re: JPL ATHLETE rover
Terrifyingly, that's a 1/2 - 1/3rd scale (I've heard both figures mentioned) version of the final lunar-bound vehicle. I've stood next to it - and even this scale test-bed is HUGE.
They're upgrading Athlete to split into two three-wheeled parts (tri-athlete) which can drive up to and wrap itself around a landed spacecraft, reconnect, and then carry it to a lunar base etc.
It can do things like bolt wrenches, drills etc onto one wheel and use it as a tool. And if it were exploring Mars and got stuck like Spirit....it could just walk out. It is an astonishing design.