A British probe the size of an open umbrella was due to land on Mars tomorrow and start trying to answer a question which has fascinated mankind for centuries - is there life on the red planet?
Beagle 2, which weighs just 34 kg, is scheduled to open its panoply of parachutes and airbags and float down to the surface of Mars just before 3.00 a.m. on Christmas Day.
The probe will emit a call sign - a tune composed especially for the occasion by British pop group Blur - which scientists hope to pick up on powerful radios aboard a pair of mission rockets orbiting the planet.
The signal will be relayed to earth where the mission's organisers will be praying in the silent hours for a smooth landing of the craft named for the ship which British naturalist Charles Darwin took to gather the scientific data that formed the basis of his groundbreaking 19th century treatise on evolution: "The Origin of Species".
"We've had no way of monitoring Beagle 2 since it was launched from Mars Express last week," said Mr Peter Barratt, head of communications for the Beagle 2 team. "But as far as we know it's on schedule and all is going to plan."
The probe still faces many potential pitfalls, including huge dust storms sweeping the surface of the volatile planet, 100 million km from earth.
If Beagle 2's parachutes open too soon the tiny craft could be blown away. Too late, and the probe risks ending its life as scrap metal strewn across the forbidding Martian landscape.
Assuming the mission is successful, Beagle 2 will start work straight away. It has an estimated maximum operational life of just 180 days before Martian dust and extremes of temperature are expected to put it out of action.