Opportunity knocks

After four days of technical difficulties dampened their spirits, NASA engineers finally had the opportunity to pat themselves on the back with a second successful Martian landing in the early-morning hours of Jan. 25.

The second rover, dubbed Opportunity, rolled to a stop nearly 7,000 miles from the ailing Spirit and almost immediately began beaming back photos of a strange, forbidding landscape that had never before gotten an up-close look.

Swaddled in airbags, Opportunity bounced right into a shallow crater, allowing it to examine multiple strata of the planet's surface without extensive digging. "We have scored a 300 million-mile interplanetary hole in one," said Steve Squyres of Cornell University, principal investigator for the science instruments on both rovers.

Initial photos showed a very different environment than the one surrounding Gusev Crater, the site of Spirit's landing. Opportunity's terrain is darker than at any previous Mars landing site and has the first accessible bedrock outcropping ever seen on Mars. The surface appears smoother and flatter than the other side of the planet, and the soil seems to contain large deposits of hematite, a mineral that typically forms in marine or volcanic environments.

"I am flabbergasted. I am astonished. I am blown away. Opportunity has touched down in an alien and bizarre landscape," Mr. Squyres said. "I still don't know what we're looking at."

He and the rover team won't get a closer look for 10 to 14 days, while engineers prepare the craft to roll off its landing platform. They hope eventually to steer Opportunity about a half-mile across the flat wasteland to a larger, deeper crater nearby.

Meanwhile, half a world away, the Spirit rover continued to sit idle while scientists worked frantically to fix a problem that all but cut off communications on Jan. 21. When Spirit initially began sending back short, garbled messages, NASA suspected a fatal flaw such as broken hardware or damage from solar radiation. After nearly a week of testing, however, project manager Pete Theisinger said the problem seemed to originate in the rover's software, meaning that new programming messages sent from computers on Earth might get the vehicle rolling again about the same time as Opportunity.

The $820 million Mars exploration program is seen as a key test of NASA's expertise-and, perhaps more importantly, President Bush's ambitious long-range plans in outer space.