Close Encounter of a Cometary Kind -- STARDUST flies through Comet Wild 2

Particle Physics and Astronomy Research Council
Swindon, U.K.

Contacts:
Gill Ormrod
PPARC Press Office
Tel: +44 (0)1793-442012
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Louis de la Foret
Open University Media Relations Office
Tel: 01908 653256
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Professor Tony McDonnell
Open University STARDUST team/NASA Co-Investigator (at JPL, California)
Tel: +44 (0) 1227 761352
Email:

Dr Simon Green
Open University STARDUST team (at JPL from 27th Dec)
Tel: +44 (0) 1908 659601
Email:

Dr Neil McBride
Open University STARDUST team (at JPL from 27th Dec)
Tel: +44 (0) 1908 659600
Email:

Professor John Zarnecki
Open University (in UK)
Tel: +44 (0) 01227 831067
Email:

3 January 2004

Close Encounter of a Cometary Kind -- STARDUST flies through Comet Wild 2

At 19:44 hours GMT on 2nd January NASA's space probe, STARDUST, successfully
flew through Comet Wild 2, collecting interstellar particles and dust on its
way. One of the instruments on board, the Dust Flux Monitor Instrument (DFMI),
has been built by a team which include space scientists from the Open University.

Since its launch in February 1999, STARDUST has covered 3.2 billion km (2.3
billion miles). It is the first mission designed to bring samples back from a
known comet. The study of comets provides a window into the past as they are the
best preserved raw materials in the Solar System. The cometary and interstellar
dust samples collected will help provide answers to fundamental questions about

Professor Tony McDonnell and Dr Simon Green from the Open University's Planetary
and Space Science Research Institute (PSSRI) are currently at the mission
command centre, the Jet Propulsion Laboratory in California, where they are
beginning to receive data from their instrument.

Dr Simon Green said: "Early indications show that the encounter with Comet Wild
2 has been successful. The sensors on the DFMI have detected a significant
number of impacts. Some of these, as expected, have penetrated the spacecraft
dust shield -- hopefully this should result in a good number of samples being
returned to Earth."

Professor Tony McDonnell added, "The whole process seems to have gone to plan
and we look forward to receiving more data over the next day or so. The
telemetry received so far includes an image from the onboard camera, which shows
a roughly spherical comet nucleus that was pockmarked with large "sinkholes".
Four or five jets of material could be seen bursting from the object."

At the time of the encounter the 3.3 mile wide comet (5.4 km) sailed past the 5
metre long spacecraft at a distance of 186 miles (240 km) and at a relative
speed of 21,960 km per hour (13,650 miles/hour). The tennis racket shaped
collector was extended on 24 December in preparation for the encounter. Now that
this has taken place a clam like shell will have encased the aerogel collector
keeping safe the particles until they return to Earth in January 2006.

"Stardust could provide a new window into the distant past," said Dr Green.
"Comets are made of ice and are very cold and have been very cold since they
were formed. That protects the material of which they were made from any process
of heating, so they haven't been changed since they were formed, right at the
beginning of the formation of the Solar System. So we can have almost a little
time capsule of what things were like 4.5 billion years ago."

UK scientists, including a team from the Open University, are also involved with
the European Space Agency's Rosetta Mission which will follow and land on Comet
Churyumov-Gerasimenko. This mission is due to be launched on 26th February 2004.

The Particle Physics and Astronomy Research Council (PPARC) is the UK's
strategic science investment agency. It funds research, education and public
understanding in four broad areas of science -- particle physics, astronomy,
cosmology and space science.

PPARC is government funded and provides research grants and studentships to
scientists in British universities, gives researchers access to world-class
facilities and funds the UK membership of international bodies such as the
European Organisation for Nuclear Research, CERN, the European Space Agency and
the European Southern Observatory. It also contributes money for the UK
telescopes overseas on La Palma, Hawaii, Australia and in Chile, the UK
Astronomy Technology Centre at the Royal Observatory, Edinburgh and the

Notes for editor:

Background information

The DFMI, part funded by the Particle Physics and Astronomy Research Council
(PPARC) records the distribution and sizes of particles on its journey through
the centre, or coma, of the comet. This will help tell us more about comets and
the evolution of our own solar system and, critical for STARDUST, its survival
in the close fly-by of the comet.

The distance between Earth and Comet Wild 2 was 390 million kilometres (242
million miles) at the time of the encounter.

Wild-2 is pronounced Vilt-2. The comet is named after the Swiss discoverer.

The spacecraft was protected from debris and rocks by a number of shields in
order to guard its solar panels and body. In preparation for this journey the
craft was pelted with rocks and debris travelling at six times the speed of a
bullet.

The cometary particles were captured on a tennis racket like grid which contains
a substance called aerogel -- the lightest solid in the Universe! This is a
porous material that allows the particles to become embedded with minimum
damage. This means that on their return to Earth they will be as near as
possible to their original state.

Once the samples are captured a clam like shell closes around them. The capsule
then returns to Earth in January 2006 where it will land at the US Air Force
Utah Test and Training Range. Once collected, the samples will be taken to the
planetary material curatorial facility at NASA's Johnson Space Centre, Houston,
where they will be carefully stored and examined.

The Open University team hope to be involved in analysing the samples that
return to Earth in January 2006.

STARDUST, is part of NASA's Discovery Programme of low cost, highly focused
science missions, was built by Lockheed Martin Astronautics and Operations,
Denver, Colorado, and is managed by the Jet Propulsion Laboratory for NASA's
Office of Space Science, Washington D.C.

Images

Images of STARDUST flying through Comet Wild 2 and the unusual aerogel material
that will capture the interstellar dust can be found on the PPARC website at
http://www.pparc.ac.uk/Nw/images.asp
Further images, including those taken from the onboard camera can be found on
the NASA website -- address below.
Websites

* NASA
http://stardust.jpl.nasa.gov
* Open University
http://pssri.open.ac.uk/missions/index.htm