US: A second US robot rover crashed through the atmosphere of Mars early yesterday at 19,000 kph and bounced to a standstill in a region called the Meridiani Planum.
The arrival makes Mars a relatively crowded place. There are already three satellites in orbit around the planet and the six-wheeled rover Opportunity was the third landing on Mars since Christmas Day.
The first, the British Beagle 2, has been silent since its arrival at a plain called Isidis.
The second, Spirit, a twin of Opportunity, made a successful landing on January 4th at a place called the Gusev crater, but ran into serious communication problems on Wednesday.
On Friday, it began to transmit again, giving engineers enough evidence to identify a software flaw which they hope to correct. But this could take weeks.
So the successful landing of Opportunity was greeted with more than the usual jubilation.
In the last four decades more than half of all missions to Mars have come to grief.
To make a safe landing, Opportunity had to hit the Martian atmosphere at just the right angle, survive a sudden burst of intense heat as it ploughed through the thin air of the planet, open a parachute, then fire a set of retro-rockets, and finally inflate a set of airbags to cushion its impact with the arid rocks of Mars.
One engineer called such a descent "six minutes of terror".
Then the rover had to settle the right way up, flip away its inflated cocoon, unfold its solar panels, and prepare to send a postcard home to mission control 160 million kilometres away in Pasadena, California.
"I came here prepared for a funeral," said Mr Ed Weiler, second in command at NASA.
"Talk about a rollercoaster ride: I saw the resurrection of one rover and the birth of another."
Like Spirit before it, Opportunity will stay on its landing platform, gathering up solar energy and checking its faculties before trundling off with its stereoscopic, eye-level camera and geological tools to investigate its new home and look for evidence of water on the parched planet.
The Americans chose the Gusev touchdown because it looked like an old lake bed.
They selected Meridiani because it seemed to be rich in the mineral haematite, normally linked with water.
But the two rovers are, in effect, only geologists.
Water is a prerequisite for life, but neither Spirit nor Opportunity is designed to look for signs of life.
Beagle 2, put together by a British consortium led by the Open University's Prof Colin Pillinger, would have been the first working biologist on Mars.
It was the first robot specifically engineered to probe beneath the Martian surface to "sniff" for telltale organic chemicals usually linked with life.
Mission scientists have not yet entirely given up hope, but its silence has been a cruel blow.
The pain was softened a little on Friday, however, by the first data from Beagle's mothership, Mars Express, which has begun to send back stunning images of the planet. It has also begun a search for water by radar and other sensing instruments. -(Guardian Service)