Space & Astronomy/Space and Astronomy (October 1993).iso/pc/text/spacedig/v15_0/v15no012.txt

Internet Message Format | 1993-07-13 | 34KB

Date: Sat, 18 Jul 92 05:02:19
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #012
To: Space Digest Readers
Precedence: bulk


Space Digest                Sat, 18 Jul 92       Volume 15 : Issue 012

Today's Topics:
            Antimatter (was propulsion questions) (5 msgs)
                              apollo 10
    FOR ALL MANKIND on TBS Sunday, July 19 (APOLLO lunar missions)
                      Galileo Update - 07/17/92
   How to find limiting magnitude? (was Re: Solar Power Satellites)
                      Looking gif horse in mouth
                 Now, where at last ? (Re: apollo 10)
            Pathogens and the Orbiting Quarantine Facility
              Space Transportation Infrastructure Costs
                        THE DIGEST IS BACK!!!!

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

Date: 17 Jul 92 14:32:00 GMT
From: Jim Carr <[e-mail]>
Subject: Antimatter (was propulsion questions)
Newsgroups: sci.space,sci.physics

In article <[e-mail]> [e-mail] () writes:
>
>    I have brought this question over into sci.physics
>    because I think this question belongs there, and
>    re-directed followups back there.

I put this answer on sci.physics too, but put the followup on sci.space

>    On sci.space there is a discussion about spacecraft
>    propulsion systems, in particular ones using antimatter
>    annihilation to generate the power source. Can anyone

>    tell me just how much energy (Joules please) would
>    be generated if 0.5 grams of X is annihilated with
>    0.5 grams of anti-X.

Gee, if you want Joules you should use MKS units, but no matter.  ;-)

When you annihilate matter and anti-matter, you get neutral bosons,
usually photons, carrying off the energy.  The energy is E=mc^2 if
we assume the matter is essentially at rest (otherwise you must add
in pc in quadrature to get the total energy available, and worry
about the transformation between to the center-of-momentum frame).

So given 0.5 gm + 0.5 gm = 1.0 gm = 0.001 kg, we get 9x10^{13} Joules.

You will note for future reference that kg*(m/s)^2 = kg*m^2/s^2 = Joules.

Also note that you could look this conversion up in the Appendix of
Halliday and Resnick if you do not trust your memory of c or whatever.

Remember that you have to expend several times this amount to create
the anti-matter in the first place (since you effectively lose energy
in making the boost from the lab to the center of momentum where the
particles are created, and then you have to collect and cool the products),
but the cost is probably worth it because of the concentrated form the
energy is stored in.

>                             With the different products
>    generated in the process does it make a defference
>    what we pick for X ( protons, electrons, whatever ).

The physics is simplest with an elementary particle like an electron,
since it just annihilates to two photons.  A proton is a composite
particle, and the actual annihilation takes place between a quark
and anti-quark in each -- hence you get a wide variety of products
possible, mostly pions I think, from the spectators.  If you are
considering this for propulsion, this choice would affect how you
would go about using and directing this energy (which comes out
isotropically if the matter is at rest) to effect propulsion.

--
J. A. Carr                                    |  "The New Frontier of which I
[e-mail]                           |  speak is not a set of promises
Florida State University  B-186               |  -- it is a set of challenges."
Supercomputer Computations Research Institute |   John F. Kennedy (15 July 60)

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

Date: Fri, 17 Jul 92 15:53:29 GMT
From: Ed Gruberman <[e-mail]>
Subject: Antimatter (was propulsion questions)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] () writes:
>    Hi
>
>    I have brought this question over into sci.physics
>    because I think this question belongs there, and
>    re-directed followups back there.
>
>    On sci.space there is a discussion about spacecraft
>    propulsion systems, in particular ones using antimatter
>    annihilation to generate the power source. Can anyone
>    tell me just how much energy (Joules please) would
>    be generated if 0.5 grams of X is annihilated with
>    0.5 grams of anti-X. with the different products
>    generated in the process does it make a defference
>    what we pick for X ( protons, electrons, whatever ).
>
>                        Nick
Nick,

It's fairly easy.  E=mc^2.  m=.001 kg, c=3x10^8 m/s, => E=9x13 J.
All in gamma rays unfortuately.  The big problema are a) how to convert
all the gamma rays into kinetic energy for your ship or whatever and b)
how to keep your cargo from getting fried.  Tough problems since gamma
rays are _very_ penetrating.  Have fun. :-)


Ed Gruberman

[e-mail] (VMS)
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              Los Alamos National Labs

____________________________________________________________________________

My opinions are my own, don't you dare give someone else credit for them!

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

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

Date: 17 Jul 92 19:25:39 GMT
From: Bill Higgins-- Beam Jockey <[e-mail]>
Subject: Antimatter (was propulsion questions)
Newsgroups: sci.space

In article <6y=[e-mail]>, [e-mail] (Ed Gruberman) writes:
> In article <[e-mail]> [e-mail] () writes:
>>    Can anyone
>>    tell me just how much energy (Joules please) would
>>    be generated if 0.5 grams of X is annihilated with
>>    0.5 grams of anti-X. with the different products
>>    generated in the process does it make a defference
>>    what we pick for X ( protons, electrons, whatever ).
>
> It's fairly easy.  E=mc^2.  m=.001 kg, c=3x10^8 m/s, => E=9x13 J.
> All in gamma rays unfortuately.

Sorry, Ed. (boot to the head) *WHUMP!*  Take a look at your Particle
Properties book.

If you interact eletrons and positrons, you get essentially 100% gamma
rays.

If you interact protons and antiprotons, or neutrons and antineutrons,
etc., you get a mixture of stuff; for engineering purposes, it's all
pions. About a third of these are pi-zeroes, 98.8% of which turn
instantly to gammas.

The rest of the output, positive and negative pions, decay to muons
and neutrinos, and the muons decay to electrons and neutrinos. Since
these are charged, you can in principle persuade them to go where you
want them to go (out the engine exhaust) with big enough magnetic
fields, if you grab them in the few dozen nanoseconds (pions) or
microseconds (muons) of their existence.  I do this for a living. (-:

The correct statement is that, given enough time for everything to
decay-- one second should do nicely-- the annihilation energy will be
divided among gamma photons, electrons, and neutrinos, all of which
are stable.  A significant share of the energy (more than 1%) is
carried by each species.  I won't look up just what the partition is.

Nick should go to the library and get *Mirror Matter* by Robert L.
Forward and Joel Davis, which is fun to read and will proably answer
most of his questions about antimatter.  (It may cause him to think of
new ones.  I'm prepared to take that risk.)

Jim Carr and Henry Spencer gave good answers to Nick's posting,
although Henry also seems to think that everything winds up in gammas.
(Don't feel bad, Henry-- Eugen Saenger made the same mistake in his
book *Space Flight*, and he was a smart guy too.)

I will resist giving Cary/Ed another Boot To The Head for having a
long signature.  Been guilty of that myself on occasion...

                  [o]
                  [|]   ///        Bill Higgins
   E               H   ///
  |8D:O:          occc))))<))      Fermi National Accelerator Laboratory
   E               H ///
                  [|]//            Bitnet: [e-mail]
                  [|]
Bumper sticker seen on a Soyuz:    SPAN/Hepnet/Physnet: 43011::HIGGINS
    GOT HARD CURRENCY?
 TRY OUR MICROGRAVITY LAB!        Internet: [e-mail]

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

Date: 17 Jul 92 19:48:08 GMT
From: SCOTT I CHASE <[e-mail]>
Subject: Antimatter (was propulsion questions)
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Jim Carr) writes...
>In article <[e-mail]> [e-mail] () writes:
>
>>    On sci.space there is a discussion about spacecraft
>>    propulsion systems, in particular ones using antimatter
>>    annihilation to generate the power source. Can anyone
>>    tell me just how much energy (Joules please) would
>>    be generated if 0.5 grams of X is annihilated with
>>    0.5 grams of anti-X.
>
>Gee, if you want Joules you should use MKS units, but no matter.  ;-)

Well, if there is no matter, then the answer is zero Joules. :-)

>When you annihilate matter and anti-matter, you get neutral bosons,
>usually photons, carrying off the energy.  The energy is E=mc^2 if

When you take a chunk of matter and bring it near a chunk of antimatter,
several processes happen.  Electrons annihilate positrons, producing photons
for the most part, but also neutrinos a small part of the time.  But
most of the energy comes from nuclear annihilation where the larger
rest mass means that more channels are open even at rest.  So, for
example, I would expect some electrons and positrons to fly out of a
gold + antigold nuclear annihilation.  Muons, pions, kaons, etc., are
also allowed.

To be strictly fair, the existence, and consequent properties of antiatoms
is still an entirely open experimental question for the most part, so this
is really speculation.  The properties of nucleon-antinucleon annihilation
are well studied, of course, but entire antinuclei are an entirely different
question.

No one has ever produced even an antihelium nucleus.  Antideuterons are
doable, as are antitritons (typically with 10-3 yield relative to antideuterons)
but more complex antinuclei are too tough to make.

So no one has ever produced anything other than an isotope of antihydrogen.
There is antimatter in the cosmic rays, but I don't know if anyone has ever
seen complex antinuclei.  Is there a cosmic ray jock out there who can
tell me what the heaviest antinuclei recorded in the cosmic rays is?

-Scott
--------------------
Scott I. Chase            "The question seems to be of such a character
[e-mail]        that if I should come to life after my death
                and some mathematician were to tell me that it
                had been definitely settled, I think I would
                immediately drop dead again."      - Vandiver

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

Date: 17 Jul 92 20:11:48 GMT
From: SCOTT I CHASE <[e-mail]>
Subject: Antimatter (was propulsion questions)
Newsgroups: sci.space

In article <6y=[e-mail]>, [e-mail] (Ed Gruberman) writes...
>
>It's fairly easy.  E=mc^2.  m=.001 kg, c=3x10^8 m/s, => E=9x13 J.
>All in gamma rays unfortuately.  The big problema are a) how to convert
>all the gamma rays into kinetic energy for your ship or whatever and b)
>how to keep your cargo from getting fried.  Tough problems since gamma
>rays are _very_ penetrating.  Have fun. :-)

All in gamma rays?  Most of the energy comes not from electron-positron
annihilation but from nuclear annihilation, which produces pions and a
whole flurry of other stuff which you need to shower in some material
in order to recoup the energy.

-Scott
--------------------
Scott I. Chase            "The question seems to be of such a character
[e-mail]        that if I should come to life after my death
                and some mathematician were to tell me that it
                had been definitely settled, I think I would
                immediately drop dead again."      - Vandiver

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

Date: 17 Jul 92 15:58:22 GMT
From: "Harold G. Andrews II" <[e-mail]>
Subject: apollo 10
Newsgroups: sci.space

In article <[e-mail]>
[e-mail] (Martin Connors) writes:
>In article <[e-mail]>
>[e-mail] (Jim Scotti x2717) writes:
>> The Apollo 16 ascent stage was accidentally left in lunar orbit when
>> a switch was not set properly for remote control of the spacecraft
>> after it's mission was completed.  It's orbit, however, had a periluna
>> of about 10 NM, and its orbit apparently decayed about 6 months after
>> the mission.
>
>Can anyone comment on why such an orbit decay would occur so rapidly in
>LUNAR orbit. There is no upper atmosphere at all to consider so I wonder
>what is the relative role of radiation pressure on such a low density
>reflective object as an LM ascent stage, or would it simply be Earth-Sun
>perturbations causing the orbital parameters to change such that the
>perilune became < lunar radius?

I seem to recall two reasons why the orbit of an object in a lunar orbit
will decay.  Neither have to do friction or radiation pressure.  Please note
I have really not had much experience in this field, and I could be way off
base here.

     Reason #1)  The moon is not a very homogeneous body.  It has regions
which are very dense and others which are not so dense.  In a lower orbit,
these regions vary the gravitational interaction between the moon and the
object in the lunar orbit.  This in return causes instabilities to occur
in the orbit until either the orbit intersects the surface of the moon, or
the object leaves lunar orbit.

     Reason #2)  In a higher lunar orbit, the periodic changes in the
gravitational interaction between the Earth and the object in Lunar orbit
will cause a instability in the orbit of the object.  It would seem that
this would eventually destabilize the orbit enough so that it intersected the
lunar surface, or caused the object the leave a lunar orbit.

These two things could be way off base.  I don't recall where I read them,
or even if it wasn't in a dream I had ;-).  So no flames please if this turns
out to be completely the wrong answer.

-Andy

*******************************************************************************
* Harold G. "Andy" Andrews II             *  Support DAM...                   *
* [e-mail]                *                                   *
* Rome Laboratory/OCPA                    *   Mothers Against Dyslexia        *
* Air Force Photonics Center              *                                   *
* Griffiss AFB, NY 13441-5700             *                                   *
* [phone]  (DSN Prfx 587)          * (Not an official  USAF viewpoint) *
*******************************************************************************

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

Date: Fri, 17 Jul 1992 18:19:36 GMT
From: Larry Klaes <[e-mail]>
Subject: FOR ALL MANKIND on TBS Sunday, July 19 (APOLLO lunar missions)
Newsgroups: sci.astro,sci.space

        For those of you in the U.S. with cable television, National
    Geographic Explorer is presenting the film FOR ALL MANKIND on the
    Turner Broadcast Station (TBS) this Sunday, July 19 at 9 p.m. ET.
    It is a film about the APOLLO manned lunar missions, taken from
    thousands of hours of NASA film footage.

        Larry Klaes  [e-mail]
             or - ...!decwrl!verga.enet.dec.com!klaes
                 or - [e-mail]
                     or - [e-mail]

             "All the Universe, or nothing!" - H. G. Wells

        EJASA Editor, Astronomical Society of the Atlantic

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

Date: 18 Jul 92 01:06:14 GMT
From: Ron Baalke <[e-mail]>
Subject: Galileo Update - 07/17/92
Newsgroups: sci.space,sci.astro

Forwarded from Neal Ausman, Galileo Mission Director

                                   GALILEO
                       MISSION DIRECTOR STATUS REPORT
                                POST-LAUNCH
                            July 10 - 16, 1992

SPACECRAFT

1.  On July 10, realtime commands were sent to change the System Fault
Protection (SFP) AACS-INIT (Attitude and Articulation Control Subsystem)
pointing slot from the sun to the Earth. These commands reconfigured the
value to the background state assumed by the EE-6 (Earth-Earth 6) sequence
memory load.

2.  On July 13, a NO-OP command was sent to reset the command loss timer
to 264 hours, its planned value for this mission phase.

3.  On July 14, a Command Detector Unit Signal-to-Noise Ratio (CDUSNR) test
along with a Radio Frequency Subsystem Automatic Gain Control (RFSAGC) test
were performed using LGA-1 (Low Gain Antenna #1) over DSS-43 (Canberra 70
meter antenna).  Quick look analysis indicates the test went well.  Detailed
analysis is in progress.

4.  On July 15, the periodic RPM (Retro-Propulsion Module) 10-Newton thruster
flushing maintenance activity was performed.  All 12 thrusters were flushed
and their performance was as expected.

5.  On July 15, the Energetic Particle Detector (EPD) motor maintenance
exercise was performed which stepped the motor through its eight operating
positions and then returned it to the normal position (No. 4).  The motor
maintenance exercise was successfully verified by Memory Readout (MRO)
commands.

6.  On July 15, realtime commands were sent to change the System Fault
Protection (SFP) to turn off the LGA-2 motor if the sequence memory load is
terminated.  This change prevents a continuous undervoltage situation in
the low probability scenario of a relay failure causing a DC bus short
circuit while retracting the LGA-2 antenna.  The commands were transmitted
but not successfully received due to a ground station problem.  Specifically,
the wrong standards and limit tables were being used in the command system at
Station 43 (Canberra).  Command retransmission is being planned.

7.  On July 16, routine Extreme Ultraviolet Spectrometer (EUV) Memory
Readouts (MROs) were performed.  The MROs were received without incident.

8.  On July 16, cruise science Memory Readouts (MROs) were performed for the
Dust Detector (DDS) and Magnetometer (MAG) instruments.  Preliminary analysis
indicates the data was received properly.

9.  On July 16, an Ultra-Stable Oscillator (USO) test was performed to verify
the health status of the USO and collect gravitational red shift experiment
data; long term trend analysis is continuing.

10. On July 16, a command threshold test was performed.  Initial results,
similar to the test run on May 14, indicates the command threshold to be
approximately -140 to -141 dbm which is its nominal value.

11. On July 16, a Radio Frequency Subsystem Tracking Loop Capacitor (RFSTLC)
test was performed over DSS-43.  Preliminary analysis indicates the capacitors
continue to operate normally.

12. On July 16, telemetry map changes were performed to replace the Command
Detector Unit Signal-to-Noise (CDUSNR) telemetry readings to the AC/DC bus
imbalance telemetry readings at the completion of the scheduled
telecommunication tests.

13. During the week, the DC bus imbalance reading has continued to change
significantly.  The DC measurement has ranged from 97DN (11.2 volts) to 151DN
(17.8 volts) and now reads 150DN (17.7 volts).  This measurement variation is
consistent with the model developed by the AC/DC special anomaly team.  The
AC measurement has decreased 1DN and reads 3.1 volts.

14. The Spacecraft status as of July 16, 1992, is as follows:

       a)  System Power Margin -  42 watts
       b)  Spin Configuration - Dual-Spin
       c)  Spin Rate/Sensor - 3.15 rpm/Star Scanner
       d)  Spacecraft Attitude is approximately 31 degrees off
           Earth (lagging) and 2 degrees off-sun (leading)
       e)  Downlink telemetry rate/antenna-40 bps (coded)/LGA-1
       f)  General Thermal Control - all temperatures within
           acceptable range
       g)  RPM Tank Pressures - all within acceptable range
       h)  Orbiter Science- UVS, EUV, DDS, MAG, EPD, and HIC are
           powered on
       i)  Probe/RRH - powered off, temperatures within
           acceptable range
       j)  CMD Loss Timer Setting - 264 hours
           Time To Initiation - 185 hours

GDS (Ground Data Systems):

1.  The July System Engineers Monthly Report (SEMR)  review was conducted
Thursday, July 16.  A review of current Project and Institutional (MOSO & DSN)
system status was conducted.  Pre-Earth 2 delivery schedules, past months
accomplishments and potential problem areas were discussed. No significant
problems or errors were reported.

2.  An end-to-end GDS data flow test was successfully conducted this past week
to demonstrate the ground capability to process and display 40 bps AACS Flood
Mode telemetry data.  First use of this telemetry format in flight is
scheduled for 24 July.


TRAJECTORY

     As of noon Thursday, July 16, 1992, the Galileo Spacecraft trajectory
status was as follows:

        Distance from Earth         135,214,000 miles (1.46 AU)
        Distance from Sun           170,085,000 miles (1.83 AU)
         Heliocentric Speed          45,300 miles per hour
         Distance from Jupiter       673,747,000 miles
         Round Trip Light Time       24 minutes, 22 seconds


SPECIAL TOPIC

1.  As of July 16, 1992, a total of 8028 real-time commands have been
transmitted to Galileo since Launch.  Of these, 3159  were pre-planned in
the sequence design and 4869 were not.  In the past week, 2 real time commands
were transmitted and all were pre-planned in the sequence design. In addition,
4534 mini-sequence commands have been transmitted since March 1991; 2283 were
pre-planned and 2251 were not.  In the past week, no mini-sequence commands
were transmitted.  Major command activities this week included commands to
update the System Fault Protection (SFP) and to reset the command loss timer.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Most of the things you
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | worry about will never
|_____|/  |_|/       |_____|/                     | happen.

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

Date: 17 Jul 92 18:36:08 GMT
From: Bill Higgins-- Beam Jockey <[e-mail]>
Subject: How to find limiting magnitude? (was Re: Solar Power Satellites)
Newsgroups: sci.space,sci.astro

In sci.space there has been a recent discussion about building a
constellation of multi-kilometer satellites to harness solar energy
and beam it to users on Earth.  One drawback is that having some
new bright objects in the sky would make it harder-- in some sense--
to do professional and amateur astronomical observations on the
ground.

In article <[e-mail]>, [e-mail] (Phil G. Fraering) writes:
> [e-mail] (Thomas J. Nugent) writes:
>>[e-mail] (Ralph Buttigieg) writes:
rb>>> Most people will live on Earth for some time to come,
rb>>> to have humanity denied the sight of the stars would be tragic.

tjn>>Well, if you live anywhere near any half pint city, you are mostly denied
tjn>>the sight of the stars.  I live in Urbana, with the local population on
tjn>>the order of 100,000.  You have to go really far out of town to see more
tjn>>than a dozen stars or so.
>
pgf> That's what bothers me about all the people griping about light pollution
pgf> from the SPS's. They probably won't be much brighter than Jupiter, and
pgf> in most major cities, the light pollution will be so bad you'll be lucky
pgf> to see the powersats to begin with.

How do you do this calculation? (It's related to "why is the sky
blue?")

The Sun provides direct sunlight in the daytime.  But some direct
light also scatters off the molecules of air above us.  Blue light
scatters through larger angles than red.  So when the Sun is up, air
all over the sky gives off blue light which is brighter than most
stars.  The Moon is bright enough to be seen in the daytime  despite
this background glow, and so is Venus, sometimes, and so are a few
other bodies, maybe.

At night, the Moon is bright enough to create the same sort of sky
glow.  The brightness of the sky when the Moon is up is enough to rule
out observing many of the dimmer objects in the sky.  Most people
don't notice this, but astronomers (professionals and amateurs) are
painfully aware of the fact.  Being rather slow, I learned about this
only at an advanced age, searching for Comet Halley during a full
Moon.  This phenomenon divides professional observers into two social
classes-- "dark sky" people, who can use telescope time only during
the two weeks a month when the Moon is absent from the night sky, and
"bright sky" people, who are lucky enough to be studying fairly bright
objects and can still do useful things with the Moon up.

When the Moon is down, our sky is still not perfectly black.  There
is still a sky glow due to other, much dimmer sources.  It would be
fun to investigate the more obscure ones, but the obvious ones include
starlight, planet light, and the glow scattered from sources on the
ground (as Tom Nugent mentions above).

So. Suppose we add another object to the sky, say, as bright as
Jupiter.  How much will this increase the background glow?  How will
it change the limiting magnitude of the dimmest object one can observe
with a telescope?  (I'll bet this is a homework problem in some class
on observational astronomy somewhere.)  How does it vary with angular
distance from the bright object?

If we can learn how to do this calculation, we can compare the alleged
damage that any proposed configuration of powersats will do to
ground-based astronomy. As Phil Fraering suggests, the effect is
probably meaningless for people close to any illuminated town.  But it
may be significant for deep-sky professional observers.

I've checked at least one handbook but it's a tougher problem than
applying one simple formula.  Perhaps someone else will *ahem* shed a
little light on the problem.

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

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

Date: Fri, 17 Jul 1992 17:27:05 GMT
From: Edmund Hack <arabia!hack>
Subject: Looking gif horse in mouth
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>Does anybody know if you can get gifs on discs (or send them
>a disc with a wish list) from Ames?  I am ftp-ing them through
>school but it takes _forever_ to get them onto my machine via
>Kermit.  I am losing valuable sack time, what with the time
>differences and all.

All of the CD-ROMs that have been mounted at ames are available from the
National Space Science Data Center at cheap prices.  The disks are $20
for the first in an order, $6 each after that.  For more info, send
email to: [e-mail] and they will send you a catalog
by email in a week or so.

Included are Viking, Viking Orbiter, Voyager and Pioneer data.  Note
that most of what is send is RAW DATA, not the pretty pictures you see
on TV and in magazines.  Some software tools for PCs and Macs for
looking at the images and limited processing is available too.



--
| Edmund Hack - Lockheed Engineering & Sciences Co. - Houston, TX
| [e-mail]    SpokesPersonp(Me,or(NASA,LESC)) = NIL
|   **** Papoon for President! You Know He's Not Insane!! ****

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

Date: 17 Jul 92 16:44:55 GMT
From: Jim Scotti x2717 <[e-mail]>
Subject: Now, where at last ? (Re: apollo 10)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Bruce Watson) writes:
>Satellite Situation Report, NASA, Project Operations Branch, Code 513,
>Goddard Space Flight Center, Greenbelt, MD, USA 20771 is published
>quarterly and is available to interested persons.
>
>It lists 1969 043C LM/descent in orbit around the moon and 1969 043D
>LM/ascent in orbit about the sun, but there are errors in this
>publication.

This publication gives the LAST KNOWN ORBIT for an untracked satellite
such as the Apollo 10 LM ascent and descent stages, so this is consistent
with what has been said in this thread.  If tracked, it also lists the time
of decay.  You might look up Apollo 9, and check the data on the LM.

---------------------------------------------
Jim Scotti
{[e-mail]}
Lunar & Planetary Laboratory
University of Arizona
Tucson, AZ 85721 USA
---------------------------------------------

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

Date: Fri, 17 Jul 1992 20:14:54 GMT
From: Brent Kellmer <[e-mail]>
Subject: Pathogens and the Orbiting Quarantine Facility
Newsgroups: sci.space,rec.art.sf.science

I've got a problem that I wonder if someone could help me with:

I'm writing an SF story in the course of which some sort of pathogen gets       through quarantine and to Earth.  I'm using NASA's 1981 Antaeus Report as
a model for the orbiting quarantine facility in the story.  What I need is
and idea or two on how such quarantine could be bypassed or broken.  I've
already thought of the possibility of an accident on board the OQF, as well
as the possibility of Industrial Espionage, but in this case, these might
be somewhat of a cliche.

If there's anyone out there that could help me, I'd greatly appreciate it.

Brent Kellmer
[e-mail]

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

Date: 18 Jul 92 00:03:03 GMT
From: Ron Baalke <[e-mail]>
Subject: Space Transportation Infrastructure Costs
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Henry Spencer) writes...
>I think the demand is going to have to come from the manned programs.
>Most of the unmanned people are very thoroughly locked into the mindset
>of never depending on new technology if they can avoid it.  (As witness
>Cassini being shrunk to fit on a Titan IV without the new SRBs... which
>have now been successfully tested.)

You left out a few pertinent details about the SRMs.  To date, the SRMs
has had only one successful test firing which occurred just a month ago,
and they still have to undergo several more test firings before they can
be declared flight ready.  The first test firing resulted in a spectacular
explosion that totally destroyed the launch complex and caused 120 million
dollars in damage.  The SRM program has been plagued by a number of setbacks,
and the contractor who built the SRM's, Hercules, have already exceeded
their contract cap of $700 million.  Hercules now has to foot the remaining
costs of the development of the SRM themselves.  Hercules has sued Martin
Marietta claiming that they did not assist them properly in the SRM
program, and Martin Marietta is countersuing.  The SRMs was originally planned
to be used with the Cassini launch, but considering the track record of
the SRM development, NASA decided that using the SRMs was too risky.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Most of the things you
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | worry about will never
|_____|/  |_|/       |_____|/                     | happen.

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

Date: Fri, 17 Jul 92 15:43:48 EST
From: "Kevin R. Cain" <[e-mail]>
Subject: THE DIGEST IS BACK!!!!

Just a quick congratulations to all those who brought the Digest back.
I was beginning to wonder what had happened.

THANY YOU THANK YOU THANK YOU.  (Just my $.02 worth)
*************************************************************************
*   KEVIN R. CAIN                 PHONE: [phone]                 *
*   USER SUPPORT                  EMAIL: [e-mail]           *
*   FLORIDA A&M COMPUTER CENTER   SNAIL: KEVIN R. CAIN, 106 PERP, FAMU  *
*                                        TALLAHASSEE, FL 32307          *
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End of Space Digest Volume 15 : Issue 012
------------------------------