Pasadena, Calif. ? NASA’s Phoenix Mars Lander spent its first full day in the Martian arctic plains checking its instruments in preparation for an ambitious digging mission to study whether the site could have once been habitable.

Sol 1, as the days are known on Mars, was a busy time for the three-legged lander, which set down Sunday in relatively flat terrain cut by polygon-shaped fissures. The geometric cracks are likely caused by the repeated freezing and thawing of buried ice.

“We’ve only looked at one tiny little slit” of the landing site, principal investigator Peter Smith of the University of Arizona, Tucson said Monday.

Phoenix planned to take more views of its surroundings to help scientists zero in on a digging site and also take images of its onboard instruments, including its trench-digging robotic arm.

Early indications show the protective cover around the arm did not unwrap all the way after landing, but it should not affect the ability to unstow the arm, said Barry Goldstein, project manager at NASA’s Jet Propulsion Laboratory.

Ground controllers won’t know how Phoenix fared on the first day until late Monday, when an orbiting Mars probe passes over the landing site and relays the data to Earth.

The earliest engineers would move Phoenix’s 8-foot-long arm will be today, but it’ll be another week before the lander takes the first scoop of soil.

After the initial taste test, Phoenix will spend the rest of the mission clawing through layers of soil to reach ice that is believed to be buried inches to a foot below the surface.

Mission co-scientist Ray Arvidson of Washington University in St. Louis is pleased with Phoenix’s progress so far.

“Like a union worker, it went right to work,” he said.

Scientists were especially interested in how the polygon patterns in the ground formed at Phoenix’s landing site. The fractures look similar to those found on Earth’s polar regions. Arvidson said Phoenix appeared within reach of a shallow trough that could be a potential place to dig.

“I was just afraid that it’ll be so flat and homogenous and that we’d be digging in soil and we wouldn’t know the context” of how it formed, Arvidson said.