Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V11_1/V11_130.TXT

Internet Message Format | 1991-07-08 | 19KB

Return-path: <[e-mail]>
X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson
Received: from beak.andrew.cmu.edu via trymail for +dist+/afs/andrew.cmu.edu/usr11/tm2b/space/[e-mail] (->+dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl) (->ota+space.digests)
          ID </afs/andrew.cmu.edu/usr1/ota/Mailbox/gZy9vV600VcJQ4ME5v>;
          Sat, 10 Mar 90 01:29:53 -0500 (EST)
Message-ID: <[e-mail]>
Reply-To: [e-mail]
From: [e-mail]
To: [e-mail]
Date: Sat, 10 Mar 90 01:29:21 -0500 (EST)
Subject: SPACE Digest V11 #130

SPACE Digest                                     Volume 11 : Issue 130

Today's Topics:
               SR-71 and dates
               Re: NASA SR-71's
                Orbital Debris
         Congressional support needed for NASA budget
             Re: Power Economics and SPS
         Re: SR-71 Record Flight Information
              Galileo Update - 03/09/90
----------------------------------------------------------------------

Date: 9 Mar 90 07:33:00 GMT
From: zaphod.mps.ohio-state.edu!rpi!rpitsmts![e-mail]  (Commander Krugannal)
Subject: SR-71 and dates



      Someone mentioned attaching the Pegasus vehicle to the SR-71.
   Someone (from Orbital Service I believe) replied that there
   was no place to do it. Actually that is wrong. Soon after the
   SR-71 was built, a drone was built based on the J-58. This was
   called the D-21. It used the same engine (the J-58) and same
   shape for wings. It was a drone that was airlaunched, flew over
   the target, ejected a film capsule on the other side, and
   destroyed itself. (Presumably...) It was air-launced from both
   the B-52 and the SR-71. It was mounted on a fin above the tail
   area of the SR-71.  It seems the Pegasus vehichle is about
   the same size, so I think that it could be done if it was at a
   all  cost effective.

      As for dates, do it like trekkies I know (ok, I admit
   sometimes I take my notes this way... :-) 9003.09.
   That would be the Year (90) Month (03) and date (09). You can
   even go further and include hours, minutes, seconds, etc...
   9003.090233 (I am postin this at 2:33 in the morning! :-)

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

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

Date: 9 Mar 90 16:30:17 GMT
From: bfmny0![e-mail]  (Tom Neff)
Subject: Re: NASA SR-71's

In article <[e-mail]> [e-mail] (Mary Shafer (OFV)) writes:
>Look, all you purists don't want NASA involved in space anyway.  You
>can't suddenly decide to include us, just because we just got a nifty
>airplane that you think would be neat to use.  :-)  (Jealousy, pure
>jealousy.)

Bite your tongue.  NASA belongs in space.  But only for facilitating
research purposes, as with aeronautics.  There's nobody in the world
better for testing high-AOA performance, for instance, than NASA.
But we'd never let them run an airline.  That's the way it should
be in space too.

The one thing I really do wish they'd do with the SR-71's is use them
to supplement the Kuyper Observatory for special events like transits.
There's much less room for equipment, but at Mach 3 and 80,000ft you
ought to be able to track rapid events with luxurious ease and view
them with crystal sharpness.

The SR-71 might also make observations of Shuttle re-entry performance
during parts of its flight path never accessible before.
--
"Take off your engineering hat   = "The filter has      | Tom Neff
and put on your management hat." = discreting sources." | [e-mail]

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

Date: 9 Mar 90 17:49:40 GMT
From: mcsun!ukc!edcastle![e-mail]  (Pavlos Papageorgiou)
Subject: Orbital Debris


    Hi! I apologise if this has been recently discussed.

    With thousands of man-made objects currently orbiting the Earth,
the issues of 'available slots' and 'orbital debris' will probably
become serious security concerns very soon.  (That is when things stop
blowing up by themselves! :-)

    Available slots: Although there is vast room out there, most
satellites tend to be placed in a few 'useful' orbits, like
geostationary.  The probabilty of a collission is still unrealistic, but
proximity in orbit can conceivably cause other problems: inteference in
communications, confusion of delicate experiments.
    Is there an agreement or organisation regulating this? A centre
for tracking the orbits? What about unreported launces (e.g.  foreign
intelligence)?

    Orbital debris: You all remember the chip-of-paint 'crater' on
the shuttle window.  Small objects (a few gramms) are quite adequate to
destroy something as delicate as voyager at the velocities involved, and
there is probably a great lot of them up there!
    Do smaller objects 'spiral down' faster? How much damage would a
minor impact cause the space station and how (un)likely is it? Would
practices like explosive bolts and discared booster stages have to be
reviewed? What about things like nuclear power cells re-entering the
atmosphere?


    Thank you for reading so far! :-)

    Pavlos
-----------------------------------------------------------------------------
    All things get old, all things die, but most things can be replaced!

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

Date: 10 Mar 90 03:42:34 GMT
From: phoenix![e-mail]  (Marc Wayne Mcconley)
Subject: Congressional support needed for NASA budget

John A. Brimble, Legislative Assistant of Spacecause, recently sent a
letter to NSS Chapters with suggestions for organized efforts to assist
the NASA budget in Congress.  The following is a summary of the content
of his letter.

As I am sure you are aware, President Bush has approved NASA's budget
proposal of $15.125 billion for FY '91.  This 22.8 % increase is crucial
for revitalizing the American space program.  The budget proposal,
however, is in need of continuing help in order to pass through Congress
and to prevent budget cuts which could be proposed later in the year.
How can you help?

One suggestion to achieving this goal, in addition to calling or writing
letters to your Congressmen, is to invite elected representatives to
events sponsored by organized groups, such as NSS chapters, local
museums, universities, and schools.

It has been suggested that these coordinated efforts will be most
effective during certain times at which Congressmen are normally in
their districts.  For 1990, these target times are scheduled for the
following dates:  April 6 to April 17, May 25 to June 3, July 1 to July
9, and August 4 to September 4.

We need YOUR help to secure NASA's budget and a more vital space
program!

--
Marc W. McConley
Vice President, Princeton Planetary Society
Reply-To:  [e-mail]  ||  [phone]

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

Date: 5 Mar 90 09:31:36 GMT
From: mailrus!b-tech!kitenet![e-mail]  (Russ Cage)
Subject: Re: Power Economics and SPS

[Followups directed to sci.space.]

All ideas go through 3 stages of acceptance:

1.)    It won't work.
2.)    It'll work, but why would anyone want to?
3.)    I always thought it was a good idea.

I think Paul Dietz is between stages 1 and 2 WRT SPS.

In article <[e-mail]>, Paul Dietz writes:
>Russ, you ignore: (1) the cost of keeping people in space (it's
>currently very high), (2) the fact that no one has built a space
>station beyond LEO, where it would require consider shielding.

Look at the LLNL proposal for a program of a space station, moon
base, and Mars base.  Total cost for all 3:  about $10 billion.
Even if they are off by a factor of 2, that's still cheap.  That
will establish the technology in no uncertain terms.

The price of keeping someone in space is limited by the cost of the
consumables they require.  If water is recycled and oxygen is available
locally, that gets much cheaper.  If some food is available locally, it
gets cheaper still.

Shielding material is available for free on the moon.  It's called
regolith.  The LLNL and NASA proposals both call for using it.  A space
habitat won't have any raison d'etre until it has something to process
(more regolith).  The original space habitat shield can be raw regolith,
which can be replaced with processing by-products later.

>Sorry, [cheaper transport is] essential.  A lot of material would still
>have to be sent into space, even with largely ET resources.

Numbers?  I haven't any handy, my studies were all borrowed or are on loan.
(Remember, commercial Proton is available for $750/lb now...)

>No, I imagine you'd need thousands of workers even with automation.
>EVA is extremely inefficient.  Remember, a single (microwave) SPS is
>ten square kilometers, and you are blithely proposing we establish
>many different industries in space.

If you say 9 is "many", I guess you're right.  I count:
1.)    Lunar material collection (regolith).
2.)    Catapult payload production (sintering regolith).
3.)    Catapult launching (from Luna).
4.)    Payload collection (in space).
5.)    Regolith refining into iron, aluminum and silicon.
6.)    Fabrication of structure (by extrusion, vapor deposition and
    spot welding), PV cells (by vapor deposition), and transmitters
    (depends on type of transmitter chosen).
7.)    Final powersat assembly.
8.)    General housing & life support.
9.)    General transport (moving people & finished products).

Technologies like extrusion, vapor deposition, sintering, assembly,
and draglines are very mature.  Refining may be child's play given
abundant solar heat; I need to check the SSI docs on this.  Assembly
of large structures is very easy in free-fall, as proven on Shuttle.
Most of this stuff would not require EVA, and assembly of really
large things is done with machinery (cranes, etc.) even on Terra.
In vacuum, vapor deposition can be done by the acre.

The point is, the technologies we need are mostly available, or
can be adapted from existing ones.

>We *don't* have the technology until someone spends the money
>to develop it.

Good point, BUT:  the level of existing technology and basic suitability
for the intended purpose gives good cause to believe that the required
amount of money will be small rather than large.

Of course, you could take the position that as long as it isn't
working yet, the potential costs are still too large to make it
practical.  This is how I read you, and that's too pessimistic.

[on lunar dragline mine]
>More wishful engineering.  It would cost hundreds of millions or billions
>of peanuts.

Betcha not.  Components are motors, motor power supplies & control, gear
boxes, cables & drums, bucket and static structure.  Using off-shelf
motors and gear boxes, tests of hardware & software could be done on
Earth for cheap.  Moving it to Luna requires space-rated motors, power
supplies and gear boxes, which can be developed and tested using
existing vacuum chambers.  That will cost more, but << $100M.

This is, of course, assuming that NASA is not the one doing the work.  :-|

>Foo. SSI's mass driver is a lab prototype that proves some of the physics
>works.  It is a scale model, contains only a small fraction of the

Works much better than anyone expected, by the way.

>drive coils, doesn't include superconducting bucket coils, doesn't

Superconductors aren't necessary.  Convenient, but not required.
There are literally dozens of ways to make this thing work.  I
thought of 2 more ways of powering bucket coils in a few hours.

>prove that the launcher can achieve the necessary velocity accuracy,

Quibble.  What did they spend on MD I-III?  $50K?  What do you think they
could prove with, say, $10M?  That is mighty cheap.

>Again, you've confused embryonic ideas with developed technologies.

And you've overestimated the amount of money required to turn these
ideas, plus off-shelf hardware, into something in which we can have
a high level of confidence (assuming NASA is not the one doing it).
In all cases, the basic science is extremely well-understood, and
there is a large body of engineering already done in most areas.

>You again make my point: the equipment is not available now.
>All we have now is lab demonstrations.  The technology would
>have to be developed, and you can bet problems would arise
>that would not be found on earth.  Problems always arise
>moving from the lab to pilot plants to full scale plants.

So put the orbital plant in a pressure vessel and spin it.  This
gives you an atmosphere and gravity, so you can operate under
near-Terran conditions.  Also, we are talking about a *small*
operation, about the size of a standard pilot plant on Terra.
It should be possible to test things at full scale on the ground
in actual-size pressure vessels.  (Make 2, spin them on tethers?)
Of course, a minimum-risk approach would go for testing as much as
possible on the ground first, and designing systems which can be so
tested.  Taking full advantage of zero-G for processing comes later.

Is there any reason this has to cost $billions?  My point is that
lab demos prove it is possible, and the engineering to prove that
a given design is feasible shouldn't break the bank.

>Why should laser beams have this high a power density?  [10 KW/m^2]

Because it's easy to do, and with hundreds of thousands of the
things instead of a few hundred they'd be impossible to police?
Also, you're pushing physical limits on window power handling.
At 800 nm & 1 MW, putting a 500 W/m^2 limit on power density from
geosync means an aperture of ~12 cm.  That's 100 MW/m^2 through
your laser window.  A 1 M mirror could put 150 KW/m^2 on a target
from geosync at 1 MW and 800 nm.  (It would take 10,000 1 MW
lasersats to equal one 10 GW SPS.  That is one heck of a lot of
orbiting stuff, and just tracking all of them, much less making
sure none were converted to weapons, would be an enormous job.)

You'd also have a sales job with lasersats.  Any beam that's
visible would be a constant reminder to people (obnoxious, maybe
threatening), and even near-IR beams would upset plant rhythms
with scattered light.  Plus losing power when the weather turns
bad...  people don't like having the lights go out even when it's
nice outside, much less when it's cold & cloudy.  The strong point
of SPS is that it can keep working through clouds.
--
  I am paid to write all of RSI's opinions.  Want me to write some for you?
[phone]        Forewarned is half an octopus.
Russ Cage, Robust Software Inc.            [e-mail]

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

Date: 9 Mar 90 21:28:00 GMT
From: ux1.cso.uiuc.edu!brutus.cs.uiuc.edu!usc!skat.usc.edu![e-mail]  (Barney Lum)
Subject: Re: SR-71 Record Flight Information


> [e-mail] (David Gardiner) writes:
>
>   On the LA->DC run, did the aircraft have to refuel?  If so, how
>   many times?
> [e-mail] (Mary Shafer (OFV)) writes:>
>No.  It refuelled just before it started the run, but did not refuel
>during the coast-to-coast run.

And if it did need refueling while enroute, it would've had to be done
by another Blackbird! (Gee... speed record for inflight refueling too :) ).

BTW, Mary, i think you mistyped the previous coast-coast record
by the American Airlines 707... it was 3 hours ~38 minutes (yeah,
those "3's" and "8's" look alike early in the morning :).

-------------------------------------------------------------------------------
              >|
              >|      [e-mail]  [e-mail]
 -->  -->  --> |   =======    ---    ---    ---    ---    ---    ---    ---
              >|      Permanent Student Pilot, On the Numbers
              >|
-------------------------------------------------------------------------------

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

Date: 10 Mar 90 01:49:49 GMT
From: zaphod.mps.ohio-state.edu!usc!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov![e-mail]  (Ron Baalke)
Subject: Galileo Update - 03/09/90



                              GALILEO
                       MISSION STATUS REPORT
                          MARCH 9, 1990

     As of noon Friday (PTS), March 9, 1990, the Galileo spacecraft
is 57,198,350 miles from the Earth, 8,765,750 miles from Venus and is
travelling at a Heliocentric velocity of 89,420 miles per hour. Round trip
light time is 10 minutes, 8 seconds. Galileo continues to spin at 3.15 rpm
in cruise mode-dual spin with a spacecraft attitude sun point angle of
2.3 degrees.

     The spacecraft successfully completed three planned SITURNS to lead
the sun on March 4, 6, and 8; all spacecraft performance indications were as
expected.

     Telecommunication system elements characterization tests involving the
Command Detector Unit (CDU) and the Radio Frequency Subsystem were successfully
performed on March 4 and 5.

     Commands were sent on March 6 to configure the Command and Data Subsystem
(CDS) via the spun Critical Controller (CRC) to route the 10 bps data stream
from the Bulk Memory (BUM) to the high rate channel in both Telemetry
Modulation Units (TMU). Beginning March 6 and lasting through March 25, the
telemetry rate will be limited to 10 bits/second in order to maintain the
required link Bit Error Rate (BER).

     The AC/DC bus imbalance continued to be relatively stable for about 6
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 RTG temperature measurement began to exhibit some erratic behavior on
March 8. Due to the very low sample rate of this measurement at 10 bps
(2 hours, 1 minute, 20 seconds), it will require several samples to determine
if this behavior is real and indicative of another RTG temperature transducer
anomaly.  The total loss of these measurements does not pose a threat to the
RTG or the spacecraft since power parameters (V, I) are measured separately
by the power subsystem electronics.

     Deep Space Network (DSN) is generating a strawman plan for the elevation
bearing maintenance at all three 70-meter stations for Project review. This
action is deemed necessary because of DSN concerns following the elevation
bearing failure in the antenna in Spain.  The Galileo Flight Control and
Support Office (FCSO) is working with the DSN to minimize the impact to
Project support that would result because of the station downtime required
to implement the plan.


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

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

End of SPACE Digest V11 #130
*******************