Thrilled NASA scientists received the first color pictures of the Martian surface from the rover Opportunity on Monday, as engineers worked feverishly to bring its ailing twin Spirit back to health.

British scientists said meanwhile that renewed attempts over the weekend had failed to establish contact with the Beagle 2 probe, which is supposed to have landed on the Red Planet on Christmas Day but has not been heard from.

Opportunity bounced to a stop on Mars at 0505 GMT Sunday inside a small crater in an area known as the Meridiani Planum, believed to be the flattest place on the planet. Scientists declared the probe in good health Monday after an equipment check.

All of Opportunity’s systems “are in perfect health” after engineers carried out the robot’s “first health check” on Sunday, scientific director Steve Squyres told reporters.

NASA also released a high-definition color postcard snapped by Opportunity’s panoramic camera showing dark red soil and the rim of a crater.

“The crater is not bigger than this room,” said Squyres, gesturing to the room in which reporters had gathered.

Jim Bell, the engineer in charge of the team running the panoramic camera, described it as “the darkest landing site where we have ever been on Mars.”

The picture, taken from the robot’s back, shows a “pretty spectacular landscape, a wonderful area for geologists,” according to Bell.

As soon as it landed on Mars, Opportunity beamed to Earth black-and-white images along with low definition color pictures.

“I am flabbergasted, I’m astonished, I’m blown away,” Squyres, 47, said upon observing the the first Opportunity images.

Squyres, a professor at Cornell University in New York state, was especially excited about the rover’s proximity to a rock outcropping that seemed very promising to geologists. Reaching this outcropping will be Opportunity’s first mission.

The outcropping is scientifically important because, unlike stones that can come from elsewhere, they are historically linked to their location, he said.

Opportunity will take about 12 days getting ready to roll off its platform to its first mission, NASA officials said.

Opportunity’s identical twin Spirit landed on Mars on January 3 but developed communications problems last Wednesday. However the robot “is doing better,” said Jennifer Trosper, in charge of surface operations for the Mars Rover Exploration missions.

According to Trosper, a software “bug” probably corrupted programs that manage files, preventing data collected by the robot from being transmitted to Earth.

“The problem that we had is associate with our ability to collect and maintain recorded data to the flash memory where we stored the data,” said Trosper. “We don’t know yet whether Spirit will be perfect again.”

Trosper believes it will take engineers two to three weeks of work before they can get Spirit operational again.

Both Opportunity and Spirit have six wheels and weigh some 180 kilos (384 pounds). They are equipped with four instruments designed to carry out geological studies as well as a powerful drills.

Their mission is to study the geology of Mars for three months, and try to determine if the conditions necessary to life existed there.

The Meridiani Planum, where Opportunity landed, is a zone of grey hematite, an iron oxide.

Scientists plan to use Opportunity’s instruments to determine whether the grey hematite layer comes from a former ocean’s sediment, from volcanic deposits altered by hot water or from other ancient environmental conditions.

While NASA scientists celebrated the promising start to the Opportunity mission, there was bad news for the British-built Beagle 2.

The European orbiter Mars Express tried over the weekend to make contact with the pint-sized craft following a 10-day period of radio silence meant to make Beagle 2 switch into emergency transmitting mode.

But Colin Pillinger, lead scientist of the Beagle 2 mission, told reporters in London the attempt had failed.

“We have to begin to accept that Beagle, if it is on the Martian surface, is not active,” Pillinger said.

“That’s not to say we are going to give up,” he said, adding that the NASA spacecraft Odyssey would try to hail Beagle 2 on Tuesday. Odyssey is the parent ship of Spirit and Opportunity.