The European Space Agency's Mars Express has blasted off from Russia's Baikonur space base.
The mission is said to be the most thorough investigation of planet Mars to date.
The Mars Express, the latest in a list of mostly unsuccessful missions to the planet, will carry the Beagle 2 space probe into orbit aboard a Soyuz-Fregat rocket.
Arrival on Mars is scheduled for December 2003.
