Washington: Ohio State University researcher Ron Li is leading a team to help humans navigate the moon after being instrumental in designing Mars rovers.

During NASA's scheduled moon landing in 2020, astronauts won't be able to use a global positioning system (GPS) because the moon lacks satellites, said Li, acting professor of civil and environmental engineering and geodetic science.

He described incidents during past lunar missions when astronauts were approaching a target site such as a crater, and got within a few yards of it - but couldn't see the crater because of difficult terrain. "They were so close, but they had to turn back for safety's sake," he said.

Li explained how the system will work: images taken from orbit will combine with images from the surface to create maps of lunar terrain; motion sensors on lunar vehicles and on the astronauts themselves will allow computers to calculate their locations.

Besides, signals from lunar beacons, the lunar lander, and base stations will give astronauts a picture of their surroundings similar to what drivers see when using a GPS device on Earth.

Researchers have named the entire system the Lunar Astronaut Spatial Orientation and Information System (LASOIS).

Keeping astronauts safe will be a top priority for Li's team, which includes experts in psychology and human-computer interaction as well as engineering.

"We will help with navigation, but also with astronauts' health as well," Li said. "We want them to avoid the stress of getting lost, or getting frustrated with the equipment. Lunar navigation isn't just a technology problem, it's also biomedical."

Li made a presentation at the NLSI Lunar Science Conference, at NASA Ames Research Centre in California. IANS