Draper Laboratory, the organization that developed the guidance, navigation, and control (GN&C) software for the Apollo moon landers is in the thick of a new moon race.

The Google Lunar X PRIZE promises $20 million plus bonuses to the first non-government team to land a mobile robot on the moon. Draper’s partnered with two of the 29 teams to provide them with GN&C. It’s betting on robots that hop from place to place with rockets rather drive around on wheels to win the prize.

On a recent visit to the lab, I shot this video of the Terrestrial Artificial Lunar and Reduced gravIty Simulator, or TALARIS undergoing a descent test. This terrestrial testbed is designed to prove out the technology needed for a lunar version, specifically for the Next Giant Leap team.

Four ducted fans provide enough downward thrust to counteract exactly 5/6 of Earth’s gravity, simulating the moon’s 1/6 g. Eight cold gas thrusters fire nitrogen in precisely timed bursts to enable the vehicle to ascend, maneuver, hover, and descend.

Major General Nick Justice of the Army Research, Development and Engineering Command watches as Draper’s Bobby Cohanim and his team of MIT students spin up the ducted fans, drop the vehicle from the ceiling (attached to a tether for safety), and let the cold gas thrusters take it through a gentle descent to the end of the tether.