Michelin has developed a new tyre for NASA. This kind of tyre doesn’t have any sidewalls. So no air at all!
They have tested it on a Audi A4 on a test track.

People who saw the spy shots were confused, and didn’t knew what it was. Well Michelin announced these tyres are made for NASA. These tyres are called “Lunar Wheel”. This wheel is based on the Michelin Tweel and maintains flexibility and constant ground pressure, allowing the vehicle to move trough loose soil and craters.

The Lunar wheel is tested on Hawaii from October 31 to November 13, 2008 as part of NASA’s lunar analogue testing and evaluation program. This test terrain on Hawaii provide a high-quality simulation of the lunar polar region, by its rocky and soil composition of Hawaii Big Island.

Below you can see how this wheel looks like. As you can see, this tyre doesn’t have any sidewalls.