Small robots the size of ride-on lawn-mowers could prepare a safe landing site for NASA's Moon outpost, according to a study by Astrobotic Technology Inc and Carnegie Mellon University's Robotics Institute.

The plan calls for two 130kg digger rovers to be landed six months in advance of human astronauts in 2020, to either clear landing sites of rocks or shield the site from the blast of landing spacecraft.

"For efficient cargo transfer, a moonbase landing site needs to be close to the outpost's crew quarters and laboratories," says William Whittaker, a Carnegie Mellon professor of robotics.

"Each rocket landing and takeoff, however, will accelerate lunar grit outwards from the pad. With no atmosphere to slow it down, the dry soil would sandblast the outpost."

Can we build it? Yes, we can!

In one solution, researchers estimated their hard-working cyber-diggers would take less than six months to build a 2.5m-tall berm around a landing site to block the sandblasting effect - a job that would require shifting over a million kilograms of lunar dirt.

The other plan envisages the rovers combing the lunar soil for rocks, gathering them up to pave a durable grit-free landing pad for the arrival of humans.

Astrobotic's first lunar robot has been undergoing field trials for several months. The company hopes to claim the $20 million Google Lunar X prize by visiting the Apollo 11 landing site and transmitting high-definition video back to Earth, as soon as December 2010