Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V13_4/V13_407.TXT

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Subject: SPACE Digest V13 #407

SPACE Digest                                     Volume 13 : Issue 407

Today's Topics:
      Re: spacesuits (Was: Re: HST in-orbit Maintenance)
            launch on Friday from the Cape
      Re: spacesuits (Was: Re: HST in-orbit Maintenance)
        Re: comsat cancellations and lawsuits
         Re: NEP to Mars!?!? - a thesis topic
        Re: Teflon (Was Re: Space technology)
             Re: Space technology
                  Re: flares
              Space News by Mail
           Questions about pioneer/Voyager

Administrivia:

    Submissions to the SPACE Digest/sci.space should be mailed to
  [e-mail].  Other mail, esp. [un]subscription requests,
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             [e-mail]

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

Date: 14 Apr 91 19:01:32 GMT
From: elroy.jpl.nasa.gov!swrinde!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!cunews!bnrgate!bmers145!bqnes39![e-mail]  (John Hogg)
Subject: Re: spacesuits (Was: Re: HST in-orbit Maintenance)

In article <[e-mail]> [e-mail] writes:
>[Space Activity Suits] have been tested in vacuum chambers with live
>subjects, which is pretty convincing.  Don't know how long for, but I
>seem to remember periods of >1hr.  This was discussed at length on this
>group a couple of years ago and someone took the novel step of posting
>a reference, so I went and looked it up on the fiche here.
>Unfortunately (*sigh*) I don't have the reference any more and I doubt
>I could find it in my available time.  Henry?

Do we need another addition to the Frequently Asked Questions list?
I posted the following just under two years ago.  One correction is in
square brackets.

Note that joints are a Solved Problem---if you can deal with the
hand, you can deal with anything.

>In article <[e-mail]> [e-mail] (Steve Smith) writes:
>>Many years ago, I saw an idea for a "spacesuit" that solved this problem
>>elegantly... [Description of Space Activity Suit omitted.]
>>
>>Does anybody have any further information?
>
>Two works on the subject are
>
>Paul Webb and J.F. Annis, *Development of a Space Activity Suit*,
>NASA CR-1892, 1971, and
>W. Mitchell Clapp, ``Advanced Spacesuit Glove Design'', in *The
>Case for Mars II*, Christopher P. McKay, ed., *American Astronautical
>Society Science and Technology Series*, Vol. 62, 1985.
>
>The Contractor's Report is *the* reference; the AAS paper adds very
>little.
>
>The original research was not carried very far; there were very few
>chamber tests to truly high altitude, and the subject passed out in one
>of them.  (This was thought to be due to blood pooling in the legs.) [I
>reread the contractor's report later.  The actual problem was in the
>breathing gear, not the suit.  Also, you could just as well say that
>there were ``several'' chamber tests.  There were certainly enough to
>prove the concept.]  Furthermore, the suit was very time-consuming to
>don and doff.  A lot of tension is required to mimic air pressure, even
>when pure O2 is used, and the torso was composed of six or seven layers
>of material.  Pulling on a single layer, or tightening it after it is
>on, was not felt to be feasible.  This is perhaps the single greatest
>snag to the concept at present.  (A need for very precise fitting would
>qualify as bug #2, since humans expand when gravity is removed.  That
>was the reason for the delay in Armstrong's ``one small step for
>man''.)
>
>If you can get around that, the SAS is a wonderful example of ``stoopid is
>beautiful''.  It can be a *lot* lighter than a conventional suit, because
>no cooling system is required beyond the user's own sweat.  (And any system
>that isn't there can't break, and needn't be maintained.)  It is much more
>flexible, and the gloves provide far greater dexterity.  And degradation
>is extremely graceful.
>
>In article <[e-mail]>
>[e-mail] (Charles Crapuchettes) writes:
>>How long would an astronaut have to be EVA to have a 50% chance of being
>>injured by a chunk of crud (either artificial or man-made)?
>>Do harder suits provide protection, or is the energy too high?
>
>If a conventional suit is breached, either by a micrometeorite or simply a
>slip of a tool, the user will almost certainly be dead by the time he or
>she can be repressurized.  On the other hand, a rip or hole in an SAS will
>affect the pressure under the tear only.  Even edema (essentially a hickey)
>need not occur if damage control is taken promptly, and that need be no
>more than the application of a simple tensor bandage!  A micrometerite will
>likely be hard on the human underneath, as well, so a first layer of
>something blood-tight would probably be needed.  But any system which
>changes a fatality into an injury is worth looking at more closely.
>
>The SAS is run at (as I recall) about .25 atm or so.  To get an idea of
>what this pressure differential means, take a syringe and chop off the
>business end, so that you're left with an open tube.  Hold this against
>your skin and withdraw the plunger to produce whatever level of vacuum you
>desire.  The movie ``2001'' is a lot closer to reality than ``Outland''...
>
>(P.S.: This is an area where the research required is quite basic, and
>there is a greater need for ingenuity than aero$pace material$.  It would
>be a good project for a group of engineering undergrads.  (Or even a high
>school class, except for the lawsuit potential.)  Local space groups, are
>you looking for something to keep your members off the streets?  Why not
>invest in Spandex...)

A subsequent idea: perhaps the most practical approach would be a
hardshell torso combined with fabric arms and legs.  The SAS did not
have seven layers of material over the entire body, just the torso;
basic mechanics says that a larger cylinder has a greater skin tension
than a smaller one for an equivalent internal pressure.  Individual arm
and leg covers of a hybrid suit would be much simpler to don and doff.
The problem of spine elongation would be neatly sidestepped, and
changes in limb volume (whether due to fluid retention, disuse of
muscles, or other causes) could be dealt with by changing (or adding or
subtracting) layers, an easy and cheap operation.

The hardsuit-to-skinsuit joint needs some care, but again, it's a Solved
Problem.  The original suit made the transition at the neck, since the
user's head still had to be in a helmet.  The Mars glove was connected
to a conventional suit at the wrist.

The drawback is that putting the entire torso in a box probably means that
a cooling system must be reintroduced.  That's a *major* pain.
John Hogg                Bell-Northern Research
[e-mail]                Ottawa, Ontario

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

Date: 14 Apr 91 16:22:44 GMT
From: dog.ee.lbl.gov!hellgate.utah.edu!caen!sdd.hp.com!spool.mu.edu!cs.umn.edu!ariel.unm.edu!triton.unm.edu![e-mail]
Subject: launch on Friday from the Cape

Does anyone have additional information on that communications satellite
that was launched Friday evening from Cape Canaveral?  All I was able to
gather from the media was that it was a communications satellite from GTE
Spacenet and that it's geostationary place will be on the longitude that Texas
covers.  My main question is if the satellite is a Television one or just a
data w/o video one.

Robert

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

Date: 14 Apr 91 20:12:11 GMT
From: prism![e-mail]  (Matthew DeLuca)
Subject: Re: spacesuits (Was: Re: HST in-orbit Maintenance)

In article <[e-mail]> [e-mail] (Fred Walter) writes:

>But 100kg suits aren't a problem in a weightless environment (once you've
>actually got them up there). So this isn't that big of a disadvantage.

Weightless though it may be, it's still got 100kg of mass.  It still takes
a lot of energy to get that suit moving and to get it stopped.  Definitely
a hassle.


--
Matthew DeLuca
Georgia Institute of Technology      "I'd hire the Dorsai, if I knew their
Office of Information Technology      P.O. box."  - Zebadiah Carter,
Internet: [e-mail]    _The Number of the Beast_

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

Date: 12 Apr 91 20:24:20 GMT
From: unisoft!fai!sequent!crg5![e-mail]  (Nick Szabo)
Subject: Re: comsat cancellations and lawsuits

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>In article <[e-mail]> [e-mail] ("Allen W. Sherzer") writes:

>>Of course shuttle prices are subsidized so much that that would be
>>impossible. They charge $150M for a flight which costs them over $500M.


>Well, if expendables are as cheap as everyone says :-), the shift would
>actually save them money, so no problem.  If not, they spent 2.5 years
>not flying the shuttle, which would have helped the finances a bit.

A couple lessons we can learn from this:

* NASA does not necessarily want to save money.  $500 million can be
  just as good as $150 million, perhaps better.  The higher the costs,
  the more jobs are generated and the more political clout ensues.
  This is exacerbated by the lack of concern about costs exhibited
  in by many in the space community.

* NASA does not care about their customers.  Other examples include
  the scrapping of expendables in the late 70's in favor of unproven
  Shuttles, and the removal of microgravity scientists out of the Fred
  plan when they asked for politically unpopular design changes they
  require for their work.

Both of these are quite natural, since NASA is a government agency
that derives its revenue from taxation, regardless of efficiency or
customer service.  Both are quite destructive of space exploration
and development.





--
Nick Szabo            [e-mail]
"If you want oil, drill lots of wells" -- J. Paul Getty
The above opinions are my own and not related to those of any
organization I may be affiliated with.

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

Date: 14 Apr 91 22:06:38 GMT
From: borg!homer![e-mail]  (Jonathan Leech)
Subject: Re: NEP to Mars!?!? - a thesis topic

In article <[e-mail]>, [e-mail] (Nick Szabo) writes:
|> Gravity assist and aerobraking can
|> be used, eg Voyager and Galileo VEEGA gravity assist trajectories, and
|> Apollo aerobraking on the return trip from the Moon.   VEEGA trades time
|> for energy, though Voyager gained both time and energy.

    The Voyagers flew a direct trajectory to Jupiter, Nick.
--
    Jon Leech ([e-mail])    __@/
UNDERWHELMING OFFER OF THE MONTH:
    "Please feel free to skip the payment on this month's statement.
     Normal finance charges will apply." - NCNB VISA

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

Date: 15 Apr 91 03:43:22 GMT
From: ub![e-mail]  (michael b moretti)
Subject: Re: Teflon (Was Re: Space technology)

In article <[e-mail]> [e-mail] (Daniel Briggs) writes:

[]   ...stuff deleted...

>I was under the impression that teflon was one of the great serendipitous
>discoveries of modern science.  Unfortunately, I don't have a written
>source for this fact, as I heard it in a public lecture given by Glenn
>Seaborg.

I'm not sure if it is true, or just more folklore that was going around
at the time, but I do believe I read somewhere that when Teflon was
discovered, they were actually trying to come up with a new, super-
strong glue or other such substance.  The only reason I am posting
this is because the rest of your post seems to agree with what I remember
reading...

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

Date: 12 Apr 91 12:31:52 GMT
From: haven!ncifcrf!lhc!adm!smoke![e-mail]  (Irving Chidsey)
Subject: Re: Space technology

In article <cjp310.671439535@coombs> [e-mail] (Chris @ SSDA ...) writes:
<[e-mail] (Phil OKunewick) writes:
<
<>In article <[e-mail]> [e-mail] (Robert W Murphree) writes:
<
<>   One space spin-off was directly related to geology (and hey, this
<>_is_ cross-posted to that newsgroup): 4.5 million-year-old moon rocks.
<>These showed that the earth and moon formed at the same time, and thus
<>partly settled one of the greatest disputes in geoscience.  From this,
<>we were able to develop a better theory on how the solar system
<>formed.  Although at first this doesn't seem nearly as useful as a
<>non-stick frying pan, the amount it has helped us understand the world
<>around us (and thus help preserve it) is incalculable.
<
<    I thought that the earth-moon configuration was caused via the
<collision of the moon onto the earth, which caused the melting of both
<objects, etc...  I saw a simulation done on a cray which showed this...
<
<Actually I know very little about this theory, anyone got any more info about
<this ???
<
<                  Chris Patterson | Ph:  [phone]
<     Social Science Data Archives | AARNet: [e-mail]
<   Australian National University | "I wonder what happens if I ..."

    Last time I looked there were several more or less plausible theories.
They all involve extrapolating a long way back from known present conditions,
and forward from assumed initial conditions.  The juncture always involves
much arm waving as the speaker crosses in front of the screen just as the
slide changes because the two extrapolations never seem to meet smoothly.
You are not supposed to see the slide that says "At this point a miracle
happens."

    Unfortunately, you cannot prove anything in science, you can only
disprove theories.  Science, like theology, is based on plausibility
arguments.  Unlike theology, disproof is possible.

                            Irv

--
I do not have signature authority.  I am not authorized to sign anything.
I am not authorized to commit the BRL, the DA, the DOD, or the US Government
to anything, not even by implication.  They do not tell me what their policy
is.  They may not have one.        Irving L. Chidsey  <[e-mail]>

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

Date: 14 Apr 91 17:07:11 GMT
From: swrinde!zaphod.mps.ohio-state.edu!wuarchive!rex!rouge![e-mail]  (Fraering Philip)
Subject: Re: flares

In article <[e-mail]> [e-mail] (Henry Spencer) writes:

(responding to question about electromagnetic shielding):
>A little bit of work was done on this for space colonies.  It's not
>totally impractical, but it's difficult.  I'd expect it to be hopeless
>for anything small.

Well, magnetic shielding, as in wrapping a solenoid around a toroidal
structure, was found to be pretty heavy. So was charging the colony
to a high positive voltage to ward off cosmic rays, not to mention
the measures needed to keep free electrons from violently grounding
the structure WRT the ambient plasma. (Anyone remember how particle
accelerators work?)

However, I remember seeing _somewhere_ in some technical journal
a design for an electric field system with some sort of multipole
structure in the electric field (non-physics people, feel free to
write for further explanation, but I don't understand how these
shields were supposed to work anyway, and I'm asking if anyone else
has seen the paper and has a reference or the paper handy _now_...)
for repelling both electrons and nuclei.

Has anyone seen the paper I have mentioned? If so, or if you even have
an inkling of where it is, please respond.

--
Phil Fraering
[e-mail]
"The reserve of modern assertions is sometimes pushed to extermes, in
which the fear of being contradicted leads the writer to strip himself
of almost all sense and meaning." - Winston Churchill, _The Birth of
Britian_
"X-rays are a hoax." - Lord Kelvin

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

Date: 15 Apr 91 01:54:40 GMT
From: mips!samsung!munnari.oz.au!metro!seagoon.newcastle.edu.au!jupiter.newcastle.edu.au![e-mail]  (robert john jongbloed)
Subject: Space News by Mail

I have a friend who does not have access to net news but would like to
receive space info anyway. I beleive there is a way to get E-Mailed the space
news (SPACE Digest??). How does one subscribe?

Any information would be useful, thanks in advance.

 -----------------------------------------------------------------------------
|  Robert Jongbloed        |   University, where the real world is something  |
|                          |   to be understood but not be a part of.         |
|-----------------------------------------------------------------------------|
|  Internet: [e-mail]   Mere mail: 62 First Street,      |
|            [e-mail]               Cardiff South, N.S.W. |
| Telephone: [phone]                               AUSTRALIA.   2285     |
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|  Robert Jongbloed        |   University, where the real world is something  |
|                          |   to be understood but not be a part of.         |
|-----------------------------------------------------------------------------|

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

Date: 14 Apr 91 23:04:23 GMT
From: usc!zaphod.mps.ohio-state.edu!caen!kuhub.cc.ukans.edu![e-mail]
Subject: Questions about pioneer/Voyager

Hi!
I have always wondered about the space crafts Pioneer/Voyager etc
sent out side the solar system.
Few Questions:
1) How was the collision with astroid belts avoided?
2) How were/are they powered? If with nuclear power; how come NASA
doesn't quote its sucess to the people demonstrating against nuclear
powered crafts?
3) People who must have watched "First Contact" the episode in
Star Trek The Next Gen might recollect the government making the
decision on whether to disclose the contact.. Now considering Earth
with many different countries/governments, who made the decisions on
revealing our presence and technological prowess? Was that a global
decision? And if there is a contact who will make the decision on
whether to or not to tell the people?

Thanx for any info..

Ajit Utagikar..

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

End of SPACE Digest V13 #407
*******************