“When are we in trouble?” asks Fairfield, his eye on a horizon indicator that would show if the rover were tilting too much.
“At 20 degrees,” his copilot says.
“We’re okay then.” In Earth gravity, Fairfield explains, the rover stays balanced because of its weight. On the moon, it will be six times lighter, so a 20-degree tilt could place it in danger of tipping over.
The details for these and other operations are figured out in the three-story High Bay, the working heart of the Robotics Center, located back on the main CMU campus. There I see a small fleet of machines, all built by Whittaker and his colleagues. The meteorite-hunting Nomad stands sentry near the door, wearing the NASA “meatball” logo. A few yards away sits Zoë, the solar-powered rover that in 2004 roamed more than 120 miles through the Atacama desert. An automated boat, Sol, awaits a dip in nearby Schenley pond. It’s a robotic wonderland.
At the far end, around the corner, is Red Rover’s shop area. Nick Miller, who is pursuing his master’s degree, shows me around. Having run through its paces, Red Rover now sits atop a rack, its solar panels removed to reveal wires, a central processing unit, and motors. This second prototype will be replaced by a third before next March. The fourth iteration—the flight version—now exists only as drawings on easel boards around the shop. In a nearby storage room, lead mechanical engineer John Thornton, wearing cargo shorts, and his team are fabricating their own carbon fiber parts. Thornton, who also has a master’s from CMU, apprenticed at Boeing’s Phantom Works.
Clearly, Astrobotic’s operation relies heavily on student power. “Nothing great ever came from robotics in our corner of the world that hasn’t had the energetic core of youth right upfront,” Whittaker told a gathering of the X Prize teams last year. Still, he admits, when it comes to making decisions, “Red is the last word. I’m not being imperial or pushy. [But] is the program going to take another minute going down a blind alley?”
BACK AT ROBOT CITY, I sit in on a Technology Interchange Meeting, where the project partners are discussing today’s engineering issues. A visiting team from Lockheed Martin is getting its first close look at Astrobotic’s plan. Collectively, the Lockheed team members have decades of experience working on NASA planetary missions, from the Mariners of the 1960s to the current Mars Reconnaissance Orbiter. On the phone are representatives of Astrobotic’s other partners: Raytheon, ATK, and the University of Arizona scientists who are planning the details of the Tranquillity Trek.
One of the topics at hand is Red Rover’s mass. With all its gear and a lander package called Artemis, the rover is overweight—its mass is more than the intended launch vehicle (Astrobotic won’t disclose their rocket supplier of choice) can lift. Not a huge problem at this early stage, but something that will need to be addressed.
The discussion moves on to the precision landing, a key part of Astrobotic’s plan. The landing will rely on Raytheon missile guidance technology adapted from the company’s Exoatmospheric Kill Vehicle. As the rover-lander descends to the lunar surface, an onboard computer will update its flight path by comparing pre-loaded photos of the terrain to real-time pictures taken during the descent. The target ellipse is just 1,100 yards long and 330 yards wide—demanding a high degree of accuracy for a planetary lander.
Tom Gardner of Raytheon presents the numbers for the final descent. At around two and a half miles above the surface, a rocket will fire to slow the lander-rover from 7,900 feet per second to 330 feet per second. It’s the equivalent of slamming on the brakes and diving down to the surface. At 23 seconds before landing, the main engine or smaller side engines will burn again for 2.5 seconds, further reducing the speed and setting up the soft landing.