Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V11_5/V11_539.TXT

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Subject: SPACE Digest V11 #539

SPACE Digest                                     Volume 11 : Issue 539

Today's Topics:
             Re: Weather Satellite Photos
  Re: US/Soviet Planetary Activity (was Re: Manned mission to Venus)
      Challenger accident (Was: Re: 10 psi overpressure)
               Re: Model rocket contest
         Re: Aim For The Moon - model rocket contest
CRRES mission briefing and spacecraft showing at KSC on June 22 (Forwarded)
               Re: 10 psi overpressure
      Re: Commercial Experiment Transporter planned (Forwarded)

Administrivia:

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

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

Date: 18 Jun 90 19:51:01 GMT
From: swrinde!zaphod.mps.ohio-state.edu!rpi!uupsi!uhasun![e-mail]  (Andrew Lindh)
Subject: Re: Weather Satellite Photos

In article <[e-mail]>, [e-mail] (Ian Wells) writes:
> I would like to have daily pictures of the earth delivered on the
> net. It would be great to have a picture of the hemisphere today
> displayed on my screen. Henry says the images are easy to obtain.

I am working on this NOW!!!!
I hope to set up my network station this week (6/18/90)
I have the PC and the WEFAX stuff will get here this week.
The last part is to put up a good antenna.

> I wonder how the images could be compressed enough to make it feasible
> to blat them out over the net. Even uuencoded compress tar file I imagine
> would be too large (final form would be postscript). Since a lot of the
> image would be the same each day, could fractal algorithms be used
> to compress the image further, given that each receiver had
> a specialized program to uncompress the image. How small could the
> transmitted image be made?
> Ian Wells  COMPASS,Inc    [e-mail]

Yes the images are VERY large. Since we only have a 9600 baud line
I don't know If I would allow too many people to get the images.
It would be nice if someone with a T1 would store the images for FTP
access. I would use compress...not uuencode. I would hope to produce
GIF files. Postscript would NOT be a good choice...too big and too
useless.

Providing just the "changes" is a good idea....use whichever is smaller
for that day.



--
Andrew Lindh, a student at the University of Hartford -- Computer Science
BITNET:    [e-mail]       INTERNET: [e-mail]
UUCP/Usenet: [e-mail]    ---- When will I grduate???
NOTE: All views here are MINE!!! Not the school's or those of anyone else!

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

Date: 18 Jun 90 20:54:27 GMT
From: clyde.concordia.ca!mcgill-vision!quiche!calvin![e-mail]  (Mark SOKOLOWSKI)
Subject: Re: US/Soviet Planetary Activity (was Re: Manned mission to Venus)

In article <[e-mail]> [e-mail] (David Lewis) writes:
>I've been watching this discussion, and I find the attitude that 'the
>only worthwhile things to do are those which haven't been done' rather
>distressing.  If that were the common attitude, there would never be any
>progress -- because nothing would ever get improved, refined, developed.
>Do you want to be reading news on a 1950-era Univac by the light of an
>Edison lightbulb?  Not I, thanks.
>

We would still be in the trees if we would restrict ourselves to things
that were done and are done on a regular basis. I think that's a
truism that almost all of us share here.

Mark S.
-------

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

Date: 18 Jun 90 20:21:41 GMT
From: zaphod.mps.ohio-state.edu!samsung!rex!rouge![e-mail]  (Fraering Philip)
Subject: Challenger accident (Was: Re: 10 psi overpressure)

On a related topic, did the Challenger have a range safety package
attached to it?

Philip Fraering
[e-mail]

"Was that civilized? No. Even if it was fun." - _Gremlins 2: The New Batch_

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

Date:         Mon, 18 Jun 90 17:40:53 CDT
From: John Nordlie <[e-mail]>
Subject:      Re: Model rocket contest

I was did some reading and a few calculations concerning the specific
impluse (Isp) of model rocket engines vs. conventional solid and
liquid fueled rockets.

Table 1 from "Introduction to Space Dynamics" by William Tyrell Thomson

Chemical Propellants                         Type     Specific Impulse, sec
---------------------------------------------------------------------------
Ammonium nitrate rubber                      Solid         170 - 210
Potassium perchlorite thickol or asphalt     Solid         170 - 210
Boron metal components and oxidant           Solid         200 - 250
Liquid oxygen alcohol                                      250 - 270
Liquid oxygen flourine JP4                                 270 - 330
Flourine hydrogen                                          300 - 385
---------------------------------------------------------------------

Table 2 from "How to Design, Build, and Test Small Liquid-Fuel
              Rocket Engines" by Rocketlab, China Lake, Calif.

Propellant Combination
   Oxidizer/Fuel                        Isp, sec
----------------------------------------------------
Liquid oxygen & gasoline                   242
Gaseous oxygen & gasoline                  279
Liquid oxygen & JP-4 (jet fuel)            255
Liquid oxygen & methyl alcohol             238
Gaseous oxygen & methyl alcohol            248
Liquid oxygen & hydrogen                   363
Red fuming nitric acid & JP-4              238
-----------------------------------------------

Estes model rocket engine instructions have a table of engine
thrust, total impulse, and propellant weight, as well as a graph of
thrust versus burn time for all the model rocket engines they sell.
I used the table to extrapolate burn times for 1 pound of propellant,
then calculated the specific impulse (Isp) for the average model rocket
motor from size "A" to size "D".

Result :  Isp = 81  on average for Estes model rocket engines.

I calculated the Isp for a selected group of engines with the longest
extrapolated burn times (about 63 seconds), and also for the average
burn time (there were some 24 second and 45 second burn time figures),
but the difference was only .37(Isp).

What does this mean?  A certin amount of energy is needed to lift a
payload out of earth's gravity well.  To supply this energy using
model rocket engines with an Isp of 81, you would need 448% more
propellant (by weight) than if you were using a oxygen/hydrogen
fuel.  I don't know the payload capacity of any small rockets
that can achieve escape velocity, but I would guess that you would
need an awful lot of model rocket engines (or one VERY big one) to
equal the lifting power.

Where did you get your figures for Isp, Vincint?  I am curious.
Also, where do you get "N" size model rocket engines?  I have not
been able to find a catalog that sells them.

====================================================================
   John Nordlie   :   I STILL haven't thought of anything clever
                  :    to say, can you believe it?
====================================================================

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

Date: 19 Jun 90 01:40:08 GMT
From: portal!cup.portal.com![e-mail]  (Patrick John Horgan)
Subject: Re: Aim For The Moon - model rocket contest

WOW!  What an idea:)  Is this really feasible?  I would have thought
that the normal construction methods for model rockets would result in
the destruction of the model by the thrust of the early stages.  Does
anyone know the altitude record for model rockets using "normal", i.e.
<= D size engines?

Patrick Horgan                         [e-mail]

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

Date: 18 Jun 90 12:58:05 GMT
From: trident.arc.nasa.gov![e-mail]  (Peter E. Yee)
Subject: CRRES mission briefing and spacecraft showing at KSC on June 22 (Forwarded)


  George H. Diller                                    June 18, 1990
  Kennedy Space Center
  407/867-2468

  KSC Release No. 105-90

  NOTE TO EDITORS AND BROADCAST NEWS DIRECTORS:

  CRRES MISSION BRIEFING AND SPACECRAFT SHOWING AT KSC ON JUNE 22


       The Combined Release and Radiation Effects Satellite (CRRES)
  to be launched aboard an Atlas Centaur rocket in mid-July will be
  the focus of a mission briefing and photo opportunity on Friday,
  June 22 at 11:00 a.m.

       CRRES will embark on a joint NASA/USAF mission to study the
  effects the radiation environment of space may have on advanced
  satellite electronics and sophisticated sensors.  Chemical
  releases from the satellite in the ionosphere and magnetosphere
  will briefly "paint" the waves and lines of magnetic fields with
  luminous particles.  Five chemical tracer elements to be expelled
  from 24 spacecraft canisters will create brilliantly visible
  releases in the Caribbean and South Pacific areas.

       Participating in the briefing will be:

  James L. Womack, Director of Expendable Vehicles
  NASA Kennedy Space Center

  William Swords, CRRES Project Manager
  NASA Marshall Space Flight Center

  Dr. David Reasoner, CRRES Project Scientist
  NASA Marshall Space Flight Center

  Colonel John E. Armstrong, Program Manager
  USAF Space Test and Transportation Program Office

  Major Stanley A. Sneegas, CRRES Program Manager
  USAF Space Systems Division


       The briefing will be on NASA Select television carried on
  Satcom F2R, transponder 13 located at 72 degrees W.  Audio only
  is also available on the V-2 circuits which may be dialed
  directly at 407/867-1220....1240....1260.  A two-way question and
  answer capability will be available at other NASA news
  facilities.

       At the conclusion of the briefing, news media will be taken
  by bus to the airlock of the Payload Hazardous Servicing Facility
  where preparations will be underway for encapsulating the CRRES
  spacecraft within the Atlas Centaur nose fairing.

       White room smocks and caps will be provided.  Photographers
  may use electronic flash and battery powered lights.  No outside
  power will be available.  No shorts or skirts are permitted and
  flat, close-toe shoes are required.  Camera accessories to be
  taken into the clean room must be transferred to special plastic
  bags which will be provided--no leather or vinyl can be taken
  into the facility.  Quality control personnel may request a wipe-
  down of photographic support equipment such as tripods before
  entering the clean room area.  The cleaning materials will be
  furnished. As propellant is aboard the spacecraft, no matches or
  lighters are allowed in the facility.

       Arrival back at the KSC News Center is expected at about
  1:45 p.m.

       Media needing accreditation for this event should contact
  the NASA-KSC News Center at 407/867-2468 to request badging.

       The date of this event is driven by spacecraft readiness for
  encapsulation, so media representatives may wish to contact the
  news center a day in advance to assure there has been no change
  in the schedule.

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

Date: 15 Jun 90 21:17:40 GMT
From: shelby!portia.stanford.edu![e-mail]  (Carl Gooch)
Subject: Re: 10 psi overpressure

In article <[e-mail]> [e-mail]
(Ralph Reid) writes:
>In article <[e-mail]>
>[e-mail] (David Anderman) writes:
>>I seem to recall that the Challenger was destroyed by air pressure,
>>rather than an explosion of the external tank. Wouldn't that indicate
>>the overpressure in the payload bay was somewhat higher than  10psi?
>> . . .

As I recall from a recent skim of the Rogers' Commission report, the
leaking field joint in the SRB melted a hole in the hydrogen (lower)
tank, while simultaneously melting the lower SRB attach point.  The
bottom of the hydrogen tank tore off completely shortly thereafter.
The SRB then slewed into the oxygen (upper) tank, rupturing it on
impact.  The force of the explosion was, I'm pretty sure, what
destroyed the Orbiter; it wasn't designed to take the stress of a
detonation wave hitting its bottom surface.

>
>You seem to have forgotten the emphasis placed on redesigning the SRB
>seals.  I remember that pictures of the Challenger just prior to the
>explosion were closely examined, and a blowtorch like flame was seen,
>which extended from one of the SRB's to the external tank.

Correct.  The photos show that clearly.

>                                                          Some one
>told me (whether it is correct or not) that the main engines may have
>been throttled up to 104% of capacity (this is a normal condition for
>the main engines during launch) before the max-q point was reached.

I don't know, but I doubt it.  They throttle down to 65% for max-q,
and I don't recall any mention to the contrary in the report.

>If you have opinions, you can put them in your own article;
>I refuse to put them in mine!

These aren't opinions, although I may have my facts wrong.

>Ralph.
>ARS N6BNO
>[e-mail]


--
Carl Gooch                       [e-mail]
Disclaimer:  You think Stanford actually agrees with this?  Hah!  If they want
             my opinions and theirs to match they should pay me enough to
             agree with them!

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

Date: 18 Jun 90 19:58:30 GMT
From: zaphod.mps.ohio-state.edu!uakari.primate.wisc.edu!dali.cs.montana.edu!ogicse!unicorn![e-mail]  (Worth Henry A)
Subject: Re: Commercial Experiment Transporter planned (Forwarded)



In message <[e-mail]>, NASA announced:
>RELEASE:  90-83
>
>COMMERCIAL EXPERIMENT TRANSPORTER PLANNED
>
>
>     The National Aeronautics and Space Administration today
>announced support for plans to develop a system for launching and
>recovering commercial spaceborne experiments.
>
>     Sponsored by NASA's Office of Commercial Programs, the
>objective of the Commercial Experiment Transporter (COMET)
>program is to develop both hardware and infrastructure to
>facilitate the commercial development of space by the
>United States. ...
>

First, a serious question
-------------------------

    Is this announcement an indication that NASA has seen the light and
realized that the Space Station Freedom is doomed?  Or, is it merely
NASA's reluctant response to past congressional pressure to develop a
commercial processing facility?

Second, the commentary
----------------------

     I hate to sound like a NASA basher -- I really want for them to prosper
and succeed, I really do, I've been a big fan since I was a kid watching
the later Mercury missions on the tube, and COMET does sound like a good
idea -- It's just that I'm not willing to wait for ...er...ah...blush,
Hades to freeze over.

    There must be another way to fund major space initiatives -- and for
that matter, other important programs -- that does not depend upon
continuous political support. I'm convinced that the solution is some form
of voluntary funding and/or private incentive program, preferably
international in scope and with potential tangible benefits for the
contributors (I've already made one rather long posting on this subject a
few days ago). If we wait for Washington to set the agenda and pace,
little will ever come out of the NASA employees' years of work and
frustration and the sacrifice of ten our finest (as well as four of the
soviets').

    Here're some fanciful thoughts to help stimulate the net's collective
grey matter:

       To augment its budget, authorize NASA to run a nation-wide lottery
    and a major Cape Canaveral casino and theme park, and perhaps at
    Edwards as well -- of course, keeping the bureaucrats' and
    politicians' hands off the earnings is a major problem, not to mention
    the ethical problem of taking advantage of habitual gamblers -- ...oh
    well, better NASA than Trump and Eisner.  :-)

       NASA is not going to benefit from the mythical peace dividend --
    the big hogs have already crowded the NASA runt from the trough, but
    don't fret... they are ALL going to go hungry -- the S&L rats have
    already emptied the slop bucket. The remaining concern is how long
    does the runt have before Farmer Sam decides to do the humane thing...
    :-(  :-(  :-(

       It's really a shame that NASA's supporters didn't get into the S&L
    business a decade ago -- they wouldn't have to be at all concerned
    about today's S&L bailout -- they would have been protected by a
    non-extradition clause in the Martian Constitution.  :-)  :-)  :-(

    I don't remember where I first heard this approach, but schemes like
the following have been used before in the private sector:

       It's time to make it more profitable to quit a useless civil-
    service job than to stay and milk the taxpayers. Any civil-servant who
    demonstrates that their job is superfluous would be awarded a
    long-term full-salary severance, even if they find another job within
    the government (after all, we would hardly want to lose such a
    conscientious civil servant, who might eliminate yet another job ).
    Similarly, civil-servants would also receive substantial awards for
    being the first to demonstrate that an vacant position is superfluous.

       The recipient would also be allowed to assign a limited portion of
    their award to a third party who has aided them in demonstrating their
    own job's uselessness, thus creating a temporary new industry for
    departing civil-servants and under-employed lawyers, and a new
    definition for "head-hunter".  The claims would be reviewed by
    inter-agency committees selected at random from existing employees,
    both management and peer, who would serve on a temporary basis.

       Such a plan would cost the government nothing, and yet would create
    larger dividends for the taxpayer (and possibly NASA) than any
    potential peace dividend. Perhaps, if Congress in its usual short-
    sightedness refused to approve significant awards, the private sector
    would be willing to create an award fund. Note, that under this plan
    you can eliminate only your own job or one that is vacant -- otherwise
    some nasty and unproductive infighting would result.

       If NASA's employees were to spearhead such a program, they would
    generate significant goodwill on Capital Hill as well with the general
    public.  :-)

            ------------------ 06/17/90 ---------------------

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

End of SPACE Digest V11 #539
*******************