Day: May 21, 2018

In March I reported that NASA’s Mars Science Laboratory rover Curiosity had taken an important step in recovering its ability to drill into Martian rocks to collect samples. Now it looks like drilling operations could be resuming.

Use of the sample-gathering drill was suspended in December 2016, after problems were encountered with the drill feed mechanism – the motor used to extend the drill head between two “contact posts” designed to steady the rover’s turret during drilling operations. In particular, there was concern that continued use of the drill feed mechanism would see it fail completely, ending the use of the drill.

Since then, engineers have been trying to develop a means of using the drill without and reliance on the drill feed mechanism, and at the end of February 2018, a new technique was tested. Called Feed Extended Drilling, or FED,  it keeps the drill bit and head extended, and uses the weight of the rover’s robot arm and turret to push the bit into a target rock. This is harder than it sounds,as it requires the weight of the rover’s arm to provide the necessary pressure to help push the drill bit into a rock – something it is not designed to do, and might actually break the drill bit or cause it to become stuck. However, the rover passed the February test with flying colours.

This success meant that engineers could focus on recovering the drill’s percussive action. This assists in both helping the drill cut into a rock and in breaking the contact area under the bit up into a fine powder that can be collected by the collection tube surrounding the bit.

On Saturday, May 19th, and following further tests using Curiosity’s Earth-base test bed twin, the command was sent to Mars for Curiosity to carry out a second drilling test using both the FED approach and with the drill percussive action enabled. Unlike the February test, however, this one has an additional goal: to actually recover a special sample of rock.

For the last couple of months, the rover has been making its way along a feature on “Mount Sharp” dubbed “Vera Rubin Ridge”, toward an uphill area enriched in clay minerals that the science team is eager to explore. In doing so, the rover passed a distinct rock formation that could fill a gap in the science team’s knowledge about Mount Sharp and its formation.

Given the progress made in trying to get the drill working again, the decision was made to reverse Curiosity’s course in mid-April and drive back to the rock formation in the hope that the May 19th test could gather a sample from it. Commenting on the decision, Curiosity principal scientist Ashwin Vasavada  said, “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.”

If the new technique has allowed Curiosity to gather a sample – at the time of writing this article, NASA had yet to provide an update on the operation – the engineering team will immediately begin testing a new process for delivering that sample to the rover’s internal laboratories. This is again a complex process, which in the past has involved the drill feed mechanism to transfer material gathered by the drill to another mechanism called CHIMRA (Collection and Handling for In-Situ Martian Rock Analysis), also mounted on the rover’s turret. CHIMRA sieves and sorts the material, grading it by size and coarseness before transferring it to the rover’s science suite, located in Curiosity’s main body.

Success with both the drilling operation and same transfer will mean – allowing for fine-tuning and other adjustments – the drill could be re-entering regular use in the near future.

Continue reading “Space Sunday: drills, telescopes, pictures and doubts” →