The Spirit rover has spent its first full day and night on the Martian surface, preparing to begin its explorations early next week.

After its seven-month journey from Earth, Spirit hit the ground on Saturday at 8:35 p.m. Pacific time, about 2:27 p.m. local solar time. Three hours later, it sent NASA controllers its first pictures of the landing site, located near the center of Gusev crater. This location is only the fourth place on Mars where a human-built contraption has ever landed, and the first that scientists actively wanted to visit.

For much of Sunday, researchers pored over the images and other data. The camera sits on a mast 1.5 meters tall, so the images closely match what you'd see if you actually stood on the planet and looked around. "It's a lot flatter than I expected," says planetary geologist Wendy Calvin of the University of Nevada. "It's a lot less rocky than I expected."

For her and team members, the site has a subtle yet powerful appeal. "It's beautiful in the same way the desert is beautiful," says Jet Propulsion Laboratory (JPL) engineer Julie Townsend. "It's a beautiful vacantness, the beauty of an undisturbed landscape."

The site has plenty of rocks to analyze, but not so many that they'll get in the way. Principal investigator Steven Squyres of Cornell University says, "This rock population is as close to ideal as I could possibly have imagined."

Most of the rocks have been swept free of dust, presumably by dust devils (a kind of mini-tornado) whose trails have been seen in orbital shots. The clean surfaces are ideal for geological study.

The light-colored flat areas are probably craters filled in by dust. The most prominent one looks to be about 30 meters away and has an exposed rim, which will be a high priority for analysis. Inside the dust bowl are dark markings that may be places where the rover bounced before coming to rest.

The atmosphere is less transparent than expected, which has reduced the solar power by one sixth but raised the temperature by about 10 degrees. Deputy mission manager Mark Adler of JPL reports that during its first night on Mars, the rover needed 20 to 30 percent less energy than predicted to stay warm.

Shortly after sending the first batch of images, Spirit went to sleep for the night. Yesterday, it woke up at 2:42 p.m. Pacific time, about 8:40 a.m. Gusev time. The main task on its second Martian day of operation (sol 2) was to establish direct communications with Earth. The first sol, Spirit had relayed data via the Mars Global Surveyor and Mars Odyssey orbiters. A UHF radio on the rover talks to the orbiters at about 128 kilobits per second, but they have to be flying overhead, which happens only for 12-minute periods several times a day. On sol 2, the rover deployed its high-gain antenna--a radio dish, about the size of a satellite TV dish, that streams data to Earth at up to 11 kilobits per second. With the direct link up and running, controllers plan to upload full-color, high-resolution images on sol 3.

"Spirit has shown us her new home in Gusev crater, and it's a glorious place," Squyres says. --George Musser in Pasadena, Calif.