[meteorite-list] Hayabusa Update - October 4, 2005

[Ron Baalke]

http://www.isas.ac.jp/e/snews/2005/1004.shtml

Current Status of Hayabusa Spacecraft
Japan Aerospace Exploration Agency (JAXA)
October 4, 2005

Excerpts:

  o On September 30th, Hayabusa descended to the distance of 6.8 km,
    Home Position, and entered into a new flight phase.

  o On that day, Hayabusa fired its RCS engines about 5cm/second to 
    raise the altitude again to keep its relative position within
    a certain control box.

  o Hayabusa will make higher latitude imaging as well as inspection of
    touching-down candidate points for a month.

  o Every scientific instrument functions normally.

Current status of Spacecraft

  o As already reported, Hayabusa lost one reaction wheel (X-axis) on 
    July 31st and has taken an alternate flight mode using two wheels
    for attitude stabilization.

  o On October 3rd, another Y-axis reaction wheel was found not
    functioning. The incident occurred at 23:08 JST on Oct. 2nd,
    while it is not operated from Japan.

On the malfunction of Y-axis wheel

  o When the incident occurred, Hayabusa was under the autonomous
    asteroid tracking mode. The task was with no trouble compensated
    by RCS (chemical engines) and the observation has been maintained.

  o Currently, Hayabusa continues the attitude stabilization using
    one wheel plus two RCS engines. And subsequent observation plan is
    studied after adequate amount of information is gathered.

  o Note, Z-axis wheel has not problem from launch and in good health.

Affect to Further Hayabusa Flight Activity

  o Still under detailed study

  o Fortunately, global mapping is almost completed.

  o In terms of guidance and navigation, Hayabusa uses radio measurements,
    and no problem is foreseen.

  o Operation team is analyzing how to reduce fuel comsumption for attitude
    stabilization.

  o Activity plan will be updated and reported, as soon as the strategy is
    fixed.

Flight Schedule Ahead

  o In the middle of October, high latitude observation and landing site
    inspection are planned
 
  o In November, a rehearsal and two touching-down samplings are performed.

  o At the beginnig of December, Hayabusa departs for Earth, returning
    samples of Itokawa in June of 2007.