Regolith Advanced Surface Systems Operations Robot - RASSOR Excavator (via NASA)
The majority of robots are designed to ‘serve’ in some form or another, but very few are able to do it on other celestial bodies other than Earth. NASA’s Mars rovers ‘Spirit’ (non-functional), ‘Opportunity’ (still functioning) and ‘Curiosity’ (the latest edition rover) are prime examples of off-world robots, which perform an invaluable service by exploring the red planet’s surface. When it comes to these robots weight becomes a factor when it concerns launching them into space. The more functions they are capable of performing usually translates into increased mass/weight which drives up the cost (or negates it completely) of getting the robots into space. As an example, NASA’s Curiosity rover is able to take and analyze biological and geological/geochemical samples, planetary processes (atmospheric analysis, etc.) along with performing a myriad of tests on surface radiation, which, with all the components needed to do so, gives the rover a combined weight of 2,160 pounds. In an effort to scale down the weight (costing around $4,000 US per pound of payload), NASA is looking to develop a smaller robot whose sole purpose is to dig holes on the moon’s surface in an effort to excavate water and ice for fuel and breathable air for astronauts.
Engineers have already designed a prototype, known as ‘RASSOR’ (Regolith Advanced Surface Systems Operations Robot), which is lighter in weight at just 100lbs. (compared to the rovers) but still retains enough mass to work on the lunar surface. The tank-shaped robot is outfitted with bi-directional rotating treads that allow it to climb over most any terrain and inclines which also gives it the ability to right itself if it falls over. It uses counter-rotating bucket drums outfitted with ‘scoops’ situated on either end of its body which provides a sort of ‘counter-force’ that allows the robot to excavate material while being anchored at one end while the other digs. Once the robot has collected a payload of 40lbs. of material it can then deposit the haul in a hopper (collection/separation bin) by propping itself up in a Z-formation. The drums can also be used as legs to step over obstacles or perform what NASA engineers call ‘acrobatics’ if the terrain becomes too much for the treads to handle. NASA has been testing the prototype at the Kennedy Space Center using a harness to simulate the gravity found on the moon with mixed results. On the one hand, the treads would slip off after becoming clogged with sand and small pebbles that was dug up by the counter-rotating buckets and on the other, the buckets performed quite well at digging in the crushed rock river-bed (used to simulate conditions on the moon). NASA has already begun designing the second prototype, called RASSOR2, that will address the tread problem (perhaps switching them with wheels) and any other glitches with testing beginning as early as 2014.
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