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(meteorobs) Excerpts from "CCNet DIGEST, 1 July 1999"
------- Forwarded Message
From: Benny J Peiser <b.j.peiser@livjm.acdot uk>
To: cambridge-conference@livjm.acdot uk
Subject: CCNet DIGEST, 1 July 1999
Message-Id: <SIMEON.9907011347.L@TR05367S.livjm.acdot uk>
Date: Thu, 1 Jul 1999 13:23:47 -0400 (EDT)
CCNet DIGEST, 1 July 1999
--------------------------
[...]
(3) NASA CANCELS COMET LANDER MISSION
Linda Wong <tps@planetary.org>
[...]
(5) BETH CLARK TO HEAD MUSES-C ASTEROID SAMPLE RETURN MISSION
Andrew Yee <ayee@nova.astro.utorontodot ca>
[...]
(7) THE (CANCELLED) CHAMPOLLION COMETARY MOLECULAR ANALYSIS EXPERIMENT
P.R. Mahaffy et al., NASA,GODDARD SPACE FLIGHT CTR
[...]
(9) LARGE METEOROIDS IN THE LYRID STREAM
M. Beech & S. Nikolova, UNIVERSITY OF REGINA
(10) THE INTERNAL STRUCTURES & DENSITY OF ASTEROIDS
L. Wilson et al., UNIVERSITY OF HAWAII MANOA
[...]
======================
(3) NASA CANCELS COMET LANDER MISSION
>From Linda Wong <tps@planetary.org>
Press Advisory: NASA Cancels Comet Lander Mission
NASA is today sending a letter to Congress announcing that they are
canceling the Champollion comet lander mission being developed for a
2003 launch. The Planetary Society urges Congress to reverse the
decision and calls for open hearings on the merits of the cancellation.
A copy of a letter from the Society to the key Congressional Committees
overseeing the NASA program is attached. For further information see
our web site <http://planetary.org/> http://planetary.org. Or you may
call Society Executive Director, Louis Friedman at (626)793-5100 or
President, Bruce Murray at (626)395-3780.
Linda Wong
The Planetary Society
65 N. Catalina Ave.
Pasadena, CA 91106
Tel: (626) 793-5100
Fax: (626) 793-5528
E-mail: tps@planetary.org
Web: http://planetary.org <http://planetary.org/>
- -------------------------
LOUIS FRIEDMAN'S LETTER TO THE US CONGRESS
June 30, 1999
The Honorable James Sensenbrenner
Chairman, Science Committee
B-374
Washington, D.C. 20515
The Honorable George Brown
Ranking Member, Science Committee
B-374
Washington, D.C. 20515
Dear Reps. Sensenbrenner and Brown:
NASA just announced it is canceling the Champollion (Space Technology
4) mission, one of the most exciting and important missions conceived
to study comets, among the least known of bodies in our solar system.
ST-4 is part of NASA's New Millennium program, started by NASA
Administrator Daniel Goldin to develop "cheaper, faster, better"
technologies for space exploration. Shutting down the program is
unjustified both on scientific and technological grounds and represents
a giant step backward for America's space program.
We urge your immediate intervention to reverse the decision to
terminate the mission. There is no reason to cancel Champollion,
scheduled for launch in 2003. The mission is being developed within
budget and on schedule.
The payload for Champollion, selected through an open, competitive,
peer-reviewed process, and ST-4 was recommended by the official New
Millennium Advisory Group. The National Academy of Sciences Committee
on Planetary and Lunar Exploration (COMPLEX) has repeatedly emphasized
the importance of cometary missions for three decades.
Champollion is led by Brian Muirhead, a highly acclaimed manager from
the Mars Pathfinder mission, which was praised throughout the world as
an extraordinary blend of science, technology and robotic adventure.
There's every reason to believe Champollion would be the equal of
Pathfinder - if Congress can prevent its silent execution.
NASA says one of the reasons it must shut down Champollion is to pay
for unanticipated problems with the Chandra Advanced X-ray
Astrophysical Observatory (AXAF) and emergency repairs on the Hubble
Space Telescope. This is the first time in more than a decade that NASA
is penalizing a successful science and technology mission to pay for
other programs that are experiencing cost overruns - a misguided
decision that sets a disturbing precedent. This is a stunning reversal
of Mr. Goldin's policy.
NASA also says it needs to cancel Champollion to pay for extra
"reserves" in the Mars Sample Return mission, but the sample return
development has just begun and there are many better ways to deal with
the future reserves problem.
The United States has landed spacecraft on the moon, on other planets,
and with the Champollion mission we will, for the first time ever, land
on a comet and collect critical scientific data about these primordial
bodies in our solar system. Champollion paves the way for advanced
technology used on the Mars Sample Return mission, on the Europa
orbiter and other outer planet missions, and on future small body
missions to comets and asteroids.
Comets are remnants from the formation of our solar system 4.5 billion
years ago. The small, icy orbs have changed little over time and
provide a unique record to learn how our solar system originated.
Because comets have impacted the terrestrial planets, including Earth,
for all of our history, they are known to have had a profound effect on
planetary evolution. Composed of organic material, they are also
important to the studies of the origin of life and are a high priority
for study by planetary scientists.
For three months Champollion would map the surface of the comet Tempel
1, which is about 3.7 miles in diameter, then land/anchor onto its
surface. Scientists know little about the surface of comets and expect
to find hills on Tempel 1 that reach as high as 100 meters. Once hooked
to the comet, the spacecraft will employ instruments to drill into the
surface and retrieve samples for analysis.
Scientific instruments aboard the spacecraft to determine the
composition, physical properties and morphology of the comet include a
near field camera, microscope, IR spectrometer, panoramic camera, gas
chromatograph, and mass spectrometer. Among the advanced technologies
the mission would validate are:
* Precision guidance systems to autonomously land and attach to
the comet's surface;
* Multi-engine ion drive that builds on the highly successful
Deep Space-1 mission;
* High-performance, inflatable solar arrays which could
revolutionize future space power systems;
* First-of-a-kind surface and subsurface sampling systems.
To reduce the cost and risk of future planetary missions, it's
essential to validate new and advanced technologies such as those
incorporated into the design of the Champollion spacecraft. For
example, the laser altimeter being developed for Champollion provides
more precise information than current radar altimeters for the steering
of a spacecraft to a safe landing. These are needed for the automated
rendezvous and docking that is necessary for the Mars Sample Return
mission.
The innovative hardware being developed to drill into the icy comet
surface would later be incorporated on the Mars Surveyor '03 and '05
missions to collect and take measurements of samples. Terminating
Champollion increases the risks in the Mars and outer planet programs,
and sets back progress on future deep space and solar power generation.
Champollion would be the first mission to utilize three ion engines and
the first spacecraft with an inflatable solar array.
As noted above, there's no reason to terminate Champollion at this
time. NASA's FY2000 budget has yet to be determined and there are many
options that can be considered short of shutting down an important and
well-performing project. AXAF and Hubble are current budget issues, and
NASA should solve them with current funding. Additionally, money saved
from Champollion will not be realized until after both of these
missions are launched. More than $16 million has already been spent on
Champollion and only $38 million is budgeted in FY 2000, money already
included in the Administration's budget request.
The Planetary Society urges your support for Champollion and your
efforts to save this highly valuable project. Are financial problems
within the Office of Space Science really so great as to raise the
prospect of terminating a strongly supported and authorized program? If
so, Congress should hold hearings so that all the facts and assumptions
involved can be scrutinized by the outside scientific and technological
communities, as well as by
the public.
Sincerely,
Louis Friedman
Executive Director
====================
(5) BETH CLARK TO HEAD MUSES-C ASTEROID SAMPLE RETURN MISSION
>From Andrew Yee <ayee@nova.astro.utorontodot ca>
Cornell researcher Beth Clark named by NASA to head research team for
2002 asteroid sample return mission (Forwarded)
News Service
Cornell University
Contact: David Brand
Office: (607) 255-3651
E-Mail: deb27@cornelldot edu
FOR RELEASE: June 30, 1999
Cornell researcher Beth Clark named by NASA to head research team for
2002 asteroid sample return mission
ITHACA, N.Y. -- Beth E. Clark, a research associate in Cornell
University's Department of Astronomy for the past three years, has
been named by NASA to lead a research team for history's first
asteroid sample return mission.
The 2002 joint mission with Japan will send a space vehicle to land
on an asteroid, collect a sample of the surface and return it to
Earth for analysis. This will be the first time that a space vehicle
has attempted a landing on an asteroid.
Clark will lead the team that will develop the near infrared
spectrometer to be carried aboard a miniature robotic rover vehicle
that will be deployed by the spacecraft to explore a small area of
the asteroid's surface. The spacecraft will shoot pellets into the
surface to collect a few grams of surface samples, which it will
transfer to the Earth return module.
In congratulating Clark on her appointment, Joseph Veverka, professor
of astronomy and incoming chair of the Cornell Department of
Astronomy, said the awarding of the contract follows "in the great
tradition of Cornell's involvement with landers," beginning with the
Apollo program, through the Viking program and currently with the
Mars Pathfinder missions. Veverka was a member of the team that
originally proposed the collaborative asteroid mission in 1997.
The mission, named MUSES-C (for Mu Space Engineering Spacecraft) will
be the third (thus the "C") in a series of missions managed by the
Japanese Institute of Space and Astronautical Science (ISAS) and
NASA's Jet Propulsion Laboratory (JPL). The mission is scheduled to
be launched from a Japanese M5 rocket in Kagoshima, Japan, in January
2002.
The target for the space mission is the asteroid 4660 Nereus, with
the asteroid 1989 ML as a backup. Both asteroids come to within about
75 million miles of Earth. The space vehicle will arrive at the
asteroid in April 2003, alight on the surface up to three times and
collect surface samples for return to Earth in January 2006.
The asteroid mission will test a number of new technologies,
including solar electric propulsion, autonomous landing and sampling
and the hyperbolic re-entry of the sample return capsule to Earth.
The NASA MUSES-C group will develop the rover and support services
for the mission. The rover, a tiny vehicle weighing about one
kilogram (2.2 pounds), will be the smallest rover ever to fly on a
space mission. It will carry several instruments to observe both in
the visual and near-infrared wavelengths.
Clark says her team's job is to work with engineers at JPL to specify
the science requirements in the development of a near-infrared
spectrometer roughly the size of a hand-held calculator. It will take
advantage of nanotechnology to build the smallest such instrument
ever flown.
Clark, a researcher in the Cornell astronomy department's Center for
Radiophysics and Space Research, obtained her B.S. in 1986 at the
University of California at Berkeley and her Ph.D. in 1993 from the
University of Hawaii. From 1993 to 1995, she was a Harlan J. Smith
postdoctoral fellow at McDonald Observatory, the University of Texas.
>From 1995 to 1996, she was a National Science Foundation visiting
professor at the Lunar and Planetary Laboratory, University of
Arizona. She joined Cornell's astronomy department as a research
associate in 1996.
For the past three years, Clark has been a convener and member of the
scientific organizing committee of the seventh International
Conference on Asteroids, Comets and Meteors, to be held at Cornell
July 26-30.
She also has served on scientific review panels for the Hubble Space
Telescope, the National Science Foundation and for NASA.
Related World Wide Web sites:
The following sites provide additional information on this news
release. Some might not be part of the Cornell University community,
and Cornell has no control over their content or availability.
* MUSES-C home page: http://www.muses-c.isas.ac.jp/
IMAGE CAPTION:
[http://www.news.cornelldot edu/releases/June99/clark.nasadot deb.html]
Beth E. Clark, a research associate in Cornell University's
Department of Astronomy (holding a model of the asteroid Phobos) has
been named by NASA to head a research team for a 2002 sample return
mission to the asteroid 4660 Nereus. Photo by Charles
Harrington/Cornell University Photography.
===============
(7) THE (CANCELLED) CHAMPOLLION COMETARY MOLECULAR ANALYSIS EXPERIMENT
P..R. Mahaffy*) et al.: The Champollion cometary molecular analysis
experiment. ADVANCES IN SPACE RESEARCH, 1999, Vol.23, No.2, pp.349-359
*) NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD,20771
The Chemical Analysis of Released Gas Experiment (CHARGE), is one of
several investigations selected for the Champollion New Millennium DS4
Mission. CHARGE is presently being designed to carry out a detailed
molecular and isotopic analysis of material collected from the surface
and several centimeters below the surface of comet Tempel I. The
highest priority scientific issues addressed by this investigation
include: the chemical conditions present in the region of cometary
formation; the chemical changes during cometary formation and over the
lifetime of the comet; the relationship of comets to other primitive
and more evolved bodies in the solar system and to the parent
interstellar cloud; the contribution of cometary material to the
atmospheres and oceans of planets; and the nature of the mixture of
ices and dust grains which give rise to the coma and extended sources
of gas as a comet approaches perihelion. CHARGE will be designed to
thermally process samples of solid phase material from near the ambient
temperature to approximately 900 K. Gases evolved from the frozen ices
will be continuously analyzed as a function of sample temperature by a
quadrupole mass spectrometer with a mass range of 2 to 300 amu. A broad
range of major and trace species, both organic and inorganic, from the
gases evolved from the solid samples will undergo both chemical and
cold trapping for subsequent analysis by gas chromatograph mass
spectrometer (GCMS) analysis. CHARGE technology heritage includes the
Galileo Probe Mass Spectrometer (Niemann et al., 1996) that
successfully measured the composition of Jupiter's atmosphere in
December of 1995. The landed portion of the mission will enable
analysis of subsurface materials and allow identification of organic
species present at sub-parts per million mole-fraction in the nucleus.
Prior to the landed operations, CHARGE will carry out measurements from
orbit for a period of several weeks. (C) 1999 COSPAR. Published by
Elsevier Science Ltd.
====================
(9) LARGE METEOROIDS IN THE LYRID STREAM
M. Beech*) & S. Nikolova: Large meteoroids in the Lyrid stream. MONTHLY
NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 1999, Vol.305, No.2,
pp.253-258
*) UNIVERSITY OF REGINA,CAMPION COLL,REGINA,SK S4S 0A2,CANADA
The outburst of the Lyrid meteor shower in 1803 was remarkable for
being rich in bright fireballs and the generation of electrophonic
sounds. The implications implicit to the detection of electrophonic
sounds are studied in this paper. We present estimates for the
minimum-sized Lyrid meteoroid capable of generating electrophonic
sounds, and compare these lower limits with the largest meteoroid that
might reasonably be ejected from a cometary nucleus through coupling
with the sublimation gas outflow. A difference of a factor of order 30
is found between the two limiting sizes. A minimum diameter of order Im
is required for a Lyrid meteoroid to satisfy the conditions necessary
for generating electrophonic sounds. The mechanisms responsible for the
placement of large, metre-sized meteoroids into the Lyrid stream are
not well defined, but they possibly relate to surface ageing effects of
the parent comet, Comet C/1861 G1 Thatcher, and to a history of nuclear
fragmentation.
==================
(10) THE INTERNAL STRUCTURES & DENSITY OF ASTEROIDS
L. Wilson*), L. Keil, S.J. Love: The internal structures and densities
of asteroids. METEORITICS & PLANETARY SCIENCE, 1999, Vol.34, No.3,
pp.479-483
*) UNIVERSITY OF HAWAII MANOA,HAWAII INST GEOPHYS & PLANETOL, HONOLULU,
HI, 96822
Four asteroidal bodies (the Martian satellites Phobos and Deimos and
the main-belt asteroids 243 Ida and 253 Mathilde) have now been the
subjects of sufficiently close encounters by spacecraft that the masses
and sizes and, hence, the densities of these bodies can be estimated to
similar to 10%. All of these asteroids are significantly less dense
than most members of the classes of meteorites identified as being
compositionally most nearly similar to them on the basis of spectral
characteristics. We show that two processes can act, independently or
in concert, during the evolutionary histories of asteroids to produce a
low bulk density. One of these processes is the result of one or more
impact events and can affect any asteroid type, whereas the other can
occur only for certain types of small asteroids that have undergone
aqueous alteration. Copyright property of the Meteoritical Society,
1999.
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