Subsurface Access & Sampling
RAT— Rock Abrasion Tool
The Rock Abrasion Tool (RAT) was the first machine ever to gain access to the interior of rocks on another planet. Designed, developed, and operated by Honeybee Robotics as a part of NASA’s twin 2003 Mars Exploration Rovers science payload, the RAT uses grinding wheels of diamond dust and resin to gently abrade the surface of Martian rocks.
The RAT stabilizes itself against target rocks by using pressure provided to it by the rover’s arm; the same pressure provides thrust for its grinding teeth. Settings of low force and high speed are used on the RAT to comply with limited power and stability available from the rover. The RAT uses a single diamond matrix wheel to scrape the rock fractions of a millimeter at a time to an ultimate depth of 5mm, with a diameter of 45mm. The RAT is equipped with two brushes that sweep abraded rocks in preparation for scientific examination.
Using three small motors the RAT requires only about 11 watts of electricity to cut into Martian rock. Weighing about 685 g (.31 lbs), the RAT measures around 7 cm (2.7 inches) in diameter and 10 cm long (4 inches), about the size of a coke can.