Mars awaits the latest model

After the Moon Buggy and the Sojourner Rover, meet Nomad - the first of the next generation of extraterrestrial wanderers. The four-wheeled machine pictured here has recently completed a 133-mile six-week trek across the rugged Atacama desert in Chile, as preparation for field trips to Antarctica, the Moon and eventually Mars.

"It's a quantum leap for planetary robotics culture - the historical standard of travel was measured in yards, not miles" said William Whittaker of Carnegie Mellon University, Pittsburgh, who led the team of scientists and engineers testing Nomad.

The vehicle is about the size of a small car, weighing 727 kilograms (1,600lbs) - substantially more than the Sojourner Rover now carrying out experiments as part of the Pathfinder mission on Mars, which weighs only about 14kg. It has four-wheel drive and all four aluminium wheels are steerable, while the chassis can expand to improve its stability in difficult terrain. It travels at about 1 mph. In remote surroundings, it would either be powered by solar cells or fossil fuel. It cost about pounds 1m to develop.

Nomad is designed with twin colour cameras, allowing high-resolution control of it by human observers. It also ran on its own for 12 miles, performing a geological examination of a rock outcrop - which turned out to be an undiscovered deposit from the Jurassic period.

"Nomad met or exceeded all of our objectives for this project," said Dave Lavery, telerobotics project manager at the US space agency Nasa.

"During different phases we configured it to simulate wide-area exploration of the Moon, the search for past life on Mars, and the gathering of meteorite samples in the Antarctic."