Getting an object off the surface of the Earth and safely transporting it across the nothingness of space to the moon is one of the greatest technological challenges mankind has ever overcome. The moon may be our closest interstellar neighbor, but it's still some 382,500km away -- on average, anyway. That's about 10 trips around the equator, all made outside of our comforting atmosphere, never with a chance to stop and regroup should anything go wrong.
But the journey to the moon is really just the appetizer for the next greatest challenge: safely landing on the thing. The moon is covered in pock-marks and craters from aeons worth of heavenly collisions. With every attempted landing comes the opportunity to make yet another. That'd be a mighty shame, after all the hard work invested in getting there.
It's this phase, that of touching down gently, that brought team Astrobotic to the Mojave desert. Astrobotic is the Pittsburgh-based entrant to the Google Lunar XPrize, a $30 million pool of prizes for the first team to land a vehicle on the moon and use it to explore, all while beaming back high-definition footage to Earth.
This summer, $6 million is being awarded to teams that can prove their ability to complete that mission through a series of terrestrial tests, and Astrobotic is one of those teams.
Astrobotic is working with Masten Space Systems to test the landing phase of its mission. Masten is itself a former XPrize contestant, winning the 2009 Northrop Grumman Lunar Lander Challenge by creating a lander that could lift off, fly up to 50 meters in altitude, fly laterally for 100 meters, and then land on a designated spot. Natural, then, that Astrobotic would work with Masten to test the landing system for its own Griffin lander.
As part of its earlier XPrize, Masten developed a vehicle called XA-0.1B -- or Xombie, for short. Masten would go on to build more advanced landers, but this initial unit was put into service for the Astrobotic test. Xombie uses a single thruster firing straight down, gimbal-mounted to allow for precise control. But this also means navigation is tricky, as the entire weight of the lander is effectively balanced on end.
In the flesh it looks more like scaffolding than spacecraft, a tall, narrow yellow structure with a series of tanks and anodized fittings stuffed within and without, plus a healthy number of GoPro mounts all over. Tests are completed without bodywork to save weight -- and because aerodynamics won't really factor into the actual task of landing on the moon.
While Masten is providing the lander for this test, it's up to Astrobotic to get it safely on the ground. The team, which includes many students from Carnegie Mellon University, developed a sensor package that sits on top of the Masten device, looking to the side and downward. It uses cameras and a laser scanner to observe the world around it, comparing what it sees to an internal map.
That map depicts the area around the Mojave Air and Space Port, a prominent locale in the history of the XPrize Foundation. It was here, in 2004, that the Scaled Composites team won the Ansari XPRIZE, the very first XPRIZE, which led to the creation of Virgin Galactic.
Astrobotic's mission goal sounds fairly simple: launch the Xombie lander up to 250 meters in altitude, then follow a 25 percent glide path toward a series of potential landing targets. Each of the targets is a concrete landing pad, necessary because the downward-firing rocket is hot enough to melt the sand on the desert floor. Molten glass flying about won't do the lander any favors.
Sandbags were placed around the three concrete pads, replicating lunar rocks and other debris that would make for an unsafe landing site. After launching, the Xombie lander with the Astrobotic brain needed to act autonomously, scanning and identifying the best place to touch down.
And, thankfully, it did just that. Though the team faced a series of delays leading up to the test, at least partly due to a laser scanner that initially reported information a few degrees off from reality, the test itself was a success. The rocket, parked amid scrub brush and tumbleweeds, blasted into the clear sky before slowly, gradually, drifting down to a vacant pad, touching down safely onto the concrete pad with a bit of a bump.
Next stop? There's plenty more testing and development to complete throughout this year and next, but the ultimate goal is for Astrobotic to land its own Griffin lander on Lacus Mortis, the "lake of death" found in the northeastern part of the moon. It's a basaltic lava flow, the sort of rock formation that commonly results in subterranean tunnels and caves. At least, that's what happens here on Earth. Nobody knows for sure whether that's the case up there, too, but if the team can find caves, that would make for an ideal spot for a future long-term manned mission on the moon.
After all, while living in caves may seem primitive, it certainly beats dragging your house across a 400,000km void.