A brief follow-up to Could Rosetta have been awakened from Earth if necessary?
The Rosetta FAQ writes to say
Q. Was Rosetta completely shut down?
Almost. Only the computer and several heaters remained active. These have been automatically controlled to ensure that the entire satellite doesn't freeze ...
The same source further writes to say (italics mine!)
Q. What has to happen before Rosetta can transmit its first signal?
The spacecraft has been programmed to only transmit its first signal once the on-board wake-up procedure has reached a certain stage. The internal alarm clock will go off at 10:00 UTC on 20 January, triggering the exit from hibernation. This process that includes switching on the star trackers, slowing the spacecraft's hibernation spin and switching on and warming up certain systems...
Having a heater to keep the systems from entering a deep-freeze makes sense. If anything such heating would be mandatory given contemporary technology, and the cold of space. Heat transfer, however, requires a medium; something that space has little of.
Closed body craft, such as ISS, possess an atmosphere which aids air-conditioning.
- How do heaters on Rosetta work?
- Are the electronics embedded in some thermally conductive medium?
- How are mechanical systems heated in such space-bound systems? Hydraulics heating?