Washington: NASA has lost contact with the US robotic probe on Mars, Spirit, because of a serious breakdown, space agency officials said today (Jan 23, 2004).

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

The National Aeronautics and Space Administration said yesterday 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.

Spirit arrived on Mars on January 3 and started searching for signs of past life on the red planet last week.

Its twin rover, Opportunity, was due to touch down overnight January 24-25. The $ 820 million mission expects each solar-powered robot to keep working for about three months.