The race is on for the $30 million Google Lunar X PRIZE for the first privately funded team to land a robot on the moon, have it traverse 500 meters, and send back high-def video (and email and Facebook and Twitter posts).

Next Giant Leap, led by entrepreneur Michael Joyce, has partnered with the organization that developed the guidance, navigation & control (GN&C) software that put men on the moon, Draper Laboratory. Instead of driving their robot around the lunar surface, Next Giant Leap’s vehicle will fire up its landing rockets after the first touchdown to cover the required 500 meters by flying, and (hopefully) touch down safely again.

The team at Draper has been putting its GN&C software through its paces in a terrestrial vehicle called TALARIS. With ducted fans exactly countering 5/6s of Earth’s gravity, the machine fires cold gas thrusters to launch from a laboratory floor a few feet in the air, hover, and then execute a controlled descent.

Put all three of those modes of flight together, and you’ve got a potentially X PRIZE winning hop (just add a bit of sideways thrust to cover ground). The software controlling TALARIS, says the manager for the project at Draper, Bobby Cohanim, will port directly over to the lunar vehicle, which is to be built by Sierra Nevada Corporation. Cohanim, tells me they’ll be able to put all the pieces together any day now. “We can shoot off the ground like it’s nobody’s business,” he told me on Monday, “but we have issues ascending to that stable fixed-attitude, fixed-altitude hover.”

Hopping gives Next Giant Leap the distinct advantage of having to develop only one vehicle to win the prize: a single spacecraft that lands on the moon, and covers the required distance on the surface. Other teams, such as Astrobotic, have to develop two separate machines: a spacecraft capable of landing on the lunar surface, and a rover that will roll off of it to make the traverse.

But Astrobotic has made significant progress on both its rover and spacecraft. A few weeks ago, a rover prototype covered a full kilometer with humans involved only in guiding the vehicle over a deliberately degraded comm link to simulate lunar conditions. And I heard yesterday from team leader and Carnegie Mellon robotics professor Red Whittaker that the structure for their spacecraft has just passed its flight qualification tests with flying colors.

You can see the lander structure coming together in the CMU planetary robotics lab and getting shipped out for shake-testing in this time-lapse video provided by the team. Note the weights standing in for tanks and other equipment that will be on board for the actual flight. Explains Whittaker: “The lander is squat and highly-stiffened, with the heavy tank loads clustered tightly toward the center. These are sure-fire principles for achieving innate stiffness.”