Having your drill break down while you’re millions of miles from the nearest hardware store would be a bummer, but that is exactly what’s happened to NASA’s Mars Science Laboratory Curiosity.
The rover, which is currently located at the lower slopes of the 3.4-mile-high Mount Sharp (officially known as Aeolis Mons), was supposed to carry out a drilling operation on a geologically interesting location on Dec. 1 when mission controllers got word that Curiosity was unable to complete its commands. Early indications show that the rover detected a fault with the “drill feed” mechanism that lowers the drill piece to the rocky sample and aborted the operation.
A front hazcam photograph from Dec. 4 can be seen above with the arm extended close to the ground.
Curiosity’s drill is an important component for its mission to the Red Planet. Since landing in 2012, the robotic geologist has used its drill in 15 locations to bore-out samples of dust from the interiors of Martian rocks. These samples are then scooped up and analyzed by the robot’s onboard chemistry lab. From its studies, scientists have made fascinating discoveries about Mars’ wet past, how minerals formed and even hints about the planet’s history of habitability. Having used its drill seven times in 2016 alone, this apparent fault brings Curiosity’s drilling operations to an abrupt halt.
“We are in the process of defining a set of diagnostic tests to carefully assess the drill feed mechanism,” said Steven Lee, Curiosity’s Deputy Project Manager at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “We are using our test rover here on Earth to try out these tests before we run them on Mars.
“To be cautious, until we run the tests on Curiosity, we want to restrict any dynamic changes that could affect the diagnosis. That means not moving the arm and not driving, which could shake it.”
As Curiosity lowers its robotic arm to the surface to commence drilling, the drill feed mechanism extends the drill bit to make contact with the ground. According to mission engineers, it appears that either a physical brake on the feed didn’t disengage fully, or Curiosity detected some abnormality with the feed’s motor’s electrical encoder. Both scenarios would have caused Curiosity to disengage.
The drill that Curiosity uses to drill into rock samples is one of several instruments mounted to its robotic arm (NASA/JPL-Caltech/MSSS)
Interestingly, this isn’t the first time problems have occurred with the instrument. The drill offers two modes of operation; the first is purely rotary, where the drill piece rotates like the hand drill you have in your toolbox and the mode that it attempted on Dec. 1. The second mode provides a percussion drilling method that has an action like a tiny pneumatic drill or a chisel. Either or both drilling methods can be employed depending on the rocky material being sampled. Since February 2015, the percussion mechanism has been experiencing intermittent short circuits, so mission managers decided to use this mode sparingly.
“We still have percussion available, but we would like to be cautious and use it for targets where we really need it, and otherwise use rotary-only where that can give us a sample,” Ashwin Vasavada, Curiosity Project Scientist at JPL, said in a statement.
As a precaution, Curiosity has been instructed to keep its arm where it is while engineers troubleshoot this new problem with the rotary drilling mode. But it’s not sitting idle. The rest of the rover’s instruments are working fine, so it’s taking time to use its mast-mounted cameras and a spectrometer, plus a suite of environmental instruments to monitor its surroundings while a drill fix is found.
Since landing, Curiosity has driven over 9 miles and since starting its slow climb up Mount Sharp, it has traveled 165 meters (541 feet) in elevation. At strategic points during its climb, the rover has been taking samples and studying the local geology to see how Mars has evolved over millions of years, adding more detail to our understanding of how the small world turned from a comparatively wet and potentially habitable place into a dry, barren wasteland we see today.