The rover has a chemical lab on board to look for basic ingredients of life, including carbon-based compounds, nitrogen, phosphorus, sulfur and oxygen. It's the first time the lab will be used.
The rover's scoop will dig into the sand on Saturday. Mission sampling chief Daniel Limonadi said the rover will take the sand sample and shake it to cleanse it of unwanted residual Earth grease. That's important for the sensitive scientific instruments that are the keystone to the $2.5 billion mission that launched last year.
The rover landed in August and has traveled three-tenths of a mile, taking pictures and analyzing the Martian air.
In another first for the rover, it became the first to check-in on another planet on the social media site Foursquare. It checked in on Mars on Thursday.
In about a month, after going to a newer more interesting location, the rover will start drilling into the ground for samples.
The Associated Press contributed to this report.