[FPSPACE] Fw: [JAXA:0052] Status of the Hayabusa

[LARRY KLAES]

----- Original Message ----- 
From: JAXA Press Release Mail Service<mailto:jaxapr at jaxa.jp> 
To: undisclosed-recipients:<mailto:undisclosed-recipients:> 
Sent: Wednesday, December 14, 2005 3:26 AM
Subject: [JAXA:0052] Status of the Hayabusa


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                 Japan Aerospace Exploration Agency
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                       Status of the Hayabusa

                                                    December 14, 2005
                                   Japan Aerospace Exploration Agency

Hayabusa spacecraft currently undergoes the recovery operation to 
resume the communication with the ground stations. It was hit by an 
abrupt disturbing torque owing to the fuel leak that occurred before,
and has been out of the ground contact since December 9th. The 
project team has a good expect to have the spacecraft resume the 
communication soon. However, the project is now not so sure to make 
the spacecraft return to earth in June of 2007 and has decided to 
lengthen the flight period for three years more to have it return to 
the Earth in June of 2010.

On December 8th, Usuda station observed the sudden shifts of the 
range-rate measurements at 4:13 UTC with the corresponding gradual 
decrease of signal intensity AGC (Automated Gain Controller) read.
The measurement and the intensity change slowly and are currently 
estimated due to the out-gassing effect that derived from the fuel 
leak-out at the end of last month. The leak occurred on November 26th
and 27th. Since the beacon signal communication resumed on 29th, the
project has made an effort to exclude the vapor gas of the fuel from
the spacecraft. The project has by now identified the out-gassing has
successfully been performed, as its exponential acceleration decay 
has shown so far.

On December 8th, the spacecraft was under the resume operation phase 
for the chemical propulsion, and was given a slow spin whose period 
is about six minutes. From the beginning of December, the project has
introduced the Xenon gas thruster control strategy for emergency,
replacing the chemical propulsion system. But the control capability
of it was not enough strong for the spacecraft to withstand the 
disturbance on December 8th. Current estimation says the spacecraft 
may be in a large coning motion and that is why the spacecraft has 
not responded to the commands sent from the ground station.

The spacecraft has been out of communication since December 9th. 
Analysis predicting the attitude property relating to both the Sun 
and Earth shows that there will be high possibility counted on for 
the resumption of the communication from the ground for several 
months or more ahead. However, the spacecraft may have to undergo 
another long term baking cycle before it starts the return cruise 
operation using ion engines aboard. And it is concluded that the 
commencement of the return cruise during December is found difficult.
The project has determined that the return cruise should start from 
2007 so that the spacecraft can return to the Earth in June of 2010,
three years later than the original plan, as long as no immediate 
resumption tales place very soon.

The spacecraft operation will shift from the normal mode to the 
rescue mode for several months to one year long. Long term predict 
indicates high probability of having the spacecraft communicated 
with the ground station again, with the spacecraft captured well in 
the beam width of the Usuda deep space antenna.

The spacecraft will take the advantage of Xenon gas attitude control 
again after enough length of baking operation. The Xenon gas that 
remains is adequate for the return cruise devised by the ion engines 
carried by Hayabusa.
The Hayabusa web page will report anything updated, as soon as it 
becomes available.


(Supplement) Hayabusa Rescue Operation
http://www.jaxa.jp/press/2005/12/20051214_hayabusa_e.html#sup<http://www.jaxa.jp/press/2005/12/20051214_hayabusa_e.html#sup>


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