Dig the Regolith.

The answer you entered to the math problem is incorrect.

Posted May 14th, 2007 by G Kontos

Four teams competed in NASA's Regolith Excavation Challenge this week for a chance to win a prize of $250K. The four teams all attempted unsuccessfully to build a robot that was able to dig 330lbs of regolith in under 30 minutes. Technology Ranch of Pismo Beach did the best with 143 lbs collected in the 30 minute time frame. All other machines broke down before the 30 minutes expired.

Regolith is the "loose heterogeneous material covering solid rock". On the moon this layer of material can be several meters thick.

More information on the competition and competitors is available here.