A UC Irvine engineer will help NASA develop ways to more accurately land unmanned spacecraft on Mars, a planet that will be explored by several new probes over the next decade.

Kenneth Mease was chosen to lead a team that will create formulas and software to guide landers similar to Spirit and Opportunity, the robots now at work on Mars.

"Pinpointing a Mars landing to within (about 300 feet) enables science instruments to be delivered close to gullies, rock outcrops or canyon walls," Mease said Monday in a statement.

In January, the Jet Propulsion Laboratory guided the rover Spirit to within six miles of the center of its landing zone in Mars' Gusev Crater. The landing easily placed the robot on a rocky plain where Spirit could do research. But more precise landings will be needed in future missions.

NASA plans to launch the Phoenix lander to Mars' northern polar region in 2007. Two years later the Mars Science Laboratory, a lander- rover, will be guided to a narrow landing zone.