Pasadena, Calif. ? The rock-strewn floor of Mars’ Gusev Crater blossomed into sharp view Tuesday with the release of the most detailed image ever obtained from the planet, taken by the rover Spirit’s panoramic camera in a tantalizing taste of “postcards” to come.

The composite image revealed a mysterious substance right at the rover’s feet, which scientists described as a “strangely cohesive” clay-like material with alien textures. Spirit exposed the material when it dragged its collapsed air bags across the Martian surface to retract them after its Saturday night bounce-down.

“The way the surface has responded is bizarre,” said lead rover scientist Steve Squyres of Cornell University, at the Jet Propulsion Laboratory (JPL), which is managing the mission. “I don’t understand it. I don’t know anybody on my team who understands it. … It looks like mud, but it can’t be mud.”

The material was mashed and clumped, like something moist and viscous, and was broken away in pieces at some spots. Squyres said one of the Viking landers of the 1970s might have seen something like it elsewhere on Mars. One explanation, he speculated, might be that moisture had percolated from below the surface, leaving a residue of salt that acted as cement.

A primary goal of the mission is to find out whether the dry, frigid and almost airless planet might once have had surface water and possibly supported life.

Spirit, a robotic field geologist, will be able to dig into the crust by locking five of its wheels and spinning the sixth, scientists noted. “Trenching into this stuff is going to be an absolute blast” once the rover has rolled off its landing platform, said Jim Bell of Cornell, lead scientist for the panoramic camera, or Pancam.

NASA announced that it had named the landing site Columbia Memorial Station in honor of the seven astronauts who died aboard the space shuttle almost a year ago. Among the images transmitted from Mars is one of a plaque mounted on the back of Spirit’s high-gain antenna in memory of the fallen astronauts.

Bell said the Pancam color “postcard” provides three or four times the detail of any images previously beamed from Mars. “These are the highest resolution pictures of Mars ever obtained. … My reaction has been one of shock and awe.” The grayness of the rocks and the dominant rusty peach of the dust are approximately the colors that a human eye would see from the same spot, he said.

In another image, a mirror mounted on a sundial aboard the lander shows “a beautiful pink-reddish sky.” The high-resolution Pancam color postcard reveals a much denser profusion of rocks in considerably sharper detail than do the black-and-white photos taken by Spirit’s navigation camera the day before — but it is still not the best the rover is expected to produce, Bell said.

Charles Elachi, left, director of NASA's Jet Propulsion Laboratory, and staff view a composite photograph of Mars during news conference in Pasadena, Calif. The photo, shown Tuesday, is helping NASA learn more about the surface of the planet.

This panoramic image from the Mars Exploration Rover Spirit's navigation camera shows the view on the Red Planet from the left stereo camera aboard the rover. The image was released Tuesday by NASA.