Nasa's two identical Mars Exploration Rovers also blast off carrying $150m, six-wheeled "Opportunity" and "Spirit" rovers to explore the Martian surface.

The first Japanese Mars orbiter, Nozomi, will also reach Mars after a four-and-a-half-year voyage from Earth.

December 2003/January 2004

December 2003/January 2004 Mars Express and the two Mars rovers arrive at their destination, but contact is lost with the Beagle probe as it attempts to land.

Japan's Nozomi probe is also abandoned as it approaches Mars, following a string of technical problems.

After successful touch downs, the twin Mars rovers roll out and begin sending back clear images of the surface. Shortly after landing, Opportunity finds layered bedrock bearing geological evidence of a shallow ancient sea.