Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V16_3/V16NO339.TXT

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Date: Fri, 19 Mar 93 05:35:00
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V16 #339
To: Space Digest Readers
Precedence: bulk


Space Digest                Fri, 19 Mar 93       Volume 16 : Issue 339

Today's Topics:
       Ah, Ceesco! Ah, Pancho! (was Re: 20Khz Power supplies.)
                      cancel wars accountability
                    CD for Pluto Mission (2 msgs)
                     Hazards of asteroids/comets
                          How to cool Venus
             HST orbit and mirror coating(s) - need info
           Just a little tap (was Re: Galileo HGA) (2 msgs)
                     Lunar ice transport (2 msgs)
                   Mars Observer Update - 03/18/93
      moon's fate when removing gravitational influence of earth
                     Need MIR packet Frequency's
         Predicting gravity wave quantization & Cosmic Noise
Small Expendable Deployer System Launch Advisory (was Re: Launch Windows
                Solar Array vs. Power Tether SSF Drag
                     Space Tug (OMV) info sought
                     SR-71 Maiden Science Flight
Water Simulations (Was Re: Response to various attacks on SSF) (2 msgs)

    Welcome to the Space Digest!!  Please send your messages to
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----------------------------------------------------------------------

Date: 18 Mar 93 17:18:12 -0600
From: Bill Higgins-- Beam Jockey <[e-mail]>
Subject: Ah, Ceesco! Ah, Pancho! (was Re: 20Khz Power supplies.)
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (fred j mccall 575-3539) writes:
> In <[e-mail]> [e-mail]
(Roland Dobbins)  [formerly The Zombie Who Would Not Die, but I think
that software problem has been fixed] writes:
>
>>Ah, Fred, back to your old tricks again.  Seems like old times on BIX.
>
> Yep, back to speaking my mind.  Pity some of you apparently have such
> a problem with little things like 'Freedom of Speech', ain't it?
>
>>Too bad there's no moderator here to get you thrown off . . .
>
> Yeah.  Fortunately, this pond is just a mite too big for the kind of
> petty politicking among people who are legends in their own minds that
> was going on on BIX when I was there.

Fred, or Roland, do you want to tell us the story?  Or should it
remain a dark secret to which you guys will continually make
mysterious allusions?

--
     O~~*           /_) ' / /   /_/ '  ,   ,  ' ,_  _           \|/
   - ~ -~~~~~~~~~~~/_) / / /   / / / (_) (_) / / / _\~~~~~~~~~~~zap!
 /       \                          (_) (_)                    / | \
 |       |     Bill Higgins   Fermi National Accelerator Laboratory
 \       /     Bitnet:     [e-mail]
   -   -       Internet:  [e-mail]
     ~         SPAN/Hepnet:      43011::HIGGINS

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

Date: Thu, 18 Mar 1993 19:23:03 GMT
From: Ed McGuire <[e-mail]>
Subject: cancel wars accountability
Newsgroups: comp.org.eff.talk,alt.privacy,sci.space,sci.astro,news.admin.policy

In <[e-mail]> [e-mail] (David Weingart) writes:

>In article <[e-mail]>, [e-mail] (Jay Maynard) writes:
>|> Not even close. Julf can't get the coward fired from his job.

>On the other hand, posting flames and personal attacks doesn't normally
>_deserve_ firing (nor did ARMM, BTW, since it was deactivated, although
>removal of net.access, either permanently, or some specified period for
>abuse of power might be in order)

I agree.  Instead of nailing the offender with a private standard for
behavior that many net sites may not even share, we should be nailing
the offender with a shared (network) standard.  That is why the
appropriate escalation path is individual, site admin, neighbor site,
not individual, boss, priest, parent.

Regards, Ed
--
Ed McGuire                   1603 LBJ Freeway, Suite 780
Systems Administrator/       Dallas, Texas 75234
 Member of Technical Staff   214/620-2100, FAX [phone]
Intellection, Inc.           <[e-mail]>

It's Only News.
Raise Usenet quality.  Read news.announce.newgroups and vote.

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

Date: 18 Mar 93 22:20:46 GMT
From: FRANK NEY <tnc!m0102>
Subject: CD for Pluto Mission
Newsgroups: sci.space

A week ago I put forth the idea of developing a proposal for a CD
(along the lines of the Voyager record) for an upcoming Pluto probe.

So far, I have listened to a resounding silence as a response.

I hope it's just because people are brainstorming and haven't come up
with anything useful to contribute yet.

--
The Next Challenge - Public Access Unix in Northern Va. - Washington D.C.
703-803-0391 To log in for trial and account info.

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

Date: 18 Mar 1993 21:54:02 -0500
From: Matthew DeLuca <[e-mail]>
Subject: CD for Pluto Mission
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (FRANK NEY) writes:

>A week ago I put forth the idea of developing a proposal for a CD
>(along the lines of the Voyager record) for an upcoming Pluto probe.

>I hope it's just because people are brainstorming and haven't come up
>with anything useful to contribute yet.

Then again, it could be that the proposed Pluto mission is extremely
weight-constrained; the slim one-in-a-zillion chance of aliens picking
up the probe probably doesn't weigh out the disadvantage of the weight
of the CD.
--
Matthew DeLuca
Georgia Institute of Technology, Atlanta Georgia, 30332
uucp:      ...!{decvax,hplabs,ncar,purdue,rutgers}!gatech!prism!matthew
Internet: [e-mail]

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

Date: Thu, 18 Mar 1993 22:43:33 GMT
From: Joe Cain <[e-mail]>
Subject: Hazards of asteroids/comets
Newsgroups: alt.sci.planetary,sci.space,sci.astro

Lines: 18
Source-Info:  Sender is really [e-mail]
Source-Info:  Sender is really [e-mail]

    One of the freshman non-science students in my class has as
his project to write up the present status of the hazards to Earth of
asteroids and comets. I have loaned him my copy of the NASA
International Near-Earth-Object Detection Workshop report chaired by
David Morrison, and he has the recent Newsweek article which started
him in this direction. Does anyone have handy any more recent
references than those listed in the Morrison report? It has a
publication date of January 25, 1992 and includes a couple of
references with 1992 dates on them, though one is "in press."
Probably nothing overwhelmingly technical would be of much use, but I
would be curious as to whether further plans or activities have ensued
of the "Spaceguard Survey."
If anyone has recent publications or reprints they can send, please
e-mail for my snailmail address.

Joseph Cain        [e-mail]
[e-mail]        scri::cain
[phone]        FAX [phone] or -0098

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

Date: Fri, 19 Mar 1993 05:27:21 GMT
From: "Richard A. Schumacher" <[e-mail]>
Subject: How to cool Venus
Newsgroups: sci.space

In <[e-mail]> TMakinen writes:

>This removing of carbon from primordial atmosphere as a byproduct of the
>chemical processes driven by living organisms is a minor cause to present-
>day lack of carbon dioxide in our atmosphere. The main deposit of carbon
>dioxide in our planet lies in the carbonate rocks which contain some
>100,000 times more CO2 than the atmosphere. CO2 is recycled through
>plate tectonics and volcanism.

Err, all that carbonate rock was created by life: corals, diatoms,
etc., make calcium carbonate for their shells, spicules, and whatnot.

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

Date: 18 Mar 93 09:02:17 EST
From: [e-mail]
Subject: HST orbit and mirror coating(s) - need info
Newsgroups: sci.space

Does anyone have the answers to the following questions:

i) how high is the orbit of the Hubble Space Telescope?
ii) what type of metal(s) and coating(s) are on the mirror?

email to the following address:    "[e-mail]"

thanks,
Eric

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

Date: 19 Mar 93 03:38:13 GMT
From: Greg Shippen <[e-mail]>
Subject: Just a little tap (was Re: Galileo HGA)
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Henry Spencer) writes:
> In article <[e-mail]> [e-mail] (Dennis Newkirk) writes:
> >Seriuosly, does anyone know if there's any hope that orbital insertion burn
> >will jolt the antenna loose? ...
>
> Some hope, but not a whole lot.
> --
> All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
>                     - Kipling           |  [e-mail]  utzoo!henry

Are they going to try to hammer the actuator during the burn?  It seems like
this would have a little greater hope...?

--
Gregory B. Shippen
Silicon Graphics Inc./MIPS Technology Inc.            [e-mail]
2011 N. Shoreline Blvd. M/S 10L-175
Mountain View, CA  94039 [phone]

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

Date: Fri, 19 Mar 1993 04:11:36 GMT
From: "robert.f.casey" <[e-mail]>
Subject: Just a little tap (was Re: Galileo HGA)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Pat) writes:
>
>Besides,  if the HGA opened, and the probes went off course, it would
>be a wash.  the orbiter would get most of the imaging data, but the probe
>mission may get lost.   kinda a trade off.   Lousy deal, but no worse then
>the deal we got now.

I would think that the probe mission is considered more important than
the lack of some imaging.  We will get some images anyway, but the probe
will give us new info that hasen't been measured before.   I wouldn't want
to loose that chance to gather observations that we have never done before.

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

Date: Fri, 19 Mar 1993 00:41:03 GMT
From: Gary Coffman <ke4zv!gary>
Subject: Lunar ice transport
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Bill Higgins-- Beam Jockey) writes:
>In article <[e-mail]>, [e-mail] (Gary Coffman) writes:
>> In article <[e-mail]> [e-mail] (Ross  Borden) writes:
>>>    So, if you were to preheat the pipeline by injecting superheated
>>>steam, could you pump water at, say, 100C the entire length without reheating?
>>>    Gary Coffman mentions using steam instead of water, but its not clear
>>>to me why.  Is it for ease of pumping?  I would think that you would be able
>>>to deliver more mass using liquid phase.
>>
>> I was suggesting a system that is *self pumping*. The solar heating of
>> the pipe during lunar daytime boils the water and the system "percolates"
>> via a set of one way check valves toward the equatorial base.
>
>Cute idea, Gary, but if it could be made to work, it would work
>only six months a year at best.

Sure, it won't work during lunar nighttime, but that's OK. The pipeline
would have to be designed to handle the expansion as it freezes, but
since pressures are low in the system, flexible piping shouldn't be a
problem.

Gary

--
Gary Coffman KE4ZV          |    You make it,     | gatech!wa4mei!ke4zv!gary
Destructive Testing Systems |    we break it.     | uunet!rsiatl!ke4zv!gary
534 Shannon Way             |    Guaranteed!      | emory!kd4nc!ke4zv!gary
Lawrenceville, GA 30244     |                     |

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

Date: Fri, 19 Mar 1993 04:44:09 GMT
From: Josh Hopkins <[e-mail]>
Subject: Lunar ice transport
Newsgroups: sci.space

[e-mail] (Bill Higgins-- Beam Jockey) writes:

>In article <[e-mail]>, [e-mail] (Gary Coffman) writes:
>> In article <[e-mail]> [e-mail] (Ross  Borden) writes:
>>>    So, if you were to preheat the pipeline by injecting superheated
>>>steam, could you pump water at, say, 100C the entire length without reheating?
>>>    Gary Coffman mentions using steam instead of water, but its not clear
>>>to me why.  Is it for ease of pumping?  I would think that you would be able
>>>to deliver more mass using liquid phase.
>>
>> I was suggesting a system that is *self pumping*. The solar heating of
>> the pipe during lunar daytime boils the water and the system "percolates"
>> via a set of one way check valves toward the equatorial base.

>Cute idea, Gary, but if it could be made to work, it would work
>only six months a year at best.

First I want to clear up one thing that might be confusing.  The problem is
with standard night/day cycles (in which the days add up to six months) rather
than a single six month night as you would expect at a terrestrial pole.  I'm
sure Bill know's this but other readers might be confused.

Secondly, I don't think it should be too hard to isolate the pipeline from the
surface to drastically cut down on the heat loss at night.  The pipeline is
then essentially radiating to vacuum.  Given the high heat capacity of water and
the two phase changes you'd have to go through before the water would freeze,
it seems to me that you could keep the pipeline running for at least part of
the Lunar night.  If I had more spare time I'd pull out my steam tables and
plug a few numbers.


--
Josh Hopkins                                          [e-mail]
          "Tout ce qu'un homme est capable d'imaginer, d'autres hommes
                     seront capable de la realiser"
             -Jules Verne

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

Date: 19 Mar 93 02:12:53 GMT
From: Ron Baalke <[e-mail]>
Subject: Mars Observer Update - 03/18/93
Newsgroups: sci.space,sci.astro,alt.sci.planetary

Forwarded from:
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE [phone]

                  MARS OBSERVER MISSION STATUS
                         March 18, 1993

     The Mars Observer spacecraft completed its third trajectory
correction maneuver (TCM-3) today at 11 a.m. Pacific Standard
Time, setting the stage for approach and capture in Mars orbit on
Aug. 24, 1993.

     The spacecraft fired four of its small 22-Newton thrusters
to achieve the desired change in velocity of 0.46 meters (1.5
feet) per second. Preliminary engineering data indicated that the
17-second maneuver was successfully completed. If necessary, a
fourth TCM will be performed 20 days before orbit insertion.

     All spacecraft subsystems and instrument payload are
performing well in the outer cruise configuration.  Uplink and
downlink communications are being performed via the high-gain
antenna.

     Since activation of the high-gain antenna in early January,
JPL has been conducting a Ka-band communications link experiment
with the Mars Observer spacecraft.  The experiment will evaluate
communications capabilities using shorter, 9-millimeter-long
wavelengths rather than the 3.5-centimeter wavelengths (X-band)
that are currently used. The experiment is the first of its kind
and was made possible with advanced technology deployed at the
Goldstone 34-meter research antenna.  Early results have been
excellent and the spacecraft will be periodically tracked at Ka-
band throughout the mission. The experiment is sponsored by
NASA's Office of Space Communications and is aimed at advancing
technology for future, low-cost planetary exploration missions.

     Today Mars Observer is about 30 million kilometers (18
million miles) from Mars, traveling at a velocity of about 11,000
kilometers per hour (7,500 miles per hour) with respect to Mars.
One-way light time to Earth is about 7.5 minutes (444 seconds).

                             #####

     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Don't ever take a fence
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | down until you know the
|_____|/  |_|/       |_____|/                     | reason it was put up.

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

Date: Fri, 19 Mar 1993 05:18:46 GMT
From: Michael Moroney <[e-mail]>
Subject: moon's fate when removing gravitational influence of earth
Newsgroups: sci.space

[e-mail] ("Hans M. Steiner") writes:

>Organization: ESA/ESRIN EDMS Software Development
>Sorry if this has been asked before, but in the FAQ list I could not
>find an easy answer to my problem.

>If one could "take away" the earth in an instant (remove the influence
>of the earth on the moon), what would happen to the moon's orbit around
>the sun?

The force of the sun on the moon is actually stronger than the force of the
earth on the moon, so if you plot its path through space relative to the
sun you get a rather wavy orbit.  The waviness is due to the strong influence
of earth of course.  If you could "take away" the earth I'd say you'd get
an earth-like orbit around the sun, and you could call the moon a small
planet.  Its orbit might be more eccentric than earth, depending on where
it was relative to earth at the time earth "vanished".

-Mike

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

Date: 18 Mar 93 15:56:08 EST
From: Steve Ford <[e-mail]>
Subject: Need MIR packet Frequency's
Newsgroups: sci.space,rec.ham-radio.packet,rec.radio.amateur.packet

In rec.radio.amateur.packet, [e-mail] (George Rachor) writes:
>Anyone remember the frequency's used by the MIR space station packet radio system?
>
>
>
>
>--
>George Rachor Jr.    Aloha, OR
>

Yep. 145.55 MHz. They tend to be a bit sporadic, so it takes a little
patience. Good luck.

73...Steve
WB8IMY

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

Date: Fri, 19 Mar 1993 02:29:13 GMT
From: Cameron Randale Bass <[e-mail]>
Subject: Predicting gravity wave quantization & Cosmic Noise
Newsgroups: sci.space,sci.astro,sci.physics,alt.sci.planetary

In article <[e-mail]> [e-mail]. (Thomas E. Smith) writes:
>>     Okay, but how does one rule out ordinary environmental perturbations
>>     that happen to occur at the appropriate times?  How does one distinguish
>>     between an ordinary dynamical triple-coincidence event and
>>     a gravitational one?
>>
>>                                  dale bass
>
>It is possible that rondom noise from different sources would be picked up
>by all three spacecraft at the same time. But it's not very likely. I mean
>take a look at what might cause the random noise:
>
>  1. Vibrations on the spacecraft. These can usually be accounted for and
>     either be predicted, or ruled out if you know where it's comming from.
>     Space is perfect for eliminating vibrations.

      You're kidding, right?  Space is perfect for inducing undamped
      thermal oscillations.  As far as predicting them goes, how long
      did it take to postdict Hubble's?  As far as the others go, I'm
      sure they're possible, but I was curious about dynamical effects
      that could mimic the expected signal.

      In any case, I'd be interested in the magnitudes of the expected
      oscillations.  As I said before, there are lots of things that
      can knock spacecraft around on millimeter scales.  Does anyone
      know offhand the expected size or characteristics of the
      'typical' signal?  Without that, we're all blowing wind about
      such effects.

                              dale bass

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

Date: 19 Mar 93 01:24:00 GMT
From: [e-mail]
Subject: Small Expendable Deployer System Launch Advisory (was Re: Launch Windows
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Samuel Bryant) writes...
>[e-mail] (Dean Adams) writes:
>
>>Does anyone have the current launch window data
>>for the two upcoming DoD ELV flights?
>
>>Last I heard, the Delta II/GPS launch was
>>scheduled for Thursday at 8pm (PT)...
>


This is Relayed from Mr. Jim Harrision, the Small Expendable Deployer
System (SEDS) Project Manager.

All Readiness reviews have been completed and the SEDS 1 mission is ready
for launch.  Liftoff time is anticipated to be around 11 pm EST tonight
March 18, 1993.

SEDS is a scondary payload to the Air Force Global Positioning System and
will be lofted into orbit on a McDonnell Douglas Delta II 7925 launch vehicle.

The deployment of the 20 km SEDS tether and instrumented end mass will
begin approximately 60 minutes after launch over Guam.  The deployment will
last for 5100 seconds approximately, after which the tether will be cut
at the Delta II end, and the instrumented end mass, built by NASA Langely
will re-enter.  This re-entry will occur off the west coast of California
(San Diego or southward into Mexico.

The tether deployer is a spinning reel type mechanism with the tether wound
around a bobbin in a  manner similar to yarn in a garmet factory.  The
tether is made of a material called SPECTRA 1000 and is stronger in
tension than Kevlar.  It also has a lower modulus of friction, which is a
key problem in the gravity forced deployment method that is used for SEDS.


End of forwarded message

Everyone keep their fingers crossed tonight. I will know by morning if the
mission worked or not.  If we are successful this could be one of the
technologies that actually help to make a significant contribution to
lowering the cost of spaceflight.

The cost of this mission from 1983 till now has only been 10 million dollars
and it is significant to note that most of the work has been done IN HOUSE
with the exception of one contractor for the tether.

The moral of this story is to give NASA the money that they say a project is
going to cost and then leave them alone and let them do their job. If there
is an overrun then shoot the managers but cut out this "you can really do it
with this much less money can't you" syndrome

Dennis, University of Alabama in Huntsville

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

Date: Fri, 19 Mar 1993 01:41:59 GMT
From: Frank Crary <[e-mail]>
Subject: Solar Array vs. Power Tether SSF Drag
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (David Pugh) writes:
>|> Oh well, tethers create 5 times as much drag as this, for the
>|> same amount of power generated. If you want to generate electricity
>|> by burning hydrazine, it looks like you'd be better off doing
>|> it in an APU, which wouldn't affect your orbital altitude...

>OK ... how about running backwards? If tether drag > array drag, then
>(assuming reasonable efficiencies), tether thrust should also be greater
>than the array drag.

That's quite possible. The main advantage would be the no fuel
consumption: If the station used a tether for station keeping,
it wouldn't require any resupply to stay on orbit.

>...A down side is that running the tether boost almost continually
>might mess up some microgravity experiments.

You could probably pulse the current, with (say) a week of reboosting
followed by a month of microgravity. Going much further would
require very excessive solar power arrays or some sort of power
storage. Of cousre, there would also be alot of extra power available
to experiments during the off cycle.

                                                       Frank Crary
                                                       CU Boulder

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

Date: 19 Mar 93 00:26:48 GMT
From: "Adam R. Brody " <[e-mail]>
Subject: Space Tug (OMV) info sought
Newsgroups: sci.space,sci.space.shuttle,talk.politics.space

[e-mail] (Fogbound Child) writes:

>Hello Everyone.

>A classmate of mine is doing research on the history and politics of the OMV
>(Orbital Maneuvering Vehicle aka "Space Tug").

>She's had some difficulty finding people from NASA or TRW who are knowledgable
>and willing to talk about the program.

>If you know anything about the program and can provide this kind of infor-
>mation, please either call Laurel L. Noel at 310-607-4488 (tell her Samuel
>sent you) or reply to me with information about how she can get in touch with
>you.

>Thanks!
>___Samuel___
>--
>_________Pratice Safe .Signature! Prevent Dangerous Signature Virii!_______
>Guildenstern: Our names shouted in a certain dawn ... a message ... a
>              summons ... There must have been a moment, at the beginning,
>              where we could have said -- no. But somehow we missed it.

Hal Coldwater at MSFC was the Program Manager.
[phone]

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

Date: 18 Mar 1993 19:08:54 -0500
From: Pat <[e-mail]>
Subject: SR-71 Maiden Science Flight
Newsgroups: sci.space

|John> In article <[e-mail]> [e-mail] (Mary Shafer) writes:
|>From: [e-mail] (Mary Shafer)
|
|>Matthew> is NASA going to run the SR-71 through its paces and find out
|>Matthew> what exactly IS its top speed?
|>
|>Only if there's a research requirement to do so.
|>
|>I wouldn't hold my breath waiting for this to happen.
|

Wouldn't some of the Dryden Pilots for the NASA SR-71  now have been former
AirFOrce  Recon Pilots?   I imagine it's just cheaper to get them on
TDY or Assignment to NASA  then to send people through SR-71 flight
school.  Actually, I once saw a picture of a two seat SR-71 Pilot trainer.
If that was de-commisioned,  it will be hard to train new SR-71 pilots.

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

Date: 18 Mar 1993 23:28:59 GMT
From: Dave Akin <[e-mail]>
Subject: Water Simulations (Was Re: Response to various attacks on SSF)
Newsgroups: sci.space

In article <[e-mail]> Allen W. Sherzer, [e-mail]
writes:
>Perhaps. The point is that nobody knows if that is true or not. Water
>training is only an approximation of zero G. We don't know what sorts
>of things it is good for and what it is bad for. If NASA had been engaged
>in a program of EVA research for the past 10 years, we WOULD know to
>a far better degree. This would remove a lot of risk from projects
>ranging from SSF to Hubble repair.
>
>Tanks may be the best simulation facility available but we also need
>to know the differences between tanks and real zero g.

I personally have been doing this professionally for fifteen years.
The folks at NASA have been at this a lot longer, and while their
approach has been more empirical than those of us in academia are
used to, I wouldn't sell their knowledge base short, either. In my
experience, the NASA EVA flight trainers can run the crew
through WETF tests for training, and come up with flight timelines
accurate to within 10%, AND know which way to bias it to give
the flight crew some slack time for resting, taking pictures of each
other, etc. While the neutral buoyancy community is pretty small,
it's not like we're amateur hackers, either...

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

Date: Fri, 19 Mar 1993 04:32:13 GMT
From: Henry Spencer <[e-mail]>
Subject: Water Simulations (Was Re: Response to various attacks on SSF)
Newsgroups: sci.space

In article <1ob0jr$[e-mail]> Dave Akin <[e-mail]> writes:
>... I wouldn't sell their knowledge base short, either. In my
>experience, the NASA EVA flight trainers can run the crew
>through WETF tests for training, and come up with flight timelines
>accurate to within 10%...

Except when they can't, e.g. the Intelsat rescue.

Nobody is saying that the water tanks are valueless.  The astronauts
themselves say that the tanks are the best ground-based simulation of
free fall.  The point is, the fidelity of most any simulation is limited,
and *we don't know where the limits are*.  The Intelsat problem was a
nasty surprise.  There are probably more such surprises lurking.  We can
either mount a systematic experimental program to discover them before
they cause trouble, or find out about them the hard way on some crucial
mission with limited slack in its timeline.

The evidence to date is that the EVA trainers *can't* accurately predict
tricky operations like satellite repairs.  They've muffed three out of
four, if we don't count the GRO contingency EVA.
--
All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
                    - Kipling           |  [e-mail]  utzoo!henry

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

End of Space Digest Volume 16 : Issue 339
------------------------------