Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V13_2/V13_258.TXT

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Subject: SPACE Digest V13 #258

SPACE Digest                                     Volume 13 : Issue 258

Today's Topics:
         Navstar GPS Constellation Status (91-03-09)
                   Re: Gaia
         [l/m 7/11] Frequently asked SPACE questions
     SOLAR TERRESTRIAL BULLETIN - 10 MARCH (SOLAR UPDATE)
              cause of shuttle disaster
             space news from Jan 28 AW&ST

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
             [e-mail]

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

Date:        Sat, 09 Mar 91 09:37:54 AST
From: [e-mail]
Subject:     Navstar GPS Constellation Status (91-03-09)


                        Navstar GPS Constellation Status
                                   (91-03-09)

Blk                       NASA   Orbit   Launch
II        PRN Internat. Catalog  Plane    Date
Seq   SVN Code   ID      Number  Pos'n    (UT)   Clock        Comment
--------------------------------------------------------------------------------
Block I
       1   4  1978-020A  10684          78-02-22      Not usable since 85-07-17
       2   7  1978-047A  10893          78-05-13      Not usable since 81-07-16
       3   6  1978-093A  11054    A-3   78-10-06  Rb  Usable as of 78-11-13
       4   8  1978-112A  11141          78-12-10      L-band signals turned
                                                       off 89-10-14
       5   5  1980-011A  11690          80-02-09      Not usable since 83-11-28
       6   9  1980-032A  11783          80-04-26      L-band signals permanently
                                                       turned off 91-03-06
       7                                81-12-18      Launch failure
       8  11  1983-072A  14189    C-3   83-07-14  Cs  Usable as of 83-08-10
       9  13  1984-059A  15039    C-1   84-06-13  Cs  Usable as of 84-07-19
      10  12  1984-097A  15271    A-1   84-09-08  Cs  Usable as of 84-10-03
      11   3  1985-093A  16129    C-4   85-10-09  Rb  Usable as of 85-10-30
                                                       operating on Rb clock
                                                       without temp. control

Block II
II-1  14  14  1989-013A  19802    E-1   89-02-14  Cs  Became available 89-04-15
II-2  13   2  1989-044A  20061    B-3   89-06-10  Cs  Became available 89-08-10
II-3  16  16  1989-064A  20185    E-3   89-08-18  Cs  Became available 89-10-14
II-4  19  19  1989-085A  20302    A-4   89-10-21  Cs  Became available 89-11-23
II-5  17  17  1989-097A  20361    D-3   89-12-11  Cs  L-band signals enabled
                                                       90-01-06
II-6  18  18  1990-008A  20452    F-3   90-01-24  Cs  Became available 90-02-14
                                                       22:26 UT
II-7  20  20  1990-025A  20533    B-2   90-03-26  Cs  Became available 90-04-18
                                                       23:13 UT
II-8  21  21  1990-068A  20724    E-2   90-08-02  Cs  Became available 90-08-22
                                                       15:00 UT
II-9  15  15  1990-088A  20830    D-2   90-10-01  Cs  Became available 90-10-15
                                                       00:39 UT
Block IIA
II-10 23  23  1990-103A  20959    E-4   90-11-26  Cs  Became available 90-12-10
                                                       23:45 UT

Notes
1.  NASA Catalog Number is also known as NORAD or U.S. Space Command object
    number.
2.  No orbital plane position = satellite no longer operational.
3.  Clock:  Rb = Rubidium; Cs = Cesium
4.  Earlier versions of this table had incorrect end-of-service dates for PRNs 7
    and 5.
5.  PRN 6 may experience problems during its eclipse season due to poor battery
    performance.

==============================================================================
 Richard B. Langley                          BITnet: [e-mail] or [e-mail]
 Geodetic Research Laboratory                Phone:  [phone]
 Dept. of Surveying Engineering              Telex:  014-46202
 University of New Brunswick                 FAX:    [phone]
 Fredericton, N.B., Canada  E3B 5A3
==============================================================================

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

Date: 10 Mar 91 05:57:28 GMT
From: munnari.oz.au!metro!socs.uts.edu.au![e-mail]  (Dan Corbett)
Subject: Re: Gaia

[e-mail] (Larry Wall) writes:

>In article <[e-mail]> [e-mail] (John Roberts) writes:

>: What part of Gaia is its appendix? :-)

>Hmm, something that uses resources but doesn't contribute to the good of
>the whole, and is, in fact, occasionally destructive?  I'll have to
>think about that one...  :-)



Politicians?

------------------------------------------------------------------------------
Dan Corbett
Department of Computer Science
University of Technology, Sydney
Sydney, New South Wales, Australia
------------------------------------------------------------------------------

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

Date: 10 Mar 91 12:01:08 GMT
From: eagle!data.nas.nasa.gov!amelia![e-mail]  (Eugene N. Miya)
Subject: [l/m 7/11] Frequently asked SPACE questions

This list does change.  Slowly.  It only changes when the members
of s.s. have something to add, correct, etc.  I no longer have time to
read s.s., and the SNR is too low.  So if this
does not change it is more a reflection of the other people
you are reading, and not me.  Think about that for a moment.
You make the difference.
    "It's not a message.  I think it's a warning." -- Ripley

This is a list of frequently asked questions on SPACE (which goes back
before 1980).  It is developing.  Good summaries will be accepted
in place of the answers given here.  The point of this is to circulate
existing information, and avoid rehashing old answers.  Better to
build on top than start again.  Nothing more depressing than rehashing
old topics for the 100th time.  References are provided because they
give more complete information than any short generalization.

Questions fall into three basic types:
1) Where do I find some information about space?
Try you local public library first.  You do know how to use a library, don't
you?  Can't tell these days.  The net is not a good place to ask for
general information.  Ask INDIVIDUALS if you must.  There are other sources,
use them, too.  The net is a place for open ended discussion.

2) I have an idea which would improve space flight?
Hope you aren't surprised but 9,999 out of 10,000 have usually been
thought of before.  Again, contact a direct individual source for
evaluation.  NASA fields thousands of these each day.

3) Miscellanous queries.  Sorry, have to take them case by case.

Initially, this message will be automatically posted once per month
and hopefully, we can cut it back to quarterly.  In time questions and
good answers will be added (and maybe removed, nah).

1) What happen to Saturn V plans? What about reviving the Saturn V
as a heavy-lift launcher?

Possible but very expensive -- tools, subcontractors, plans, facilities
are gone or converted for the shuttle, and would need rebuilding,
re-testing, or even total redesign.

2) Where can I learn about space computers: shuttle, programming,
core memories?

%J Communications of the ACM
%V 27
%N 9
%D September 1984
%K Special issue on space [shuttle] computers

%A Myron Kayton
%T Avionics for Manned Spacecraft
%J IEEE Transactions on Aerospace and Electronic Systems
%V 25
%N 6
%D November 1989
%P 786-827

Other various AIAA and IEEE publications.

Computers in Spaceflight: The NASA Experience
James E.  Tomayko
1988?

3) SETI computation articles?

%A D. K. Cullers
%A Ivan R. Linscott
%A Bernard M. Oliver
%T Signal Processing in SETI
%J Communications of the ACM
%V 28
%N 11
%D November 1984
%P 1151-1163
%K CR Categories and Subject Descriptors: D.4.1 [Operating Systems]:
Process Management - concurrency; I.5.4 [Pattern Recognition]:
Applications - signal processing; J.2 [Phsyical Sciences and Engineering]:
astronomy
General Terms: Design
Additional Key Words and Phrases: digital Fourier transforms,
finite impulse-response filters, interstellar communications,
Search for Extra-terrestrial Intelligence, signal detection,
spectrum analysis

You can make it change.  Just discuss the changes on the net, then mail the
resolution to me.

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

Date:    Sun, 10 Mar 91 01:30:02 MST
From: [e-mail] (CARY OLER)
Subject: SOLAR TERRESTRIAL BULLETIN - 10 MARCH (SOLAR UPDATE)
X-St-Vmsmail-To: st%"[e-mail]"

                /\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\

                        SOLAR TERRESTRIAL BULLETIN

                              10 March, 1991

                    Updated Solar Activity Information

                /\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\


UPDATED SOLAR ACTIVITY INFORMATION

     No major flares occurred on 09 March, although significant spot
activity has been observed in Region 6538.  This region, which was the
source of strong solar activity on 07 March has become slightly more
compact.  Spots within this region have increased from 63 on 09 March to
107 on 10 March.  High levels of shear still appear to exist in this
region.  Some magnetic complexity is also apparent in this beta-gamma
system.

     Region 6538 is now centered at a location of S23E32 and is now capable
of producing moderate to high terrestrial impacts if a significant major
solar flare erupts.  Proton activity won't be a real threat until after 12
or 13 March.  However, geomagnetic and auroral impacts could be high if a
strong solar flare erupts anytime between now and approximately 18 or 19
March.  Proton impacts will be possible until after this region passes
beyond the west limb, which is expected sometime near 20 March.  PCA
activity will also be possible anytime after about 13 March until near 20
March.

     A 245 MHz solar radio noise storm was in progress throughout all of 09
March.  This noise storm is most likely associated with Region 6538, which
has shown some high spot activity recently.

     Major flaring is still expected to occur from Region 6538.  Major
M-class flaring is likely to be observed.  Isolated major X-class flares
are also possible.  Minor M-class flaring is a certainty from this region.
Flare sizes could still reach a 3B optical rating.

     Minor to major geomagnetic storming has been observed several times
during the UT day on 09 March over high latitudes.  Activity increased to
major storm levels over the high latitudes at approximately 01:50 UT on 10
March.  Activity has since subsided somewhat, although pulses of minor to
major magnetic storming is still expected to occur over the high latitude
regions over the next 24 hours.

     Middle latitudes have experienced a couple of brief periods of minor
geomagnetic storming.  However, overall activity has not yet surpassed
storm level thresholds over the middle latitudes.  A sudden magnetic impulse
was observed over middle latitude magnetic observatories at 22:46 UT on 09
March.  The intensity of this SI ranged from approximately 30 to 45 gammas.
Low to moderate intensity minor storming was observed over middle latitudes
between 01:50 UT and 05:30 UT on 10 March.  However, no significant rapid
magnetic excursions were observed with this activity.  The geomagnetic field
over the middle latitudes has declined to generally very active levels.
Minor storm periods are still possible (if not expected).

     Auroral activity increased after 01:30 UT on 10 March.  Moderate
auroral activity was observed over middle latitude regions.  The auroral
oval has shifted optically southward.  The leading edge of the oval was
measured to be at an elevation of approximately 50 degrees above the
northern horizon at N49W112.  A diffuse auroral arc was the primary activity
observed during the observation.  No further significant migration of the
auroral oval is expected over the next 24 hours.  Migration back to the
higher latitudes will occur on 11 and 12 March.  Overall geomagnetic and
auroral activity will subside on 12 March (barring any significant solar
activity).

     HF radio signals have suffered some degradation due to the recent
burst of geomagnetic and auroral activity.  Areas most heavily affected are
the high latitudes and northerly middle latitudes.  Radio signal paths
which enter or cross through the auroral zone (ex. polar or high latitude
paths) have experienced moderate fading and increased absorption.  Auroral
flutter is very apparant in the high and middle latitude signals.  So far,
the flutter fading has not been too intense (judging by the reports
received so far).

     VHF auroral backscatter communications may be possible over the
northerly middle and high latitude regions.  Best opportunities for
DX contacts exist using CW.

     Please report any DX contacts on the VHF bands to "[e-mail]".
And again, reports of auroral activity sightings can also be directed to
the above address.  Thanks, to all those who send in reports.


**  End of Bulletin  **

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

Date: 10 Mar 91 15:12:18 GMT
From: zaphod.mps.ohio-state.edu!samsung!news.cs.indiana.edu!nstn.ns.ca!Iris1.UCIS.Dal.Ca![e-mail]  (Greg Roberts)
Subject: cause of shuttle disaster

I have watched this thread of discussion about two 'high level' engineers
and their claim about the cause of the accident. I suggest that for anyone
interested in the facts, they obtain Volume 1 of the Presidential Commission
on the Space Shuttle Challenger accident, and look at the photographs on pages
22 - 36 and 74 - 81.
The strut failure is a nice theory, but has no photographic evidence to
support it. What the photographic (still and video) does support is exhaust
gas erosion of the ORing, which caused a hole in the SRB casing. This resulted
in hot exhaust gas burning the insulation on the ET, and causing a rupture.
It was the combustion of the contents of the ET causing the severe loading on
the shuttle. The strut broke because the lower attach point gave way from the
weakened ET causing it to rotate about the support.

I would like to see the 'evidence' cooked up by these two. Did they appear at
the Rogers Commission to testify? Do they have any materials testing reports,
independent photographic analysis, fatigue analysis or the like to support
their claim? Enquiring, although seriously skeptical minds, want to know.

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

Date: 11 Mar 91 06:38:45 GMT
From: news-server.csri.toronto.edu!utzoo![e-mail]  (Henry Spencer)
Subject: space news from Jan 28 AW&ST

Amroc proposes Aquila, a four-stage hybrid launcher for Motorola's Iridium
mini-comsat network, claiming 1500lbs to 300nmi at about half the cost of
current alternatives.

ESA declares Ulysses fully operational.

Space insurance rates expected to rise after circa $200M losses on recent
in-orbit satellite failures.

USAF Space Command has set up special data links to get data from missile-
warning satellites directly to Patriot batteries nearly in real time.
This plus other measures to improve communications have boosted warning
time for Scud attacks to nearly 5min from 90-120s.  Warning-satellite
officials say Iraq's Scud tests late last fall were serious blunders,
because they gave the US a priceless opportunity to debug the warning
setup before it was needed in combat.

Final design details have been settled for the field joint of the ASRM.
The new joints are bolted together, the O-rings remain visible as the
joint is mated, and the joint is designed to close up under pressure
rather than opening.  Looking at the diagram, inboard of the bolts the
joint is two flat flanges touching each other, and two O-rings are set
into the surface of the lower flange near the inner edge.  The upper
flange goes to the edge of the lower flange and then turns downward
around it, with a third O-ring set into the outer surface of this lip,
seating against the inner edge of the lower flange.

Another major ASRM design change is careful design of the internal shape
of the fuel so that thrust drops off somewhat for a brief period early
in the flight, eliminating the need for the SSMEs to throttle back during
the period of maximum dynamic pressure.  This eliminates assorted possible
failure modes related to throttle-back and the following throttle-up.
Other changes include a revised casing design that has fewer assembled
parts, one less field joint, welded factory joints, and better steel;
a simpler nozzle design eliminating assorted joints and seals; and a
redesigned igniter.  Finally, a lighter casing, a larger diameter holding
more fuel, and a slightly more energetic fuel give higher thrust, longer
burn, and about 18% more shuttle payload.  An important change unrelated
to the booster design is the shift to highly automated manufacturing,
since each handling step increases the odds of trouble.  [Another aspect
of this, not mentioned, is that the ASRM plant at Yellow Creek will be
NASA-owned, so NASA will be less tied to a single contractor and can
exert more control.]

ASRM still has its critics, however.  Some say the $971M would be better
spent elsewhere, especially on the SSMEs and on incremental improvements
to the existing boosters (since ASRM is still five years away).  There
is the possibility of political pressure to shift money to heavylift
boosters, and concerns about the environmental effects of the rather
"dirty" solid fuels.  Finally, there is still strong skepticism in some
areas about the safety of manned flight on solid boosters, given the
sensitivity to manufacturing flaws and the impossibility of test-firing.
Cost considerations are likely to preclude abandoning SRBs, however.

[That's it for space news in this AW&ST.  They are rather preoccupied
with other current events...  However, here's a *very* interesting bit
from the 15 Feb issue of Science:]

Congress is very interested in the Augustine commission's recommendation
for a heavylift launcher, and there is starting to be specific interest
in one particularly heavylift launcher... the Saturn V!!  Truly, questioned
about the matter, says the plans still exist.  It's pretty obvious, though,
that NASA would really prefer a shuttle-derived launcher.  Congress may
pursue the matter, although there is the obvious problem that tooling is
gone and many subcontractors are gone, so resurrecting the Saturn V would
be costly.
--
"But this *is* the simplified version   | Henry Spencer @ U of Toronto Zoology
for the general public."     -S. Harris |  [e-mail]  utzoo!henry

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

End of SPACE Digest V13 #258
*******************