NASA’s Curiosity rover on Mars has finally drilled deep enough into a rock to acquire a powdered sample for analysis.

The fine grey tailings from the 6cm-hole will be sieved and inspected before being delivered to the robot’s onboard labs in the coming days.

It will represent a historic first in planetary exploration – never before has the interior of a rock on another world been probed in such a way.

The US space agency said the drilling was an immense achievement.

“This is the biggest milestone accomplishment for the Curiosity team since the sky-crane landing last August, another proud day for America,” said Prof. John Grotizinger, the mission’s chief scientist.

Drilling is absolutely central to the rover’s mission in Gale Crater, a deep bowl sited on Mars’ equator.

Curiosity is investigating whether past environments at this location could ever have supported life, and getting inside rocks to analyze their make-up will provide some of the most telling evidence.

Engineers have waited a full six months before deploying the drill tool, which is held on the end of the rover’s 2.2 m-long robotic arm.

Its first action was just to hammer down briefly on a rock target last weekend – a simple check to prove the machinery was behaving as it should.

This was followed in the week by the drill turning in the chosen rock to cut a shallow, 2cm hole.

It produced a fine powder that engineers deemed suitable to try to pick up. So, the command was given to drill a second hole that was deep enough to push some tailings into the tool’s sample acquisition chamber.

NASA’s Curiosity rover on Mars has finally drilled deep enough into a rock to acquire a powdered sample for analysis

Some of this material will be used to scrub the machinery’s innards of any contamination that may have travelled with the rover from Earth.

The rest will be sorted to a size and volume that can be put inside Curiosity’s Chemin and Sam labs.

These instruments will determine the rock sample’s precise chemistry and mineralogy, and identify any interesting carbon chemistry that may be present.

Chemin will likely set to work on the powder first. This is because its findings can influence the settings run the Sam experiments..

“We may alter our temperatures depending on what they see in Chemin,” said Paul Mahaffy, the principal investigator on Sam.

The flat slabs of rock currently being investigated by the rover have been dubbed “John Klein”, the name of a Curiosity engineer who died in 2011. They lie in a small depression referred to as Yellowknife Bay, about half a kilometre from the robot’s point of touchdown last year.

The rocks contain very fine-grained sediments but are cut through with pale veins of what could be calcium sulphate.

Curiosity has already seen plenty of evidence for past running water in Gale Crater and the results from the drill-hole analysis are expected to reveal further information about that wet history.

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