Inflatable robots on Mars?

The NewScientist.com news service has a fun story today about a proposal to build "an army of inflatable, spherical robots," shaped like soccer balls, that could economically explore Mars and other planets. "Our inflatable rovers are lightweight, travel great distances, use very low energy and will be fairly cheap," said Fredrik Bruhn of Angström Aerospace Corp. in Uppsala, Sweden. His group has funding from Rymdstyrelsen, which is the Swedish National Space Board. The advantages? Since they're inflatable, they take up less cargo space on the trip to Mars. Being spherical, they are energy-efficient to move, and they're perfect for rolling around on irregular surfaces. The inflatable shell would be made of polyaryletheretherketone, which is tough and capable of withstanding high temperatures. The surface would incorporate solar panels to capture energy that would power the craft.