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Subject: SPACE Digest V13 #490

SPACE Digest                                     Volume 13 : Issue 490

Today's Topics:
         NASA Headline News for 05/03/91 (Forwarded)
              Re: Why the space station?
            SPACE Digest V13 #486

Administrivia:

    Submissions to the SPACE Digest/sci.space should be mailed to
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Date: 3 May 91 20:09:29 GMT
From: [e-mail]  (Peter E. Yee)
Subject: NASA Headline News for 05/03/91 (Forwarded)


             Headline News
Internal Communications Branch (P-2) NASA Headquarters

  Friday, May 3, 1991    Audio Service: 202 / 755-1788

This is NASA Headline News for Friday, May 3, 1991 . . .

Activities aboard Discovery continue to go very well.  Yesterday's
Strategic Defense Initiative experiments involved three spacecraft:  The
Shuttle Pallet Spacecraft and Discovery, which  were in observing
positions; and two of three chemical release subsatellites, which released
chemical samples into the thin atmosphere.  Following these successful
observations, which included ground observers located at Vandenberg Air
Force Base, Discovery closed in on the SPAS and the crew used the remote
manipulator system to grapple and reberth that satellite.  The SPAS is
back on the end of the robot arm today, where it will stay through
tomorrow morning, for observations of the final chemical release
experiment and additional earth limb observations.  SDI and Air Force
program officers continue to express their appreciation for how well their
experiments have been going and the exceptional quality of the data.
Discovery and crew are also performing very well.  Landing at Edwards
is set for 2:57 pm EDT Monday.

Endeavour left Edwards Air Force Base atop the new NASA shuttle
carrier aircraft this morning at 9:17 am EDT bound for Biggs Army Air
Field, El Paso, Texas.  The 747 carrier aircraft and Endeavour will
layover in El Paso through tomorrow morning when the 747 crew will
again assess weather conditions for the continuation of their trip to the
Shuttle Landing Facility at Kennedy Space Center.  If weather permits,
Endeavour will leave El Paso for Kennedy tomorrow, otherwise the crew
will perform a day-by-day weather assessment.

All seven STS-40 flight crew members are due to arrive at Kennedy on
Sunday, May 5, in anticipation of the mission terminal countdown
demonstration test, set for Monday and Tuesday, May 6 and 7.

                   * * * * * * * * * * * * * * * *

NASA announced yesterday that it is taking candidates for the 1992
astronaut candidate class.  Because of future payload and mission
requirements, the agency is seeking individuals with backgrounds in the
medical sciences, microgravity research, and materials processing.
Applications will be taken until July 1.

Also yesterday, NASA announced it has selected two payload specialists
for the first U.S. Microgravity Laboratory mission, now set for flight
in June, 1992.  NASA selected Dr. Lawrence J. DeLucas, University of
Alabama, Birmingham, and Dr. Eugene H. Trinh, Jet Propulsion
Laboratory.  DeLucas has a doctorate in biochemistry and Trinh has his
doctorate in applied physics.  The USML mission crew is scheduled to
perform more than 30 experiments in materials, fluids and biological
processes in a payload-bay mounted Spacelab module.

                   * * * * * * * * * * * * * * * *

Astronaut Dr. Mary Cleave will leave the astronaut corps to become
the deputy project manager for the SeaWiFs project at the Goddard
Space Flight Center.  SeaWiFs, or the Sea Viewing Wide Field Sensors
project, is a joint NASA and commercial project which will study the
chlorophyll content of the world's oceans to help determine the biological
mass present.  Cleave said that Earth observations experience she gained
during her two shuttle missions will be helpful in her new position.

                   * * * * * * * * * * * * * * * *

Joust 1, a commercial suborbital rocket carrying 10 materials and
biotechnology experiments, will be launched from Cape Canaveral Air
Force Station launch complex 20 Monday, May 6 at 7:00 am.  The
mission is sponsored by the University of Alabama, Huntsville's
Consortium for Materials in Space (one of the NASA Centers for the
Commercial Development of Space).  The launch will be carried live on
NASA Select TV.

Here's the broadcast schedule for Public Affairs events on NASA Select
TV.  Note that all events and times may change without notice, and that
all times listed are Eastern.

Friday, 5/3/91
    All day    Payload and crew flight deck activities, live from Discovery and
          flight controller activities, live from Johnson Space Center.
    3:00 pm    Flight director change-of-shift briefing, live from JSC.
    6:00 pm    Chemical release operations live from Discovery.
    9:00 pm    Playback of STS-39 flight day 6 activities, from JSC.
    11:00 pm    Flight director change-of-shift briefing, live from JSC.

Saturday, 5/4/91
    All day    Payload and crew flight deck activities, live from Discovery and
          flight controller activities, live from Johnson Space Center.
    7:00 am    Flight director change-of-shift briefing, live from JSC.
    7:56 am    Berthing of SPAS satellite, live from Discovery.
    3:00 pm    Flight director change-of-shift briefing, live from JSC.
    4:20 am    Cabin television, live from Discovery.
    8:00 pm    Playback of STS-39 flight day 7 activities, from JSC.
    11:00 pm Flight director change-of-shift briefing, live from JSC.

Sunday, 5/5/91
    All day    Payload and crew flight deck activities, live from Discovery and
          flight controller activities, live from Johnson Space Center.
    7:00 am    Flight director change-of-shift briefing, live from JSC.
    3:30 pm    Flight director change-of-shift briefing, live from JSC.
    6:30 pm    Playback of STS-39 flight day 8 activities, from JSC.
    8:38 pm    Earth observations, live from Discovery, through 10:53 pm.
    11:00 pm Flight director change-of-shift briefing, live from JSC.

Monday, 5/6/91
    1:18 am    Earth observations, live from Discovery, through 3:03 am.
    5:03 am    Deorbit preparations, live from Discovery.
    7:00 am    Joust-1 launch, live from Cape Canaveral AFS, pad 20.
    2:04 pm    Discovery deorbit maneuver (no video) orbit 133.
    2:57 pm    Discovery landing, live from Edwards Air Force Base.
    4:30 pm    Post-landing press conference, live from Dryden Flight
          Research Facility.

This report is filed daily at noon, Monday through Friday.  It is a service of
NASA's Office of Public Affairs.  The contact is Charles Redmond, 202/453-8425
or CREDMOND on NASAmail.  NASA Select TV is carried on GE Satcom F2R,
transponder 13, C-Band, 72 degrees West Longitude, transponder frequency is
3960 megaHertz, audio is offset 6.8 MHz, polarization is vertical.

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

Date: 5 May 91 21:01:06 GMT
From: usc!rpi![e-mail]  (Michael V. Kent)
Subject: Re: Why the space station?

In article <[e-mail]> [e-mail] (Frank Crary) writes:
>From these conclusions, NASA went to Congress and President Nixon. Neither
>wanted to pay for the whole package... So NASA thought "Well, the first
>thing we will need is the reusable Earth-to-orbit transport. Lets get
>that done first." So NASA focused on the Space Shuttle (without really
>remembering why they needed it). They got Congress to pay for it,
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

You were doing pretty good, until you got to this point.  NASA has always said
the main purpose of a space shuttle is space station support.  Don't blame
NASA for the Vietnam-era politics in which it found itself.

>but the final product is not well suited for its origional purpose:
>building and supporting a space station.

Supporting, yes, but the shuttle was not meant to build the space station.
That was to be done with the Saturn V.  It was only after NASA was forced to
make the choice between the Space Shuttle and the Saturn V that they decided
to build the space station with the Shuttle.

>Now, having the shuttle, NASA wants to proceed with their origional plan:
>The "Next Logical Step" is a space station. So NASA, again forgeting WHY

No, NASA knows very well why they want a space station.  But the space station
they want must be built incrementally, like the pieces of their overall plan.
Freedom will be expanded into an orbital base as soon as NASA is given the
money to do so.

Mike

--
Michael Kent                                   [e-mail]
McDonnell Douglas                              Rensselaer Polytechnic Institute
All facts in this post are based on publicly available information.  All
opinions expressed are solely those of the author. Official positions may vary.

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

ReSent-Message-ID: <[e-mail]>
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Resent-From: Tommy Mac <[e-mail]>
Resent-To: [e-mail]
Date:         Wed, 1 May 91 01:48:19 EDT
Reply-To: [e-mail]
From: [e-mail]
Subject:      SPACE Digest V13 #486
Comments: To: [e-mail]
To: david polito <[e-mail]>, Tom McWilliams <[e-mail]>

The remainder of this article consists of elucidations, some of them
more than slightly condescending, a bit of flamage, and a pinch of
humor.  People who do not wish to waste their time, hit "N" now.

(it's about 5 pages of junk!)

(Page down to those of you  stuck on the old systems)













You were warned...


:>>>with terrible efficiency. While for a rocket, the longer it runs, the
:>>>faster it goes since it's mass ratio is continually improving right
:>>>up until burnout.
:>>This statement ran my bogosity meter off the scale....
:>I'm not sure what a 'bogosity meter' is, but I reckon it's a phrase you draw u
:>whenever you don't have a real answer.
:>Point is that what was said about rockets being more efficient in the later
:>stages of a trip is neither 'ignorant' or 'careless', but rather; QUITE TRUE.
:>No wonder you won't bother to 'pick it apart'.

:Bogosity is a measure of how bogus something is, and you are wrong.
                              ^^^^^
Does this term refer to using undefined words?  Like bogus? Isn't that
self-referential?

:1.)     The quoted statement confuses acceleration and mass-ratio.

I think it's pretty clear that he meant 'the faster it accelerates'.  I think
you knew it too.

:2.)     A rocket is most efficient (transforms fuel energy into
:        final payload energy with the greatest efficiency) when it
:        has a mass ratio of approximately 4.  Today's orbital
:        boosters have much higher mass ratios.

He wasn't referring to absolute mass-ratio but the change in mass-ratio as
the flight went on.  He also wasn't claiming that the rocket approached the
best efficiency a rocket can have, but just that it's efficiency improved,
which it does.

:3.)     The "mass ratio" is the fuelled mass divided by the empty
:        mass, and cannot be meaningfully said to "improve" in flight.

You know damn well what he meant.  Quit screwing around.  The rocket's fuel
is used less on other fuel and more on actual payload at later times in the
flight.  Just admit that he knew what he was talking about!

:4.)     While the acceleration can increase, the efficiency of a
:        rocket is < 100% whenever its exhaust velocity is not exactly
:        equal to its speed, otherwise it leaves its exhaust at non-zero
:        speed relative to the point of origin.  This leaves wasted
:        kinetic energy in the exhaust, which contributes nothing.
:        Naive calculations of "efficiency" do not consider the
:        kinetic energy of the fuel in the tanks before burning,
:        which was paid for previously with more fuel.

I'm reaching into some very dark memeories at this point, but if I remember
correctly, efficiency is <100% whenever the exhaust velocity is < c, and the
mass conversion is less than 100% in the fule system.  So what was your point?

:>Sunlight does bloom, as does starlight, aurora light, light pollution, etc.
:>Just ask the guys that paid for the hubble scope (since it was supposed to
:>get, literally, above the blooming problem).

:You prove that you don't know what thermal blooming is; you
:have confused it with atmospheric turbulence.  Thermal blooming
:is a phenomenon in which absorbtion of a light beam by the
:medium (such as air) heats it, causing the index of refraction
:to change locally and defocussing the beam.

Sorry, I had assumed that blooming not only meant
the ionization of material, but also the refraction.
Which brings us back to the original question : How does you get past the, call
them 'dissipative effects'?

:>>[The] pitfalls experienced by the LF workers will not be applicable.
:>
:>Nonesense.  Of course it will.  Both need to transmit high amounts of energy
:>via an EM beam which has been focused on a target of tiny angular
:>size.  To claim otherwise is to prove the need for sanity checks yourself.

:... with vastly different requirements in pulse width, *many* orders
:of magnitude difference in power level at the target, huge differences
:in the optics... need I go on?

Yes.  Again the problem is the dissipative effects.  The problem, as I under-
stand it, is that at certain power levels, the atmosphere blocks the beam.
Since you've about ignored the idea of using different parts of the spectrum, I
will assume ( since you know so much more than me ) that it is impossible to
use ,say, radio or microwave to avoid the dissipative effects.

Pulse-width doesn't change the power level (Energy per second), nor do the
optics on the ground.  Breaking up the beam or using different wavelengths
seem promising, but you seem to be pushing single, large power, visible light
lasers (They would look impressive on the news!).

So, since you are such a wealth of useful info;  spread it around!

HOW DO IT WORK?


:>Rather than pointing out what was incorrect, or providing information to the
:>other party, you seem to feel it's ok to (try to) insult/belittle someone for
:>making a factual error or expressing an idea you don't like / disagree with.

:The information has been repeated in this newsgroups many times.

So.  Maybe the guy is new to this group.  If you have such great stuff to
share with the group, share it.  Don't blast some dude 'cuz he made the
mistake of not reading your mind first (maybe he tried and it was too closed)

:For Coffman (or you) to ignore it without first refuting it is
:dishonest.  For Coffman to claim that all cases of X are
:impossible after:
:a.)     Pulling a bogus number out of the air to "prove" it, or
:b.)     Considering only the naive case
:is ridiculous.  So I ridiculed him.  He should know better.

If that kind of behavior is expected, I'm getting off this group right now!  I
absolutley don't have the disk space for all the crap that would come down the
line!  Many of the posts are 'bogus out-of-nowhere' facts or 'the naive case'.
(You're kind of new to this group, aren't you?)

Pointing it out is one thing (Which is done quite a bit), but blasting people
for it shows, not ignorance, but plain old lameness and immaturity.

:>It's especially worthy of ridicule when you are doing exactly what you are
:>flaming someone else for doing!

:When Coffman quotes numbers like "1000 to 1000000 times", I want to
:know where he gets them and why he doesn't agree with the people who
:appear to be more experienced than he.  Since he has not posted a
:rebuttal, my suspicion that his figures are bogus is reinforced.

Haven't you heard?  If you can get astronomers and engineers to agree on the
magnitude of the exponent, you're ahead.  people constantly use order-of-mag
estimates on systems that are un-proven (or un-existent).

:>For example, claiming someone is ignorant while being quite ignorant yourself

:I have not claimed expertise in anything, save rocket mass ratios
:and energy requirements.

And you blasted Coffman for making a true statement about them.  Even an
 'expert' can talk like he/she is ignorant.


:>Or calling for sanity checks while invoking irellevant facts.

:Show me where I cited an irrelevant fact.  And spell it right next time. ;-)
                           You mean CORRECTLY I assume?  ^^^^^

Claiming that the most efficient mass-ratio has some effect on whether or not
one mass-ratio is better than another is a good start.

:>P.S. maybe I'm wasting space, but I feel that keeping the flak and not-so-
:>     friendly sparring to a minimum is important.  Especially since, by the
:>     nature of my abrasive personality, I find it so easy to join in.

:Had I known you existed, I would not have tempted you.  Perhaps,
:after being put back in your place, you are now feeling so small
:that I can once again consider you non-existent for the purpose
:of responding to net postings.  ;-)

Jeez, you missed not only the point, but the joke, too.  What a rube!

Naturally, being insulted for telling someone to be a little more civil and
maybe even professional has certainly shown me my place.

Serves me right for joining into a flame fest with someone that would rather
flame than share views/thoughts/information about the subject at hand.

Please, don't follow up.  I don't give a rat's ass what you have to say.

Tommy Mac and the Mac Attack
Acknowledge-To: <18084TM@MSU>

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

End of SPACE Digest V13 #490
*******************