Question

Another topic that no one seems to consider is driving a 4x4 truck across the surface of Mars, years of experimenting with a robot vehicle when you have 100 years of progress with the motorcar.

So you have a fuel laden Chevy Silverado with air tanks for the fuel/air mixture and you set it on a course to drive a long distance photographing the terrain as it goes, even deploy a drill that is powered by the enging. The result is a quicker mapping of the surface, sampling and a huge coup for a motor manufacturer, the first Car on Mars.

The Opportunity Rover has travelled 40km in 10 years, a Silverado could run 400km in a couple of days.

Answer 1

The truck would never be able to operate on Mars. First of all, it's ridiculously heavy and inefficient to send there. Second, internal combustion engines require us to bring fuel and oxygen, which means more mass we have to bring. Third, there would not be enough air pressure to properly ventilate the truck and you couldn't close the system, so the oxygen you bring with would escape and not get used in combustion. Fourth, a truck requires a human driver, which we haven't sent to Mars. Fifth, if using a Silverado was cheaper and a better idea, we'd have done that. Sixth, a Silverado uses rubber, air-filled wheels, which is a bad idea on Mars because not only do these wear and need to be replaced, they also can pop (which they certainly would in the low pressure of Mars) and deflate. Good luck changing the tires from 450 million km away. Seventh, there are no roads on Mars, and while the Silverado may be a 4x4, the lower gravity means there is going to be a lot more displacement on the suspension system. The axle and the shock absorbers would not be able to handle the drive.

Opportunity uses an electric motor to drive across Mars. This means so long as we have a way to power it, it could (in theory) keep going. A Silverado requires fuel. Once that fuel runs out, that's it. Sending fuel to Mars is expensive. Furthermore, it's not the distance travelled that's important. Opportunity could have driven farther than 40km, but it stopped along the way to perform science experiments. Last time I checked, a Silverado doesn't have scientific equipment on it that can test the soil or the weather.

The Chevy Silverado is built to drive on Earth. Opportunity was built to drive on Mars. When it comes down to it, that's what I think most people are comfortable with. Let the Earth cars drive on Earth and the Mars cars drive on Mars