AN ANOMALY IN the night sky, a reddish dot in a galaxy of silvery stars. The closest celestial body to Earth and our moon it may be, but the red planet remains a mystery that may - or may not - hold a key to our existential ponderings. We would seem to need Mars, and the answers it may conceal, more than it needs us.
The next few weeks are the most crucial in mankind's quest to better understand the planet, and thereby better understand ourselves. If the three craft hurtling towards it - Europe's Mars Express and two rovers from the National Aeronautics and Space Administration (Nasa) - touch down successfully, they are designed to provide the most revealing answers yet about the history of our galactic cousin. In doing so, they hope to answer the brightest-burning question of all: Was Mars ever capable of sustaining life?
If so, a galaxy of more searching questions materialises. With its polar ice caps, gargantuan canyons, volcanoes and supposed river beds, it's the most similar topographic match to Earth in our solar system. So if Mars once sustained life, how did it then die out? If a meteor strike really did wipe out the dinosaurs on Earth, could the same thing have happened to a race of beings on Mars, too? And as species after species continues to die out during our own, extremely short habitation of the Earth, does the arid, radioactive wasteland of Mars serve as a warning of what might become of us?
Since the killjoy Viking Landers in 1976 put paid to any wild fantasies about green Martian meanies, public interest withered - only to be seriously rekindled 21 years later when Nasa's 1997 Pathfinder mission marked our return.
Things may now reach fever pitch in a few days, if Europe's Beagle 2 Lander (which contains Hong Kong parts) makes it to the surface for an anticipated Christmas Day touchdown. Nasa's two Mars Exploration Rovers will follow. They are the first robots sent to Mars equipped to perform as field geologists with inbuilt spectrometers, panoramic cameras, a rock hammer and a cutting tool.
'If you want to read about the path of a planet, you read its rocks,' says Firouz Naderi, manager of Nasa's Mars exploration programme. Its two robot geologists, named Spirit and Opportunity, will land at different sites on January 4 and 25, respectively. 'Opportunity is aimed at a site called Meridiani Planum, a location known to have large deposits of grey haematite, a mineral that usually forms in a wet environment,' says Naderi. 'Spirit is going to Gusev Crater, which may once have held a lake.'