Photographs give thrilled scientists amazing view of life on Mars

SCIENTISTS marvelled at crisp photographs of the surface of Mars while the NASA rover that snapped them switched from black-and-white to colour as it continued to send back images of the pancake-flat plain where it landed.

NASA last night released the initial batch of colour photos the first from the surface of Mars in seven years. NASA began receiving its second batch of black-and-white pictures from its Spirit rover late on Sunday.

The new images showed further details of what scientists believe is the rocky bed of an ancient lake that may have once harboured life.

The golf cart-sized Spirit landed on Mars on Saturday, safely returning NASA to the planet's surface for the first time since the 1997 Pathfinder mission.

Just three hours after the unmanned robot landed, it began zipping the first black-and-white images of its surroundings to Earth, 106 million miles distant at the time.

"It was so gorgeous to see the horizon in the pictures. It's what we'd been imagining for so long," said Julie Townsend, a mission avionics engineer.

The first images from Spirit show a flat, wind-scoured plain peppered with small rocks, none more than a foot high. The scene enthused scientists, eager to send the rover prospecting among the rocks for evidence that the landing site was once awash in water.

"It's all stunning, it's all new and it's all different," said Wendy Calvin, of the University of Nevada, a scientist on the mission.

Ms Calvin said the terrain appeared flatter and featured fewer and smaller rocks than the sites that Pathfinder and, in 1976, the twin Viking landers visited.

"I see a race track where we can drive for metres and metres and metres," Ms Calvin said.

On Sunday, NASA successfully established a link from Earth with Spirit's high-gain antenna. That link allows NASA to shuttle data directly between Spirit and Earth at transmission rates greater than 11,000 bits per second about one-fifth the rate of a 56K dial-up connection to the internet on Earth.

Spirit's fastest connection, at 128K, is expected to be through its UHF antenna. The antenna transmits data to the Mars Global Surveyor and 2001 Mars Odyssey spacecraft for later relay to Earth. The two satellites are in orbit around Mars.

The $820 million NASA Mars Exploration Rover project also includes a twin golf cart-sized rover, Opportunity, set to reach the opposite side of Mars from its sibling on January 24.