Hubble control system failure – STS-125 launch date delayed

by Chris Bergin

A major failure of the “Side A” control system on the Hubble Space Telescope has delayed STS-125’s launch as far as 2009.

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.

“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.”

However, later in the day, both the FRR and the process of switching to Side B were delayed.

“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,” the memo warned.

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).

Those evaluations have now resulted in the delay of STS-125 until at least Feb, 2009 based on replacing the failed unit. This is due to a long process of testing Hubble’s switch to Side B, and the new training that the crew will undergon for STS-125’s mission.

Optional plans are being drawn up, which include launching Endeavour on STS-126 in November, and Atlantis to Hubble in February or at another time in the first quarter.

“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.”

Three plans are being looked at for re-arranging the near term launch manifest, as listed:

1. Keep Atlantis and Endeavour on Pad A and B, wait for a repair/switch over to Side B of the CUSDF if possible and the launch in the currently scheduled sequence – now dismissed.

2. Launch STS-126  from Pad B before STS-125 launches from Pad A. STS-119 would roll to Pad B as the LON for STS-125.

3. Swap pads in order to launch STS-126 from Pad A before STS-125.  STS-125 would be “stored” at Pad B.  After STS-126 launch, STS-125 will go back to Pad A and STS-119 would be integrated and rolled to pad B as the 400 HST LON mission.  STS-125 would launch from Pad A.

However, it is now confirmed that STS-125 will not launch before mid February. This has caused a review of the schedule’s Time and Cycle requirements.

Managers are requesting that any managers that have a concern about Atlantis staying at the Pad for an extended period should forward their concerns for further evaluations this week.

This will allow any potential issues to be debated, particularly if there are any requirements that would require Atlantis to de-stack or roll back to the OPF as opposed to stay at the Pad.

Fallout from the delay will be felt by the Constellation Program, which now have to delay Ares I-X – due to Pad 39B requirements – from its April, 2009 launch date.

Another article will follow on Tuesday, based on updated options.

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