    and do not reflect NIST policy or agreement.
Subject: Niven's spacecraft drives


>Subject: Re: Niven's inertialess drive (was Re: Dyson spheres, heat flow)
>In article <[e-mail]> [e-mail] (Steven P Coltrin) writes:
>:In article <[e-mail]> [e-mail] (Clive D.W. Feather) writes:
>:>But in "Flatlander" an Outsider ship accelerates Beowulf and Elephant to 0.9c
>:>in a matter of minutes. This can't be a simple reaction drive; it has to act
>:>on the occupants as well as the ship, or they'd be squashed.
>:>
>:The Outsiders likely just have unghodly gravity generators and are able to
>:compensate.  I'm not nearly sure, but I think one of the Louis Wu stories
>:mentions grav. generators needed to compensate for thruster acceleration.

Niven is better as an imaginative storyteller than as a physicist. For instance,
his characters use laser weapons to blast apart massive objects at close
range without being blinded or knocked down by the concussion. His variable-
swords probably wouldn't work as described. His stasis fields have some
strange inconsistencies.

Anyway, he basically doesn't write these anymore. He spends his time with
computer guru Jerry Pournelle writing huge socially-oriented novels containing
hundreds of characters with names like Harpanet (no Husenet or Hbitnet yet :-).

With that out of the way...

 - The L.B. had a hyperdrive motor for interstellar travel, with fusion engines
   on the wings for local travel (hundreds of gravities of acceleration,
   internally compensated).

 - To avoid violating conservation of momentum, one would have to assume that
   the reactionless thruster pushes against extremely distant objects (perhaps
   the universe as a whole).

 - The one-man ship in "There is a Tide" has a reactionless thruster with a
   peak acceleration of around 30 gravities.

             John Roberts
             [e-mail]

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

Date: 4 May 90 16:58:12 GMT
From: unmvax!sci.ccny.cuny.edu!rpi!iear.arts.rpi.edu![e-mail]  (Charlie Figura)
Subject: Re: Soviet VENERA Landers on the Surface of Venus.

In article <[e-mail]> [e-mail] writes:
>        VEGA 2, in tandem with VEGA 1, delivered the first balloon-
>    borne payloads into the thick Venusian atmosphere in June of 1985.
>    The probes also deposited two landers on the surface, and then
>    flew on for the first spacecraft encounters with Comet Halley in
>    March of 1986.  VEGA is the combined names of VENERA and HALLEY
>    (Halley in Russian is Gallei; there is no letter H in the Russian
>    alphabet).
>        Incidentally, the VEGA 2 lander survived on Venus' surface
>    for only 57 minutes.

    Okay, my source is a bit screwey....
Upon further analysis, I see that the atmospheric balloon
returned data for 46 hours before succumbing to the heat/pressure/
corrosion.
    The source (an astronomy textbook, blek) remarks that
Venera 16 deposited the lander & balloon, then was renamed
Vega 2, and continued to Halley's comet... It says the same
for Venera 5 & Vega 1.


    Still, it doesnt speak much for manned landers on Venus...

    (I'd rather forget my girlfriend's birthday....  :-(

------------------------------------------------------------
Charlie Figura    --  (cholly figura-Daemon) | "Can you sing?"
 ------- [e-mail] ---------  | "A little....
 "So *WHAT* if I'm a physics major??!?!?"  | ..I can dance."
------------------------------------------------------------

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

Date: 4 May 90 18:29:09 GMT
From: mcgill-vision!quiche!calvin![e-mail]  (Mark SOKOLOWSKI)
Subject: Re: Manned mission to Venus

In article <F_5#AX=@rpi.edu> [e-mail] (Charlie Figura) writes:
>In article <[e-mail]> [e-mail] (Mark SOKOLOWSKI) writes:
>>I would like to start a new discussion about a manned mission to Venus.
>>I know that given the inferno that's there, it sounds crazy, but Venus has
>
>    Okay, wait a minnit..... you know about the inferno?
>    You know that its the hottest terrestrial planet?
>    Do you know that the longest any UNMANNED craft has
>    survived is a few hours?
>
Sorry, but those spacecrafts were mainly built to contain scientific
instruments, and given the price per Kg of the material send there,
a cooling system was highly inappropriate (But it's true that The Veneras
were cooled to 0 C prior to athmospheric reentry, with resources taken from
the bus). So that considering the fact that they only relied on their
thermic inertia once on the surface, their survival time gives me highly
optimistic hopes for the survival of a small manned station. This station
would have the same structure as some specialized submarines used for
great depth plunging (Even easier to build, considering that the surface
pressure on Venus is 1/10th of that in the deepest point in the ocean).
And now what about this: The thermic energy in Venus's athmosphere is lower
than that of Earth's!!!! If you look at the pressure: 90 athmospheres, and
the temperature: 700 K, this is about 16 to 20 times more energy than for
the 300 K of Earth's athmosphere (We raise the proportion to the 4th power).
And Earth's athmosphere is 90 times less dense!!!! So imagine what would
happen if all of the sudden I would compress the air around you to 90
athmosphere: You would carbonize. On the other side, if a sudden
recompression accident took place on a manned station on Venus, the poor
guys would probably be killed by impacts of carbon ice (Well, of course
the temperature would raise quickly as the equilibrium would be reached...).
As for the activities that can take place in such a facility, going
outside and walking wouln't be difficult, with cooling liquid (water should
be sufficient, I think) coming through small cables from the station to the
suits.
And think about the recent deep water experiments in which divers were
able to breath trinix or hydrox (mix of hydrogen-helium-oxygen) at tens
of athmospheres: Doing the same in the station would nullify the possibility
of a recompression!

Mark S.
-------

| And for those that doubt about my seriousness, I am glad to tell that I
| will be the first to volunteer to go there... After all our technology
| can enable us to make life bearable even at 900 F and 90 athmospheres

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

End of SPACE Digest V11 #358
*******************