Tires on the ground ...

This is starting to look about right.

The rover package should be the same size as the one in the four wheel rover. IOW, a lot smaller than the tire.

The circumference of the tire is a little over 3 meters. We could put three (and a half) of those flexible solar panels on the inside of the tire.

I wonder if both sides of those panels convert light to electricity?

I imagine that those panels are designed for industrial use, so they are going to be thick enough to handle big steeplejack blokes' handling. Flexible, yes but not too flexible for the job. The company must have looked at the idea of very thin cells for heated tinted glass. I would use gold rather than aluminium for that, still cheap as it would be thin enough to see through. If not, then I think it would have to be cut into strips like a car window heating element.

For the ball we could put a camera on each arm, for stereo imaging. If we have a good DEM of the landing area, then we can drop a couple of virtual cameras onto it and do a 360 shot of the horizon. That woud give us an idea of where our real pictures are coming from. A back up against gyro failure as well

The two motor housings at the end of the axle, are they to be about the same size as the central load unit? Also, how low do you want this unit to hang down below the axle?

Suppose we did a wall poster of Mars for school science labs. We give basic details on it, and we show graphics of a manded landing and end with the NASA "cheap and cheerful" concept, together with other theories about Mars. Swift, Burroughs, Marconi. Maybe sneak in the exploding planet hypothesis.

Add to that a cd of Mars data. Then we look for a sponsor. Do they sell Mars chocolate bars in the States? Eat ten million bars and the school gets the cd and wall chart, the winners of a comp get a week in astronaut school. Hey, NASA gets to use Jesuit deviousness on kids for a week, can't be bad. [8D]

<b>[Stoat] " ... we could put a camera on each arm ..."</b>

Yes, that solves the problem of trying to look out through the tire. But it creates another problem. The cameras are no longer protected inside the tire. In the event of a fall, if the rover landed on one of the axel ends the camera there could be damaged. An acceleration sensor could be used to retract the camera, I suppose.

<b>[Stoat] "The two motor housings at the end of the axle, are they to be about the same size as the central load unit?"</b>

These will be for cameras (and crash bags?). The motors will be inside near the rover module, so they can rotate that module relative to the axel for propulsion. And the trailing sticks need to go away. (What if you need to back up?)

<b>[Stoat] "Also, how low do you want this unit to hang down below the axle?"</b>

That is still TBD, but I'm thinking that more than one support will be needed. The package needs to hang about half the distance between the ground and the axel. That leaves plenty of cushion for protection in a fall (and perhaps also in landing?) but puts the package far enough off center to make it an effective counter weight for propulsion.

In addition to rotating around the axel, the package will also need to be able to tilt to either side, for steering. Or, perhaps the package should be split into two modules, side by side on the axel. Rotate both at the same rate for forward or reverse, rotate one faster than the other to steer.

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Can you add the solar panel the ball rover? Start with this:

A thin-wall cylinder 50 cm tall and 0.95 meters in diameter.
Rotate it so that it's axis is horizontal, like the axel of the rover.
Mount it inside the tire, centered between the ends of the axel.
For now don't try to show any mounting hardware, just let it "float" inside the tire.

LB

What if we have just the one motor, that hangs down as the load module. Then we adapt a differential gearbox, which supplies power through the diff in such a way, that a tiny impulse to left or right will make the motor module swing more in the desired direction.