NASA's Phoenix probe landed gently near the north pole of Mars. After a 679-million-kilometre voyage from Earth, it set down at the exact minute engineers had predicted before its August 4 launch.

Scientists hope Phoenix, only the sixth probe to safely reach the Martian surface, will use its 2.3-metre robot arm to scratch red planet's surface and find ice.

Launched on Aug. 4, 2007, Phoenix landed farther north than any previous mission to Mars, at a site expected to have frozen water mixed with soil just below the surface. The lander will use a robotic arm to put samples of soil and ice into laboratory instruments. The arm is designed to scoop up the ice and melt it in one of eight tiny ovens.

While Phoenix is not designed to directly seek life, scientists hope that by analysing soil samples the robot explorer will be able to determine whether Mars has, or has ever had, the chemistry - and the water - needed to support life as we know it. Half a world away, NASA scientists were just as excited as those in Tidbinbilla. "In my dreams, it couldn't have gone as perfect," said the Phoenix project manager, Barry Goldstein.

Some scientists had predicted Phoenix would spot traces of carbon dioxide ice and snow on the surface, left over from the last Martian winter.

The 410-kilogram solar-powered Phoenix set down close to its target, at a latitude similar to Greenland or far northern Canada. Expected to operate for three months, it is almost identical another probe that crashed in 1999 while trying to land near the Martian south pole.