QUESTION:
Why did NASA choose to use tires instead of tracks on the Sojourner rover?

ANSWER from Henry Stone on November 13, 1997:
1) A track design means that you have to do skid steering like a tank which
is very inaccurate, hard to automatically monitor and control, and very
difficult from the point of view of trying to maintain knowledge of the
vehicle's position and orientation using dead reckoning.

2) The 6 wheel rocker bogie suspension system out performs any track design
for a given scale of vehicle.

3) The 6 wheel rocker bogie suspension system, unlike a tracked design,
minimizes the change in orientation of the central body.

4) The 6 wheel rocker bogie suspension system is designed to maintain equal
ground pressure on all 6 wheels to maximize traction and forward thrust.

5) Track systems have the inherent problem of throwing of tracks on very
rigid, non-compliant surfaces (e.g., lava flows, solid rock surfaces, etc).