Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V11_4/V11_498.TXT

Internet Message Format | 1991-07-08 | 20KB

Return-path: <[e-mail]>
X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson
Received: from beak.andrew.cmu.edu via trymail for +dist+/afs/andrew.cmu.edu/usr11/tm2b/space/[e-mail] (->+dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl) (->ota+space.digests)
          ID </afs/andrew.cmu.edu/usr1/ota/Mailbox/saPSb2a00VcJ00jE5Y>;
          Thu,  7 Jun 1990 01:44:35 -0400 (EDT)
Message-ID: <[e-mail]>
Precedence: junk
Reply-To: [e-mail]
From: [e-mail]
To: [e-mail]
Date: Thu,  7 Jun 1990 01:44:09 -0400 (EDT)
Subject: SPACE Digest V11 #498

SPACE Digest                                     Volume 11 : Issue 498

Today's Topics:
          Re: HAWAII/ROCKET very long - 61k
              Re:  SPACE Digest V11 #495
         NASA Headline News for 06/06/90 (Forwarded)
    Re: Terraforming Venus (was: Manned mission to Venus)
           Ulysses: Status and opposition to launch
           Re: Does DoD Want Hawaii? (was: Re: Haw
        Re: "CCD imagers in HST" from EE Times
            Ulysses risks II: PuO2 dangers

Administrivia:

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

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

Date: 6 Jun 90 15:11:15 GMT
From: [e-mail]  (SERRE GLENN)
Subject: Re: HAWAII/ROCKET very long - 61k

Jay Hanson writes:
A Federal Government publication entitled "REDUCING LAUNCH
OPERATING COSTS", Sept. 1988,  states that the minimum reliability
for the Delta rocket is 90%, for the Atlas rocket, it is 81%.
This means if the operators of the facility have bad luck, one out
every ten Delta rockets and one out of every five Atlas rockets
will explode.  This number of failures is considered acceptable to
those who launch rockets.

Correction:
The last sentence above is simply NOT true.
I am not sure obout Delta or Atlas, but I can only assume that their situation
is similar to Titan.

The Titan IV contract for payload integration requires a 100%
launch success rate in order
for Martin Marietta to receive the full award fee.  One launch failure reduces
payload integration award fees for present, future, and past [not a typo]
launches.  Anything less than 100% success is clearly not acceptable, from a
profit-making perspective.

Other comment:
Agreed, a realistic enivronmental impact statement is a very good idea,
but what else is new?  I see no other point to the posting (as regards this
newsgroup).

--Glenn Serre
[e-mail]

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

From: [e-mail]
Date:     Wed, 06 Jun 90  13:41:04 EDT
Subject:  Re:  SPACE Digest V11 #495

Re "Plymouth," the proposed new sci-fi TV show. Just what the
american idiot box audiences need, another TV show about this
country's nonexistent space program. We keep doin' it on TV, and
the Soviets, and the Japanese, and the French, and the British,
and the Indians, and just about everybody who is anybody, keep
DOIN' IT IN SPACE. Like I said a couple of weeks ago, the u.s.
doesn't have a space program, it has a program to use large
bullets to put smaller but more powerful "bullets" into low Earth
orbit. And from the postings apparently the Congress is about to
sound the final death knell for the u.s. space program.

                                         Marlen
                                         AZM@NIHCU

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

Date: 6 Jun 90 17:23:37 GMT
From: trident.arc.nasa.gov![e-mail]  (Peter E. Yee)
Subject: NASA Headline News for 06/06/90 (Forwarded)

-----------------------------------------------------------------
Wednesday, June 6, 1990              Audio Service:  202/755-1788
-----------------------------------------------------------------

This is NASA Headline News for Wednesday, June 6........

Kennedy Space Center managers are analyzing the test data that
revealed leakage in the orbiter Columbia's 17-inch and 4-inch
propulsion lines.  Technicians concluded a tanking test this
morning to isolate the leaks.  Liquid hydrogen was flowed through
the orbiter and into the external tank.  Extra sensors were
placed in strategic areas for the test.  Launch of STS-35 has
been put on hold until the leak can be corrected.  A news
conference is planned tomorrow to announce a proposed launch
date.
                            ********

Although visual inspection has shown no obvious damage, there
remains some concern for hidden damage to the orbiter Discovery's
payload bay door.  An accident caused one edge of the 60-foot
long door panels to be flexed out of shape for a short time.  A
review board will focus on possible damage to the door latches.

                            ********

Meanwhile, preparations are underway to roll the Space Shuttle
Atlantis to the Vehicle Assembly Building at KSC early
tomorrow.  The orbiter was powered down yesterday to conduct a
structural leak check.  Technicians will perform weight and
center of gravity checks before attaching the Atlantis to the
orbiter transporter.
                            ********

A historic photo from the Voyager I probe is most likely the only
shot we may ever see looking back at our own solar system.
Jurrie van der Woude of the Jet Propulsion Laboratory said the
once-in-a-lifetime picture is a series of images crafted into a
mosaic taken last February 13.  It took Voyager 30 minutes to
transmit each image while traveling at 186,000 miles per second
taken at 3.98 billion miles away from Earth.  The picture will be
available at this afternoon's news conference.

                            ********

Operators report the Hubble Space Telescope has successfully
taken two more images.  The checkout procedures are operating
extremely well.  The telescope can now hold a fine lock on guide
stars through multiple day to night transitions.  Work will
continue to improve the performance of the pointing control
systems and further refine the secondary mirror.

                            ********







---------------------------------------------------------------
Here's the broadcast schedule for Public Affairs events on NASA
Select TV.  All times are Eastern.


Wednesday, June 6.......

        2:00 P.M.             Voyager I Solar System "Family
                              Portrait" news conference.


Thursday, June 7........

       11:30 A.M.             NASA Update will be transmitted.


-----------------------------------------------------------------
All events and times are subject to change without notice.  These
reports are filed daily, Monday through Friday, at 12:00 P.M.
EDT.  This is a service of the Internal Communications Branch,
NASA HQ.  Contact: JSTANHOPE on NASAmail or at 202/453-8425.
-----------------------------------------------------------------
NASA Select TV:  Satcom F2R, Transponder 13, C-Band 72 Degrees
West Longitude, Audio 6.8, Frequency 3960 MHz.
-----------------------------------------------------------------

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

Date: 5 Jun 90 20:54:16 GMT
From: decvax.dec.com!jfcl.dec.com!imokay.dec.com![e-mail]  (Doug Borsom)
Subject: Re: Terraforming Venus (was: Manned mission to Venus)

Acutally there is an old science fiction story titled
"Maxwell's Demon," in which a Hilsch vortext tube plays
a major role.

As I recall from an old _Scientific_American_ "Amateur Scientist"
article, the feed line into the tube has to be at a pretty high
pressure to yield any useful temperature differential between
the two output tubes.  There goes that free lunch.

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

Date:     Wed,  6 Jun 90 19:22 CDT
From: William Higgins <[e-mail]>
Subject:  Ulysses: Status and opposition to launch
Original_To:  SPACE


I want to review the current status of Ulysses, then discuss what I know about
ongoing efforts to prevent NASA from launching it this fall.

The Ulysses solar probe is intended to study the solar wind, magnetic field,
X-ray and radio emissions, and plasma waves at high solar latitudes.  All
previous probes (including Earth-based observatories) have orbited near the
plane of the ecliptic, and so have had a good view of the Sun's equator. But no
spacecraft has ever observed the Sun's poles.

Leaving Noordwijk and Amsterdam, the Ulysses spacecraft arrived at Cape
Canaveral Air Force Station on 17 May.  (Aboard a plane, of course.) It's
scheduled for launch 5 October aboard the Shuttle orbiter *Discovery* on
mission STS-41.  Ulysses will be boosted toward Jupiter on an IUS (Inertial
Upper Stage, Interim Upper Stage, call it what you will...) combined with a
PAM-S.  In a February 1992 encounter the planet's gravity will bend the
spacecraft's trajectory southward, out of the ecliptic, so that it will pass
over the Sun's south pole in May 1994. It crosses the ecliptic in February
1995, more or less reaching perihelion at this time. (Sorry, I don't have the
numbers, but my best guess is perihelion about 1.3 AU, aphelion at Jupiter's
distance, 5.2 AU.  [Thanks for the cribsheet, Dale Greer!]) Then  Ulysses
passes over the north solar pole in May 1995.

The 369-kg probe carries a radioisotopic thermoelectric generator (gee, what a
mouthful! But one should always spell out acronyms the first time, no?
Hereinafter, RTG.), an electric power source containing 11 kilograms of
plutonium-238, in the form of plutonium dioxide ceramic.  Note that this device
is NOT a nuclear reactor; it works on different principles, and the nature of
its radiation hazard is quite different.  Plutonium-238 decays with the very
short half-life of 88 years, and it emits all its radiation in the form of
alpha particles.  So it can be shielded safely by a very thin cladding, yet it
puts out lots of energy; the lump of PuO2 is warm to the touch.  Pu238 must be
specially produced for RTG's.  The fissionable isotope used in nuclear weapons
is Pu239.

Last fall three groups-- the Florida Coalition for Peace and Justice, the
Christic Institute, and the Foundation on Economic Trends-- joined to seek a
temporary restraining order to prevent NASA from launching the RTG-powered
Galileo probe, but they were unsuccessful.  They did, however, manage to
attract a great deal of attention, both from the press and from Space
Digest/sci.space readers. (-:

The Christic Institute is now seeking an injunction against all launches of
RTG's.  In addition to this, many groups have filed comments on NASA's
Environmental Impact Statement for the launch, including the Florida Coalition
for Peace and Justice, the Federation of American Scientists, Physicians for
Social Responsibility, and the Committee to Bridge the Gap.  Other
organizations filing  (my list is incomplete at this time) are the National
Space Society (which favors the launch and points out the environmental risks
of *failing* to study the Sun's poles) and the United States Air Force.

Bruce Gagnon, state coordinator of the FCFP&J, has contacted leaders of other
peace groups asking for help in opposing the Ulysses launch.  Working in his
favor are two things: (1) he and his cause have a much higher profile than they
did this time last year, thanks to the attention the Galileo affair gained, and
(2) there are four months remaining, time to prepare more than the hasty effort
of 1989.

A good review of the technical facts and issues is given by Daniel Salisbury in
"Radiation Risk and Planetary Exploration-- The RTG Controversy," *Planetary
Report*, May-June 1987, pages 3-7.  Another good article, which also reviews
the events preceding Galileo's launch, "Showdown at Pad 39-B," by Robert
G. Nichols, appeared in the November 1989 issue of *Ad Astra*.   (Both
magazines are published by pro-space organizations, the Planetary Society and
the National Space Society respectively.)

For details of the Ulysses mission, see *ESA Bulletin* No. 60, November 1989,
page 8-12, and No. 48, November 1986.  I'll bet NASA has a slick pamphlet on
Ulysses, too, but I have yet to dig it up.

In another posting soon I'll try to review the technical details of the RTG's,
and the risks associated with them.  I have made inquiries to learn more about
the struggle to stop Ulysses;  I'll post new information as I receive it.

                      ______meson   Bill Higgins
                   _-~
     ____________-~______neutrino   Fermi National Accelerator Laboratory
   -   -         ~-_
 /       \          ~----- proton   Bitnet: [e-mail]
 |       |
 \       /                          SPAN/Hepnet/Physnet: 43011::HIGGINS
   -   -
     ~                              Internet: [e-mail]

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

Date: 6 Jun 90 05:30:00 GMT
From: swrinde!zaphod.mps.ohio-state.edu!uwm.edu!bionet!arisia!cdp![e-mail]
Subject: Re: Does DoD Want Hawaii? (was: Re: Haw


I am trying to figure out what kind of impression you wish to leave?

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

Date: 6 Jun 90 19:25:58 GMT
From: hao.hao.ucar.edu![e-mail]  (Derek Buzasi)
Subject: Re: "CCD imagers in HST" from EE Times

In article <[e-mail]> [e-mail] (Stephen J. Friedl) writes:
#From _EE Times_, 4 June 1990, pg 33  (reproduced w/o permission)
#
#    TI CCD Imagers Give Hubble Better Vision - Greenbelt, MD
#
#    The first image returned from the Hubble Space Telescope
#    was matched with a similar image from a telescope in Chile,
#    and proved to be distinctly clearer.
#
#    Texas Instruments supplied the thermoelectrically-cooled
#    CCD imager arrays on the Hubble; they are set up in four
#    tiled, 2048x2048 pixel imagers.
#
#    Ground-based observatories have telescopes based on lower
#    quality (fallout) CCD imagers, also often supplied by TI.
#

I hate to rain on anyone's parade, but the CCDs used on the HST are not
even close to being state of the art by modern standards, although they
may qualify based on 1982 standards. These chips have low quantum
efficiency (around 32% at best), high noise levels (~15 electrons),
and relatively low dynamic range by modern standards.

Ground-based observatories have access to significantly superior CCD
arrays -- I can speak from experience, having last month used a TEK
512x512 CCD at Kitt Peak. Although it is true that HST produces (for
the time being -- beware active optics, though!) "clearer" (i.e. higher
resolution) images than any ground-based instrument, this is due to
the lack of atmosphere in orbit, which enables HST to approximate it
theoretical resolution limit, something not possible from the ground.

#--
#Stephen J. Friedl, KA8CMY / Software Consultant / Tustin, CA / 3B2-kind-of-guy
#[phone]  / [e-mail]  / {uunet,attmail}!mtndew!friedl
#
#"I will defend to your death my right to my opinion" - me


--
******************************************************************************
Derek Buzasi                     *    "History is made at night.
High Altitude Observatory        *     Character is what you are in the dark."
[e-mail]                 *             -- Lord John Whorfin

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

Date:     Wed,  6 Jun 90 21:36 CDT
From: William Higgins <[e-mail]>
Subject:  Ulysses risks II: PuO2 dangers
Original_To:  SPACE

This continues the discussion of the Ulysses probe, its radiothermal
generators, and their risks.

HOW DANGEROUS IS THE PLUTONIUM?

I hope to research the toxicology of plutonium dioxide further.  Here's what
I've got so far.

Plutonium-238 is an isotope with a half-life of 88.6 years.  It is an excellent
choice for RTG fuel because the only radiation it gives off is alpha particles
of 5.5 MeV, making it very easy to shield (though there are fuels with higher
power density).

 The plutonium dioxide fuel is a yellow-green compound with a density of
11.46 grams/cubic centimeter.  It has a melting point of 2240 Celsius.  My CRC
Handbook says that it is insoluble in water and slightly soluble in hot
concentrated sulfuric, nitric, or hydrofluoric acids. This implies that even if
there is a breach of the RTG cladding (within the impact shell, within the
insulator, within the aeroshell, within the GPHS housing), it would not easily
get into the environment.  If ingested by animals or people, it wouldn't
dissolve and would likely be excreted after a short time.

The alpha radiation given off by plutonium-238 has a very short range, and
would be unlikely to do much damage during a few days in the digestive system.
Note this point (for it seems to come up again and again in discussions of
RTG's): Plutonium dioxide is not the most toxic substance known, and in fact is
not very toxic at all if ingested.

The greatest danger posed would be from particles inhaled into the lungs. A
small particle of PuO2 would give off lots of alphas, which are highly ionizing
and lose energy in a very short distance.  (This is why they're so easy to
shield against.) If a particle were in proximity to lung tissue, a small
thickness of tissue would be pounded over and over, and the chances of inducing
cancer would become very high.

For Ulysses to cause this kind of problem, an accident must breach the RTG fuel
cladding, somehow pulverize the plutonium dioxide, and disperse it into the air
where somebody can breathe it in.   A launch accident with enough violence to
do this is *highly* improbable.  For example, the *Challenger* accident, in
which flames leaking from the solid rocket boosters triggered the explosion and
rupture of the hydrogen-bearing external tank, exposed payload-bay components
to 10 psi of overpressure.  The RTG aeroshells and impact shells have been
tested at overpressures up to 2000 psi with no release of the fuel.

Downrange of the Kennedy Space Center launch site is ocean for several thousand
miles.  In the case of a launch accident, debris will most likely end up
underwater, where it will be harmless.

Reentry accidents are another possibility.  (At the moment, I have little hard
information on this topic, and will discuss it at length after I've snagged
some more documentation.)  The Apollo 13 lunar module, with an RTG aboard to
power lunar surface instruments, re-entered at over 40,000 km/hour in 1970.  A
program of air and ocean sampling around its impact site detected no release of
plutonium.

REFERENCES

Gordon L Chipman, Jr., "Advanced Space Nuclear Systems" (AAS 82-261), in
*Developing the Space Frontier*, edited by Albert Naumann and Grover Alexander,
Univelt, 1983, p. 193-213.

*Handbook of Chemistry and Physics*, Chemical Rubber Company, 1989.

William Corliss and Douglas Harvey, *Radioisotopic Power Generation*,
Prentice-Hall, 1964.

Robert G. Nichols, "Showdown at Pad 39-B," *Ad Astra*, November 1989, p. 8-15.

Daniel Salisbury, "Radiation Risk and Planetary Exploration-- The RTG
Controversy," *Planetary Report*, May-June 1987, p. 3-7.

                      ______meson   Bill Higgins
                   _-~
     ____________-~______neutrino   Fermi National Accelerator Laboratory
   -   -         ~-_
 /       \          ~----- proton   Bitnet: [e-mail]
 |       |
 \       /                          SPAN/Hepnet/Physnet: 43011::HIGGINS
   -   -
     ~                              Internet: [e-mail]

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

End of SPACE Digest V11 #498
*******************