[3pac]

It also has a vidicon tube for gathering images, although that can no longer be switched on.

[hilbert42]

Do we know the reason? Heater/cathode failure or HV supply would be likely reasons, or is there now insufficient power from the Pu source to run it?

(The HV supply on a vidicons is usually about 700V—that's high enough to be quite stressful on P/S components.)

[3pac]

There is a heater for the vidicon which had to be shut off due to power budget. This heater had been on since launch. After being switched off, turning on this heater back on, or the vidicon's cathode filament (itself a separate heater) would have cracked the tube due to the cold of space.

[jgalt212]

Yes, to save power. But there's nothing to photograph out there.