A major failure of the “Side A” control system on the Hubble Space Telescope may delay STS-125’s launch to 2009 - should managers decide to send up a replacement unit, or if a mitigation plan fails to restore the Telescope’s functionality.
The failure has shut down Hubble’s science operations, and is currently unable to send data back to Earth. Attempts will be made to switch to the “Side B” control system later this week.
Switching over to the Side B control system has never been attempted in the lifetime of the telescope, although it is hoped the process will work, and return Hubble back to functionality.
“Side A of the CUSDF (Control Unit/Science Data Formatter) in HST went into safe hold, this means science operations have stopped. The spacecraft is still operational but unable to operate the instruments,” noted information acquired by L2.
“Attempts to recover the A side have failed so the project is now working to transfer science operations to the B side, this requires transferring the whole spacecraft from Side A to Side B so its a significant operation.
“Side B side has not been operated on orbit, for HST’s entire on orbit service life it has operated on Side A. However, the B side was fully tested before launch.
“The plan as of now is to complete the transfer to the B side later this week. The details for this will be provided later by the project.
“If the B side comes up fine we could still launch on time so I propose that we do not postpone the (Agency) FRR (Flight Readiness Review) at this time.
“If the B side does not come on line then we clearly have no mission as there is no way to get science data down. ”
Evaluations are taking place on whether a replacement control system - to return redundancy to the telescope - will now be required to launch with STS-125. If this becomes the case, the mission would have to wait until the replacement part has been tested and sent to the Kennedy Space Center (KSC).
This would delay STS-125 until 2009.
Optional plans - in the event Hubble’s problem will result in a delay to STS-125 - are being drawn up. This includes launching Endeavour on STS-126 in November, and Atlantis to Hubble in February.
“Options are in work. Earlier we had a plan to launch STS-126 first in November and follow up with HST in Feb. with the Feb. 2009 flight as back-up,” added one response to the memo.
“We will dust off our plans and see what we can do.”
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