The Mars rover Curiosity is preparing to start digging into the soil of the Red Planet in a search for signs of life.
Nasa's $2.5bn, one-tonne vehicle landed in August to start a two-year mission on the alien world.
It is searching for signs of microbial life - or the signs that Mars was once able to support it.
Curiosity's ability to dig soil and put the samples into instruments for analysis its "central" to that effort, Nasa said - and it's about to start doing just that.
In just a few days the rover will start digging rocks and placing samples into analysis, said Mission Manager Michael Watkins of NASA's Jet Propulsion Laboratory.
The rover's current location - named "Rocknest", which is hundreds of feet from its original landing site - has been judged a good place to make the initial tests.
And on Wednesday it paved the way for the tests by "scuffing" the soil under its wheels to expose new material to analyse.
"Curiosity has been so well-behaved that we have made great progress during the first two months of the mission," he said.
The next step will be to shake the soil inside its sample-processing chamber, then discard it. It will do this three times then place the material in an observation tray so it can be analysed by cameras mounted on its mast, as well as delivered to its chemical analysis labs.
"It is standard to run a split of your sample through first and dump it out, to clean out any residue from a previous sample," said JPL's Joel Hurowitz, a sampling system scientist on the Curiosity team. "We want to be sure the first sample we analyze is unambiguously Martian, so we take these steps to remove any residual material from Earth that might be on the walls of our sample handling system."
At first the rover will scoop small amounts of soil into its analysis instruments. Later it will use a hammering drill to produce its own powdered samples from rocks.