Robot Space Excavator Being Developed By NASA
January 27, 2013

Blue Collar Lunar Excavator Could Produce Fuel, Water On The Moon

redOrbit Staff & Wire Reports - Your Universe Online

NASA engineers are working on a prototype lunar soil excavator that comes equipped with sturdy digging equipment, can take on a wide array of different shapes to complete its various tasks, and is reliable enough to operate on a daily basis for several years.

The robot, which is known as the Regolith Advanced Surface Systems Operations Robot or RASSOR (pronounced “razor”), uses a pair of digging bucket drums — one at each end of its body — that rotate in opposite directions, giving one end traction and allowing the opposite to dig through the soil, the US space agency said in a statement on Friday.

RASSOR, which NASA has referred to as “a blue collar robot,” is in an early state and will not be ready to go into space anytime soon, but even at this point they report that it has shown signs of promise. Rachel Cox, a Kennedy Space Center engineer involved on the project, said that she and her colleagues were “surprised” what could be accomplished with the machine thus far.

“The primary challenge for any digging robot operating off Earth is that they have to be light and small enough to fly on a rocket, but heavy enough to operate in gravity lower than that of Earth,” NASA explained. “RASSOR tackles this problem by using digging bucket drums at each end of the robot's body that rotate in opposite directions, giving enough traction on one end to let the opposite side dig into the soil.”

The RASSOR team has constructed a weight off-loading harness that simulates operating in the moon´s one-sixth gravitational field, the agency said. A concept mission for the digger would involve the approximately 100-pound instrument, as well as a one-ton payload that would be used in part to process the lunar soil the machine delivers.

RASSOR´s drum also includes “staggered shallow scoops that shave the soil a bit at a time rather than scoop large chunks of it all at once, the way bulldozers do on Earth,” NASA said, adding that it looks similar to “a small tank chassis with a drum at either end, each attached with arms.”

“The drums are perhaps the robot's most innovative feature,” they added. “Because they are mounted on moving arms, they can act almost as legs letting the robot step and climb over obstacles.” Thanks to the way the robot is constructed, it can “safely drive off the lander and right itself, flip itself over to get unstuck from fine soil and lift the whole body off the ground to let its treads run smoothly to remove built up soil.”

RASSOR can transform its body into a Z-shape in order to place the earth it collects into a hopper, and stands about 30 inches tall when the drums are positioned above its main body. It is being designed to skim lunar soil, dumping it into a device that extracts ice and water out the dirt, then converting chemicals into rocket fuel or oxygen for astronauts working on the surface of the moon, according to NASA.

That device would be part of the lander that would transport the robot to the moon, making it so that RASSOR “would be the feeder for a lunar resource processing plant, a level of industry never before tried anywhere besides Earth,” NASA´s statement explained. If they could use it to produce water and fuel directly on the moon, it would “save the tremendous expense of launching the supplies from Earth, since 90 percent of a rocket´s mass normally consists of propellant, which can be made on the moon.”

In theory, the same thing could also be done on Mars, as the soil on that planet is believed to contain massive amounts of ice, especially at the poles, engineers said. However, in order to obtain enough materials to create a useable amount of resources, the robot would have to operate 16 hours per day for a total of five years.

“Devising a robot for such demands called for numerous innovations, and the team says it has at least one major decision to make before it begins construction of the second generation RASSOR prototype: keep going with tracks like those that tanks use, or switch to wheels,” NASA said. “The tracks showed some flaws in recent testing, mostly relating to the pebbles and sand particles clogging the gears and making the track slip off.”

“The group tried out RASSOR on several surfaces at Kennedy, including the crushed river rock dug up from the crawlerway,” they added. “The rock, even though pulverized by the gigantic crawlers, is not a great substitute for lunar soil, the engineers said, but as long as the robot handles that matter well, they say they know it will manage whatever the moon soil offers.”