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Subject: SPACE Digest V11 #543

SPACE Digest                                     Volume 11 : Issue 543

Today's Topics:
         NASA Headline News for 06/18/90 (Forwarded)
         Re: Aim For The Moon - model rocket contest
               Re: Model rocket contest
           Hubble Space Telescope Update - 06/16/90
      Compression of similar images: WAS:WeatherSatellitePhotos

Administrivia:

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

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

Date: 19 Jun 90 18:20:28 GMT
From: trident.arc.nasa.gov![e-mail]  (Peter E. Yee)
Subject: NASA Headline News for 06/18/90 (Forwarded)

-----------------------------------------------------------------
Monday, June 18, 1990                Audio Service:  202/755-1788
-----------------------------------------------------------------

This is NASA Headline News for Monday, June 18.......


The orbiter Atlantis successfully completed the Shuttle Interface
Test this weekend.  It rolled out to Launch Pad 39-A late last
night.  Before the Rotating Service Structure is placed around
the Space Shuttle, a hot-firing test of the Auxiliary Power Units
will take place tonight at 10:00 P.M.  The STS-38 flight crew
will arrive at 8:30 P.M. to prepare for the Countdown
Demonstration Test and emergency safety training scheduled for
Wednesday and Thursday, June 20-21.

                            ********

The Combined Release and Radiation Effects Satellite to be
launched aboard an Atlas Centaur rocket in mid-July will be the
focus of a mission briefing on Friday, June 22 at 11:00 A.M.
The mission will study what the effects the radiation environment
of space may have on satellite electronics and sensors.  Chemical
releases from the satellite in the ionosphere and magnetosphere
will briefly "paint" the waves and lines of magnetic fields with
luminous particles.  Tracer elements expelled from the spacecraft
canisters will create visible releases in the Caribbean and South
Pacific Areas.
                            ********

NASA plans to support efforts to develop a system for launching
and recovering commercial spaceborne experiments.  The Commercial
Experiment Transporter Program will develop both the hardware and
infrastructure to facilitate the commercial development of space
in the U.S.  The COMET Program calls for a mid-1992 launch of a
free-flyer that contains both a service module and a recovery
system into equatorial orbit.  It weighs 1,800 pounds and the
experiments onboard the spacecraft can be carried out during a
nominal 30-day mission.
                            ********

Pennsylvania State University researchers plan to study how to
keep muscles and bones healthy in space.  Dr. Peter Cavanagh will
head a 3-year NASA study to examine how impact forces can be
applied to astronauts' feet and legs during prolonged space
flight in order to counteract hypokinetic osteoporosis.  A
weightlessness simulator will suspend a subject on a "wall-tread
mill" supported by a system of elastic bunjy-like cords with
force-measuring devices.  Researchers expect it to be up and
running this August.
                            ********








--------------------------------------------------------------
Here's the broadcast schedule for Public Affairs events on NASA
Select TV.  All times are Eastern.


Tuesday, June 19........

          12:00-2:00 P.M.     NASA Video Productions

Wednesday, June 20......

           2:00-4:00 P.M.     Tape of President Bush arrival
                              at Marshall Space Flight Center.

           4:00 P.M.          X-29 Press Conference taped
                              at 12:45 P.M. at Watergate.

Thursday, June 21

          10:00 A.M.          STS-38 countdown demonstration
                              test.  Liftoff will be at
                              11:00 A.M.

          11:30 A.M.          NASA Update will be transmitted.

Friday, June 22.........

          11:00 A.M.          CRRES mission briefing and photo
                              opportunity.  For more information
                              call 407/867-2468.

-----------------------------------------------------------------
All events and times are subject to change without notice.  These
reports are filed daily, Monday through Friday, at 12:00 P.M.
EDT.  This is a service of the Internal Communications Branch,
NASA HQ.  Contact: JSTANHOPE or CREDMOND on NASAmail or at
202/453-8425.
-----------------------------------------------------------------
NASA Select TV:  Satcom F2R, Transponder 13, C-Band 72 Degrees
West Longitude, Audio 6.8, Frequency 3960 MHz.
-----------------------------------------------------------------

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Date: 20 Jun 90 02:55:49 GMT
From: sam.cs.cmu.edu![e-mail]  (Vincent Cate)
Subject: Re: Aim For The Moon - model rocket contest


Patrick John Horgan
>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.

Feasible really boils down to, "How much money can you spend?".  If you
have $30,000 I am rather sure it is feasible.  If you have $5,000,
I think it is.  If you have $2,000, maybe.  A big part of the contest
would be designing for low cost.

I don't think the high Gs would be all that much more than model
rockets are used to.  There is no real reason that the acceleration
from the lower stages would be any higher than the upper stages.  If
each stage is half the size of the previous one (with the payload
equal to the weight of the last stage), each motor is pushing on upper
stages about equal to its starting weight (modulo cases).  Thus each
stage could add about the same delta-V with about the same acceleration.


From: [e-mail] ("1st Lt. Henry S. Cobb")
>Five years ago, the MIT ...
>
>The goal was to put 1 kilogram in orbit.  We learned a lot, especially that
>things like guidance systems do not shrink nearly as easily as fuel tanks.
>
>The SCOUT Planning Guide says that a Scout booster (21500 kg GLOW) can put
>a 250 kg payload into a 200 Km orbit, which is about as low as you can get
>and still call it an orbit.  Linear scaling says that an 86 kg model rocket
>could put 1 kg into the same orbit.  Unfortunately, the scaling ain't
>linear!

If we only put 1 oz or 100 grams into space it would still be loads of fun.
Only :-) control, the motor cases, and air resistance are not linear.
If large rockets cost about $10,000/lb to send stuff into GEO then getting
1 oz near the moon for $5,000 still leaves a factor of 8 for non-linear
scaling.  You just aren't thinking small enough!!!!

>Scout is about as simple a rocket as you can get.  The stages are all solid
>fuel, more or less the same as high-class model rocket engines.  The
>guidance system is incredibly simple: a roll-yaw stabilization gyro, a
>pitch stabilization gyro, and a timer.  The timer kicks the pitch gyro
>occasionally to bend the trajectory downrange.  Even though it's 1960
>technology, you're not going to build a system much lighter than that
>with microprocessors.  The fourth (and optional fifth) stages are spun up
>pointing in the right direction, but otherwise unguided.

What if we just use fins on the first stage or two to get going and
spin things up, and then just use the spin for all of the later stages?
No control computer or servos at all!!!!  If we can keep within 15 degrees
of vertical we should be just fine, assuming the goal is just to get up.
It would be just about as fun to fly past the moon 100,000 miles away
as it would be to hit the moon.  Also, remember that the moon will pull
things towards it.

Getting into orbit would need active control and so ruin the scaling.
You would need lots of servos and a computer.  I don't think you need this
just to "Aim For The Moon".

   -- Vince

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

Date: 19 Jun 90 11:48:28 GMT
From: netnews.upenn.edu!grad2.cis.upenn.edu![e-mail]  (Walter Santarelli)
Subject: Re: Model rocket contest

In article <Added.gaTJW6m00jZdId=[e-mail]> [e-mail] (John Nordlie) writes:
>
    [reference deleted referring to model rocket contest idea]
>
>This sounds like a very neat idea, if it can be done.  However, I have
>some difficulty believing that a gun powder (model rocket engine
>propellant is basically gun powder, with some other burn-controlling
>chemicals added) rocket could achieve escape velocity, starting from
>the earth's surface.  I remember reading in a book on rockets and
>jets that a gun powder powered rocket the size of a Saturn V cound
>not reach escape velocity.  The chemical potential energy per unit
>weight is simply not high enough.
>
>I have never heard of an "N" model rocket engine ("A" - "F" yes,
>but not "N"), so I may be wrong about the fuel used in them.  If these
>"N" engines were to use a suitably volatile solid fuel, it MIGHT
>be possible to get one into LEO, or better.
>

There are larger engines than "F". Many of the "E" and higher total
impulse engines use a perchlorate fuel which supplies a pretty high
specific impulse. These engines are not manufactured by Estes and can
usually only be obtained through mail-order. However, despite the
higher energy capacity of these larger engines, there is significant
amount of packaging material mass around the fuel. When I was in
high-school some people at MIT did some calculations about getting
into LEO using "F"'s and found that the packaging mass defeats the
gains obtained from increased numbers of engines in series or
parallel. This may not apply to the larger "G" and "H" engines which
are available. I am not aware of any place that will sell "N" size
engines to someone without special licensing. These are in the
"Amateur" rocket range. Amateur rocketeers launch what can be
described as small sounding rockets, and they don't even get into
orbit. They do get sub-orbital flights with altitudes of 20-30 miles.
Even LEO requires a heck-uv-alot of energy.

>
>------------------------------------------------------------------------
>John Nordlie      :     (Sorry, I couldn't come up with any clever
>                  :      message/quote/disclaimer today)
>------------------------------------------------------------------------

-wally


------------------------------------------------------------------------------
Walter A. Santarelli    University of Pennsylvania, Computer and Info. Science
  (Grad Student)          "My opinions are my own etc."
e-mail:[e-mail]   (the only address I know that works)
------------------------------------------------------------------------------

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

Date: 19 Jun 90 15:34:33 GMT
From: usc!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov![e-mail]  (Ron Baalke)
Subject: Hubble Space Telescope Update - 06/16/90


                          Hubble Space Telescope
                             June 16, 1990

     First analyses of the Planetary Camera (PC) images are in, essentially
they confirm the first visual impressions of the data.  A significant change
in the image quality did occur after the focus movement on June 14: encircled
energy plots show that the core of the images narrowed and there was an
expansion of the faint halo.  Both the images and the encircled energy plots
show clear improvement.  The images taken after the tilt and decentering
movement of the secondary show essentially no significant difference between
the before and after images.  Why there was no change is still not understood.
Resolution of the puzzle must await further wavefront measurements, now
scheduled for June 18.  Scientific Instrument (SI) activities have gone
extremely well: Faint Object Spectrograph (FOS) recovered from safemode and
all Goddard High Resolution Spectrograph (GHRS) testing has gone
extraordinarily well.  Faint Object Camera (FOC) first light is still
scheduled to begin early on June 17, with the first of the 10 images to be
taken at 3:40 AM EDT. Tape recorder dumps will be scattered throughout the
FOC run.

     Nothing new on any of the Pointing Control Subsystem (PCS) problems.
The mirror movements on June 15 required a new alignment matrix to be
constructed since it changed the relationship between the Fixed Head Star
Tracker (FHST) and Optical Telescope Assembly (OTA) optical axes.  This was
successfully done and the changes were what was anticipated.  FHST updates
have been working very well but this should not be taken as proof that the
FHST problems are solved.  It has been pointed out that virtually all of
the updates have been at the same few attitudes, attitudes that have been
very thoroughly checked out by the Astrometry team.  A better assessment
of how the FHST's are doing can be done once the spacecraft is moved to new
attitudes.

     Analysis of the past few days mirror movement was given above.  The image
quality was significantly improved by the focus movement but uneffected by the
subsequent tilt and decentering.  It is known that this latter movement
actually did occur because of the change in the FHST/FGS (Fine Guidance
Sensor) alignment matrices.  Why it had essentially no impact on the image is
under study.  No mirror movements will be made between now and the FOC first
pictures.  On June 18 more wavefront measurements will be made to check out
the optics in a more rigorous way.  All next week (Monday through Sunday)
Bootstrap focus and alignment proposals will be only HST activity.

     FOC is still in hold on the B side awaiting FOC first light.  The FOC
first light will be 10 images obtained with the F/96 side of a field in
NGC 188 containing two astrometric standards.  Each exposure is 10 minutes
in length (through 6 magnitudes of ND filters). The purpose of the images is
to locate and map the 22 arcsec Field of View (FOV).

     FOS is in hold, having successfully recovered from safemode.  Nothing is
planned for the FOS for the next few days.

     GHRS has had a very active and successful weekend.  Activity on June 15
was all done on Side 1, Side 2 testing starts on June 16. Detailed analysis
of the data is in progress.  Preliminary comments: High Voltage (HV) on
went very well, the focus was found to be identical to that found in thermal
vacuum tests, pulse height results look fine, and all apertures were seen
during the bright earth observation.  If the next set of GHRS tests go well
this will complete their OV 1 activities.

     The Wide Field Planetary Camera (WFPC) is in full operate mode.
No more PC pictures are scheduled until next week.
       _   _____    _
      | | |  __ \  | |       Ron Baalke           |  [e-mail]
      | | | |__) | | |       Jet Propulsion Lab   |  [e-mail]
   ___| | |  ___/  | |___    M/S 301-355          |
  |_____/ |_|      |_____|   Pasadena, CA 91109   |

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

Date: 19 Jun 90 21:41:29 GMT
From: usc!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!watserv1!maytag!watdragon!rose![e-mail]  (Shawn E. Koppenhoefer)
Subject: Compression of similar images: WAS:WeatherSatellitePhotos

>> 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

What if a particular image was used (call it IM_0) and then successive
images (IM_1 IM_2 ... IM_n) then compared with IM_0 and only
the differences saved and transmitted across the net. When the image becomes
too different a new 'parent' is created ( IM_0' ) and the process repeats.
So each image-file IM_t would have a special header identifying it as a
unique parent (parent0000) or as a child of a particular parent (child_of_0000).
Comments?
--
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~|       _ _       KLEIN BOTTLE for sale...
        Shawn E. Koppenhoefer |        |        enquire within.
 ...watmath!rose!sekoppenhoef |           -
~~~~~~~~~~~~~~~~~[e-mail] [e-mail]

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

End of SPACE Digest V11 #543
*******************