Tires on the ground ...

Re: hot air balloons: "Don't forget about the pressure of the Martian atmosphere - about 1 percent of Earth's sea level atmospheric pressure."

I doubt that a hot-air balloon would be practical in the air density on mars. It would have to be too big to keep hot enough to lift any significant payload.

How about adapting the brain of a flying insect to be the controller of such a rover?

Heck, the rover is a "insect" adapted to the mars environment. It becomes our eyes and ears on the planet. Or a turtle - the longest surviving creature we know of still roving the earth. maybe that's our model.

[Stoat] " ... the diameter of the wheels on this model are 30 mm as per Larry's sizes but won't the view from such a small rover be pretty depressing?"

Actually the diameter is 50 mm. 30 mm is the thickness. But at this stage of the game such details are not critical. Besides, smaller is usually less expensive. Nano rovers?

Mounting certain sensors, like the camera, on a stick can address the "depression factor". But on the other hand, humn beings are very adaptable.

LB

Sorry, I posted the above before reading pages 2 and 3; thought there was only one page.

[jrich] " ... if you had sufficiently powerful braking rockets ... "

We do, but they are politically incorrect. However, there are signs that they are about to make a comeback. The performance and safety (especially for the crew of manned missions) of nuclear rockets relative to chemical rockets is so much better that we will not be able to pretend otherwise for much longer.

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But, right now we are stuck with chemical rockets. So we either make do with what we have, or we wait.

LB

FWIW, the density of air at sea level is about 1.2kg/m³. The density of a 1km hollow sphere of iron with a 1m thick shell is 23.5kg/m³. So in order to float at sea level the thickness of the shell would have to be around 4cm.

JR

Thanks. When I find that article I'll see if I am mis-remembering any of the dimensions.