NASA's Mars Curiosity rover tests new way to drill

NASA's Mars Curiosity rover has conducted the first test of a new drilling technique on the red planet since its drill stopped working reliably, the US space agency said.

This early test produced a hole about one centimetre deep at a target called Lake Orcadie - not enough for a full scientific sample, but enough to validate that the new method works mechanically, according to NASA.

This was just the first in what will be a series of tests to determine how well the new drill method can collect samples, it said.

"We are now drilling on Mars more like the way you do at home," said Steven Lee, deputy project manager at NASA's Jet Propulsion Laboratory in California.

"Humans are pretty good at re-centring the drill, almost without thinking about it. Programming Curiosity to do this by itself was challenging - especially when it was not designed to do that," said Lee.

The drill is used for pulverising rock samples into powder, which are then deposited into two of Curiosity's laboratory instruments, Sample Analysis at Mars, or SAM, and Chemistry and Mineralogy, or CheMin.

Curiosity has used its drill to collect samples 15 times since landing in 2012.

However, in December 2016, a key part of the drill stopped working.

The drill was designed to use two finger-like stabilisers to steady itself against rock; a faulty motor prevented the drill bit from extending and retracting between these stabilisers.

After months of effort, Curiosity's engineering team was able to extend the drill all the way out past the stabilisers, but the motor issue persisted.

The team wanted to see if it could hack the space robot's drill so that it did not require stabilisers.

Images of a new hole on upper Vera Rubin Ridge, Curiosity's current location, suggest this "MacGyvering" is paying off.

By leaving the drill in an extended position, engineers were able to practice this freehand drilling for months during testing here on Earth.

This hole at Lake Orcadie provides the first insights into how this operation will work in the martian environment.

If the previous method was like a drill press, holding the bit steady as it extends into a surface, it is now more freehand, NASA said.

The rover is using its entire arm to push the drill forward, re-centring itself while taking measurements with a force sensor.

That sensor was originally included to stop the rover's arm if it received a high-force jolt. It now offers Curiosity a vital sense of touch, preventing the drill bit from drifting sideways too much and getting stuck in rock.