Thursday, November 8, 2007

Safemode

“My” spacecraft, the Mars Reconnaissance Orbiter, went into “safemode” yesterday. This happens whenever something on the spacecraft happens that it detects and doesn’t understand. Essentially, it stops whatever it’s doing, turns off all it’s instruments, and turns so it’s solar panels face the sun. Sometimes it will reboot it’s onboard computer or perform a “side-swap” -- we actually have two computers (and two of a lot of other things, as well) on board that it can toggle between. In this case, it turned to the sun and did a simple reboot. An email from management tells the story pretty well:

Date: Wed, 7 Nov 2007 22:08:05 -0800
To: Big Cheese Mars Manager
From: MRO Project Manager
Subject: MRO Status
Cc: Other Mars Big Cheeses, including NASA Headquarters Guy, and Other Project Management

Big Cheese Mars Manager-

As you know, shortly after 15:20 (UTC) this morning, MRO went into safe mode. The proximate cause was a gimbal motor error on the +X solar array. The on board fault protection identified that the +X array was moving slower than the commanded rate, swapped out the motor controller for the gimbal, and then initiated a warm reset when the second controller couldn’t maintain speed.

Analysis of the fault indicates that the gimbal fault was due to the autonomous keep-out zone software erroneously allowing the solar panel to come into contact with the thermal blankets covering the +X bay. Analysis shows that no contact was made with any part of the spacecraft structure, and analysis is continuing to verify that no damage has been done to the thermal blanket.

The vehicle is healthy, and is currently being recovered from safe mode. At present there is a Project briefing required before returning to nadir (Mars) point, and a further briefing required before returning to off nadir observations. The first hold is to ensure that the anomaly is completely understood and it is safe to return to vector tracking. The second briefing is to verify that we have a plan to ensure that the excursion of any appendage into the keep-out zones is reliably prevented.

Provided all analysis is complete, the draft time-line would have the spacecraft returned to nadir point no earlier than Friday, and a return to targeted observations no earlier than Saturday (11/10).

Further status will be provided tomorrow.

-MRO Project Manager


So, life is even more complicated for me right now. We’re working to get things back up and running as soon as we can, and while we do have a plan, it’s just a lot of work. There’s also a ton of analysis that needs to be done, sequences to be built, and we think we want to take this opportunity to do some testing we’ve been waiting on. Busy, busy!

1 comment:

Anonymous said...

Roy I am sorry you have to go through this stress. It is good that you have the knowledge to fix it. I can not imagine what you know.

Love MOm Glad

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