Astrobotic Technology assembled a full-size prototype of Polaris, a solar-powered robot that will search for potentially rich deposits of water ice at the moon's poles.

Polaris is the first robot of its kind and can accommodate a drill to bore 1 meter into the lunar surface. It will operate in lunar regions characterized by dark, long shadows thanks to three large solar arrays arranged vertically to capture light from low on the horizon and creating an average of 250 watts of electrical power.

Astrobotic, a Carnegie Mellon University spinoff that develops robotics technology for planetary missions, is developing Polaris for an expedition to the moon's northern pole. The robot would launch from Cape Canaveral atop a SpaceX Falcon 9 launch vehicle. The company, in partnership with CMU, seeks to win the Google Lunar X Prize of more than $20 million.

Although Polaris is a flight prototype, it has the same configuration as the rover that eventually will land on the moon. This configuration will enable Astrobotic team members to spend the coming months testing and improving the robot's computer vision, navigation and planning software, and developing software that can plot the rover's position on the moon within 10 feet. Polaris includes a number of flight-worthy components, including wheels and chassis beams constructed of light but tough composite materials.

"It is the first rover developed specifically for drilling lunar ice," said William "Red" Whittaker, Astrobotic CEO and founder of the Field Robotics Center at CMU's Robotics Institute. "What Polaris does is bring those many ideas together into a rover configuration that is capable of going to the moon to find ice."

Observations by NASA and Indian spacecraft suggest that a substantial amount of water ice could exist at the lunar poles. That ice could be a source of water, fuel and oxygen for future expeditions.

“To find the ice, a rover must operate as close to the dark poles as possible, but not so far that it cannot use solar arrays for power,” Whittaker said. Polaris makes use of software that keeps track of the rover's position relative to the sun's rays in order to maximize solar energy and conserves battery power for use in the long shadows and dark regions found at the poles.

Polaris, 5 1/2 feet tall, 7 feet wide and almost 8 feet long, can move at about a foot a second on 2-foot-diameter composite wheels. Like Scarab, a NASA-funded robot built by CMU, its suspension will enable the rover not only to rise up over rough terrain but also to lower itself to the ground to drill. The rover will weigh about 330 pounds and can accommodate a drill and science payload of a bit more than 150 pounds.

"The composite materials are of aerospace quality, and that's a huge step up for us," Whittaker said. The lighter structural materials are essential for Polaris to accommodate the heavy drill and the massive batteries it will need for low-light operations. The carbon fiber and Kevlar materials are also important to the mission because they won't release gases in the moon's hard vacuum; the robot's science package will include gas sensors that could be disrupted by such outgassing. 
Whittaker said the lunar day lasts about 14 Earth days, though only about 10 days are suitable for water prospecting at the poles. The Astrobotic team expects Polaris could drill between 10 and 100 holes during that time as it locates and characterizes water ice deposits. If Polaris successfully survives the long, frigid lunar nights, as is anticipated, the prospecting mission could be extended indefinitely.