Current Status of Hayabusa Mission and Events Scheduled in November(Forwarded)

Institute of Space and Astronautical Science
Japan Aerospace Exploration Agency
Sagamihara City, Japan

2005/10/27

Current Status of Hayabusa and Events Scheduled in November

Hayabusa that arrived at the target asteroid Itokawa on September 12th
of this year has performed detailed scientific observation so far by
varying its relative position around Itokawa.

As already reported, Hayabusa carried two reaction wheels were lost on
July 31st and October 3rd, and its attitude has been maintained by a
single wheel together with the chemical engines aboard, while the
spacecraft has been operated normally.

In order that the flight can be carried out and completed until the
return to the Earth, the fuel consumption required for stabilizing the
attitude has to be reduced, and a strenuous effort has been poured to
devise the strategy including a number of firing tests in vacuum on the
ground. A new control scheme making the firing impulse small enough has
now been developed assuring the attitude control resolution to be well
managed. This assures the fuel amount required is adequate within that
remains. The on-orbit function test was already conducted and it was
verified functioning by the actual flight hardware and software aboard.
The Hayabusa project team concluded the flight operation until the
return to the Earth is feasibly performed, as long as the existing
instruments and hardware aboard continue working normally as they are.

The proximity operation assumed in November next month consists of one
Rehearsal Descent plus two Touching-downs for sampling. They are
scheduled as follows:

1. Rehearsal Descent November 4th,
2. 1st Touching-down for sampling November 12th,
3. 2nd Touching-down for sampling November 25th.

These events will occur around noon in Japan Standard Time [0300 UTC] in
the midst of the operation period from Japan. There are several
Rehearsal and Touching-down sites candidates and the events instances
may be shifted earlier or later by 6 hours at maximum, depending on the
operation status. The concrete schedule will be released as soon as they
are determined.