Space & Astronomy/Space and Astronomy (October 1993).iso/pc/text/spacedig/v16_3/v16no332.txt

Internet Message Format | 1993-07-13 | 35KB

Date: Thu, 18 Mar 93 05:29:54
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V16 #332
To: Space Digest Readers
Precedence: bulk


Space Digest                Thu, 18 Mar 93       Volume 16 : Issue 332

Today's Topics:
                         a Plan for NASA,etc.
        Flight time comparison: Voyager vs. Gallileo (3 msgs)
                         Lunar Ice Transport
                          MYSTERY SATELLITE?
         Predicting gravity wave quantization & Cosmic Noise
                          Retraining at NASA
                       The courage of anonymity
    Threat of mass cancellings was Re: Anonymity is NOT the issue
           Three Spacecraft to Conduct Gravity Wave Search
    Water Simulations (Was Re: Response to various attacks on SSF)
                   What do we do now with Freedom.

    Welcome to the Space Digest!!  Please send your messages to
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----------------------------------------------------------------------

Date: Wed, 17 Mar 1993 12:39:57 GMT
From: Gary Coffman <ke4zv!gary>
Subject: a Plan for NASA,etc.
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Bill Jameson SPS Pres.) writes:
>
> Someone i saw on this group recently was talking about NASA not having a
>plan, a long-term goal, or purpose that was well defined. Perhaps we have not
>been exposed to this plan (there were also complaints about NASA's poor PR),
>but whether it exists or not, I offer my own plan for our nation's (or,
>preferably, nations' ) space program.
> As the population of our measly little planet grows, we will need increasing
>amounts of the land area for food production and living space, things which
>would be economically impractical off-planet. (I mean LARGE SCALE living, not

>to say that permanent manned bases are a bad idea) Thus, it would be useful
>and considerate of our environment (Which includes us!!!) for the more nasty
>aspects of our technological life style to be carried out where they won't
>pollute the surface of the planet- hence, off-planet.
>  The things which I suggest as most likely practical are off-planet mining
>of asteroids, moons, or other planets, and material processing up there too.
>Perhaps have a lunar ironworks.

IM not so HO, applications other than communications and Earth sensing
will remain uneconomic into the foreseeable future. Even with Nick's
native materials projects, processed resources still cost much more in
orbit than they do on the surface. Turning those resources into useful
technological devices still requires a large technical infrastructure
that exists only on Earth. The only economic extraterrestrial materials
markets I see are in orbit for use in orbit, mainly reaction gases. Those
markets are likely to remain small if they can't produce things desired
on Earth where the real money and markets exist.

Again IMHO, the only reasons for the space program outside of communications
and Earth sensing, are scientific curiosity and humanity's desire to
expand it's limits. Curiosity is a luxury item of a civilization with
excess leisure. Frontier seeking is a cultural curiosity that drives only
a small percentage of a population. On this forum the latter are over
represented by a large factor. A frontier is no relief valve for population.
The rapid expansion into North America was fuelled primarily by the market
for recreational drugs, precious metals, and gems. It was only later, after
significant infrastructure was in place in NA that bulk trade items like
cotton, and manufactured goods, became economic. Tobacco was the driver
that opened NA. What equivalent product will open space? It certainly won't
be SPS. Power is too cheap to generate down here on the surface by any
number of technologies, many of which are clean by any rational standard.

Gary
--
Gary Coffman KE4ZV          |    You make it,     | gatech!wa4mei!ke4zv!gary
Destructive Testing Systems |    we break it.     | uunet!rsiatl!ke4zv!gary
534 Shannon Way             |    Guaranteed!      | emory!kd4nc!ke4zv!gary
Lawrenceville, GA 30244     |                     |

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

Date: 18 Mar 1993 00:38 UT
From: Ron Baalke <[e-mail]>
Subject: Flight time comparison: Voyager vs. Gallileo
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Hayim Hendeles) writes...
>In 1977, the Voyager spacecraft was launched towards Jupiter,
>and took approximately 2-3 years to get there without any gravity
>assists. Yet, the Gallileo spacecraft is taking 6 (?) years to reach
>Jupiter - and that's with 3 gravity assists! Why is there such a big
>difference? Is this another fiasco due to the Space Shuttle?

Two main differences.  Galileo is an orbiting mission and is much
more constrainted to a slower trajectory to Jupiter for orbit insertion, while
Voyager simply had to flyby.  Also, Galileo had to carry along a larger
fuel tank to be used for orbit insertion.  Galileo was mandated to be
launched from the Space Shuttle, which had a number of problems along
with the upper stages that caused the spacecraft the be redesigned a
number of times.

>Another question on the same topic, concerns our inability to send a
>mission to Pluto. I remember, back in the 70's, they considered sending
>one of the Voyager's to Pluto via a gravity assist at Jupiter. I don't
>remember the details, but I do remember the flight times were not that
>excessive.  Now since the Earth, Jupiter and Pluto are in the same
>relative positions every 13-14 years (approximately - if I guess
>correctly), this type of mission should be quite feasible again, with a
>reasonable flight time. So why isn't it a "simple" matter to launch
>a Voyager-type spacecraft to Jupiter?

There was an option to send Voyager 1 to either Titan or Pluto, but not
both.  Titan was chosen because of it was the only known moon with an
atmosphere, and there were some uncertainties about whether Voyager would
survive long enough to be able to reach Pluto.

There is a proposed mission by JPL called the Pluto Fast Flyby.  A
number of options were looked at including a Jupiter gravity assist.
It turns out that the next opportunity for a Jupiter gravity assist
isn't until the year 2004, and the minimum flight time is 8.7 years.
A disadvantage of a Jupiter gravity assist is that the spacecraft
would have to be radiation hardened, which adds mass and cost to the
spacecraft.  It is actually quicker to launch a smaller spacecraft
directly to Pluto.  With a Titan IV launch in 1999, it would only
take about 7 years to launch a 164kg spacecraft to Pluto.  There is work
to reduce the mass of the spacecraft even further down to 110kg, which would
shave another year off the flight time.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Don't ever take a fence
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | down until you know the
|_____|/  |_|/       |_____|/                     | reason it was put up.

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

Date: 18 Mar 1993 01:06 UT
From: Ron Baalke <[e-mail]>
Subject: Flight time comparison: Voyager vs. Gallileo
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Henry Spencer) writes...
>No, the fundamental problem is that Galileo really could have used a
>trip to the fat farm.  Galileo is much, much heavier than the Voyagers,
>to the point where it can only barely fly its intended mission.  Its
>weight growth during development was nothing short of spectacular.

Not true.  Galileo is a heavier spacecraft than Voyager, by design.
Galileo is an orbiter, whereas a flyby spacecraft can be built much smaller.
Also, Galileo had to be redesigned so many times because of
problems with the Shuttle and the Centaur/IUS, and its mass was even
reduced at one point.

>Originally it wasn't going to need the gravity assists, but only
>because it was going to use the heaviest booster combination the US
>had -- Shuttle plus Centaur.  When Centaur was banned from the shuttle
>after Challenger, the gravity assists became necessary.

True, but you forgot to mention that the original booster that Galileo
was originally scheduled to use, the IUS, did not meet up to expectations,
and the Shuttle/Centaur combination was then substituted in.

>Had Galileo stayed within earlier weight targets, the IUS that boosted
>it into the gravity-assist trajectory could have sent it direct to
>Jupiter, like Ulysses.

You've got this one backwards.  The IUS failed to meets its
design specs, and was unable to send Galileo directly to Jupiter as
was the originally intended to do.

Also, comparing Ulysses to Galileo is like comparing apples to oranges.
Ulysses is a flyby mission, Galileo is an orbiting mission.  Ulysses
required a very fast trajectory to Jupiter so that is can use
Jupiter's gravity to be deflected out of the ecliptic plane. Galileo,
on the other hand, has to approach Jupiter at a more leisurely velocity
to go into orbit around the planet.

Here's what Galileo had to endure just to be launched.

1975 - NASA decides that the proposed Jupiter Orbiter Probe (JOP)
       will be the first planetary spacecraft launched on the Space Shuttle.
       The mission was later renamed to Galileo.

1977 - Congress nearly cancels the Galileo program, but it survives and
       is approved for launch in 1982 and arrival in 1985.  A new IUS
       (Interim Upper Stage) is to be built that will propel Galileo
       directly to Jupiter.

1980 - The Space Shuttle program falls far behind schedule and Galileo's
       launch is slipped to 1984 with arrival delayed until 1986.  Since the
       1984 trajectory is unfavorable NASA decides on a major engineering
       change.  The spacecraft is split in two, an orbiter section and an
       atmospheric probe section, and are to be launched separately. The
       spacecraft and the mission are completely redesigned.

1981 - The IUS (now cleverly renamed to Inertial Upper Stage) cannot meet
       its design specs and cannot propel Galileo directly to Jupiter.
       NASA opts for the more powerful liquid fueled Centaur stage.
       The probe and orbiter are recombined for a single launch, and the
       spacecraft and mission are redesigned once again.  The launch date is
       slipped to 1985.

1982 - David Stockman cancels the Galileo program.  The program is restored
       by Congress.

1984 - Problems with the Space Shuttle and Centaur delay the launch again
       to 1986 with arrival in 1988.

1986 - Challenger explodes just four months before Galileo was to have
       been launched.  The Centaur program is cancelled for safety reasons.
       Without a launch vehicle to get the spacecraft to Jupiter, the
       mission is on the verge of cancellation.

1987 - The VEEGA trajectory is developed and can get Galileo to Jupiter
       using the IUS.  Galileo is scheduled again for launch in 1989.

1989 - Galileo is finally launched from the Space Shuttle with the IUS.
       Cruise time to Jupiter with the VEEGA trajectory is now six years.
       Arrival time is late 1995, ten years after the original arrival date.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Don't ever take a fence
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | down until you know the
|_____|/  |_|/       |_____|/                     | reason it was put up.

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

Date: Thu, 18 Mar 1993 00:06:18 GMT
From: Gary Coffman <ke4zv!gary>
Subject: Flight time comparison: Voyager vs. Gallileo
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>the moment, I don't think the U.S. has anything that will launch anything of
>Voyager size from earth.

Voyagers went up on Titan-Centaurs.

Gary

--
Gary Coffman KE4ZV          |    You make it,     | gatech!wa4mei!ke4zv!gary
Destructive Testing Systems |    we break it.     | uunet!rsiatl!ke4zv!gary
534 Shannon Way             |    Guaranteed!      | emory!kd4nc!ke4zv!gary
Lawrenceville, GA 30244     |                     |

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

Date: 17 Mar 1993 19:11:50 -0500
From: Pat <[e-mail]>
Subject: Lunar Ice Transport
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (fred j mccall 575-3539) writes:
|In <[e-mail]> [e-mail] (Pat) writes:
|
|>Fred talks about accuracy problems in Ballistic delivery due to masscons
|>and weight variations.
|
|>I imagine tha tthe  problem is not that difficult.
|
|>First, a highly accurate gravity map would be available,  and this
|>would be over a single well known route.
|
|I'm not convinced that such a map would be available.  Simply making
|such a map seems like quite an undertaking.
|

If the CIA could get gravity maps of the Wasrsaw pact countries during the
cold war,  Then It must be within our National Technical Means.

Besides worst case, we send Henry and Nick overland with gravitometers.:-)

|
|>I imagine loads would be weight and balance checked before launch,
|>and may even fly with an emergency trajectory correction package
|>for abort purposes.  i.e.  the gun loses power on the final 10%
|>of acceleration.
|
|The problem here is twofold.  Any variance in mass distribution of the
|load or of power and efficiency of the launcher are going to lead to a
|miss.  I think this is a more difficult problem over the distances
|being talked about than Pat seems to believe.  'Mere engineering',
|perhaps, but that makes it no more tractible.
|

Like I said, weight and balance checks before launch and a TCM package.
If Magnavox can put Steering fins on 8" cannon shells,  and copperhead
missiles can be launched out of 155 mm howitzers  and use laser seekers
to hunt tanks,  the technology should be adaptable to sling shots.

All state of the art stuff.  The biggest thing is making sure the TCM
packages are highly reliable.  99.9 % or better.  maybe fault tolerance,
in the package.   Any TCM  package should true up the course,
or arrange an abort into a convenient mountain.

|>Remember, using 18"  cannon,  in atmosphere,  the US navy had a regular
|>accuracy of 50 meters in 35 miles.
|
|The U.S. Navy has never had a ship mounting an 18" gun.  The Japanese

No, but we tested them.  we laid keels for 18" battleships, but the war ended.


|
|Now do the triginometry to compute what a 50 metre error over a 40

Like I said, TCM  for final guidance.  Without an atmosphere,  guidance
is much less variable.  It's  just that once in a blue moon error is
a doozy.  Any catcher should not be close  to any manned facilities.

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

Date: 17 Mar 93 18:44:00 GMT
From: Leo Wikholm <[e-mail]>
Subject: MYSTERY SATELLITE?
Newsgroups: sci.space

-> > : Recently while walking to the grocery store, I saw a bright star
-> like > : object in the night sky.  When I was on the way TO the store
-> this > : star-sized light was in the western sky, about 14 deg. elev.
-> A few hours > : later, about 6 hours, I saw the same thing, only this
-> time it was in the > : eastern side of the sky.  Do you know what
-> this could be?  Is it Hubble? > : It's easy to describe because its
-> the brightest star/satellite out there.

There are thousands of satellites in orbit so it was one of them.
It seems like it was a low earth orbiting satellite. Sometimes
they may be a very bright objects in the sky.

Yours,

Leo Wikholm
e-mail: [e-mail]

----
+-----------------------------------------------------------------------+
| Delivered by: ComPart BBS  Finland  [phone] lines V.32bis |
+-----------------------------------------------------------------------+

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

Date: 18 Mar 1993 01:04:09 GMT
From: Mark <[e-mail]>
Subject: Predicting gravity wave quantization & Cosmic Noise
Newsgroups: sci.space,sci.astro,sci.physics,alt.sci.planetary

In article <[e-mail]> [e-mail] (Ron Baalke) writes:
>     Three interplanetary spacecraft, now headed quietly toward Mars,
>Jupiter and over the poles of the sun, soon may prove the
>existence of elusive waves in the universe's gravitational field by
>bobbing on ripples in space like corks bobbing on ripples in a pond.

I'm betting that the following will be observed:  Cosmic Noise.  A large number
of components will be detected at around wavelengths of 1 AU and above with
VERY low intensity, if the configuration is sufficiently tuned.  The
components will have wavelengths that occur at discrete jumps of about 1
millimeter at 1 AU.

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

Date: 17 Mar 1993 19:34:35 -0500
From: Pat <[e-mail]>
Subject: Retraining at NASA
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Brian Donnell) writes:
>In article <[e-mail]>, [e-mail] (Nick Szabo)
>wrote:
>[...various foam-at-the-mouth drivel deleted...]
>

Yeah, I'll have to agree.  I'd like to see more NASA people
using sci.space as a forum for honest engineering discussion.
I just don't want to see any Hatch act violations.

>In article <[e-mail]>, [e-mail] (Allen W. Sherzer)
>wrote:
>>
>> Talk to SDIO. Their support infrastructure for SSRT represents less then
>> 1/60 of the program cost. Yet they are doing more to support cheap routine
>> access to space than NASA has ever done.
>>
>BTW - I disagree with the previous estimate of infrastructure costs being
>50% of NASA's overall costs.  Before we quibble about this - why don't
>you list what you consider to be infrastructure (civil service, maintenance
>of existing programs, etc.).
>

Okay, Brief Infrastructure Listing, with ROM costs.

STS  4 Billion/year.
SSF  1 Billion/year
DSN  200 Million/year
TDRSS 500 Million/year
Facilities O&M 1.5 Billion/year.

    Fixing roofs,  power bills,  grass cutting, PR, NASA education....
    everything associated with owning some 15 Major centers.

Given NASA  has a 14 Billion dollar budget,  i'd say that works out to
50%.  BTW most organizations have between 50- 80% overhead.   Only
young organizations can live at 10-15%.

Investment in infrastructure often times limits modes of thought.
DSN for example.  A marvelous set of gear,  operated well, doing
things way beyond the original specs,  but  because there is all
this available Deep space radio gear,  little effort is placed on
deep space laser comms.   Ergo, each new project tends to be tied
to DSN availability.

I'd think a little investment on space qualifying and developing
this technology would have massive gains in almost all areas of
space flight.  And if they were blue-green lasers, they'd really
help in Naval applications.

>> Agreed that is a problem. Yet other parts of government deal with the
>> same problems all the time.
>>
>
>Other govt agencies due not have to deal with unknown and volatile domains
>to the extent that NASA does.

NIH has problems as serious as NASA's.  And you guys don't get
picketed by angry screaming dying people.  You guys think I can
get long and angry, you should see an ACT-UP activist or an
Animal Rights activist.  at least the FET doesn't break into your
labs.

>
>> Clementine, Delta Clipper, Timberwind...  I'll stack SDIO's record for
>> promoting space against NASA any day. Better, cheaper, faster is new
>> to NASA but it was always SOP at SDIO.
>>
>
>For their focused domain, these are good. But I will bring us back to the
>big-picture point again that NASA has to keep in mind.
>

Yes, but their 'focused' domain seems to be doing more basic engineering
work then your 'big picture'.  All three of the above are engineering
missions to qualify and develope hardware with numerous other applications.

NASA needs to have a basic annual flight program just to test new pieces
of gear out there.  DO you know, that as of 1989,  no LED's were
space-qualified?  Even though LED's  have lifetimes 10 times greater then
light bulbs.  Light bulbs were still shelf spec for space gear.

I think HST used a line CCD array, instead of a CCD matrix, because that
was all that had been space qualified.  of course, HST sat on the shelf
5 years waiting launch, but that's a whole nother flame war.

pat

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

Date: Wed, 17 Mar 1993 21:47:14 GMT
From: Gary Wells <[e-mail]>
Subject: The courage of anonymity
Newsgroups: comp.org.eff.talk,alt.privacy,sci.space

[e-mail] (David L. Cathey) writes:

>In article <[e-mail]>, [e-mail] (Dave Hayes) writes:
>> [e-mail] (Melinda Shore) writes:
>>>> And I ask you: How many people here give different weight to ideas on
>>>>Usenet based on the author?
>>>I do, often.  Over the years you come to know that certain
>>>people know what they're talking about, while others are
>>>monomaniacal crackpots.

Two points: 1) I don't give wieght to an article by its address.  Sometimes, I
do recognize an author.  Authors who consistently post trash, soon wind up in
my killfile.

2) I don`t generally bother to read posting that are anon, either as poster
or as site, becuase, in general, I find them to be nothing but trash (where
trash is defined as not containing enough interesting and/or pertinent
information to be worth my time and effort to read.)

I liken anon postings to an unsigned, unaddressed, undated letter that might
happen to wind up in my USnail box, or dropped on my desk.  Trash, no matter
what the content.  If I can't verify the source, I can't verify the accuracy of
the information.  And if the information can't be proven accurate and timely,
either by fore knowledge of the source or by verifcation of the information,
it is useless.  An anon posting (or letter) prevents me from verifying any of
these items, so it gets trashed.

There's no issue of censorship.  There's no issue of privacy.  There's no
issue of personal saftey.  If you really think there is, you've been watching
to many movies, or listening to Rush Limbaugh (sp?).  I'm covering my tail,
so that _I_ don't appear to be an idiot, rushing around tilting at
non-exsistant windmills.  (Tilting at windmills is specically OK, we still
need dreamers)

Besides, if the information in the anon posting _was_ accurate, and a great
conspiracy _does_ exist, and enough people asked enough hard questions
because of the anon posting, and the suppressed information was made public
and the great conspiracy broken, how would we know who to thank?  I realize
that most anon posters are selfless individuals who wouldn't want to be thanked,
but I bet a whole bunch of "I was the anon poster" postings would appear, just
the same.

--
--------------------------------------------------------------------------------
Still working on _natural_ intelligence.

[e-mail]

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

Date: Wed, 17 Mar 1993 20:06:30 GMT
From: Ron Asbestos Dippold <[e-mail]>
Subject: Threat of mass cancellings was Re: Anonymity is NOT the issue
Newsgroups: news.admin.policy,comp.org.eff.talk,sci.space,alt.privacy

[e-mail] writes:
>[e-mail] writes:
>    "Two wrongs does not make a right."

>Quite so -- I'm not recommending it.  But in order to have applied that
>aphorism, you must have acknowledged that what Johan is doing is wrong.

Or have made an argument from the point of view of the other.  Arguing
"Assuming xxx is true (which I don't agree), then..." is a common tactic.

The problem is nobody is thinking big enough.  If you want to make a
right follow the fundamental law of progessivism: a right is made as
the number of wrongs approaches infinity.  Simply cancel all postings
from everyone.  No posts, no problems.
--
Most women loathe limericks, for the same reason that calves hate cookbooks.
  -- Legman

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

Date: 17 Mar 1993 23:47 UT
From: Ron Baalke <[e-mail]>
Subject: Three Spacecraft to Conduct Gravity Wave Search
Newsgroups: sci.space,sci.astro,sci.physics,alt.sci.planetary

Donald L. Savage
Headquarters, Washington, D.C.                              March 17, 1993
(Phone:  [phone])

Franklin O'Donnell
Jet Propulsion Laboratory, Pasadena, Calif.
(Phone:  [phone])

RELEASE:  93-48

THREE SPACECRAFT TO CONDUCT 3-WEEK GRAVITATIONAL WAVE SEARCH

     Three interplanetary spacecraft, now headed quietly toward Mars,
Jupiter and over the poles of the sun, soon may prove the
existence of elusive waves in the universe's gravitational field by
bobbing on ripples in space like corks bobbing on ripples in a pond.

    Such waves of gravity have never been directly detected, although
their existence was predicted decades ago in Einstein's theory of
relativity and there is indirect evidence that they exist.  The waves
are believed to be produced by supernova explosions, collapsing black
holes and other catastrophic events.  Past searches with ground-based
equipment and single spacecraft have failed to discover them.

     Astrophysicists are hoping to make this major discovery by
spending the next few weeks "listening" for passing gravitational
waves with three "borrowed" spacecraft at the same time in the most
sensitive detection system yet assembled to search for very low
frequency gravitational waves.

     The spacecraft, now on their way to separate destinations in the
solar system, are NASA's Mars Observer, Galileo and the European
Space Agency (ESA) Ulysses spacecraft.

     The joint NASA-ESA experiment will run from March 21 to April 11,
marking the first time three spacecraft will make observations
simultaneously, greatly increasing the reliability of any detection.

     "If this experiment succeeds in detecting gravitational waves it
may answer fundamental questions about the nature of gravity as well
as give further support for Einstein's theory of general relativity,"
said Dr. Robert Stachnik, Gravitational Wave Program Scientist in
NASA's Astrophysics Div., Office of Space Science, Washington, D.C.

      "We're also very excited about the possibility of making a major
discovery with such a cost-effective experiment.  We were able to
take advantage of three spacecraft already in space which soon will be
in the correct relative positions and distances we need to do this
experiment.  We can just borrow them for a few weeks, without any added
cost for equipment and no change to their missions.  It's big science
on a small budget," Stachnik said.

     "Einstein predicted the existence of gravitational waves in his
theory of general relativity, and radio astronomy observations of
pulsars have suggested they indeed exist -- but no one has ever
detected a gravitational wave directly," said Dr. John W. Armstrong of
NASA's Jet Propulsion Laboratory, Pasadena, Calif., who will work with
the Mars Observer and Galileo spacecraft.

     The experiment is built around a simple concept.  During the
3-week experiment, the antennas of NASA's Deep Space Network (DSN)
on Earth will beam radio signals to the three spacecraft at precisely
known frequencies.  Each spacecraft will send signals back to Earth at
the same frequency it receives.  If no gravitational waves are passing
through the Solar System, the signals returned to Earth should have
exactly the same frequencies as the original signals sent from the DSN,
shifted only by the Doppler effect of spacecraft motion.

     However, if a strong enough gravitational wave passes -- produced
perhaps from collapsing masses of stars in the hearts of galaxies or
from the spiraling together and collision of two black holes -- both
the Earth and the spacecraft will experience a slight "bobbing" from
the ripple-like passage of the gravitational wave.  This interaction
cannot be directly detected at either the Earth or the spacecraft
alone, but would show up as a slight change in the frequency of the
radio signal finally received back at Earth.

     The hydrogen maser clocks that control the DSN transmitters and
receivers are so accurate that scientists will be able to detect a
change in radio frequency of as little as a few parts in a quadrillion
(a quadrillion is 1 followed by 15 zeroes).

     "This should allow us to detect gravitational waves from objects
such as massive pairs of black holes hidden in the hearts of other
galaxies," said Hugo D.  Wahlquist of JPL, who will work on the Ulysses
spacecraft with Sami W. Asmar of JPL, Prof. Bruno Bertotti of the
University of Pavia, Italy, and Prof. Luciano Iess of the University of
Rome La Sapienza.

     Scientists emphasize, however, that snaring a gravitational wave
during the 3-week experiment will depend on a good bit of luck --
whether a suitable astronomical event happens to occur during the
relatively brief opportunity when data can be taken.  All three
spacecraft will be in the Earth's night sky at that time, so
interference with their radio signals due to charged particles in the
solar wind will be at a minimum.

     Successful detection of gravitational waves could open up an
entirely new kind of astronomy.  Because the gravitational waves do not
readily interact with matter, detecting them may open a window
to the interiors of powerful -- and sometimes catastrophic -- events
such as supernova explosions and collapsing black holes.

     "Gravitational wave research is now in the hands of physicists.
Once signals are detected, the astronomers will be beating down the
doors," said Stachnik.

     Sensitive ground-based interferometer antennas now are being built
in both the United States and Europe to search for gravitational waves
with wavelengths of thousands of kilometers.

     "In addition to searching for the shorter waves that can affect
antennas here on Earth, we now will be using radio signals sent to
spacecraft hundreds of millions of kilometers away to search for waves
of much longer wavelength," said Dr. Frank B.  Estabrook of JPL, who
will work with the Galileo spacecraft.

     Detection of the gravitational waves, even if they occur, will
still take at least several months of patient data analysis.  "The
spacecraft systems can detect large enough gravitational waves, if they
exist," said Dr. Bevan M. French, Program Scientist for the Mars
Observer.  "But it won't be one of those sudden 'Eureka!' situations.
We'll be looking for a few small wiggles in a huge amount of radio
data.  It will take time."

     To identify the unique signals of gravitational waves, the
scientists also will have to eliminate such mundane effects as
planned changes in the orientation of the spacecraft, interference from
charged particles (plasmas) in space and even atmospheric changes, rain
and snow on Earth.

     Mars Observer, launched in September 1992, will reach the Red
Planet Aug. 24 of this year.  Launched in 1989, NASA's Galileo
spacecraft will arrive at Jupiter in 1995.  The ESA Ulysses spacecraft
was launched in 1990, and it will fly over the sun's poles in 1994 and
1995.

     Gravitational wave research is supported by the Astrophysics
Division of NASA's Office of Space Science and by each of the
three spacecraft projects, which scheduled the radio searches during
their interplanetary cruise periods.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Don't ever take a fence
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | down until you know the
|_____|/  |_|/       |_____|/                     | reason it was put up.

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

Date: 17 Mar 1993 17:36:35 GMT
From: CLAUDIO OLIVEIRA EGALON <[e-mail]>
Subject: Water Simulations (Was Re: Response to various attacks on SSF)
Newsgroups: sci.space

Even though they had all that problem during the INTELSAT retrieval, the water
tanks are still a very good way to train for EVA. That is the closest thing NASA can
get for training for EVA during long periods of time. Weren't for the short periods
of time of low gravity in the KC-135 and, let us say too, in the Lewis' Lear jet, flying
parabolic would had been the next best thing after being up there but, of course, 30
seconds is not enough to train for retrieving a satellite and I bet neither a mock-up
satellite would fit in the cargo bay of the KC-135.

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

Date: 17 Mar 1993 19:51:02 -0500
From: Pat <[e-mail]>
Subject: What do we do now with Freedom.
Newsgroups: sci.space

Okay.  Now that i have thoroughly abused the SSF people let's
get productive.  What changes in politics/management should be done
if we want to deliver a working station at some reasonable cost
and reliability.   Here's my punchlist,  now you NASA folks
get to take pot shots at me :-)

1)  Compress the management structure.  keep reston, but fire all but
30 people.   Everyone at reston should be a top technical specialist
just keeping tabs on cost, budgets and capabilities.  Fewer managers, less
paper,  less confusion.

2) COmpress the centers.  Either Johnson or MSFC should take lead
on Building and Fabbing the whole thing.  Have 1 contractor as prime.
Have 1 NASA guy,  who gets shot if the thing don't fly.   And put
1 NASA guy in charge of each major system.  He gets a budget and a
performance spec.  If he can't meet it,  he gets cement overshoes.
If he meets it,  he gets the Medal of Honor.

3) Use Russian Heavy launch gear.  The energiya could sling large
prefab structures up, and also relax the tightness of mass budgets.

4)  GO to 51 degree incline orbits.  Take the hit on shuttle payloads,
but now get more service capacity from Russian centers.

5)  Look at ET wet facilities for additional space.  Dennis doesn't
like it,  but the ET's provide lots of volume cheap.  some mods and
they could be easily clipped onto the truss.

6)  Building ground spares,  both for methodology developement and
in case you need to cannibalize.

7)  More standardization.  Sure  the SSF lab Modules are Spacehab
compatible and all sorts of great stuff, but what's so bad about
23" equipment racks?

8)  engineering developement flights, to improve knowledge base.
Take some of the key risk areas,  build some sort of testbed, and
sling it up on a T4 or Proton and let all that gear run for a few years
in vacuum.  Instrument it like crazy and see if some of those large
brush contactors, work in vacuum.

pat

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End of Space Digest Volume 16 : Issue 332
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