February 2010

Extra-terrestrial excavation

Canadian tele-operated mining tech challenges for the moon

By G. Baiden

Students, startup entrepreneurs, industry professionals and inventors gathered this past fall for the Regolith Excavation Challenge to see how well their lunar excavators could tackle the job of mining on the moon. The competition, held October 16 to 18 at the NASA Ames Research Park in Mountain View, California, promised $750,000 in prizes. To claim the purse, teams had to design, build and operate a mobile robot that could dig up and deposit at least 150 kilograms of lunar regolith (moon soil) from a simulated lunar surface and deposit it into a collection bin. Using tele-robotic or autonomous operation, contestants had the additional challenge of completing the task in only 30 minutes. The team whose machine deposited the most material beyond the 150 kilogram standard was promised a $500,000 first prize.

The competition was designed by NASA and conducted by the California Space Education and Workforce Institute to replicate the mining needs for moon missions and further space exploration. If an operator could run a mining machine on the moon to gather lunar regolith, the material could then be transferred to a processor and converted into hydrogen, oxygen, water and rocket fuel. These materials would be needed to establish an outpost on the moon as well as a launch station for travel further into the solar system.

The challenge

About a year ago, Penguin Automated Systems Inc. was approached by a group in the United States to assist them in building a robot for the challenge. The rules had changed to allow tele-operated robots into the competition because, in its short two-year history, no one had won the competition. The group felt that Penguin ASI might have the technology to win because they specialize in the tele-operation of robots.

The contenders

The team — Laurentian Rock — was composed of secondary school students and undergraduates from Laurentian and Queen’s universities, as well as creative engineers and industry professionals from Colorado and Penguin Automated Systems Inc., the team’s primary sponsor. The U.S. members of the team were mining/space professionals who believed that NASA needed to see what mining industry professionals were capable of delivering in terms of equipment, systems and techniques. Each member provided significant contributions and together made a cohesive and productive group that built an innovative robot, the Rokbot, from concept to design in just six months.

The unit was designed to maximize traction and friction with the ground, while the high-powered stepper motors generated the thrust to push the unit through the lunar regolith. As the motors pushed, the front scraper dug into the ground and plowed the material into a windrow for deposition onto the conveyor and into the dump bin.  The Rokbot then returned to the dumping area where the entire unit was lifted and tilted to deposit the lunar regolith.

The main onboard computer system managed several devices. These included all the sensors and actuators for the control of the tracks, conveyor and camera. A gyroscope and accelerometers, linked to the radio network, provided information about the location of the machine to the main tele-operation control device.

The innovations

The Laurentian Rock entry had several innovations, including a specialized immersive display for the operator, state-of-the-art power systems and special digging systems. One of the hardest challenges was to overcome the simulated four-second delay, which represents the time a control signal would take to go from the earth to the moon. This is akin to driving a vehicle on earth whereby the steering wheel is turned and four seconds later the vehicle turns. This issue was dealt with by providing video data and having the operator practice with the Rokbot on the delay.

The team’s immersive display, a hemispherical screen that wraps around the operating console, allowed the operator to get the equivalent of 3-D information while minimizing the amount of information required to achieve immersion.

The Rokbot also used the latest in battery technology, polymer lithium, with tremendous charge capability. Canada Lithium was the main sponsor for the battery. The digging system was created from scratch. It required powerful electric motors for track thrust, an oscillating digging unit to supply material to a belt and, finally, the dump box.

The results

All together, 24 teams competed in the regolith excavation, including first-time competitor, Laurentian Rock. After two years in which no prizes had been claimed, innovators finally met the challenge. All three prizes were handed out to teams that returned to compete with modified designs. The Laurentian Rock team dumped regolith; however, the property of the regolith caused it to stick in the dump bin, limiting the amount the Rokbot deposited for weighing purposes. Nevertheless, this was still an amazing success for the entire team, which was pleased with the results and intends to use the lessons learned to make the appropriate modifications to the robot to compete again next year.

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