By Dr David Whitehouse
BBC News Online science editor
Researchers have deployed an autonomous robot to traverse Chile's Atacama Desert as part of a project to develop advanced rovers for Mars exploration.
The next best thing to Mars
"Our goal is to make genuine discoveries about the limits of life on Earth, and to generate knowledge that can be applied to future missions to Mars," says project leader David Wettergreen, of the Carnegie Mellon University Robotics Institute, US.
The rover, called Hyperion, is already a veteran of an expedition to the Arctic, another region of the Earth with similarities to Mars.
"We will conduct three annual field experiments in Atacama. Each time, an increasingly capable robot will use sensing and intelligence to find land forms or environmental conditions that could harbour life," says Wettergreen.
Go its own way
Hyperion will travel about 10 kilometres through the desert this year. Last year, it was deployed at Devon Island in the Canadian Arctic, where it demonstrated a concept called Sun-Synchronous Navigation - tracking the Sun as a source of power.
In the Atacama, the robot's solar panels have been laid flat on top of its body so it can capture the maximum amount of sunlight in the desert environment. In the Arctic, the panels were mounted vertically because the sun was low on the horizon.
Finding intelligent life
Researchers will monitor Hyperion as it travels through the hostile region collecting data using instruments such as a near-infrared spectrometer and a high-resolution panoramic imager.
Based on this year's experience, next year's robot should be able to travel about 50 km. The target for the 2005 expedition is 200 km, traversing contrasting areas where life is abundant and areas where life has not been detected.
During the 2005 expedition, researchers will introduce a time delay and a limit on communication with the robot to simulate the constraints of working with a robot more than 100 million km away on the surface of Mars.
"We'll operate under the constraints of Martian exploration in order to better develop procedures for seeking life on another planet," says Wettergreen.
"The robot will monitor its own power, balance, locomotion, communication and science operations as it goes.
"It needs to be able to move into unknown terrain using cameras and internal sensors - the same instruments and information that would be available to a robot exploring Mars."
Nathalie Cabrol, a planetary scientist at the US space agency's Ames Research Center and the Seti (Search for Extraterrestrial Intelligence) Institute, says: "This project will field test innovative combinations of science instruments and new rover search modes.
"If life appeared once on Mars and has been preserved in some way, whether as fossils or extant communities, it is then critical that future missions be capable of automatically and unambiguously detecting it.
"This project is aiming at achieving this goal in the Atacama in three years as a stepping stone to Mars."