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Subject: SPACE Digest V11 #158

SPACE Digest                                     Volume 11 : Issue 158

Today's Topics:
         Re: Commercial Titan/Intelsat Launch Failure
     Re: Coilgun on a 747 - supplies to orbit at $20/lb?
                 Mass drivers
     Re: Coilgun on a 747 - supplies to orbit at $20/lb?
         NASA Headline News for 03/16/90 (Forwarded)
     Re: Coilgun on a 747 - supplies to orbit at $20/lb?
              Galileo Update - 03/16/90
                 HST
----------------------------------------------------------------------

Date: 16 Mar 90 21:21:30 GMT
From: agate!brahms.berkeley.edu![e-mail]  (Dmitry Gokhman)
Subject: Re: Commercial Titan/Intelsat Launch Failure

In article <[e-mail]> [e-mail] (George William Herbert) writes:
>Yesterdays attempted launch of a commercial Titan III with an Intelsat VI
>comsat aboard apparently failed.  From sketchy reports, it looks like the
>transfer stage did not seperate from the second stage, and the Intelsat VI
>was stranded in LEO after being jettisoned from the second/kick stages after
>the seperation failure.
>    Reports [unconfirmed] stated that there was a loss of signal with the
>    sattelite.
>Additional reports from NORAD's space tracking people suggested that the
>Intelsat was in a orbit that was stable for at least twelve days, and could be
>stabilized further with the use of the onboard thrusters.
>
>If anyone has better info that this please post it asap, as a large number of
>people are interested...  thanks
>
>-George William Herbert

From what I heard on the network news, the satellite was stranded but
stable (for longer than twelve days from the sound of it).  It is the
remaining stage(s) that are also in a similar orbit but with no means
of stabilization that is/are due to come down fairly soon hopefully
not on our heads.
---------------------------------------------------------------
- Mr. Gumby    * \oo7    Dmitry Gokhman
   says:        `/v/-*   Brahms Gang/University of Cauliflower/
MY BRAIN HURTS  J  L     Broccoli CA 94720
---------------------------------------------------------------

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

Date: 16 Mar 90 21:19:12 GMT
From: sam.cs.cmu.edu![e-mail]  (Vincent Cate)
Subject: Re: Coilgun on a 747 - supplies to orbit at $20/lb?


Jim Kasprzak
>Ever hear of recoil?

Henry Spencer:
>Whoa, Nelly.  Remember that accelerating a mass to near-orbital velocity
>in the space of a hundred meters or less involves very high accelerations,
>i.e. very large forces.
>...
>Try thinking in terms of grams, not thousands of kilograms, and it
>might work.

I guess I did not make myself clear.  I was thinking of many small projectiles.
One of the questions I asked was:

>How small would the projectiles have to be so that the force did
>not hurt the 747?

I am thinking along the lines of 50 lb projectiles with the gun able to
recoil inside the 747.  If the gun weighs 50,000 lbs the gun will go
backwards at 1/1000th the velocity of the 50 lb projectile.  If the
projectile is doing 15,000 MPH relative to the plane then the gun will
go back at 15 MPH relative to the plane.  At 1/3 g something moving at
15 MPH can stop in a couple seconds and about 20 feet.  If the gun is
50,000 lbs at 1/3 g the rest of the plane should be feeling less than
1/6 g for these 2 seconds (since a 747 is over 100,000 lbs).  Anyone on
the plane would have their seatbelt pull on them but the plane should be
ok.  If this is still too much the projectile can be made smaller.

So, will it work if I think in terms of 10 to 20 kg?

One problem is that small projectiles have greater air resistance per
lb.  This could make launching from the ground more economical even
if the plane method were possible.

Paul Dietz, when you said such guns are to large to fit on a 747
were you thinking of todays guns or always?  What size projectiles
were you thinking of?  Is there any other type of gun (maybe a real
railgun) that might be made to work?  (weigh under 50,000 lbs, less
than 300 feet long, fire small objects at near orbital speed...)

Another thing that might not have been clear in the first post is
from an airplane a 5 to 10 degree launch angles should work where we must
use 15 to 90 when firing projectiles from the ground due to the
air resistance.  At 20 degrees, when fired from the ground, the delta-v
needed to get the projectile into a circular orbit is still around 2 km/s
(IEEE trans on Magnetics Vol 25 No 1 p 393).  A 10 kg object needing
a 2000 m/s delta-v can be about 1/3 payload.  If it only needs a
1000 m/s delta-v then it can be 0.62 payload.  The graph in the paper
does not show payload fractions for lower delta-v but from other
information it is clear that a projectile fired at 5 degrees from
30,000 feet would need less than 500 m/s of delta-v to get into orbit.
It looks like a projectile fired from a plane could be 3/4ths payload.

It still seems like a this type of approach (maybe using some other
type of gun, but firing from a high flying airplane) has the potential
for sending supplies into orbit for something like $20/lb.

  -- Vince

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

Date:         Fri, 16 Mar 90 09:53:14 PLT
From: Wayne Fellows <[e-mail]>
Subject:      Mass drivers

The latest Scientific American has an article about an investment group that wa
nts to build a mass driver in Hawaii for polar launches.  Aparently they hope t
hat this will be a good showcase for the technology.  Does anyone know how seri
ous this effort is and how one might invest in such a corporation?

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

Date: 16 Mar 90 09:14:35 GMT
From: zaphod.mps.ohio-state.edu!rpi![e-mail]  (Jim Kasprzak)
Subject: Re: Coilgun on a 747 - supplies to orbit at $20/lb?

In article <[e-mail]> [e-mail] (Vincent Cate) writes:
>
> [speculations on the possibility of launching stuff to orbit with a
>  747-mounted coil gun deleted]
>
>What are the hard parts of this type of approach?
>
 Not wrecking the 747 in the process. Ever hear of recoil? I think that
even from 747 cruising altitude, the recoil generated by any reasonably
large payload is going to wreak havoc on your plane.

 But hell, why settle for a 747? We have those retired SR-71's now,
right? Put a coil gun on one of *those*, and you've got a lot better
starting altitude and velocity...

 (-: (If it wasn't obvious, that paragraph was not serious.)


--
 Jim Kasprzak          [e-mail] (internet)
 RPI, Troy, NY         [e-mail]
 "A spirit with a vision is a dream with a mission."  -Rush

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

Date: 16 Mar 90 19:42:02 GMT
From: trident.arc.nasa.gov![e-mail]  (Peter E. Yee)
Subject: NASA Headline News for 03/16/90 (Forwarded)

-----------------------------------------------------------------
Friday, March 16, 1990                        Audio: 202/755-1788
-----------------------------------------------------------------
This is NASA Headline News for Friday, March 16......


The STS-31 Space Shuttle is at Launch Pad 39-B this morning.
Rollout was delayed Thursday morning until last night while
shuttle managers investigated data on the nose landing gear axle
on the orbiter Discovery.    Nose wheel axle problems had been
previously observed on Columbia and Atlantis.

If further analysis indicates a problem on Discovery...and it
would jeopardize the STS-31 mission...the stack would be rolled
back to the Vehicle Assembly Building for demating and repair.


The ozone layer over the north pole is thinning.  That's the
finding of a coordinated study conducted last fall by NASA, NOAA
and a variety of other research organizations.  Data indicate
from 15 to 17 percent of the ozone over certain parts of the
north polar region has been destroyed.   Research studies
indicate the north polar ozone hole will grow larger, but not as
large as the ozone hole known to exist over the Antarctica.


Space Fax Daily says the Tokyo Broadcasting System will
announce in April which of two Japanese journalists will go into
space in December.  The TV reporters have been in training since
last fall for an eight day mision aboard the Mir space station.
The TV network will pay the Soviets close to $10-million for the
cosmonaut training and space flight.


Engineers from Intelsat are closely watching the Intelsat 6
spacecraft that's marooned in a low Earth orbit following an
abortive launch attempt earlier this week aboard a commercial
Titan 3.  They're now beginning to stabilize the spacecraft to
allow on-board thrusters to boost it into a higher, safer and
longer-life orbit.  In its present orbit it would decay in a few
weeks.  A rescue attempt has been mentioned, but NASA says it has
not yet been approached for assistance to rescue the spacecraft.


The final frames of a 64-frame mosaic of our solar system taken
by the Voyager 1 cameras will be beamed back to Jet Propulsion
Laboratory beginning today.   Transmission of the frames will run
through March 27.   Seven of the nine planets in our solar system
should be seen in the mosaic.


                           *****




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

Today..............

         12 noon        Video tape replay of STS-31 rollout at
                        KSC


Monday, March 21.....   From Johnson Space Center

          9:30 A.M.     STS-31 flight directors mission overview

         10:30 A.M.     Secondary middeck student experiments

         11:30 A.M.     STS-31/HST flight crew news conference


Wednesday, March 21.......

         1-2:30 P.M.    Total Quality Management in Action
                        Colloquium

Thursday, March 22......

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

All events and times are subject to change without notice
-----------------------------------------------------------------
These reports are filed daily, Monday through Friday, at 12 noon,
Eastern time.
-----------------------------------------------------------------
A service of the Internal Communications Branch (LPC), NASA HQ

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

Date: 16 Mar 90 16:56:00 GMT
From: usc!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Coilgun on a 747 - supplies to orbit at $20/lb?

In article <[e-mail]> [e-mail] (Vincent Cate) writes:
>I don't know, :-), but to continue on let me make some guesses.
>Assume that coilgun and support takes up 50,000 lbs and that 2/5ths of
>the weight of a projectile ends up being overhead.  Starting with
>100,000 lbs on the plane, we would still end up sending 30,000 lbs
>to orbit...

Whoa, Nelly.  Remember that accelerating a mass to near-orbital velocity
in the space of a hundred meters or less involves very high accelerations,
i.e. very large forces.  Be generous and call it a hundred meters long
(I forget how long a 747 is, but this is probably too long already).
Now, v^2 = 2ad for a body starting from rest, and orbital velocity is
circa 8000 m/s, so acceleration is 32000G.  If the payload is 30000lbs,
we're talking about forces of circa one *billion* pounds.  Your coilgun
will rip itself out of the 747 instantly.  Also, accelerating 13000kg
to 8000m/s requires 416 GJ of energy, which is a Whole Lot, something
like half a second's electrical power output for the entire US.  Your
power-storage gear will not fit in a 747.

Try thinking in terms of grams, not thousands of kilograms, and it
might work.
--
MSDOS, abbrev:  Maybe SomeDay |     Henry Spencer at U of Toronto Zoology
an Operating System.          | uunet!attcan!utzoo!henry [e-mail]

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

Date: 16 Mar 90 22:00:01 GMT
From: elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov![e-mail]  (Ron Baalke)
Subject: Galileo Update - 03/16/90


                               GALILEO
                       MISSION STATUS REPORT
                           March 16, 1990

     As of noon Friday (PST), March 16, 1990, the Galileo spacecraft is
63,810,650 miles from the Earth, 10,496,450 miles from Venus and was
travelling at a heliocentric velocity of 87,640 miles per hour.  Round trip
light time is 11 minutes, 18 seconds. Galileo is in cruise mode-dual spin
with a spin rate of 3.15 rpm. The spacecraft attitude sun point angle is at
0.4 degrees.

     Several SITURNS to lead the sun were successfully accomplished on
March 10, 12, 14 and 16.  Spacecraft performance for all events was as
expected and without incident.

     A switch from LGA-2 (Low Gain Antenna) to LGA-1 was successfully
completed on March 12.  The antenna switch was necessary to assure adequate
command and telemetry link performance to accommodate for the changing sun,
earth, and spacecraft relative geometries.  After the switch to LGA-1, the
telecommunications performance was near predicted levels.

     The ninth RPM thruster "flushing" activity was completed on March 15, as
planned.  The activity "flushed" the Z, L and S thruster only.  The
P-thrusters were not flushed since they are used to perform the SITURNS.
Unlike earlier "flushing" activities performed at 1200 bps, the temperature
profiles for the thrusters were not available due to the low telemetry rate of
10 bps. Successful "flushing" was inferred from other spacecraft
measurements/events, including attitude control performance and thruster
counts.

     The AC/DC bus imbalance continued to be relatively stable for about 7
weeks.  The DC measurement has varied between about 21.3 and 21.6 volts; the
AC measurement has varied between 48.36 and 48.75 volts.  All other
power-related measurements (bus voltages, bus currents and shunt current) and
other subsystem measurements have all been as expected.

     The Earth Venus Earth (EVE) Integrated Cruise Activity Plan (ICAP) was
reviewed and approved by the project on March 7.  The EVE ICAP is the highest
level product integrating engineering and science activities and covers the
period from VE-3 (April 23, 1990) to VE-15 (April 29, 1991).

     The VE-2 Preliminary Sequence was reviewed and approved by the project
on March 15.  The VE-2 sequence controls spacecraft activities from March 26
to April 23.

     The Galileo project participated in an acceptance test of the new Deep
Space Network (DSN) Telemetry Processor Assembly (TPA) software during a
Goldstone track of the Galileo spacecraft.  The new TPA software will provide
a new standard for telemetry time tagging that will eliminate differences
between different TPA configurations and projects.  The new software is
expected to begin operations support on March 29th after the completion of
Multimission Verification Tests (MVTs) scheduled next week.

 Ron Baalke                       |    [e-mail]
 Jet Propulsion Lab  M/S 301-355  |    [e-mail]
 4800 Oak Grove Dr.               |
 Pasadena, CA 91109               |

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

Date: 17 Mar 90 03:12:00 GMT
From: zaphod.mps.ohio-state.edu!rpi!rpitsmts![e-mail]  (Commander Krugannal)
Subject: HST


      I know that when Hubble was designed, tehy actually ground
   two mirrors. I don't think that the second was ever coated, it
   was kept as a backup in case the primary one was scratched or
   somehow ruined.
      My question is, does anyone know what if anything happened to
   the second mirror? If it is still around, do you think it would be
   possible to finish the grinding, coat it and fit it out with
   the needed gear and send it up as a second HST? Seems like this
   would be a cheap way to get a second one. (Since they know most
   of the problems they would run into and that it would hopefully
   not have to sit around too long.
     Just a thought.

   [e-mail]
   Disclaimer: Why do I need one? everyone else has one!

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

End of SPACE Digest V11 #158
*******************