Aucbvax.4152
fa.space
utzoo!decvax!ucbvax!space
Thu Oct 1 04:19:09 1981
SPACE Digest V2 #1
>From OTA@SU-AI Thu Oct 1 04:08:42 1981
SPACE Digest Volume 2 : Issue 1
Today's Topics:
Administrivia
Down to the wire with Halley - M. Mitchell Waldrop article in SCIENCE
Sen. Proxmire
Soviets reenter the manned space business
A second reverberating gamma ray burst discovered
Where are They??
Anybody out there??
----------------------------------------------------------------------
Date: 30 Sep 1981 1229-PDT
From: Ted Anderson <OTA SU-AI AT>
Subject: Administrivia
To: space at MIT-MC
In case you were wondering what the reason for the change from volume one to
volume two was, it is the occasion of the fiscal new year. Happy New Year!
In an effort to dampen the excitement of the start of the new fiscal year, the
perversity of nature (AKA Murphy's Laws) have conspired to cause many people
(mostly on MC, I think) to miss the last digest of volume one. This is
issue 204. So if you missed V1 #204 let me know and I will mail you a copy.
In case you don't keep close track of the issue numbers this digest contained
an unusually large number of messages mostly about Life in the Universe.
Also a message from Dietz comparing 1micro-arc-second to the angle subtended by
an atom held at arms length (wow).
Anyway if you missed this one let me know.
------------------------------
Date: 30 Sep 1981 1212-PDT
From: Bob Amsler <AMSLER AT SRI-AI>
Subject: Down to the wire with Halley - M. Mitchell Waldrop article in SCIENCE
To: space at MIT-MC
Down to the Wire with Halley
(SCIENCE 2 October 1981, V.214,No.4516 p.35)
(by M.Mitchell Waldrop)
Given the air of fiscal austerity in Washington these days the odds
of the Regan Administration's financing a $300 million spacecraft to
fly by Halley's comet look slimmer than ever. But until the
Administration actually says "No," the space science community is
going all out to win approval for the mission. The answer will have to
come within the next few weeks. At Jet Propulsion Laboratory in
Pasadena, California, planning and design work for the mission is well
along, but the schedule is very tight, says project manager Raymond L.
Heacock. If the spacecraft is to meet the comet in 1986, it must be
launched in the summer of 1985, which means that JPL must start
letting contracts no later than next January. This in turn, will be
possible only if the Halley mission is included as a new start in
NASA's fiscal year 1983 budget, which is being drawn up now.
Laurence Soderblom of the U.S. Geologic Survey, chairman of NASA's
Space Science Advisory Committee, voices a widespread frustration in
the space science community: "It's absolutely insidious, crazy, tragic
that we ever got ourselves into a position where we can't do a Halley
mission." But in fact, a big part of the problem is that NASA
headquarters has never really pushed for Halley. With the space
science budget being squeezed every year by the immense cost of the
space shuttle, agency officials have been more concerned about
preserving such high priority missions as the Galileo orbiter/probe
mission to Jupiter and the Venus Orbiting Imaging Radar.
Proponents of a Halley mission counter that the comet represents a
once-in-a-lifetime opportunity: no other young, active comet has an
orbit that is predictable enough for planning a mission. These are the
kind of comets that are thought to retain pristine material from the
formation of the solar system, and whose dynamics are most
interesting.
Proponents have also stressed national prestige. The European Space
Agency is going to Halley with its "Giotto" spacecraft. The Japanese
are going. The Russians are going. So why aren't we going? Besides,
they say, the United States has a big lead in navigation and imaging
technology. Its close-ups of the comet, the best by far, would give
the country a public relations coup on a par with the Voyager
missions. (In fact, without such images most people will probably be
disappointed in Halley. On this trip its most spectacular displays
will occur on the far side of the sun from the earth.)
During the recent Voyager 2 encounter with Saturn, JPL director Bruce
C. Murray forcefully argued the case for Halley to presidential
advisor Edwin Meese and NASA administrator James M. Beggs. Not
surprisingly, Meese and Beggs have remained noncommittal, pending
submission of NASA's budget proposal. But presidential science advisor
George A. Keyworth is interested in the mission, and has asked NASA to
prepare a list of options for how it might be done. The space agency's
reply is expected to include the following:
* JPL's $300 million "baseline" mission. During the 60-day
"observatory phase" before encounter the spacecraft would monitor the
comet's development with some 3000 long-distance images. During the
3-hour "encounter phase" it would attempt to image the kilometer-sized
nucleus. It would also perform in situ measurements of the comet's
composition and its particle and field environment.
* A somewhat less expensive imaging/sample-return mission. This
version is attractive, says Jeffrey D. Rosendhal, deputy head of
NASA's Office of Space Science, because it would compliment the other
three missions. It would retain the observatory and encounter phase
imaging, which is unique, while dropping the in situ experiments that
duplicate those planned for ESA's Giotto. The dramatic idea of a
sample return came up only last June, very late in the game, says
Rosendhal. The spacecraft would capture a few milligrams of comet
material on what is esentially a sticky surface, then proceed on a
trajectory that would carry it back to earth some 5 years later.
Unfortunately, he adds, the sample-return technology is new, poorly
understood, and risky.
* A swing by Halley with the Galileo spacecraft as the latter heads
toward Jupiter. This is the least attractive option, says Rosendhal.
It would mean sending Galileo on a long, slow loop around the sun,
with a several-year delay in its arrival at Jupiter. Only
long-distance imaging would be possible, and from a bad angle at that.
But if the Administration cancels development of the high-thrust
Centaur booster, which is required to get Galileo to Jupiter on a more
rapid trajectory, this version of the Halley mission might be a way of
salvaging something. On the other hand, doing Galileo in this way
would add another $300 million to its cost--not far below the $445
million price tag for Centaur, and almost exactly the price of the
baseline Halley mission. -- M.Mitchell Waldrop.
------------------------------
Date: 29 Sep 1981 19:22:41-PDT
From: chico!duke!unc!smb at Berkeley
In-real-life: Steven M. Bellovin
To: chico!duke!unc!space@Berkeley
Subject: Sen. Proxmire
That great champion of fiscal responsibility, Sen. Proxmire, made a
16-hour speech that cost -- in lighting, printing, etc. -- $64,000.
The ostensible purpose of the speech was to prevent a needed increase
in the national debt limit -- which is going to pass anyway. Proxmire
is the person primarily response for the demise of SETI.
------------------------------
Date: 30 Sep 1981 1350-PDT
From: Ted Anderson <OTA SU-AI AT>
Subject: Soviets reenter the manned space business
To: space at MIT-MC
n536 0237 30 Sep 81
BC-SPACE-09-30
EDITORS: The following is from the London Telegraph and is for use
only in the United States and Canada.
By Adrian Berry
Daily Telegraph, London (Field News Service)
LONDON - Four months after announcing the end of all manned space
flights until further notice, the Soviet Union has reversed its
position and started preparing for new flights.
The earlier decision to halt manned space missions was taken almost
immediately after Easter's maiden flight of the American space
shuttle, which the Russians claim is a military threat to them.
Tuesday's announcement, reported in Pravda, that the space flight
control center near Moscow is being re-equipped, suggests that the
Russians appear to have recovered from their initial panic.
They are likely soon to launch a new manned mission toward the
Salyut 6 space station, which Wednesday begins a fifth year in orbit,
having circled the Earth more than 25,000 times.
Salyut 6, originally designed for a working life of only 18 months,
has been visited by 16 crews, including eight non-Russian cosmonauts
from Soviet-bloc countries.
The space station will be kept in orbit ''as long as the designers
require,'' the newspaper said Tuesday. Planners envisaged further
space stations, some of them equipped with powerful telescopes for
probing deeper into the universe.
And others are likely to have on board instruments of espionage
which will probe more deeply into Western defenses.
END
nyt-09-30-81 0538edt
***************
------------------------------
Date: 30 Sep 1981 1355-PDT
From: Ted Anderson <OTA SU-AI AT>
Subject: A second reverberating gamma ray burst discovered
To: space at MIT-MC
n009 0707 30 Sep 81
BC-GAMMA
By WALTER SULLIVAN
c. 1981 N.Y. Times News Service
NEW YORK - Examination of a backlog of recordings made in earth
orbit four years ago by the first High Energy Astronomy Observatory
has revealed a burst of gamma rays indicating a catastrophic event
far out in space, though how far and in what direction remain
unknown. The burst was followed by a half minute of 4.2-second
reverberations, suggesting its probable association with a superdense
neutron star rotating at that rate.
Only one other such reverberating gamma ray burst has been recorded,
on March 5, 1979. The newly discovered event was detected on Oct. 29,
1977.
The 1979 burst was detected by nine spacecraft scattered around the
solar system. By comparing precise arrival times of the burst at each
of them, it was possible to determine that it came from the direction
of the Large Magellanic Cloud, a small galaxy of stars about 200,000
light years away, not far from the outer fringes of the Milky Way.
If the source was that far away, within seconds it must have emitted
as much energy as all the stars of the Milky Way combined. Many
astronomers believe the source was a neutron star within that star
cloud. A neutron star is formed when a large star exhausts its
nuclear fuel, cools and collapses into an object of extremely small
size, high density and rapid rotation.
The newly recognized event was recorded by X-ray detectors placed on
the orbiting observatory by the Naval Research Laboratory under the
direction of Dr. Herbert Friedman. The detectors were able to record
the burst because, while it was primarily in gamma rays, it
overlapped the X-ray spectrum.
The rays were too weak for recording by other spacecraft. Hence the
direction of the source has not been determined.
The suddenness and violence of the 1979 event were difficult to
explain. As noted last week by Friedman, it soared to full power in
only 12-hundredths of a second. In the next three minutes it tapered
off, reverberating at an eight-second rate.
One suggested explanation was that a comet fell on a neutron star
rotating every eight seconds. Another was that an asteroid fell on
the star. About 60,000 miles out, the asteroid would have begun to
disintegrate under the influence of the neutron star's extreme
gravity, stretching into a long trail of debris.
This debris would have encircled and fallen on the star, approaching
the speed of light and, in one-billionth of a second, becoming heated
to two billion degrees Fahrenheit. This could have generated the
sharp pulse of gamma rays.
The newly found, but earlier, burst, Friedman said, does not fit
this model. The two-second time required for the pulse to reach full
power was not compatible with an almost instantaneous impact. One
possibility, he added, might be that material that had accumulated in
orbit around the star fell on it when perturbed in some manner.
Another explanation would be sudden contraction or some other form
of extremely massive transformation within the star.
nyt-09-30-81 1008edt
***************
ota - I should note that I went to a talk given by Edward Teller on this
subject and he suggested that the March 5, 1979 event was a neutron star /
asteroid (or planet) collision. Note, however, that such a "collision"
would be more aptly described as a neutron star puncturing the planet(esimal)
and the planet very shortly afterwards exploding.
------------------------------
Date: 1 October 1981 00:14 edt
From: Schauble.Multics at MIT-Multics
Subject: Where are They??
To: space at MIT-AI
Suppose every civilization has its share of Proxmires. In fact,
suppose that evolution tends to create Proxmires.
Then most of not all civilizations would not be exploring for the
same reason we are not. They're Proxmired down.
Gad, what a horrible thought.
Paul
------------------------------
Date: 1 October 1981 06:02-EDT
From: Robert Elton Maas <REM MIT-MC AT>
Subject: Anybody out there??
To: TAW at SU-AI
cc: SPACE at MIT-MC
Proxmire's reason for canceling SETI is idiotic.
Of course we don't expect meaningful duplex communication with
a civilization 1000 light-years away (thus 2000-year turnaround
time for each communication interchange). But that isn't
the main goal of SETI, it's finding out if there is anybody out
there in the first place! Getting that info would be VERY IMPORTANT!!
(It's hard to imagine anything more important.)
Maybe he has good reasons for canceling SETI, but the infeasibility
of meaningful duplex communication isn't one of them.
<ABOVE DCA AUTHOR DOESN'T VIEW LIST OF OR CONTRACTORS AND THE NECESSARILY REPRESENT OPINION MAILING SPACE ITS IS>
------------------------------
End of SPACE Digest
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