QUESTION:
Why didn't you use the Martian winds to provide additional electric energy
to the lander/rover?

ANSWER from David Dubov:
That's a good question. Mars often does have high speed winds. But even in
the fiercest gales on Mars, the pressure that the winds can generate (and
therefore the ability to perform work) is surprisingly small. This is
because the Martian atmosphere is only 1/100th as dense as Earth's. To
"feel" the equivalent of a 10 mile per hour "Earth" breeze (enough to turn a
windmill), a Martian wind must be 10 times the speed, or 100 mph! It is a
very rare day on Mars when the winds get anywhere close to that speed! Most
of the time the winds are less than 20 m/s (50 mph) which is comparable to
only a light Earth-breeze of 5 mph. Not much power there! To get energy out
of a breeze like that would require large windmills (bigger that Pathfinder)
much like those that are built on giant windmill farms in places with lots
of wind on Earth. For Pathfinder, we decided that we cold get more "bang"
for our buck by using arrays of Gallium Arsenide solar cells.