The United States will launch a mission in 2010 to land two stationary robots on the moon to collect rock samples before returning to earth, a US scientist said here Thursday. Carle Pieters of Brown University's Department of Geological Sciences, who is involved in the US space programme, said the aim of the Moonrise Mission was to land at the moon's largest and oldest crater - the South Pole Aitken Basin. "The purpose is to study how long ago the basin was formed and return materials derived from the deep interior to earth for analysis," Pieters said. "It will also help us to understand the unique process of how basins are formed." Pieters is also the chairwoman of the International Lunar Exploration Working Group, an organisation formed to promote cooperation between nations. She said scientists in the United States were still identifying which landing spots in the basin would be good for the twin robots to gather samples.