May 18 (UPI) -- Curiosity and its drill haven't had a full range of motion since 2016 when one of the drill's motors short circuited. Over the last year, engineers have developed a workaround drilling technique called Feed Extended Drilling, or FED, which uses the rover's robotic arm to direct and push the drill into the ground as the drill bit spins.
In February, Curiosity used the FED technique to once again drill into the Martian surface. The effort failed to yield a rock sample, but it was still a partial success, producing data that allowed scientists to fine-tune the method back in the lab.
Now, engineers are preparing to add percussion, or a hammering rhythm, to the technique. Over the last few weeks, scientists have tested the technique using a Curiosity model on Earth. This weekend, scientists will program Curiosity to use the method.
"This is our next big test to restore drilling closer to the way it worked before," Steven Lee, Curiosity deputy project manager at JPL, said in a mission update. "Based on how it performs, we can fine-tune the process, trying things like increasing the amount of force we apply while drilling."
Because engineers are testing and improvising on the fly, it's been difficult to plan ahead. Should the new percussive drilling technique produce a rock sample, engineers don't yet have a plan for transmitting the sample back to the rover's internal lab. They'll have to go quickly back to the drawing board.
The stakes are high, as the rover's science team is eager to sample a portion of Mount Sharp's Vera Rubin Ridge rich in clay minerals.
"We've purposely driven backwards because the team believes there's high value in drilling a distinct kind of rock that makes up a 200-foot-thick [about 60 meters] layer below the ridge," project scientist Ashwin Vasavada said. "We're fortunately in a position to drive back a short way and still pick up a target on the top of this layer."
Curiosity has yet to sample the type of rock found along the ridge.
"Every layer of Mount Sharp reveals a chapter in Mars' history. Without the drill, our first pass through this layer was like skimming the chapter. Now we get a chance to read it in detail," Vasavada said.