Why and how did you decide to send Spirit to the Gusev Crater?
We have sent several orbiters to Mars, most notably the Viking, Mars Global Surveyor, and Odyssey missions. They have found many places on Mars that appear to have features that were cut by flowing water a long time ago. We wanted to land Spirit in one of those places. We had to find one that was big enough to land in, at least 60 or so miles across based on how well we can aim, that was near the equator so that we would have enough solar power, and that was smooth enough that we could land safely. We found all of that in Gusev Crater. Gusev has a large channel that cuts into it from the South that suggests at one time Gusev Crater was filled with water. The North rim of the crater has a break in it, indicating that that was where the water eventually flowed back out again. The crater is about 100 miles across, is flat, and has a low enough concentration of rocks that we could land safely. Many other landing sites were considered, but Gusev Crater for Spirit and Meridiani Planum for Op
