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.