QUESTION:
How long is the lander and rover mission on Mars? After that time, who and
on what bases decides to "turn Mars Pathfinder off"? Or will you perhaps
work with it until it totally breaks down and stops responding?

ANSWER from William Dias:
The nominal expected life (the "prime mission") is 30 days for the lander
and 7 days for the rover. However there is no known absolute maximum system
life for either the lander or rover. Those numbers were chosen because the
lander's rechargeable battery was qualification tested for 30
discharge/recharge cycles, and the duration of thermal testing applied to
the rover's electronics box. The project has programmed funding for a year
on the surface, in case it lasts that long.

It really will be "against the odds" for the system to survive that long.
But if the spacecraft is still functioning at that time, or if we run out of
money before that for some reason, I for one would certainly hope that more
money could be allocated. It is hard to believe that ANYONE would turn off a
functioning spacecraft on the surface of Mars, especially since it gets
cheaper and cheaper to run it the more time goes by. Now, it is true that
some parts of the mission objectives are completely satisfied very early in
the mission. For instance, we can take a picture of all the terrain features
using every filter in the lander camera and send all that data in the first
month, and there is probably no reason to take those pictures again. However
more time will always add more value in other areas of investigation. The
weather (including data from atmospheric imaging) could be profitably
measured for years, and so long as the rover can move, new photo angles are
always possible. These would include not just new terrain, but also pictures
of the lander, so see what parts were damaged in landing, the airbags, the
landing path ground imprints, etc. But, I hope we have this problem! It
really will be "against the odds" for the system to survive that long.

--William Dias, Surface Mission Operations Planner