by Kevin Berry
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After decades of designing and operating robots full of scientific gear to study
other worlds, NASA is working on a prototype that leaves the delicate
instruments at home in exchange for a sturdy pair of diggers, plus the
reliability and strength to work all day, every day for years.
Dubbed RASSOR — for Regolith Advanced Surface Systems Operations Robot,
and pronounced "razor" — the autonomous machine is far from space-ready,
but the earliest design has shown engineers the broad strokes of what their
lunar soil excavator needs in order to operate reliably.
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.
RASSOR tackles this problem by using digging bucket
drums at each end of its robot body that rotate in
opposite directions, giving enough traction on one end to
let the opposite side dig into the soil.
The team built a weight off-loading harness that
simulated working the rover in the Moon’s 1/6th gravity
field. “We proved that if you engage one bucket, it pulls
itself, but when you lower the other bucket and rotate it,
once they both catch in, it starts digging,” commented
A.J. Nick, an engineer on the RASSOR team.