Actually - Sojourners NON-rechargable batterys died on Sol 56. Thus by solar power alone, Sojourner woke up every morning, worked fine and went to sleep every evening on pure solar power alone - for another 25 odd sols before 'mum' died on Sol 83.

Now - with a very very well insulated chassis, a handfull of 1W radioactive heater cells - it's not hard to imagine the electronics not doing too bad in there.

Infact - given the MER experience that solar power can work for a long time, and your arrays can get a good cleaning from time to time. It really isn't beyond the realms of possibility ( all be it perhaps not probable ) that Sojourner does indeed wake up for Lunchtime every now and again. Is everything working so it can still drive....unlikely BUT...not impossible.

Doug