QUESTION:
How long is the earth visiable from the landing site?  When does Earthrise
occur?

ANSWER from Greg Wilson on July 12, 1997:
On average, the Earth is in view from the pathfinder landing site 12 hours
and 20 min.  On July 10, the earth rise is at 1:30 pm PDT and will set at 2
am PDT (July 11).  This changes by about 40 min everyday (later!). The
length of time that the Earth is in view depends on the time of season.

Thanks for the question!

Greg
Mars Pathfinder ASI/MET Science Team