U.S. researches say autonomous rovers exploring moons and asteroids could be a significant step toward a human mission to Mars.

Researches at Stanford University, in collaboration with NASA's Jet Propulsion Laboratory and the Massachusetts Institute of Technology, have designed a robotic platform that could undertake such rover missions. Researchers have proposed sending a mission consisting of a mother spaceship dropping one or more spiked, spherical rovers onto the surface of the martian moon Phobos.

The small "hedgehog" rovers, less than 2 feet across, would roll and hop across the surface of Phobos, sending back data on its soil and other surface materials to their "mother ship," a Stanford release said.

The data would then be transmitted back to Earth.

Human control would be unnecessary for many mission parameters, researchers said.

"It's the next level of autonomy in space," said Marco Pavone, a professor in Stanford's Department of Aeronautics and Astronautics.

Although such rovers and a mother ship could explore any of the solar system's smaller inhabitants, including comets and asteroids, Pavone said he designed it with Phobos in mind.

Such a mission could test technologies for potential use in a human missions in the solar system, he said.

"It's a piece of technology that's needed before any more expensive type of exploration is considered," Pavone said of the mothership-rover system. "Before sampling we need to know where to land. We need to deploy rovers to acquire info about the surface."