FOR over a century, people world over had been intrigued by possibility of life on Mars and science fiction writers and astronomers added to their curiosity. The back-to-back missions to the Red Planet-----European Space Agency's first attempt in the Beagle 2 and NASA's Rovers Spirit and Opportunity-----have once again turned the world attention on probing such a possibility.

Of the nearly three dozen expeditions to Mars-----the mythological god of war-----over two-third have failed in their quest to win over the Red planet, the latest to join the list of failures being Beagle 2.

The successful landing of NASA's spacecraft to Mars and the subsequent pictures of the Martian landscape sent back to the earth by Rover Spirit have generated quite an excitement among the scientists and the common man alike.

"We aim to look for water. If you find it there, the chances of life on Mars brighten considerably," Amitabh Ghosh, planetary geologist with NASA, said.

Ghosh, in India on an invitation from the National Geographic Channel, however, offers a word of caution. "It's too early to say anything. Once we get a detailed analysis from the spectrometers aboard the spacecraft, things will be clearer," he says.

The speculation of life on the Red planet has its moorings in the late 19th century when Italian astronomer Giovanni Schiaparelli first mapped the Martian landscape using a telescope.

Schiaparelli's maps, in 1877, showed the presence of canali (channels in Italian) on the Martian landscape and here began the fantasy of finding a civilisation on the earth's neighbour.

Percival Lowell's book Mars As Abode to Life, published in 1910, furthered the myth of civilisation on the Red planet. His book, depicting Mars as a dying planet home to a civilisation, captured the public imagination.

Based on his visual observation, Lowell painted a vivid picture of the Red planet and its inhabitants who had constructed the vast canal system to bring water from the polar region to their fields along the Martian equator for irrigation purposes.

The expeditions to Mars by the United States and the then Union of Soviet Socialist Republics too conclusively mixed the canal theory put forth by Schiaparelli and Lowell by sending images of the cratered Martian surface.

The Viking Experiments carried out by NASA in 1976 on the Red planet threw up conflicting results and fuelled the debate of life on Mars.

"The successful landing of Spirit is definitely an incredible achievement, particularly since the missions way to Mars is so challenging that many expeditions have failed," Ghosh says.

The debate on existence of life on Mars got a further boost when in 1996 scientists declared to have found ancient bacterial forms on a meteorite purportedly from the Red Planet.

The meteorite------ALH84001------found in Antarctica in 1984 showed presence of bacterial fossils and revived the debate on origin of life from space.

Indians too contributed to this debate with astrophysicist Jayant Naralikar along with his Sri Lankan colleague conducting experiment to prove that seeds of life were sown from outer space.

The Martian neighbourhood, with five spacecraft in its vicinity ----- European Space Agency's Mars Express, it's pillion rider Beagle 2, NASA's two Rovers Spirit, and Opportunity with a scheduled January 25 landing ----- would become a crowded Place by this month-end.