Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V13_3/V13_386.TXT

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Subject: SPACE Digest V13 #386

SPACE Digest                                     Volume 13 : Issue 386

Today's Topics:
      Re: spacesuits (Was: Re: HST in-orbit Maintenance)
             Re: I want to go to orbit...
        Re: comsat cancellations and lawsuits
              Re: SPACE Digest V13 #364
              Re: Railguns, EM launchers
       Re: Why does every SAR have another resolution?
         Re: Space Stations, Money, Startrek
             Re:  Nuclear rockets
            A Dire Need to Network
             Re: Fred on the Moon
             shuttle radiator experiment
             Re: I want to go to orbit...

Administrivia:

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

Date: 10 Apr 91 02:38:10 GMT
From: agate!headcrash.Berkeley.EDU![e-mail]  (George William Herbert)
Subject: Re: spacesuits (Was: Re: HST in-orbit Maintenance)

In article <[e-mail]> [e-mail] (J Gillespie) writes:
>[e-mail] (Fraering Philip) writes:
>At least one SF writer (Jerry Pournelle) has postulated spacesuits
>made from thin, flexible, elastic material, rather like the neoprene
>used in wetsuits.  Cooling would be by sweating through the suit
>itself (would Gore-tex be of any use? :-).  From my very vague
>knowledge of current spacesuits, most of the bulk is radiation and
>micrometeorite shielding, and one of the main problems is the joints.

Such suits are being developed.  Major known problems include:
    Wierd joint bending characteristics in skin-tight membranes
    Problems with solar heating
Gore-Tex won't work, it doesn't retain pressure.  However, dense membrane
technology accomplishes the same goal.
    You're memory/information is pretty close, most of the bulk in the
suit proper is insulation (which doubles as armour for impacts/abraisons).

>Hmmm.  That triggers a memory.  Some time ago (a couple of years?) I
>saw a feature on a new type of diving suit on some TV science show
>(Beyond 2000?  Tomorrow's World?).  It was a new type of atmosphere
>suit, and the arms and legs were articulated with a series of
>ingeniously arranged revolute joints, rather than the spherical type
>which has caused so many problems in the past.  It was much lighter
>and simpler than an equivalent JIM type suit, and I'm sure that some
>mention was made of NASA being interested in the design.  Anyone else
>got a better memory?

Vik Vyukal (sp) at NASA Ames has been doing rotating-joint hardsuits for a long
time now.  That's what the Ames hardsuit uses.  Disadvantages are that the
joints themselves weight a whole lot, leading to 100kg suits (not including
the life support!).


  == George William Herbert ==   * UNIX ate my last .sig, Waiting for Plan 9! *
 == JOAT for Hire: Anything, ==  #########  I do Naval Architecture, ##########
===+++ Anywhere, my price +++=== # Spacecraft Design, UNIX Systems Consulting #
 ==   [e-mail]   ==  # RPG writing/development, and lots of other #
  ==   [e-mail]   ==   ## random stuff, of course.  I'm a JOAT 8-) ##

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

Date: 9 Apr 91 13:49:23 GMT
From: rochester![e-mail]  (Paul Dietz)
Subject: Re: I want to go to orbit...

In article <[e-mail]> [e-mail] (Donald Heskett) writes:
>
>If I remember correctly, Truax had built a vehicle, based on surplus
>Atlas vernier engines, to loft a person to 100km (about 62-miles), the
>IAF's definition for the threshold of space, thus qualifying that
>person as an astronaut. Recovery was to be via parachute. Last I
>heard, the vehicle was complete, ready to carry the first person with
>the $1,000,000 ticket price.
...
>I haven't read anything about Truax in perhaps five years and am also
>curious about what he is up to these days, if anything.

Truax sold his "Volksrocket X-3" to the US Navy in the fall of 1988
for $750,000, to be used as a test vehicle for part of the SEALAR
program (a program investigating using a two-stage sea-launched rocket
to put 10,000 lb. into low orbit, with the recoverable first stage
recovered 400 miles downrange in the ocean).

What's the status of SEALAR, guys?

    Paul F. Dietz
    [e-mail]

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

Date: 9 Apr 91 13:17:42 GMT
From: fernwood!uupsi!pbs.org![e-mail]
Subject: Re: comsat cancellations and lawsuits

In article <[e-mail]>, [e-mail] (Fraering Philip) writes:
>
> This is really twisted, when you think about it: "Based on past
> wrongs by 'aerospace companies' which may or may not include Hughes
 (they do include Hughes)
> ... gives the government the right
> to abbrogate contracts without penalties."
Before this gets too far away from the original post, it is only Hughes and
Henry who made the statement a contract was abbrogated.  NASA and the
government believe the CHALLENGER situation so changed the circumstances that
various escape clauses came into play.  By the way, the suit is against NASA
and not the government even though the decision to bump comsats from the
shuttle originated not with NASA, but the WHITE HOUSE.  If Hughes REALLY thinks
it has a gripe, it should have gone after the Government.  NASA is just as much
a victim as Hughes.


> Come on, if the government thinks something wrong has occured, then
> they should fight for their rights,
  The government IS fighting and HAS brought charges against some aerospace
firms.  In fact the recent cancellation of the A-12 attack bomber is an example
of the government's new get tough policy on overcharging and mismanagement, not
to mention misleading the Secretary of Defense with inaccurate claims about the
atack bomber's state of development.

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

Date: 9 Apr 91 14:35:27 GMT
From: usc!elroy.jpl.nasa.gov!sdd.hp.com!caen!sol.ctr.columbia.edu!emory!wa4mei!ke4zv![e-mail]  (Gary Coffman)
Subject: Re: SPACE Digest V13 #364

In article <[e-mail]> [e-mail] writes:
>Re: E.T.'s
>
>My biggest problem with getting into SETI would be;  Suppose you find evidence
>that there is life 3.5 million light years away;  So what?  What do you do now?

It would have profound psychological effects and philosophical effects right
here on Earth. Finding intelligent life elsewhere in the cosmos would be the
equivalent of the Copernican Revolution all over again.

>Another problem is;  What if the guys you find don't think of us as enemies, or
>even potential slaves, but FOOD?  No thanks!
>There is the argument, tho, that since we have now advertised our presence to
>the surrounding 60 ly sphere in space (TV started in 1936), we should at least
>find out if we are attracting unwanted attention that we should prepare for.

If our aliens are still using radio, then I would guess that they still
face the speed of light limit. I wouldn't worry too much about fleets of
invading starships. If they have found a way around c, then we won't hear
them, and they are unlikely to notice us. Either way, the threat of invasion
seems miniscule.

Gary

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

Date: 10 Apr 91 01:41:36 GMT
From: agate!headcrash.Berkeley.EDU![e-mail]  (George William Herbert)
Subject: Re: Railguns, EM launchers

In article <[e-mail]> [e-mail] (Harold G. Andrews II) writes:
>>Unfortunately, those chemical rockets aren't designed for a horizontal
>>takeoff.  You could get useful gains by catapulting them at such speeds
>>*vertically*, and in fact there was a recent Japanese proposal to do
>>just that.
>What kinds of problems are the Japanese running into, and what kinds of set-ups
>are they looking at?  Are the EM launchers under-ground?  Could you point
>me to some articles discussing the Japanese efforts?  Just curious.

The japanese proposal was to use a compressed-gas cannon to loft a H-2
rocket at transonic speeds.  NASDA was last heard complaining about safety of
fueling such a vehicle in the gun's barrel...

-george william herbert
[e-mail]

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

Date: 10 Apr 91 02:36:38 GMT
From: geology.tn.cornell.edu![e-mail]  (Eric Fielding)
Subject: Re: Why does every SAR have another resolution?

In article <[e-mail]>,
[e-mail] (Henry Spencer) writes:
|>Radarsat's main advantage is a much bigger, and custom-built,
|>antenna.
|>Magellan is SAR on the cheap, using hardware out of NASA's junkbox.
|>An
|>important secondary issue is the ten years or so that separates their
|>design efforts.

RADARSAT does have an antenna designed for SAR, which helps, but I think
that the electronics and especially the downlink capacity are much more
important factors. The design date is definitely *not* a factor because
the RADARSAT resolution is roughly the same as that of SEASAT which was
launched in 1978. In fact, the high resolution of SEASAT has been blamed
for its premature failure since its data was not encrypted in any way
(nudge, nudge, wink, wink).

                ++Eric Fielding

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

Date: 9 Apr 91 11:32:12 GMT
From: prism![e-mail]  (Matthew DeLuca)
Subject: Re: Space Stations, Money, Startrek

In article <[e-mail]> [e-mail] (Steve Emmerson) writes:
>In <[e-mail]> [e-mail] (Matthew DeLuca) writes:

>>Nobody is 'afraid' to ask for help.  But you never learn anything if all
>>you do is copy from your neighbor.

>Odd.  I've learned a lot using data I never personally collected.

Okay, I should be a little more accurate here.  You will make no contributions
to knowledge if all you do is copy from your neighbor.  If all we want is
other people's data, we can just sit at home, watch TV, and pay out the wazoo
for the knowledge of others.  Of course, after twenty or thirty years of this,
we'll be too poor, relative to others, to keep this up, but that's another
story.

--
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:         Tue, 09 Apr 91 14:09:27 EDT
From: Richard Ristow <[e-mail]>
Subject:      Re:  Nuclear rockets

On 6 Apr 91 17:30:25 GMT, Steven King
 (agate!bionet!uwm.edu!cs.utexas.edu!ut-emx!nowhere![e-mail])
 wrote, among other comments on nuclear rockets,

>   There were, as I remember, a few technical problems to be considered.
> Pump too much energy into diatomic hydrogen and it tends to disassociate,
> sucking up a substancial amount of energy, pump more energy into it
> and one gets a wild mixture of H-, H+, H2, etc., this both limits the
> specific impulse and produces a very reactive exhaust that needs to be
> considered in the design of the nozzle and even the fuel pellets.

  I thought I'd heard, in long-ago discussions of nuclear rockets, that
  reaching temperatures where H2 dissociates is a highly desirable, though
  (at least formerly) unattainable, goal.  Exhaust velocity, or Isp, is
  proportional to the square root of (Temperature/molecular weight), both
  quantities measured in the exhaust.  The only reason a thermal nuclear
  rocket can have higher Isp than an H2/O2 chemical rocket is the lower
  molecular weight of the exhaust;  nobody hopes to design a reactor that
  will hold together at the temperature of the H2/O2 chamber.  Dissociating
  H2 completely give you an automatic 40% Isp boost at no increase in
  temperature, so there's a big jump in the Isp-temperature curve at that
  point, making it a very desirable goal.  (I realize the "point" is actually
  a range.)  This doubles the energy input per unit of reaction mass, but raw
  energy is what's cheap for a nuclear rocket.  Certainly the chemical
  reactivity of the hot atomic hydrogen makes this much harder than the
  temperature suggests.

-------------------------------------------------------------------------
Richard Ristow       [e-mail]       (BROWNVM on BITNET)

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

Date: 9 Apr 91 19:58:42 GMT
From: prism!prism.gatech.EDU![e-mail]  (NORD,THOMAS DAWSON)
Subject: A Dire Need to Network


    I apologize if this might be regarded as a sin for putting
this in these newsgroups!


    To whom it might concern:

    I am an ambitious junior Mechanical Engineering
student at Georgia Tech.

    I would like to correspond with any engineers or
engineering technicians in the fields of Aerospace and Mechanical
Engineering.

    I would like to know more about your jobs and what exactly is
done on your jobs so that I might have a good idea about where I would
like to work and what kinds of things would be expected of me.

    My greatest intrests lie in aircraft, space
probes and vehicles, satellites, and any related technologies.

    Any help would be greatly appreciated!

                    -Thomas Dawson Nord
                     [e-mail]


Thomas D. Nord           | GEORGIA TECH - 1991 National Champions !!!!
[e-mail] |
Junior, Mechanical Eng.  | THANK YOU for supporting our allied troops!
Georgia Tech, Atlanta, GA| Give blood today....and save a life.

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

Date: 9 Apr 91 22:51:33 GMT
From: sdd.hp.com!usc!rpi!news-server.csri.toronto.edu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Fred on the Moon

In article <[e-mail]> [e-mail] (Jose Pina Coelho) writes:
>But you can't have something like a Saturn V fueled, so we have a
>minimun of 3 days of trip plus time to get the emergency solutioning
>equipment ready and assembled plus(1) time to fuel the beast(2).
>(2) - How long did it take to fuel them ? Henry ?

I don't have exact numbers on tap, but like the shuttle, it was a matter
of a few hours.  The bigger problem is that, as with the shuttle, a launch
was the culmination of a carefully-orchestrated campaign of assembly and
checkout lasting months.  If you kept one ready, stacked on a dedicated
mobile launcher in a dedicated VAB bay, you might be able to get most
of the work done in advance and have only a day or two of work for rollout,
final checks, and launch... given that it was an emergency.

In any case, this is all a wee bit silly.  As others have pointed out, we
routinely accept much longer rescue times for remote areas on Earth.  We're
talking seriously about Mars expeditions with no rescue possible.  And in
any case, by far the easiest and quickest way to rescue a lunar-base crew
is to have them climb into a return vehicle and head for Earth.
--
"The stories one hears about putting up | Henry Spencer @ U of Toronto Zoology
SunOS 4.1.1 are all true."  -D. Harrison|  [e-mail]  utzoo!henry

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

Date: 9 Apr 91 16:50:19 GMT
From: rex!samsung!emory!ducvax.auburn.edu![e-mail]
Subject: shuttle radiator experiment

I hear on CNN that there was a space station radiator experiment on board.
They never say what kind of radiator, yet it involved fluid.  Does anybody
knw what type of radiator the experiment was testing?  Since space
radiators are what the main thrust of my thesis' desin prject, any
information would be helpful.

                                        Brendan

==========================================================================
              Disclaimer?  I don't need no stinkin' disclaimer!
                           Brendan C. Bayne

                        [e-mail]
                        [e-mail]

                           Making it happen!
==========================================================================

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

Date: 8 Apr 91 16:46:02 GMT
From: dev8a.mdcbbs.com![e-mail]
Subject: Re: I want to go to orbit...

In article <[e-mail]>, [e-mail] (Matt Clairday) writes:
> In article <[e-mail]>, [e-mail] (Mark SOKOLOWSKI) writes:
>>
>>     What are the steps in order to build a reliable space-shuttle like
>> spaceship in order to send myself to orbit for the summer holidays?
>> I'm thinking about a 20-30 ton rocket with a 900 kg payload made up of
>> a car sized hypersonic glidder, fitted with 3 rocket engines. There will
>> be 2 boosters of about 10 tons each, and a main liquid hydrogen-oxygen
>> tank of about 10 tons too. I have a Chalet near a lake with some forest
>
>   Mark, this shouldn't be any problem.  Just see your local nasa surplus
>   dealer for the relevant parts.  A bright guy like you should have
>   no trouble deducing the assembly instuctions from sifting through
>   relevant space shuttle articles of the period 1981-1990.
>
>
>> I guess I'll break the canadian law forbidding to send rocket of more
>> than 650 gramms (20 oz) in the air... but I'll land somewhere else.
>> Thanks in advance for any advice.
>>
>
>   I would suggest using stealth technology to hide your project from
>   the canadian govt. officials.  good luck, and happy holidays.


Now that we've all had a small chuckle over this gentlemans ambitions
(You're sailing WHERE, Christopher?), may I ask if anyone has seen of or heard
from Robert Truax lately. He is the ex-NASA rocket scientist who was building
his own 1 man orbital rocket a few years back. Last I heard, he had the booster
completed, and was trying to fund the actual vehicle.

Michael

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

End of SPACE Digest V13 #386
*******************