A few minutes ago, the Hubble Space Telescope's Public Affairs Office tweeted that a mystifying problem has arisen with the Hubble's new Science Instrument Command and Data Handler (SI C&DH) that was installed during last month's repair mission. For the gory details, you can read their press release here.
But, in short, the SI C&DH is a computer that runs the science cameras; it controls the cameras and formats the science data for return to Earth. The original SI C&DH failed last September, leading to the 6+ month delay in the repair mission. In the meantime, the backup SI C&DH was booted up and did the job just fine. During the repair mission, a new SI C&DH (actually a spare that had been on Earth and was rebuilt for use in space) replaced the failed one.
Since the Hubble repair mission, the telescope has not been taking science pictures. It has been slowly running through checks of all the new instruments. This is taking a long but not unexpected amount of time. Virtually every camera was replaced or repaired, the new SI C&DH was installed, the new batteries needed to be charged up, and new insulation changed the thermal properties of the telescope, so the checkout has been deliberately slow and methodical.
The problem with the SI C&DH is that it unexpectedly started returning zeroes for all data. The SI C&DH claimed that it had placed all the instruments into safe mode (a protective mode for when something goes wrong), but Hubble's main computer showed that the instruments were not in safe mode. NASA rebooted the SI C&DH, which then seemed to be working, but to be cautious all of the instruments have been put into safe mode manually until the computer problem can be tracked down.
To me it sounds like the SI C&DH went into teenager mode. I can just hear Hubble's main computer talking to the SI C&DH:
Hubble: What'd you do today?
SI C&DH: Nothing.
Hubble: Did the Imaging Spectrograph leave any data for me?
SI C&DH: No.
Hubble: What'd you learn from the Advanced Camera for Surveys?
SI C&DH: Nothing.
Hubble: Did you place COS in safe mode like I asked?
SI C&DH: Uh-huh.
Hubble looks and sees COS blinking and whirring on the shelf.
Hubble: Did you really?
SI C&DH: Yeah.
COS continues to blink and emits a little chime.
Hubble: No you didn't! Now I'm going to have to reboot you in the rear. And you are grounded until NASA calls home and we can figure out what to do about you! Those astronauts risked their life and limb to make you happy and comfortable, and all you can do is mope around and complain about how miserable you are. Well, you'd better shape up or else we're going to shut you down and put the spare data handler in charge. And... Don't you dare glare at me like that!
In short, I'm not worried. Yet. Some analysis, some new software, and maybe the SI C&DH will grow up into a fine young data handler.