Spirit 'upgraded from critical to serious'

Opportunity, the second of NASA's twin rovers, has made the descent to the surface of Mars, touching down successfully at 0505 GMT Sunday (12:05 a.m. ET). NASA now has two rovers on the ground, after Spirit landed on the red planet exactly three weeks ago on January 3. Though Spirit's landing was near perfect, the rover mission has had serious complications in recent days. Dampened by the problems with Spirit, it had been a nervous few moments at mission control as NASA officials counted down and checked off the various descent maneuvers during what appeared to be a flawless six-minute sequence. As planned, the airbag-encased craft bounced on the Martian surface and rolled gently for a few minutes before coming to a complete stop upside down. NASA was awaiting further signals and communications from Opportunity, including images of the landing site. There were "no fault tones" detected in the radio signals back to Earth, suggesting that the spacecraft arrived in good shape on Mars, a mission control official said. Moments after the landing, California Gov. Arnold Schwarzenegger and former Vice President Al Gore walked through mission control to congratulate the workers there.