Back to the Moon


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Astrobotic plans to land its lunar vehicle on the moon in October 2015. Image: Astrobotic

A strong contender for the Google Lunar X Prize, which offers $20 million to the first private group that lands a spacecraft on the moon, successfully travels more than 500 meters, and transmits back high-definition images and video, is moving closer to its goal of a moon landing. If all stars align, Pittsburgh-based startup Astrobotic will land its lunar vehicle on the moon in October 2015.

“We are looking good for October 2015. We have a launch vehicle and have lined up payloads,” says Astrobotic’s CEO John Thornton, a mechanical engineer from Carnegie Mellon University. The company recently tested a rocket launching and landing in the Mojave Desert using its hazard-detection system, which uses cameras and lasers to guide the lander toward a safe touchdown.

“That’s the closest we can get to the moon landing here on earth,” says Thornton, adding that one of the biggest challenges is doing an autonomous landing on the surface of the moon. “We use a scene-matching algorithm, which is basically looking at the images seen below the lander and matching those up to onboard maps to identify where we are in terms of landing.”

The Griffin lander will deliver a rover and other payloads to the moon’s surface. Image: Astrobotic

Safe Landing

As Astrobotic’s chief engineer, Thornton led the build of the Griffin lander. Almost the size of a car with a mass of 525 kg, Griffin uses a laser scanner to determine if there are any rocks or craters that can interfere with the landing. The lander is also equipped with advanced navigation software. Radio time-of-flight and Doppler provide the lander with the primary means for navigation during cruise while sun sensors and the star tracker enable attitude determination.

When approaching the moon, cameras register the spacecraft to lunar terrain for precision landing and laser sensors construct 3-D surface models of intended landing zone to detect slopes and hazards and determine a safe landing spot. “We compile the sensor feedback and match it with onboard maps to land our spacecraft accurately on moon,” says Thornton. Ramps mounted on the top of the deck enable rover egress, and four legs provide stability and shock absorption as the lander touches down.

The pyramidal shape of Red Rover regulates heat and the radiator rejects excess heat. Image: Astrobotic

Lake of Death

Part of the X Prize requirement is to traverse 500 meters on the moon and send images and video. Astrobotic’s Red Rover is being developed for that. The pyramidal shape of the lightweight (mass 80 kg) rover regulates heat during hot lunar days and its batteries survive and hold charge at cryogenic temperatures, enabling the rover to hibernate through two-week lunar nights and resume activities the next day. Red Rover is also equipped with a pair of stereo cameras and a camera with a telephoto lens. It navigates, detects obstacles, and captures 3D video footage and maps.

According to Thornton, the rover’s first spot on the surface of the moon will be the Lacus Mortis, which translates to the "Lake of Death." “The reason we want to go there is because of the unique skylights that exist only on the moon – 100 m deep and across. If you get to the bottom, there are underground caves that could be a potential destination for future human missions to the moon because if you are underground, you’re protected from micrometeorites, cosmic radiation, and other hazards on the lunar surface,” he says. “Our lander will be landing next to that and our rover will drive and explore the pit, which will be the first time anyone has seen it this close.”

Moon Race

The last U.S. lunar landing (Apollo 17) was 40 years ago and NASA has been trying to relive it since then. This is the first time in history that start-ups and universities are competing with nations to land on the moon. Spun out of Carnegie Mellon University’s Robotics Institute in 2008, Astrobotic has grown to a team of 14 that’s composed of mechanical, electrical, robotics, and software engineers. “It takes all disciplines to land on the moon,” says Thornton.

Astrobotic has signed a deal with SpaceX to launch their lander on a Falcon 9 rocket in October 2015 and recently also formed a partnership with NASA for the development of robotic lunar landing capability. “Once we are close to the moon, we drop into lunar orbit and descend. We will be dropping payloads on the way. We are able to carry 270 kg of other payloads, so we are offering that for sale and already have dozens of customers around the world who are interested in our moon mission,” says Thornton.

There are several future lunar missions scheduled or proposed by various nations or organizations but the challenge is astronomical. No wonder, out of the 33 teams that initially registered for the Lunar X Prize, only 18 remain. CEO Thornton is confident that Astrobotic will win the moon race, “We are one of the only teams with a launch vehicle contract. We are selling payloads and also have a strong partnership with NASA. We have built prototypes, are doing testing, and have our rover ready to go.”

We compile the sensor feedback and match it with onboard maps to land our spacecraft accurately on moon.

John Thornton,
CEO, Astrobotic

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June 2014

by Chitra Sethi, Managing Editor, ASME.org