'It's got to work'

It is the first spacecraft to head there since an embarrassing double failure two years ago but Nasa commentator Joel Wells called Odyssey's lift-off "a flawless launch."

The £208m spaceship, about the size of a compact car, took off from Cape Canaveral in Florida to begin a 286 million-mile odyssey to Mars. It will search the planet for water, hoping to determine if life ever existed there. It will also lay the foundations for robotic rovers due to land in 2003 and assess radiation levels to decide if astronauts can ever land safely.

In 1999 boffins confused imperial and metric measurements for the Mars Polar Lander, leaving it to crash straight into the planet it was supposed to be taking pictures of. The Mars Climate Orbiter mission also failed that year.

Nasa's Ed Weiler said: "I don't know what more we could do to make a successful Mars mission." Odyssey's project manager, George Pace, added: "It's got to work." But despite all 220,000 of Odyssey's measurements being double- and even triple-checked, the odds are not good - only 40 per cent of all missions to Mars have succeeded.