Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V08/V8_300.TXT

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Date: Thu, 28 Jul 88 01:05:24 PDT
From: Ted Anderson <[e-mail]>
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Subject: SPACE Digest V8 #300

SPACE Digest                                      Volume 8 : Issue 300

Today's Topics:
               Re: Space Suits
            Re: Electromagnetic Launchers
              the Space Program
             Re: Von Braun quote
             Re: Von Braun quote
          RE: Lithium cells for use on Space Shuttle
                Spy Satellites
----------------------------------------------------------------------

Date: 13 Jul 88 17:40:34 GMT
From: cfa!cfa250![e-mail]  (Steve Willner P-316 x57123)
Subject: Re: Space Suits

From article <[e-mail]>, by
[e-mail] (Bruce D. Wright):
>   Trying to hold 3 psi pressure in your lungs reletive to the
> pressure outside of your body would probably cause an embolism to
> occur, not to mention that breathing extreme possitive pressures
> like this would be REALLY exhausting.

From personal experience, I can say that pressure breathing at even a
fraction of a psi is extremely uncomfortable and tiring.  This is NOT
a viable option for normal EVA, and a whole psi is probably not even
an option for emergencies.

> Also, breathing pure oxygen at such low total pressure causes
> atelectasis to occur.  This is alveoli collapse caused by the
> oxygen in the alveoli being absorbed into the blood.

Breathing pure oxygen in a pressure chamber at pressure altitude of
40,000 feet (less than 3.5 psi) is acceptably comfortable at least up
to a half hour or so.  (I have not tried it longer than that.)  The
biggest discomfort is wearing the oxygen mask itself.  (The second
biggest is expansion of trapped gases in the digestive tract, but
this is an effect of the pressure decrease from atmospheric, not of
the low pressure itself.)  Does atelectasis require more time to
develop, or does it just not affect most people?
--
Steve Willner            Phone [phone]         Bitnet:   willner@cfa
60 Garden St.            FTS:      830-7123           UUCP:   willner@cfa
Cambridge, MA 02138 USA                 Internet: [e-mail]

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

Date: 13 Jul 88 16:23:20 GMT
From: ns![e-mail]  (John Logajan x3118)
Subject: Re: Electromagnetic Launchers

In article <[e-mail]>, [e-mail] (Mike Stuard) writes:
> If a magnetic track was long enough the extended period of
> acceleration would reduce the G-forces enough for more sensitive equipment

Here is a rule of thumb for launcher lengths:

To reach escape velocity you need to accelerate at:

1g for 4000 miles.
2g for 2000 miles.
4g for 1000 miles.
8g for 500 miles
16g for 250 miles.
32g for 125 miles.
etc .............

- John M. Logajan @ Network Systems; 7600 Boone Ave; Brooklyn Park, MN 55428 -
- {...rutgers!umn-cs, ...amdahl!bungia, ...uunet!rosevax!bungia} !ns!logajan -

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

Date: Wed, 13 Jul 88 16:57:55 MDT
From: [e-mail]
Subject: the Space Program


This being my inaugeral message on the SPACE digest, I decided to attack two
points of concern to me, one very important, the other not so.

I recently returned from Washington, DC, where I spent six weeks working for a
senator.  Naturally, I was working in the space/technology pod, where I was
intent on doing everything in my power to sway any of my senator's votes that
had anything to do with space.  There were, however, a few major problems.

Nobody gives a damn.

To be more precise, in the six weeks I was there, the office received only ONE
PIECE OF MAIL asking the the space program be fully funded.  ONE PIECE!!!
Compare this with well over 450 in just a couple of weeks concerning the INF
treaty, or the dozens that came in with great regularity concerning waste and
fraud in our defence department (prior to the FBI investigation, that is!).  A
senator will not listen to just one piece of mail; he can't afford to.  If
everyone out there who is serious about the space program were to send two
letters to each of their senators, and a letter to each of their represen-
tatives, we might see some more discussion among the senators about money for
the space program.

The space program is difficult for a senator to justify politically.  Tangible
benefits are difficult to clarify, and "manifest destiny" just don't cut a 10.8
billion dollar budget, no matter what.  When I went to Washington, I was very
gung-ho about the space program, especially the MANNED space program, but now
I'm not so sure.  The money for the space program has to come from somewhere,
be it Vet's benefits, defense, social programs or wherever.  Unless those who
support the space program are able to instill their own long-range vision upon
those who are responsible for dividing the money, we are going to be trapped
on this planet for a long time.

Right now the space program is more of a political tool then a scientific one.
Very important decisions are being made by managers and administrators instead
of scientists.  These trends must change, or the people who understand space
so well will dig their own graves...on earth.

You will notice that I have not mentioned NASA once in this digression.  I hes-
itate to discuss NASA's predicament because the issue is so clouded that I find
myself unable to divine what course we should take.  NASA's mission is to
explore and take advantage of the resources space offers us.  Is manned space
flight, a very significant portion of the NASA budget, important enough to
consume the money it does?

These are important questions that every one of us on this net should be asking
ourselves.  Talk is talk, and talk is cheap.  I find the discussion of launch
loops and skintight spacesuits fascinating, but I was forced to experience the
real world for a few weeks, and I regret it.


Space is indeed the place, and it is the responsibility of those who understand
that to see that it happens, be it for my generation or my children's.  Less
then 400 human beings (as I recall) have escaped this planet's atmosphere...

.and I want to join the list :).

And now, to switch from the somber, depressive note, will the moderator of this
list please explain to me what damn order these messages come in!!?  I get the
digest, and I often fail to get all the messages in a series.  For example, I
never saw the original message about the launch loop.  What's the deal?





David Birnbaum                           [e-mail]
Programmer, Small Systems                [e-mail]
New Mexico State University         <--  they pay my bills, but they don't
Las Cruces, New Mexico  USA              write my opinions....

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

Date: 14 Jul 88 06:10:53 GMT
From: [e-mail]  (Joe Beckenbach)
Subject: Re: Von Braun quote

>> [ whoever is @killer; sorry I lost your attribution ]

In article <[e-mail]> [e-mail] (Phil R. Karn) writes:
>Good point. But how many applications really require six second response
>time? Voyager seems to have been highly successful without humans on
>board, despite round trip times measured in hours.  There may well be
>"deep space" applications which require short human response times and
>therefore humans in space, but this is a tiny fraction.

    Most of the craft sent out so far are designed to have limited human
interaction, more on the order of "policy & managerial" rather than the detailed
work. To make this more concrete, for the interplanetary craft, there is no
way to put a human pilot into the loop, therefore the only interaction humans
have are the navigational work on the ground, done weeks(?) in advance.
The detailed work which would require human (tele)presence is left to the
specialized instrument hardware and software.

>> Also, the computers these days are not nearly advanced to do the sort of
>> problem manegement that you describe.  Show me an unmanned launch vehical
>> which can do as much as the shuttle can!

    Minor match-lighting: what shuttle? (Blow out spark. :-)

>>  The most advanced computer in
>> the world is that 10 pound ball of grey matter resting on your neck...

    Ten-pound heads are great computers.... but for what purpose in particular?
It is the lousiest for some applications (like calculating interplanetary orbits)
and the best for others (like writing doggerel-- no computer poetry program
can get as bad as some human poetry! :-)

>Most people know that there are some things computers do much better
>than humans, and there are other things that humans do much better than
>computers. An intelligently designed system will apply each resource
>where it is best suited. There is certainly room for discussion and
>disagreement as to exactly how to do this in any project.
>Phil

    What he said.
        Joe Beckenbach

--
[e-mail]        | Mars Observer Camera Project
Live fast. Die young.            | Caltech Planetary Sciences Division
Convince people you're a tiny Mars-bound graphite-epoxy blob from Pasadena.

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

Date: 14 Jul 88 06:12:36 GMT
From: ucsdhub!jack!sdeggo![e-mail]  (David L. Smith)
Subject: Re: Von Braun quote

In article <[e-mail]>, [e-mail] (Phil R. Karn) writes:
> > The state of communications has not gotten so good as to defy phyics, now
> > has it?  The non-manned approach works fine when in earth orbit, but what
> > happens when you get up there to around the moon?  By the time the person
> > on the ground has reacted to a problem, six seconds will have passed in
> > transmission time!  In a critical situation, this could mean the destruction
> > of the craft.
>
> Good point. But how many applications really require six second response
> time? Voyager seems to have been highly successful without humans on
> board, despite round trip times measured in hours.  There may well be
> "deep space" applications which require short human response times and
> therefore humans in space, but this is a tiny fraction.

Voyager is a wonderful tool, but it's not a very useful tool in general.
It has a camera, a spectograph, and some other instruments.  It does not
have the ability to land on a moon of Jupiter and pick up a sample, or
to mine an asteroid.  If something comes up for which it does not have the
tools to deal with it does not have the ability to fabricate something
from the materials at hand.

> Most people know that there are some things computers do much better
> than humans, and there are other things that humans do much better than
> computers. An intelligently designed system will apply each resource
> where it is best suited. There is certainly room for discussion and
> disagreement as to exactly how to do this in any project. But in the
> realm of space travel, emotional romanticism has gotten the upper hand
> over rational design as in almost no other area of technology. The
> result? Expensive turkeys like the Shuttle that have sucked away almost
> all money from other, far more cost-effective projects and have nearly
> wrecked our space program in the process.

What is our space program?  To go out and take snapshots?  Hell NO!  The
reason we have a space program is to get mankind living, working and
exploiting the resources in space.  "Emotional romanticism" is a basic
part of human make-up.  Why do we fly to Paris when we could watch it
on videotape? Why do we climb mountains when we could send a camera on
a balloon?  The arguments about the cost-effectiveness of unmanned probes
only make sense when the only purpose of the space program is to feed data
to a bunch of researchers sitting on their duffs.  If we're not going out
there, why should we _care_ about what's on Jupiter, the makeup of the
Oort cloud or whether there's planets around Barnard's Star?  If
the only reason we have a space program is to satisfy the curiousity of
a bunch of scientists whose work will probably be of little value to the
rest of the race if we stay at home here on Earth, they can bloody well pay
for the program out of their own pockets!

--
David L. Smith
{sdcsvax!jack,ihnp4!jack, hp-sdd!crash, pyramid, uport}!sdeggo!dave
sdeggo![e-mail]
Sinners can repent but stupid is forever.

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

Date:     Thu, 14 Jul 88 13:19 EDT
From: <[e-mail]>
Subject:  RE: Lithium cells for use on Space Shuttle

>>>The reason NASA bans them from the Shuttle is because they have been
>>>known to explode when shorted. [...]

   Well, they can explode, or as we preferred to say, "rapidly out-gas",
but to my knowledge as an eight year design engineer at NASA JSC, they are
still approved for use.

   Most credit for demonstrating the explosive power of Lithium cells to
NASA must be given to an ILC technician who placed a bare Lithium D cell
assembly on steel lab shelf overnight and returned the next morning to find
a 1/2 inch crater in its place.  This incident was well publicized within
JSC as we were, at the time, trying to qualify an 8 cell Lithium battery
for use in the Shuttle crew module. After a two year qualifying process
we finally flew 25 packs on STS-5 for use with the Wireless Communication
System.  We were required to design and install a small PC board in each
battery with 1/4 amp load fuses and reverse protection diodes for each cell.
Although our milled aluminum housing was not explosion proof it was designed
to contain most of the solid electrolyte that could leak out under deep
discharge.
   At the end of my term with Lockheed/EMSCO at NASA Johnson Space Center
last August Lithium batteries were still approved for use in the Shuttle.
Both the Spacesuit headlight assembly and EMU television assembly use Lithium
Bromide complex (LI-BCX) cells from Electrochem Industries. The battery
lab at JSC has over 6 years experience at devising evil ways to treat the
cells and have blown up quite a few.  The main thrust for new crew module
applications seems to a Zinc-Air battery that has comparable energy density.
Unfortunately this cell requires Oxygen for electron transport and cannot
be used in Payload/EVA applications. The search goes on...................

>Now you can tell me what is wrong with my scheme: build a fuse in series
>with each cell.....This should work to prevent a battery from exploding
>due to external shorts.

    Recessed-pin battery connectors are the simple answer to external shorts
that we used in the 8 cell Lithium pack previously mentioned.  The real
problem is reverse charging.  If one string of a two string parallel configured
Lithium battery pack has diminished capacity it can be reverse charged
by the stronger string. This condition sounds contrived but is fairly common
after a days use.  We were required to use germainium diodes to protect
each individual cell from voltage reversal. Each diode was individually
screened for forward turn-on voltage and the inspectors were meticulous
about slowing down our production schedule. The approval and design process
was a two year struggle of negotiation with NASA QA.  I would hope to see
some future use for these high energy density cells to recoup our research
work and all of our tax money.

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

Date: 14 Jul 88 19:33:06 GMT
From: [e-mail]  (Richard the Nerd)
Subject: Spy Satellites



Hello space enthusiasts,

There has been some talk on the net lately about spy satellites.  It
might be of interest to you that our amateur satellite group (based in
Toronto) has tracked down a few of these.  NASA is not too cooperative
in this respect since they keep the orbits of these things classified,
so we find them on our own.  Presently, the best object we are
tracking is one of the two KH-11's (Big Birds).  These are huge and
low, and hence bright to see; about 0th magnitude on a good pass.
Since I have software which can distribute satellite predictions
automatically (I do this for about 130 people for MIR), I figured that
any of you who are interested in seeing KH-11 can also get on that
list.  If interested, please email your location (name of town,
latitude and longitude to at least 2 decimal places, elevation above
sea level, time zone, and whether daylight savings time is in effect
in your area).  You can also request any other satellites you would
like to see.  I will put you on the list and send you predictions
weekly.  Better hurry for KH-11, though:  The observing window ends
by August and the next one isn't till next April!

-Rich Brezina
 (Kevin Renner, really ;-)

 [e-mail]   (works from most nets)

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

End of SPACE Digest V8 #300
*******************