First results from the unmanned spacecraft Mars Express sketched the vision of a planet whose surface was once sculpted by seas and glaciers and confirms indications that its South Pole is capped by frozen water.

That boosts hopes that big reserves of ice may lie beneath the surface, providing fuel and sustenance for a future manned mission, European Space Agency (ESA) officials said.

The agency's scientists were cock-a-hoop, for the instrument-packed orbiter only took up position off Mars on December 25 and the mission was struggling to overcome the disappearance of a small lander, Beagle 2.

"We have identified water ice on the South Pole," ESA scientist Vittorio Formisano, declared.

The ice is not covered by frozen carbon dioxide (CO2), unlike the Martian North Pole, where US spacecraft have detected a mixture of CO2 and frozen water.

And, said astrophycist Jean-Pierre Bibring, every indication was that the newly-found ice was year-round and did not come and go with the Martian summer and winter.

NASA's Mars Odyssey orbiter, in March 2002, gave strong indications that there was water ice on the southern pole.

It used a gammma ray spectrometer, which detected hydrogen, which with oxygen makes up water.

Mars Express' data amounts to a confirmation, for it arrives at the same conclusion but by a different technique: a spectrometer that analyses visible and infrared light rather than the gamma part of the energy spectrum.

Its instrument, Omega, uses as its source sunlight that is reflected from the planet's surface and atmosphere.

Other images sent back by Mars Express add meat to skeletal evidence that billions of years ago Mars was awash with water.

But as the planet cooled, the surface water froze or evaporated into space through a thinning atmosphere, the theory goes.

However, some may have remained frozen in the soil or trapped in underground reservoirs, as well as at the poles, according to this notion.

High-resolution images taken by a sophisticated camera of 1.87 million square kilometers (0.75 million sq. miles) "confirms the former occurrence and erosional activity" of water on the Martian surface, said ESA scientist Gerhard Neukum.

A large crater, Hecates Tholus, also showed signs of past glaciation, he said.

Meanwhile, Nasa's Mars probe Spirit has stopped sending data back to Earth following what the US space agency on Thursday called a serious breakdown.

"We have a very serious anomaly on the vehicle," said Pete Theisinger, project manager for the Mars Exploration Rover mission.

The communications breakdown came as the National Aeronautics and Space Administration prepared for the arrival on Mars this weekend of the second exploration rover, Opportunity.

Nasa said Wednesday that thunder and lightning storms over Australia had prevented scientists from sending Spirit its daily instructions.

But experts now think a more serious problem caused the blackout, possibly a glitch in the computer software that controls Spirit's transmissions to Earth.

Theisinger said Nasa experts had sent a command to Spirit on Thursday but are not sure if they got an acknowledgement.