Nasa's Maven probe to study why Mars atmosphere changed over time

Nasa hopes its newest Mars spacecraft lives up to its know-it-all name.

The robotic explorer, called Maven, is due to blast off today on a 10-month journey to the red planet. There, it will orbit Mars and study the atmosphere to try to understand how the planet morphed from warm and wet to cold and dry.

"A maven is a trusted expert," said Nasa's space science chief, John Grunsfeld. Maven will help scientists "build a story of the Mars atmosphere and help future human explorers who journey to Mars", he added. The US$671 million mission is Nasa's 21st crack at earth's most enticing neighbour, coming on the heels of the Curiosity rover, still going strong a year after its grand Martian arrival.

When Maven reaches Mars next September, it will join three functioning spacecraft, two US and one European. An Indian orbiter also will be arriving at about the same time.

Maven will be the 10th orbiter to be launched to Mars by Nasa; three have failed, testimony to the difficulty of the task.

"No other planet, other than perhaps earth, has held the attention of people around the world [like] Mars," Grunsfeld said.