Nasa and Microsoft launched an interactive website on Tuesday that allows web surfers to become Mars explorers.

The "Be a Martian" website invites members of the public to help scientists perform such research tasks as improving maps of the red planet, the US space agency and US software giant said.

"We're at a point in history where everyone can be an explorer," Doug McCuistion, director of Nasa's Mars Exploration Programme, said in a statement.

"With so much data coming back from Mars missions that are accessible by all, exploring Mars has become a shared human endeavour," Dr McCuistion said.

"People worldwide can expand the specialized efforts of a few hundred Mars mission team members and make authentic contributions of their own," he said. Users can, for example, count craters on Mars, a task Nasa said had posed a challenge in the past because of the vast numbers involved.

"The collaboration of thousands of participants could help scientists produce far better maps," Nasa and Microsoft said.

"There's so much data coming back from Mars. Having a wider crowd look at the data, classify it and help understand its meaning is very important," said Michelle Viotti, director of Mars Public Outreach at Nasa's Jet Propulsion Laboratory. "And we're also accomplishing something important for Nasa."

"The beauty of this type of experience is that it not only teaches people about Mars and the work Nasa is doing there, but it also engages large groups of people to help solve real challenges that computers cannot solve by themselves," said Marc Mercuri, a Microsoft director of business innovation.