THE Americans regained the upper hand in the Mars exploration race yesterday with the safe landing of their second rover, two days after its European rival claimed its orbiter had found water for the first time.
The arrival of Opportunity came as a further boost for the National Aeronautics and Space Administration (NASA) after it re-established contact with the Spirit rover, which is already on Mars.
"We’re on Mars everybody," Rob Manning, manager of the entry, descent and landing portion of the Mars mission, shouted as fellow scientists at NASA’s jet propulsion laboratory (JPL) in Pasadena, California, burst into wild applause.
Minutes after the landing, the former vice-president, Al Gore, and the governor of California, Arnold Schwarzenegger, strode through mission control at the JPL, shaking hands with elated scientists.
Together, the twin rovers make up a single 455 million mission to determine if Mars ever had enough water to sustain life.
NASA launched Spirit on 10 June. Opportunity followed on 7 July.
The six-wheeled, golf buggy-sized Opportunity landed on the opposite side of the Red Planet to its twin. Four hours later, it was beaming back the first stream of pictures of its new terrain - the smooth, flat plain of Meridiani Planum.
Opportunity is 6,600 miles from Spirit, which landed three weeks ago at Gusev crater, believed to have once contained a lake.
The landscape is believed to contain grey hematite, an iron-bearing mineral which forms in marine or volcanic environments rich in water.
Sean O’Keefe, NASA’s administrator, said no-one had dared hope that both rover landings would be so successful.
Officials are also optimistic that they will enable Spirit to continue with its explorations after it started sending unintelligible messages back to Earth last Wednesday. Scientists have disabled the computer’s memory on the rover, and started receiving limited data again on Friday.
However, while they now describe Spirit’s condition as "serious" rather than "critical", the cause of the problem has still not been found and it could be up to three weeks until the rover can go for another drive on the Martian surface. Charles Elachi, the JPL director, said: "I am completely confident, without any hesitation, that I think we will get that rover back to full operation."
Meanwhile, the leaders of the Beagle 2 mission will announce today whether Mars Express has picked up any signals from the lost probe during two sweeps of its landing site at the weekend.