Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT_ZIP/spacedig/V13_3/V13_373.ZIP/V13_373

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Subject: SPACE Digest V13 #373

SPACE Digest                                     Volume 13 : Issue 373

Today's Topics:
            Space Digest Archives
              Re: SPACE Digest V13 #364
              Re: SPACE Digest V13 #367
             re: Nuclear Rockets
         Re: NEP to Mars!?!? - a thesis topic
     Re: Another Dinosaur Barfs (Was Re: How 'bout them Titans?)
               HST in-orbit Maintenance
               * SpaceNews  08-Apr-91 *

Administrivia:

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

Date:  Fri, 5 Apr 91 16:24 EST
From: [e-mail]
Subject:  Space Digest Archives



What is the INTERNET site number for the Space Digest Archives??  Does
this archive shiite also contain programs, GIF's,\and other images?  I'd
like to do some catch-up on the digest.

Thanks!!

                                     Joe

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

Date: Fri, 5 Apr 91 13:56:35 -0800
From: James R. Schaeffer <[e-mail]>
Subject: Re: SPACE Digest V13 #364
Newsgroups: sci.space
Cc:

In article <[e-mail]> you write:
>Re: E.T.'s
>
>Actually, I think they're trying to cope with three facts that make their task
>almost intractable:
>
>1) They don't know where a signal might come from, or where to send it to

But if you limit the search to "near solar type" stars, you have a chance.

>2) They don't know what frequency it will be carried on (EM waves)
>   Or whether it's AM or FM (or who knows what)

There are some pretty good arguments in favor of a rather narrow range of
frequencies, and type of carrier.  It's well understood that to detect
radio waves from civilizations like ours (or ours for the next few hundred
years), that the signals have to be beamed, and all sorts of other
things.  So, assuming a civilization is broadcasting with the intent of
another civilization detecting the signal, you've limited parameter
space QUIT a bit.

>
>My biggest problem with getting into SETI would be;  Suppose you find evidence
>that there is life 3.5 million light years away;  So what?  What do you do now?
                                                   ^^^^^^^

Are you so mindless that you'd even consider this question?  Just the fact
that we KNOW life exists elsewhere in the universe is important.  As far
as we now know, WE COULD BE ALL THE LIFE THERE IS.  WE JUST DO NOT KNOW
if life evolved elsewhere.  If WE KNOW life exists elsewhere in one
other place, the odds are vastly improved that yet another pool of
live exists on yet another planet around another star.

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

Date: Sat, 6 Apr 1991 02:06 CST
From: "Jon Ciliberto::" <[e-mail]>
Subject: Re: SPACE Digest V13 #367

Well, I've tried three times and...does one need to be a rocket scientist
to de-subscribe to SPACE digest?  I mean, I enjoy the posts and all, but I
just don't need the space, I s'pose.  Thankee.

jon

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

Date: 6 Apr 91 16:19:49 GMT
From: agate!bionet!uwm.edu!rpi!zaphod.mps.ohio-state.edu!ub!ubvmsb.cc.buffalo.edu![e-mail]  (Craig L Cole)
Subject: re: Nuclear Rockets

From the article, they state that a Titan IV outfitted with nuclear
rockets could loft 70 tons. Great -- but on an expendable, what
happens to the nuclear pellets after the stage is spent?

A lot of people are going to get upset if the pellets just rain
back down to Earth with the spent stage.

Craig Cole
[e-mail]
[e-mail]

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

Date: 7 Apr 91 00:24:23 GMT
From: portal!cup.portal.com![e-mail]  (Mark Robert Thorson)
Subject: Re: NEP to Mars!?!? - a thesis topic

A book you may want to obtain is OUTER SPACE PROPULSION BY NUCLEAR ENERGY,
Hearings Before Subcommittees of the Joint Committee On Atomic Energy,
Congress of the United States, Eighty-Fifth Congress, Second Session
on Outer Space Propulsion by Nuclear Energy, January 22, 23, and February
6, 1958 (U.S. Government Printing Office, 1958).  There is a number on
the front of the book which might be a reference code: 506015 O.
You might be able to find this in an official government document repository.
These are located in many large libraries, such as the one at UC-Berkeley.
It also might be possible to find the same material in the Congressional
Record.

The book describes several designs for nuclear-powered spacecraft and
their powerplants, and estimates the requirements for lunar and Mars
missions.

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

Date: 7 Apr 91 00:45:12 GMT
From: mnemosyne.cs.du.edu!isis![e-mail]  (Glenn A. Serre)
Subject: Re: Another Dinosaur Barfs (Was Re: How 'bout them Titans?)


Nick:
How about those Dinosaurs (oops, I mean Titans)?  Yes, $300+ million in a
ball of smoke sure looks pretty, if you are into expensive fireworks
shows, and don't care too much about reliable transporation.  Titan IV
costs will now rise to Shuttle levels, and we will be lucky if Titan
IV can catch up to Shuttle's reliability %.  So much for the "expendable
vs. reusable" debate.  In the long run, they are both losers, and those
of us who want to get our payloads into orbit are the biggest losers of
all.

Me:  There you go, showing your ignorance about chemical systems again.
The SRMU (Solid Rocket Motor Upgrade) that blew up was the first TEST fire
of an SRMU (out of five originally planned, I'm sure they'll have more now :-).
It was not a complete Titan IV, and it was little like the current SRMs
(except that it uses solid fuel and is about the same size)

Nick:
It's time for USAF to go to smaller, more redundant payloads and launchers,
and start looking at the alternatives to chem rockets.  These dinosaurs
are history.

Me:
No argument there.

Mary Shafer:
>Before everyone gets excited and blames the wound casing,
>[metal fails too]

Me:
But the failure mechanics of metals (the ones used in the SRMs) is better
understood than that for the wound casing on the SRMUs.  Also, wound casing
or not, the structure has very low design margins (due, IMHO, to the fact that
rocket design is still performance and not cost or reliability oriented), so
one might expect a few minor :-) problems during test.  Another likely cause
for the failure would be a defect in the pour of the solid propellent.  Each
segment is pretty big (bigger than the shuttle's SRM segments, I think), so
getting the propellent poured into the casing is probably a major problem.

More ramblings.

--

--Glenn Serre
[e-mail]
--

--Glenn Serre
[e-mail]

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

Date: 6 Apr 91 16:27:45 GMT
From: comp.vuw.ac.nz!am.dsir.govt.nz!marcamd!mercury!kcbbs![e-mail]  (George Muzyka)
Subject: HST in-orbit Maintenance

Hubble Space Telescope was made to be serviced fully, on the ground
that is; partially in space with the mere aid of spacewalking astronauts
during a Space Shuttle mission.

I ponder whether space telescopes should be serviced in LEO on a larger
scale, as Hubble Space Telescope is not the only space telescope planned;
the ole drawing boards of course showed generations of space telescopes,
from little space telescopes to large space telescopes. So what would
I infer by "larger scale" in-orbit servicing? Well I think it might
be time to start thinking about designs for service frames and possibly
service tents (ie a sphere pumped up to a low enough pressure to prevent
damage from any burst).

Method:
1. Assembly a large cubical frame structure made up of trusses and beams,
   much like on one of the U.S. Shuttle missions; the Large Array. (?)
2. Manouevering of this cubical frame so the target spacecraft/satellite
   is within its centre. Need plenty of leeway space, but also some
   beams with attachment arms to temporarily hold the target object
   still in attitude relation to the frame.
3. The covering of the cubical frame with a temporary skin, to hold
   in any small or medium-sized items that may slip out of astronaut
   gloves and drift away. Aid of a laser sensitive moving debris device
   could show where a small item is heading. The skin/covering material
   could be lined with a catchy texture (not a sticky adhesive!) to
   prevent rebounds/deflections.
4. The target spacecraft/satellite could now be opened and large
   sections separated with the attachment arms keeping hold of each
   section.
5. After in-orbit repair, and reassembly, one side of the cubic frame's
   covering could be removed and the whole framework carefully manoeuvered
   away from the target, and the framework probably dismantled until
   next time.

So I wonder, whether Hubble Space Telescope, say after the 1993 servicing,
could receive a major servicing in orbit as layed out above.

I also wonder, if a more permanent mod. to Hubble's mirrors is later
required, then the above in-orbit service scheme could possibly involve
the repositioning of the secondary mirror to allow for a centred zero-offset
for the primary mirror which would allow for full focal adjustment as
originally designed. (I am probably assuming a _lot_ here!)

I consider the add-in lens for Hubble in 1993 to probably be a temporary
modification, as it sits in at the back of the primary mirror rather
than in between the primary and the secondary themselves.

Another thing. I guess the 1 cm (10 mm) beam of concentrated light at
the hole region on the primary mirror, where only 10 ~ 15 percent of
the overall light is getting through, that it would be silly to carefully
drill a bigger hole??? :-) (Too much dust or fragmental debris would
result?... depends on the drilling technology).

Just some ideas and thoughts.

Anything here in light of what is being planned for HST in 1993+?


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

Date: 6 Apr 91 00:08:00 GMT
From: ka2qhd![e-mail]  (John Magliacane)
Subject: * SpaceNews  08-Apr-91 *


SB SPACE @ AMSAT < KD2BD $SPC0408
* SpaceNews  08-Apr-91 *

Bulletin ID: $SPC0408


                              =========
                              SpaceNews
                              =========

                         MONDAY APRIL 8, 1991

SpaceNews originates at KD2BD in Wall Township, New Jersey, USA.  It
is published every week and is made available for unlimited distribution.


* MICROSAT NEWS *
=================
Numerous ground station operators around the world have reported difficulties
accessing LUSAT (LO-19) over the past several days.  Ordinarily, connection
can be established but little other traffic can be handled.  The LUSAT
command team in Argentina is examining various possibilities including
PACSAT software problems and satellite receiver problems in various hardware
configurations.  LUSAT is transmitting a short beacon message to users
alerting them of the degraded situation.

The DOVE (DO-17) operating system apparently crashed sometime on Thursday 28
March 91.  On Saturday, 30 March 91, the S band transmitter was succesfully
commanded on providing very limited telemetry data, power system balance,
and (most importantly) evidence that DOVE is still quite alive.  A
concentrated effort to place DOVE into full service is planned following
diagnostic memory dumps and an operating system reload during April.
Special thanks go out to PY2BJO and ON6UG for their critical S band
monitoring duty.

Eric Rosenburg, WD3Q, reported that updated operating software was
apparently uploaded to UO-14 on 01-Apr-91.  This change has the server
identify the station it is handshaking with when it acknowledges a
bulletin request.

[Info via ANS]


* RADIO ASTRONOMY *
===================
Radio astronomy can be done on any frequency you can find which is
free of terrestrial radio signals.  There are many types of celestial
radio emitters which generate (generally wide band) noise.  At the lower
frequencies the emissions are dominated by non-thermal (i.e synchrotron
etc.) mechanisms.  For example, the planet Jupiter is a *very* strong
emitter of synchrotron radiation in the 5-39 MHz range.  Indeed much of the
background noise you hear on HF is quite often dominated by these signals.

At higher frequencies you get continuous emission from interactions
between free electrons (free-free emission) again producing broad band
noise.  You also get spectral line emission from atomic recombination
and molecular transitions.  These emissions such as the neutral hydrogen
line at 1420.406 MHz appear at discrete frequencies instead of being
broad band in nature.  It is not generally reasonable to expect the
casual amateur astronomer to be able to "see" these signals since they
are comparatively weak and often localized.

If you have an OSCAR station and want to do a simple experiment try
this:  Point your 2m antenna straight south and up 30 or so degrees
(in the northern hemisphere).  Tune your 2m rig to an unused frequency
in your area and set the mode to SSB (or CW).  Turn on your GaAsFET
preamp and write down the S-meter reading of the background noise
every half hour or so for a day or as long as you want.  You will notice
the noise level going up and down from S-0 to S-6 or so with a 24 Hr
period.  CONGRATULATIONS - you have just made your first radio observation
of the galactic center!  You might also see another hump in your data
at about local noon corresponding to the sun.  The sun however is not
nearly as strong as the galactic center at 144 MHz.

[Story by US Astronaut Ron Parise, WA4SIR]


* SHUTTLE FREQUENCIES *
=======================
NASA Malabar (Palm Bay) HF Networks in MHz:

 2.405 Data Buoys                       2.622 SRB Recovery (Primary)
 2.664 Backup Mission Audio-Cape/Hou    2.678 ETR Range Control
 2.716 Navy Harbor Cntl-Port Canav.     2.764 SRB Recovery Channel
 3.024 Coast Guard SAR (Primary)        3.187 SRB Recovery Ships Channel
 4.376 Primary Recovery Zone SAR        4.510 SRB Recovery Ships Channel
 4.856 Cape Radio/Leader                4.992 Cape Radio/Coast Guard Ships
 5.180 NASA Tracking Ships              5.187 NASA Tracking Ships
 5.190 ETR Primary Night Channel        5.350 Launch Support Aircraft
 5.680 Launch Support Ships             5.810 ETR Secondary Night Channel
 6.720 SAR Primary Atlantic             6.896 Cape Radio
 6.837 Cape Radio                       7.412 SAR Communications With Bahamas
 7.461 Cape Radio/Launch Support A/C    7.525 NASA Ground Tracking Net
 7.676 Launch Support Aircraft          7.765 SRB Recovery Ships
 7.919 Data Channel                     7.985 Data Channel
 9.022 Launch Support Aircraft          9.043 Launch Support Aircraft
 9.132 Launch Support Aircraft         10.305 Space Missile Tactical Net
10.310 Malabar-to-Ascension Is-MUX     10.780 ETR Primary Day Channel
11.104 Launch Support Ships            11.252 Launch Support Ships
11.407 SRB Recovery Ships              11.414 Cape Radio
11.548 Cape Radio                      11.621 SRB Recovery Ships
13.227 Launch Support Aircraft         13.237 Data Channel
13.495 Data Channel                    13.600 Malabar-to-Ascension Is-MUX
13.878 Launch Support Aircraft         14.937 Ascension Is-to-Malabar-MUX
18.009 Launch Support Ships            19.303 Launch Support Ships
19.640 Cape Radio                      19.966 Ascension Is-to-Malabar-MUX
20.186 Tracking Net                    20.192 Malabar-to-Ascension Is-MUX
20.198 OCC Shuttle Mission Audio       20.390 ETR-Secondary Day Channel
22.755 Ascension-Is-to-Malabar-MUX     23.413 Cape Radio
27.065 NASA CB Radios

HF used at the Kennedy Space Center: 2.182 MHz, 3.023 MHz


* TNX QSL! *
============
A special thanks to all those who sent QSLs to SpaceNews:

N3CIP   : Bob Balogh, Jr, Lebanon, Pennsylvania, USA
N3EDN   : Karla Balogh, Lebanon, Pennsylvania, USA
W4NG    : Earl Tonjes, Gainesville, Florida, USA
N9KJJ/7 : Wayne Wagner, Bremerton, Washington, USA

...and e-mail messages:

GW0KYT, KA1JFP, K2TV, K2SK, KB2JPD, N2IKJ, WB2VVS, KC4QYG, KB8FIR


SpaceNews:  The FIRST electronically published newsletter to
=========   be read on a manned spacecraft in low-Earth orbit!


73 de John, KD2BD

/EX
--
John A. Magliacane                 FAX  : [phone]
Electronics Technology Department  AMPR : KD2BD @ NN2Z.NJ.USA.NA
Brookdale Community College        UUCP : ...!rutgers!ka2qhd!kd2bd
Lincroft, NJ  07738  USA           VOICE: [phone] ext 607

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

End of SPACE Digest V13 #373
*******************