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(meteorobs) Excerpts from "CCNet DIGEST, 29 June 1999"


A juicy one today! For those with travel options, note in
particular the British Astronomical Association - Meteor
Section meeting coming up in November!

Clear skies,
Lew Gramer


------- Forwarded Message

From: Benny J Peiser <b.j.peiser@livjm.acdot uk>
To: cambridge-conference@livjm.acdot uk
Subject: CCNet DIGEST 29 June 1999
Date: Tue, 29 Jun 1999 14:46:41 -0400 (EDT)

CCNet DIGEST, 29 June 1999
==================================

[...]

(2) CHAMPOLLION MISSION TO BE CANCELED
    SpaceViews, 29 June 1999

(3) NANOROVER BOUND FOR ASTEROID
    CNN INTERACTIVE, 28 June 1999

(4) RETURN TO TUNGUSKA
    BBC ONLINE NETWORK, 28 June 1999=20

[...]

(6) BAA METEOR SECTION MEETING
    Neil Bone <bafb4@central.susx.acdot uk>=20

[...]

(8) HYPERVELOCITY IMPACT STUDIES
    K. Morishige et al., INST SPACE & ASTRONAUT SCI

(9) UPDATE ON THE LEONIDS
    P. Jenniskens, NASA, AMES RES CTR

[...]

(11) EFFECTS OF SPACECRAFT & SPACE DEBRIS ON ASTRONOMICAL OBSERVATIONS
     D. McNally & R.H. Rast, UNIV LONDON OBSERV


==================================

(2) CHAMPOLLION MISSION TO BE CANCELED

>From SpaceViews, 29 June 1999
http://www.spaceviews.com/1999/06/29b.html

A planned NASA mission to land a spacecraft on the nucleus of a comet
will soon be canceled, SpaceViews has learned.

Top project officials told SpaceViews that the Space Technology 4
(ST4) mission, also known as Champollion, will be canceled as part of
a budget-tightening effort by NASA.

"We understand that NASA Headquarters has proposed [canceling
Champollion] to the Office of Management and Budget and we think that
Office of Management and Budget will accept that," ST4 project
manager Brian Muirhead said.

Other sources, including the Associated Press, have reported that
Champollion has already been canceled, but Muirhead said late Monday,
June 28, that he has received no official notification of the
project's cancellation. However, he noted, "everybody from [JPL
director] Ed Stone on down is speaking as if that were the case."

The Planetary Society and the scientific community are organizing
efforts to lobby Congress to save the mission, but Muirhead said that
the chances of reinstating the project that way are low, "given all
the other challenges that exist in Washington these days."

Champollion faced possible cancellation earlier this year, when NASA
headquarters officials expressed concern that the mission would not
be able to meet its planned cost and mass goals. However,
Muirhead and team members redesigned the mission, combining a planned
orbiter and lander into a single spacecraft to land on a comet
nucleus, that won approval from NASA officials.

Muirhead said the expected cancellation of Champollion had nothing to
do with the project or the team or "any force outside of the budget
forces that NASA is struggling with."

The cost of the extra Hubble servicing mission planned for October,
along with costs associated with delays with the launch of the
Chandra x-ray telescope, have put pressure on NASA's space
science budget. In addition, Congress may impose caps on all federal
budgets as part of an earlier deficit-reduction deal that could cut
NASA's budget by up to 10 percent -- despite an expected $100
billion budget surplus for this year.

Champollion may be the first victim of NASA's belt-tightening, but
Muirhead said it's unlikely to be the last. "They can kill ST4 but
that doesn't fill the bucket," Muirhead said. "There are still other
problems that exceed our level of funding."

The Planetary Society reported earlier in June that both Champollion
and the 2001 Mars Surveyor lander were in danger of cancellation. The
society later reported that the Mars lander was out of danger.

Other sources have indicated that NASA may cut funding from proposed=20
extended missions for spacecraft currently in operation, including=20
Deep Space 1 and Galileo. Extended mission funding allows spacecraft=20
to continue operations at a lower level after the originally planned=20
mission comes to an end.

Champollion is part of NASA's New Millennium Program, an effort to=20
flight-test advanced technologies that could be utilized on future=20
missions. Scheduled for launch in 2003, Champollion would have been=20
the first spacecraft to land on the nucleus of a comet when it=20
touched down on Tempel 1 in 2005.

The mission would have returned key information about the composition=20
and structure of a comet nucleus while testing advanced instruments,=20
solar panels, and other technologies, including an advanced version=20
of the ion engine tested on Deep Space 1, another New Millennium=20
Program mission.

"It's certainly a very challenging mission, one that not only had=20
great technology and great science but a level of public interest=20
that would blossom as people came to know more about it," Muirhead
said.

News of the impending cancellation has left the team very=20
disappointed. "We just assembled a really incredible group of=20
people," Muirhead said, "and if anyone could pull this off we could."

"People will go on to other jobs, but I think it will be hard to find=20
anything as exciting as anything we had just been attempting."

Copyright 1999, SpaceViews

==================================

(3) NANOROVER BOUND FOR ASTEROID

>From CNN INTERACTIVE, 28 June 1999
http://cnn.com/TECH/space/9906/28/asteroid.probe/index.html

By Robin Lloyd
CNN Interactive Senior Writer
=20
(CNN) - NASA's next rover can leap small buildings in a single bound=20
but weighs just a little more than Superman's cape.=20

Unlike its Mars-touring cousin Sojourner, the latest rover, called a=20
nanorover because it is so small, is being designed to hop around an=20
asteroid measuring a kilometer, or about a half-mile, in diameter. The=20
red planet is about 6,774 kilometers, or 4,200 miles across.=20

Engineers at NASA's Jet Propulsion Laboratory are refining the advanced =

rover in preparation for a mission called MUSES, overseen by the=20
Japanese space agency and set for launch in January 2002. The trick is=20
learning how to drive on an asteroid.=20

"You've got the same problem as a car on Earth on a sheet of ice," said =

Don Yeomans, NASA's project scientist for the mission. "There is very=20
little friction between the wheels and the surface."=20

"So you can creep along at 1 millimeter per second or you can take=20
these enormous leaps, and that's the preferred mode of operation," he=20
said.=20

A more sophisticated rover

The MUSES rover, about the size of a fat paperback novel, hops by=20
squeezing its struts together like scissors. The asteroid's small=20
gravitational field would allow it to hop up to tens of meters, or=20
yards, high and land in a new spot, Yeomans said.=20

If the rover lands on its back, it is designed to right itself. "The=20
trick is to not be too enthusiastic, to start off with a little jump,"=20
he said. "We don't want to put this thing in orbit."=20

The MUSES rover is 10 times smaller than the Mars Pathfinder mission's=20
Sojourner, has a more sophisticated on-board computer and has a color=20
camera, not black and white, Yeomans said.=20

And where Sojourner had to settle for detecting the basic elements=20
found in surface rocks, the MUSES rover will have an infrared=20
spectrometer that can detect more complex minerals at the asteroid's=20
surface.=20

The MUSES rover also will have a grid of wires on its solar panels that =

can be charged up to reject dust and keep it from mucking up the=20
machinery.=20

Asteroids to get lots of traffic

Many people became more aware of asteroids in 1998 with a false alarm=20
for an asteroid-Earth collision and the release of asteroid movies=20
"Deep Impact" and "Armageddon."=20

NASA is sponsoring other missions involving asteroids, including Deep=20
Space 1 which is set to pass by asteroid 1992KD next month and the Near =

Earth Asteroid Rendezvous mission which is set to enter the orbit of=20
the asteroid Eros on Valentine's Day, 2000. The European Space Agency=20
also plans to send up a spacecraft to land on a comet and fly-by two=20
asteroids.=20

Yeomans says MUSES is uniquely challenging.=20

"We hope to bring back surface samples for study in Earth-based=20
laboratories," he said. "And we intend to drop the little nanorover on=20
the surface and have it run around and make TV images and detect what=20
the thing is made of in terms of minerals and the elemental components=20
of the rocks -- iron, calcium, magnesium and oxygen in a particular=20
rock."=20

MUSES is set to visit an asteroid called Nereus which orbits near=20
Earth. At the time of the craft's arrival to the object, it will be=20
about 245 million miles from Earth.=20

Up to three asteroid samples will be collected by the lander. After a=20
two-month stay on the asteroid, the plan is for a capsule with the=20
samples to separate from the lander and eventually parachute to Earth's =

surface in 2006.

The NASA portion of the mission costs about $30 million. A team of six=20
U.S. scientists was named this week to work on the rover part of the=20
mission, including Peter Smith of the University of Arizona, who=20
oversaw the camera on Sojourner.=20

Copyright 1999, CNN

==================================

(4) RETURN TO TUNGUSKA

>From the BBC ONLINE NETWORK, 28 June 1999=20
http://news.bbc.codot uk/hi/english/sci/tech/newsid_380000/380060.stm

By BBC News Online Science Editor Dr David Whitehouse=20

Scientists hope to solve the mystery of the greatest cosmic impact of=20
the century by undertaking an expedition to a remote region of=20
Russia.=20

The impact happened on 30 June, 1908, at Tunguska in central Siberia.=20
With no warning, a small comet or meteor hurtling through space=20
collided with the Earth and exploded in the sky.=20

The impact had a force of 20 million tonnes of TNT, equivalent to=20
1,000 Hiroshima bombs. It is estimated that 60 million trees were=20
felled over an area of 2,200 square kilometres. If the explosion had=20
occurred over London or Paris, hundreds of thousands of people would=20
have been killed.=20

The first expedition to reach the site was led by Russian scientist=20
L.A.Kullik in 1938. His team was amazed to find so much devastation=20
but no obvious crater.=20

So began the mystery of Tunguska: What was the object that caused=20
such destruction and why did it leave no crater?=20

Lake bottom=20

It may have been a small comet, made of rock and ice, that was=20
fragile enough to be vaporised in the explosion before it struck the=20
ground. Alternatively it may have been a low-density meteorite.

To search for answers, the second University of Bologna expedition is=20
about to travel to the isolated region taking with them a battery of
high-tech equipment.=20

One of the team, Dr Luigi Foschini, told BBC News Online that one of=20
their main aims will be the study of sediments at the bottom of Lake=20
Ceko.=20

This lake is 8km (five miles) away from the centre of the 1908=20
explosion. The lake is about 500 metres wide and 47m deep.=20

"We will be using a 'sub bottom penetration system,' to make a=20
structural map of it to decide where to drill for samples from the=20
lake bed," he said.=20

At the same time, a "side scan sonar" will take ultrasound =20
photographs of the lake bottom. A remotely-controlled, underwater=20
telecamera will also be used in the research.=20

Large fragments=20

Undisturbed samples will be collected by using a "box corer." Dr=20
Foschini hopes to collect microparticles from the disintegration of=20
the cosmic body to determine once and for all what it was.=20

They will also continue a search for microparticles preserved in tree=20
resin. This was carried out on the earlier expedition in 1991. The=20
researchers will also undertake an accurate aerial survey of the =20
region and compare their data with that obtained in 1938 by Kullik.=20

The comparison between the 1938 pictures and the new survey should=20
give further information on the direction of the tees felled by the
explosion.=20

Some scientists believe that large fragments may have reached the=20
ground before the main impact. If the cosmic body was a meteorite,=20
then it may be possible to find these fragments.=20

A search will be made for them among the ground rocks of Tunguska=20
using neodymium magnets together with a metal detector.=20

Copyright 1999, BBC

==================================

(6) BAA METEOR SECTION MEETING

>From Neil Bone <bafb4@central.susx.acdot uk>=20
=20
BAA Meteor Section Meeting
Institute of Astronomy, Madingley Road, Cambridge
Saturday October 30 1999, 1.30 pm

An afternoon of talks and discussion timed just a couple of weeks
ahead of what could be the meteor display of the 1990s, the Leonid
maximum of Nov 17-18. The programme is at an early stage of
construction, but will include a review of last year's spectacular
Leonid return and what it might mean for forecasting this year's
peak, and contributions from the Section's triangulation group which
netted some excellent results in November 1998. Further details
should be available soon.

General enquiries can be addressed to the Meteor Section Director:
Neil Bone, The Harepath, Mile End Lane, Apuldram, Chichester, West
Sussex, PO20 7DZ. Tel. (01243) 782679.

Local arrangements are being handled by the Comet Section Director:
Jonathan Shanklin, 11 City Road, Cambridge, CB1 1DP.

Best wishes,
Neil Bone

==================================

(8) HYPERVELOCITY IMPACT STUDIES

K. Morishige*), H. Yano, Y. Maekawa, S.P. Deshpande, M.J. Neish,=20
S. Kibe: Three dimensional analysis of impact crater profiles on the=20
SFU spacecraft's Teflon radiators. ADVANCES IN SPACE RESEARCH, 1999,=20
Vol.23, No.1, pp.113-117

*) INST SPACE & ASTRONAUT SCI,PLANETARY SCI DIV,KANAGAWA=20
   2298510,JAPAN

We report on three dimensional morphology of about 100 hypervelocity=20
impact craters on the Teflon radiators of the SFU spacecraft measured=20
by scanning laser microscope and X-ray CT technique. We also=20
performed impact calibration experiments using a two-stage light-gas=20
gun at ISAS with alumina, glass and copper bead projectiles of=20
diameters 50 to 80 mu m at velocities from 3.5 to 4.5 km/s, in order=20
to reproduce impact crater profiles formed in space. As a result, the=20
depth to diameter ratio of these impact craters constrains bulk=20
density, velocity and size of impactors, which are complementary=20
information to elemental analysis regarding the origin of the=20
impactors, namely meteoroids or space debris. (C) 1999 COSPAR.=20
Published by Elsevier Science Ltd.

==================================

(9) UPDATE ON THE LEONIDS

P. Jenniskens: Update on the Leonids. ADVANCES IN SPACE RESEARCH,=20
1999, Vol.23, No.1, pp.137-147

*) NASA,AMES RES CTR,SETI INST,MAIL STOP 239-4,MOFFETT=20
   FIELD,CA,94035

Meteor storms are of concern to satellite operators because they are=20
a natural impact hazard. Little is known about their cause and=20
effect. Meteor storms are rare and have never been studied by modern=20
techniques. Now, the upcoming Leonid returns of November '98 and '99=20
offer a once-in-a-lifetime opportunity to gather data that can help=20
assess the impact hazard of meteor storms and provide a wealth of=20
data on the physics and chemistry of meteoroids accreting into the=20
Earth's atmosphere. Three months before the Nov. '98 return, we here=20
give gn update of what to expect and what observing efforts are going=20
to be made. (C) 1999 COSPAR. Published by Elsevier Science Ltd.

==================================

(11) EFFECTS OF SPACECRAFT & SPACE DEBRIS ON ASTRONOMICAL OBSERVATIONS

D. McNally*), R.H. Rast: The effect of spacecraft and space debris on=20
astronomical observation. ADVANCES IN SPACE RESEARCH, 1999, Vol.23,=20
No.1, pp.255-258

* UNIV LONDON OBSERV,MILL HILL PK,LONDON NW7 2QS,ENGLAND
  CASIA,ALBUQUERQUE,NM,87109

It is shown that debris trailing of astronomical fields results from=20
field crossing by on orbit spacecraft and larger pieces of debris=20
capable of reflecting sufficient sunlight to register on astronomical=20
detectors. Such incursion into observed fields of view leads to=20
degradation or loss of the observation. Measures to mitigate the=20
problem are suggested. The paper is prefaced by expressing concern at=20
recent proposals for efficient thin film solar reflectors which could=20
have very serious long term consequences for optical astronomy. (C)=20
1999 COSPAR. Published by Elsevier Science Ltd.

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