Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V16_4/V16NO484.TXT

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Date: Sat, 24 Apr 93 05:11:27
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V16 #484
To: Space Digest Readers
Precedence: bulk


Space Digest                Sat, 24 Apr 93       Volume 16 : Issue 484

Today's Topics:
          Command Loss Timer (Re: Galileo Update - 04/22/93)
                   Eco-Freaks forcing Space Mining.
      JPL's VLBI Project Meets with International Space Agencies
                   New planet/Kuiper object found?
              PLANETS STILL: IMAGES ORBIT BY ETHER TWIST
                     SIRTF Mission is Still Alive
                      Stephen Hawking Tours JPL
                        Sunrise/ sunset times
                         Vandalizing the sky.
               Why DC-1 will be the way of the future.

    Welcome to the Space Digest!!  Please send your messages to
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Date: Fri, 23 Apr 1993 16:08:08 GMT
From: fred j mccall 575-3539 <[e-mail]>
Subject: Command Loss Timer (Re: Galileo Update - 04/22/93)
Newsgroups: sci.space,sci.astro,alt.sci.planetary

In <[e-mail]> [e-mail] (Alan Carter) writes:

>In article <[e-mail]>, [e-mail] (Ron Baalke) writes:
>|> 3.  On April 19, a NO-OP command was sent to reset the command loss timer to
>|> 264 hours, its planned value during this mission phase.

>This activity is regularly reported in Ron's interesting posts. Could
>someone explain what the Command Loss Timer is?

The Command Loss Timer is a timer that does just what its name says;
it indicates to the probe that it has lost its data link for receiving
commands.  Upon expiration of the Command Loss Timer, I believe the
probe starts a 'search for Earth' sequence (involving antenna pointing
and attitude changes which consume fuel) to try to reestablish
communications.  No-ops are sent periodically through those periods
when there are no real commands to be sent, just so the probe knows
that we haven't forgotten about it.

Hope that's clear enough to be comprehensible.

--
"Insisting on perfect safety is for people who don't have the balls to live
 in the real world."   -- Mary Shafer, NASA Ames Dryden
------------------------------------------------------------------------------
[e-mail] - I don't speak for others and they don't speak for me.

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

Date: 23 Apr 1993 12:46:35 -0400
From: Pat <[e-mail]>
Subject: Eco-Freaks forcing Space Mining.
Newsgroups: sci.space

Organization: Express Access Online Communications USA
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Source-Info:  Sender is really [e-mail]

In article <[e-mail]> [e-mail] writes:
>In article <1r6b7v$[e-mail]>, [e-mail] (Pat) writes:
>>  Besides this was the same line of horse puckey the mining companies claimed
>> when they were told to pay for  restoring land  after strip mining.
>===
>I aint talking the large or even the "mining companies" I am talking the small
>miners, the people who have themselves and a few employees (if at all).The
>people who go out every year and set up thier sluice box, and such and do
>mining the semi-old fashion way.. (okay they use modern methods toa point).


Lot's of these small miners  are no longer miners.  THey are people living
rent free on Federal land,  under the claim of being a miner.  The facts are
many of these people do not sustaint heir income from mining,  do not
often even live their full time,  and do fotentimes do a fair bit
of environmental damage.

These minign statutes were created inthe 1830's-1870's  when the west was
uninhabited  and were designed to bring people into the frontier.  Times change
people change.  DEAL.  you don't have a constitutional right to live off
the same industry forever.  Anyone who claims the have a right to their
job in particular,  is spouting nonsense.   THis has been a long term
federal welfare program,  that has outlived it's usefulness.

pat

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

Date: 23 Apr 1993 17:38 UT
From: Ron Baalke <[e-mail]>
Subject: JPL's VLBI Project Meets with International Space Agencies
Newsgroups: sci.space,sci.astro

From the "JPL Universe"
April 23, 1993

VLBI project meets with international space agencies

By Ed McNevin
     Members of JPL's Space Very Long Baseline Interferometry
(VLBI) project team recently concluded a week-long series of
meetings with officials from Russia and Japan.
     The meetings were part of "Space VLBI Week" held at JPL in
early March and were intended to maintain cooperation between
international space agencies participating in the development of
the U.S. Space VLBI Project, a recently approved JPL flight
project set for launch in 1995.
     U.S. Space VLBI will utilize two Earth-orbiting spacecraft
-- the Japanese VSOP (VLBI Space Observing Program) satellite
with its 8-meter radio telescope, and a Russian RADIOASTRON
10-meter satellite. Both spacecraft will team up with
ground-based radio telescopes located around the world to create
a radio telescope network that astronomers hope will expand radio
telescope observing power by a factor of 10.
     Japan's VSOP satellite will use a limited six-hour orbit to
conduct imaging science, while the Russian RADIOASTRON spacecraft
will exploit a larger, 28-hour Earth orbit to conduct exploratory
radio astronomy. Each satellite will point at a source target for
roughly 24 hours, while approximately 20 ground-based radio
telescopes will simultaneously point at the same source object
while within view on Earth.
     According to Dr. Joel Smith, JPL's project manager for the
U.S. Space VLBI, meetings like those held at JPL will permit
Japan and Russia, who have little previous experience in radio
interferometry, to establish working relationships with the radio
astronomy communities that will be vital during the complex
observations required by the Space VLBI project.
     "One of our main activities is developing the methodology
for international coordination, because the two spacecraft
simultaneously rely on the corresponding tracking stations while
using the ground-based radio telescopes to observe the same
celestial objects," said Smith.
     Three new tracking antennas are being built at DSN
facilities and other three other tracking facilities located in
Japan, Russia and Green Bank, W.Va. This global network of
ground-based radio telescopes will use precision clocks and
high-speed recorders to collect observation data and forward the
information to a correlator located at the National Radio
Astronomy Observatory in Socorro, N.M. The correlator will
combine and process data, then make it available to mission
investigators in Moscow, Tokyo, and JPL via electronic mail.
     Smith is optimistic that the massive radio telescope created
by the Space VLBI network will provide radio astronomers with
better resolution than has ever been achieved before by
ground-based radio telescopes, allowing astronomers to take a
closer look at distant objects in space.
     "There is a long history of radio astronomy using
ground-based telescopes," said Smith. "What we intend to do is to
extend radio astronomy into Earth orbit. Our goal is to look
deeper into the cores of galactic nuclei, quasars and other
active radio sources to understand what drives those things we
have seen so far with radio astronomy."
     Smith noted that if one examines "the active galactic
nuclei, you'll find jets appearing to spew at speeds greater than
light, and at energy levels that are millions of times greater
than you would expect."
     He said some astronomers believe that black holes may be
located in the cores of these galaxies, and that they may fuel
the jets. Smith hopes that "by using Space VLBI to look further
into the cores, this theory may be supported or disproved."
     Russian space-flight hardware, including transponders and
transmitters, are now being tested in the United States, and
Japanese hardware is scheduled to arrive for testing later this
year. Analysis of this hardware will permit U.S. scientists and
engineers to understand how to modify the high-speed VLBA
Correlator operating at the NRAO in order to accommodate the odd
data patterns that will originate from the more than 20
ground-based radio telescopes involved in Space VLBI.
     Smith is particularly pleased that meetings with the
Japanese and Russian space agency officials -- like those held at
JPL in March -- have proceeded smoothly. Yet he knows that the
political uncertainty in Russia could jeopardize that country's
participation in the project.
     "Nothing is ever smooth," he said, "but the Russians have
been incredibly open with us. We always anticipated some
likelihood that we will not succeed because of political factors
beyond our control, yet there tends to be a way of keeping these
things going, because scientists on both sides are trying hard,
and people recognize the value of cooperation at this level."
     Smith points out that the Japanese space agency has more at
stake than just fulfilling an international commitment to a
science mission.
     "The Japanese have been extremely cooperative, since
international cooperation is essential to their science mission,"
he said.
     But Smith also noted that Japanese space agency officials
look at the U.S. Space VLBI mission as an opportunity to showcase
the technology involved with VSOP spacecraft, and their highly
regarded Mach V launch vehicle.
     Yet regardless of the risks involved in undertaking such an
ambitious project, JPL's Smith is satisfied that planning for the
Space VLBI Project is beyond the significant financial and
political hurdles that otherwise might threaten the project.
     "Fortunately, we have the virtue of having two partners, and
if either falls out, we would still have something with the
other. By themselves, both spacecraft are independent,
scientifically exciting missions."
                           ###
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | The aweto from New Zealand
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | is part caterpillar and
|_____|/  |_|/       |_____|/                     | part vegetable.

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

Date: Fri, 23 Apr 1993 17:06:52 GMT
From: James Davis Nicoll <[e-mail]>
Subject: New planet/Kuiper object found?
Newsgroups: sci.space

    If the  new  Kuiper belt object *is*  called 'Karla', the next
one  should be called 'Smiley'.

                            James Nicoll

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

Date: Fri, 23 Apr 1993 16:54:59 GMT
From: Jack Coyote <[e-mail]>
Subject: PLANETS STILL: IMAGES ORBIT BY ETHER TWIST
Newsgroups: sci.space,sci.astro

In sci.astro, [e-mail] (David McAloon) writes:

[ a nearly perfect parody  -- needed more random CAPS]


Thanks for the chuckle.  (I loved the bit about relevance to people starving
in Somalia!)

To those who've taken this seriously, READ THE NAME! (aloud)

--
Thank you, thank you, I'll be here all week.  Enjoy the buffet!

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

Date: 23 Apr 1993 17:30 UT
From: Ron Baalke <[e-mail]>
Subject: SIRTF Mission is Still Alive
Newsgroups: sci.space,sci.astro

From the "JPL Universe"
April 23, 1993

SIRTF is still very much in business

By Mark Whalen
     In these times of extra-tight NASA budgets, the very
survival of a number of missions has been uncertain. But thanks
to major design refinements implemented in recent months, JPL's
Space Infrared Telescope Facility (SIRTF) -- a major project
considered to be in trouble a couple of years ago -- is "alive
and well," according to Project Scientist Michael Werner.
     A lighter spacecraft, revised orbit and shorter mission have
added up to a less expensive project with "tremendous scientific
power" and a bright future, said Werner.
     Designed as a follow-up to the highly successful Infrared
Astronomical Satellite (IRAS) and Cosmic Background Explorer
(COBE) missions, SIRTF -- a cryogenically cooled observatory for
infrared astronomy from space -- is scheduled for launch in 2000
or 2001 if plans proceed as scheduled.
     IRAS' pioneering work in space-based infrared astronomy 10
years ago allowed astronomers to view the Milky Way as never
before and revealed, among other things, 60,000 galaxies and 25
comets. It provided a sky survey 1,000 times more sensitive than
any previously available from ground-based observations. COBE has
measured the infrared and microwave background radiation on large
angular scales, and revealed new facts about the early universe.
     But to illuminate SIRTF's potential, Jim Evans, JPL's
manager of Astrophysics and Fundamental Physics Pre-Projects,
recently said that the project is "1,000 to 1 million times more
capable than IRAS," based on technological advances in infrared
detector arrays.
     However, despite the enormous strides in infrared
exploration SIRTF promised, and the fact that it was cited as the
highest priority new initiative for all of astronomy in the 1990s
(by the National Academy of Sciences), it took a "diet or die"
directive from NASA Headquarters last year to keep the project
going, according to Werner.
     The project is now known as Atlas SIRTF, based on the key
factor in its new design: The satellite will orbit the sun
instead of the Earth, permitting the use of an Atlas rocket
launch instead of the formerly proposed and heavier Titan. "The
main advantage of the solar orbit is that you can use all of your
launch capability for boosting the payload -- you don't have to
carry up a second rocket to circularize the orbit," Werner said.
The other advantage to a solar orbit, he said, is that "it's in a
better thermal environment, away from the heat of the Earth."
     Additional major changes in SIRTF's redesign include
shortening the mission from five to three years and building a
spacecraft that is less than half as heavy as in the original
plan -- Atlas SIRTF will weigh 2,470 kilograms (5,400 pounds)
compared to Titan SIRTF's 5,500 kilograms (12,100 pounds).
     All of that adds up to "a less stressful launch
environment," Werner said, and a cost savings of more than $200
million for the launch, in addition to increased savings in the
design of the smaller, less massive spacecraft.
     Werner said SIRTF's redesign came as a result of Congress'
telling NASA "you're trying to do too many things. If you want us
to support SIRTF, which is a good project, develop a plan to see
how it fits into (NASA's) overall strategy."
     Shortly thereafter, SIRTF was named as NASA's highest
priority "flagship" scientific mission by the interdisciplinary
Space Sciences Advisory Committee, in addition to the blessing
from the National Academy of Sciences.
     While the spacecraft and its instruments required descoping
to keep the project alive, SIRTF's major scientific contribution
always promised to come about from its advanced infrared detector
arrays, which will allow images to be developed "tens of
thousands of times faster" than before, according to Evans.
     "Up until a couple of years ago," Werner said, "all infrared
astronomy was done with single detectors -- or very small arrays
of individually assembled detectors. Since then, the Department
of Defense has developed a program to produce arrays of tens or
hundreds of thousands of detectors, rather than just a few, and
those are very well suited for use on SIRTF."
     Werner noted that in addition to dealing with budget
pressures, Congress is currently watching NASA projects with an
eye out for any "technological spinoff."
     "On that question, I think we have some things to say," he
said, "because the detectors we're using are straight off various
military developments. Also, SIRTF will be built by the U.S.
aerospace industry, and it's a real technological and engineering
challenge in addition to being a tremendous scientific project.
     "SIRTF will be used by the entire astronomical community,"
Werner added, but the revised three-year mission "puts a premium
on observing time. We have to educate the user community and
develop a program that involves early surveys and quick
turnaround of the data."
     Werner said the downsizing of the project required a
reduction in scope and complexity of SIRTF's three instruments --
the infrared spectrograph, infrared array camera and multiband
imaging photometer. However, these reductions will only result in
losses of efficiency rather than capability, he said.
     The project hopes to start a "Phase B" activity in 1995,
which will provide a detailed concept for development and design.
Building the hardware would begin about two years later.
     Projected cost estimates, Evans said, are $850 million-$950
million.
     "I am very optimistic about SIRTF," he said. "It will
provide a tremendous return for the investment."
     Werner added that an additional benefit from the project
will be the "enrichment of our intellectual and cultural
environment. People on the street are very interested in
astronomy ... black holes, the possibility of life on other
planets, the origin of the universe ... and those are the kind of
questions SIRTF will help answer."
                              ###
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | The aweto from New Zealand
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | is part caterpillar and
|_____|/  |_|/       |_____|/                     | part vegetable.

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

Date: 23 Apr 1993 17:32 UT
From: Ron Baalke <[e-mail]>
Subject: Stephen Hawking Tours JPL
Newsgroups: sci.space,sci.astro,sci.physics

From the "JPL Universe"
April 23, 1993

Cosmologist Stephen Hawking tours Lab

By Karre Marino
     Some 15 years after his first visit to JPL, Prof. Stephen
Hawking, Lucasian professor of mathematics at Cambridge
University and author of "A Brief History of Time," returned to
the Lab April 5.
     On a tour hosted by JPL Chief Scientist Dr. Moustafa Chahine
and Merle McKenzie, manager of the International Affairs Office,
Hawking visited a variety of facilities, met with Lab Director
Dr. Edward Stone and various project scientists and managers, and
felt "like royalty," he said. Hawking, whose theories attempt to
explain the origin of distant galaxies, black holes and alternate
dimensions, wanted to re-visit JPL, he explained, "because while
I'm most interested in those things in space that are farther
away, I know that here is where the first steps are taken."
     Hawking, who was accompanied by his family, two graduate
students and his aides, began the tour in von Karman Auditorium,
as David Evans, deputy assistant Lab director in the Office of
Flight Projects, and Dr. Arden Albee, Mars Observer's project
scientist, briefed him on current and past flight projects.
     Voyager was pointed out to him, with special attention paid
to a gold plate with a series of engraved images. Should
extraterrestrial life stumble upon the spacecraft, Evans noted,
they would find a variety of images that would explain something
of Earth. The professor asked if we were still communicating with
the spacecraft, and Evans affirmed that we are.
     Using a model of Mars Observer, Albee spent several minutes
describing the project and the spacecraft's features. In answer
to a question from Hawking, Chahine described a proposed
drag-free satellite, but confirmed that at this point, "it's only
a concept." Chahine, who had met Hawking at Caltech about five
years before, described the professor as "a living miracle of the
power of the brain. He's miraculous, and he has such a good sense
of humor."
     The next stop, a demonstration on scientific data
visualization in Section 384's Digital Image Animation Lab,
entertained and delighted the group, as everyone donned goggles
to view 3-D images of Mars. Project Scientist Dr. Eric De Jong
showed off the latest data -- a comet that had only recently been
discovered in orbit close to Jupiter. Hawking was curious about
its composition, and as he was shown how images are developed, he
asked several questions on their interpretation.
     Norman Haynes, ALD, Office of Telecommunications and Data
Acquisition, briefed the professor on the Space Flight Operations
Facility, and then Hawking spoke with Stone.
     The day ended with two technical discussions of particular
interest to the professor. Technical Group Leader Dr. Frank
Estabrook and Senior Research Scientist Hugo Wahlquist described
a three-spacecraft gravity wave experiment, currently under way.
Then planetary astronomer Dr. Richard Terrile explained the
philosophy and plans for extra solar system planetary detection.
     The Hawking party, which had been visiting Southern
California for five weeks, was headquartered at Caltech, and
planned to leave for England within a few weeks after the Lab
tour. Upon departing, the Cambridge-based scientist promised
Chahine that he would return to JPL for another visit.
                          ###
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | The aweto from New Zealand
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | is part caterpillar and
|_____|/  |_|/       |_____|/                     | part vegetable.

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

Date: Fri, 23 Apr 1993 16:20:14 GMT
From: Simon Tardell <[e-mail]>
Subject: Sunrise/ sunset times
Newsgroups: sci.misc,sci.math,sci.space

In <[e-mail]> [e-mail] (Joseph Wetstein) writes:

>Hello. I am looking for a program (or algorithm) that can be used
>to compute sunrise and sunset times.

>I would appreciate any advice.

I once thought it would be easiest fitting a sine to the times. But not.
This gave  discrepancy of upto six minutes. If you fit a sine series
you'll get a very good fit after just three or four terms though. This
presumably has to do with the eccentricity of the Earths orbit.

--
Simon Tardell, Ff88, [e-mail]              V}ga v{gra cgs!

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

Date: Fri, 23 Apr 1993 17:05:30 GMT
From: "George F. Krumins" <[e-mail]>
Subject: Vandalizing the sky.
Newsgroups: sci.astro,sci.space

[e-mail] (Jeff Cook) writes:

>In article <[e-mail]> [e-mail] (Enzo Liguori) writes:

>>Now, Space Marketing

>>What about light pollution in observations? (I read somewhere else that
>>it might even be visible during the day, leave alone at night).

>I can't believe that a mile-long billboard would have any significant
>effect on the overall sky brightness.  Venus is visible during the day,
>but nobody complains about that.  Besides, it's in LEO, so it would only

When I was at the Texas Star Party a few years ago, the sky was so dark
that Venus did, indeed, cause light pollution until it set.

Even if the billboard were dark it could cause a problem.  Imagine observing an
object and halfway through your run, your object was occulted!

I would guess that most of the people stating positive opinions are not
fanatically serious observers.

It is so typical that the rights of the minority are extinguished by the
wants of the majority, no matter how ridiculous those wants might be.

George Krumins
--

--------------------------------------------------------------------------------
|  George Krumins                                                              |
|  [e-mail]                                                   |

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

Date: Fri, 23 Apr 1993 16:04:01 GMT
From: fred j mccall 575-3539 <[e-mail]>
Subject: Why DC-1 will be the way of the future.
Newsgroups: sci.space

In <1r6ub0$[e-mail]> [e-mail] (Pat) writes:

>In article <[e-mail]> [e-mail] (James Davis Nicoll) writes:
>>    Hmmm. I seem to recall that the attraction of solid state record-
>>players and radios in the 1960s wasn't better performance but lower
>>per-unit cost than vacuum-tube systems.
>>


>I don't think so at first,  but solid state offered  better reliabity,
>id bet,  and any lower costs would be only after the processes really scaled up.

Careful.  Making statements about how solid state is (generally) more
reliable than analog will get you a nasty follow-up from Tommy Mac or
Pat.  Wait a minute; you *are* Pat.  Pleased to see that you're not
suffering from the bugaboos of a small mind.  ;-)

--
"Insisting on perfect safety is for people who don't have the balls to live
 in the real world."   -- Mary Shafer, NASA Ames Dryden
------------------------------------------------------------------------------
[e-mail] - I don't speak for others and they don't speak for me.

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

End of Space Digest Volume 16 : Issue 484
------------------------------