[meteorite-list] Japanese Probe Parks Near Asteroid Target

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue Sep 13 12:45:34 2005
Message-ID: <200509131644.j8DGiPN29986_at_zagami.jpl.nasa.gov>

http://www.newscientist.com/article.ns?id=dn7990

Japanese probe parks near asteroid target
Kelly Young
New Scientist
13 September 2005

After two years of travel through the inner solar system, Japan's
Hayabusa spacecraft has reached its target - asteroid Itokawa. The probe
"parked" about 20 kilometres away from the asteroid on Monday.

Launched on 9 May 2003, Hayabusa aims to be the first ever craft to
bring pieces of an asteroid back to Earth.

The spacecraft will immediately start mapping the asteroid and will
determine its surface composition by analysing the spectra of the light
it reflects. At the end of September, it will approach to about 7 km
from the 630-metre-long asteroid and make a more detailed map.

Then in November 2005, Hayabusa will descend toward the asteroid's
surface and touch down twice. Each time, a fabric cone will touch the
surface, triggering the firing of a pellet into the asteroid at 300
metres per second. After each firing, the probe will take off and
attempt to collect the dust ejected from by the impact. The Japanese
Aerospace Exploration Agency (JAXA) will also attempt one practice run
before the pair of real touchdowns.

During its initial descent, the spacecraft will also deploy a little
hopper called Minerva. The coffee-can-sized device will attempt several
10-metre-high jumps on the asteroid's surface, taking temperature
readings and pictures.

Surprise surprise

So far, pictures of Itokawa have surprised mission planners. The shape -
similar to a knobbly potato - is not what they predicted based on radar
images.

Another space mission, NASA's Near Earth Asteroid Rendezvous (NEAR)
visited the asteroid Eros in 2000 and found it to be fairly homogenous.
That does not appear to be the case for Itokawa, says Jun'ichiro
Kawaguchi, Hayabusa project manager at JAXA. Early pictures of the
asteroid appear to show hilly and rocky regions in addition to some very
smooth features.

This asteroid's edges appear rounded. This could be the result of eons
of being pelted by other space objects. There also appears to be some
dust and rocks left over from impacts on the asteroid's surface. This is
another surprise because Kawaguchi says that small asteroids, with such
tiny gravity, were not expected to have so-called "regolith" clinging to
them.

Contrast and compare

Hayabusa is expected to return to Earth in June 2007, makingits final
descent by parachute. Once the asteroid samples reach the lab,
scientists will analyse their composition and compare this to
collections of meteorites that have fallen to Earth.

"There are many asteroids and visiting all of them is out of question,"
Kawaguchi told New Scientist. "Instead, the correlations will tell which
asteroid is made of what." This approach will potentially leads to a new
way of examining the solar system, he says.

After the Hayabusa return capsule comes back to Earth, JAXA says it may
attempt another asteroid mission.
 
Received on Tue 13 Sep 2005 12:44:25 PM PDT