Scientists send a probe to land on a comet

AFTER a decade-long, $1.83 billion pursuit across the solar system, the wait is finally over. One of the most audacious space missions ever is upon us.

AFTER a decade-long, $A1.83 billion pursuit across the solar system, the wait is finally over.

A probe will attempt to land on a comet 506 million kilometres away in one of the most audacious space missions ever attempted.

Scientists at the European Space Agency will watch for seven hours as Philae – a craft the size of a dishwasher – slowly descends on to the lump of rock and ice known as 67P/Churyumov–Gerasimenko.

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Given a glimpse....The picture was taken with the navigation camera on Rosetta and shows the boulder-strewn neck region of Comet 67P/Churyumov–Gerasimenko. Picture: AP Photo/ESA

Rosetta providing us with insights....The picture also taken with the navigation camera on Rosetta shows a raised plateau on the larger lobe of Comet 67P/Churyumov–Gerasimenko. Picture: AP Photo/ESA

The probe will be dropped at 8.35am UK time by Rosetta, a carrier craft that blasted off from Earth in March 2004 and has travelled 6.43 billion kilometres.

It is due to touch down at 3.30pm – but a radio message confirming the landing will not arrive until 4pm, having taken half an hour to travel through space. All the while Rosetta and the comet will have been flying in tandem at 41,000mph between Mars and Jupiter’s orbits.

Getting ready...Scientists at the European Space Agency are making final preparations to land the first spacecraft on a comet next week. Picture: AP/dpa, Boris Roessler

The probe is primed to find information about the origins of the solar system by taking samples with an array of sensors, cameras and drills.

There is no guarantee the landing will succeed. Engineers will not be able to control Philae’s descent, meaning Rosetta has to be in perfect position prior to the 13-mile drop. If their calculations are wrong, scientists will be powerless to do anything but watch as the machine floats off into space. Mission director Paolo Ferri told the Mail, “Imagine the comet as Mont Blanc”.

“You fly with an aircraft at 13.6 miles (21.8 kilometres) in altitude – so twice the altitude of a normal airline. At a certain point you have to drop a box and hope that it lands on the mountain within a square kilometre.”

Will it work...The Rosetta mission poster which illustrates the deployment of the Philae lander to comet 67P/Churyumov–Gerasimenko. Picture: AP Photo/ESA

José Luis Pellon-Bailon, one of eight flight engineers responsible for the descent, said “Landing on a comet is a first, and it’s a very delicate operation – it will be very emotional”.

After its launch, Rosetta had to swing around Earth three times – and Mars once – to gain enough speed to chase down the comet. It reached the icy rock in August.

The vast distance means the European Space Agency has to rely on Nasa’s deep space network of giant radio antennas to communicate with Rosetta. Philae will send back data until next March, when the heat as the comet approaches the Sun will finally burn it out. Rosetta will orbit the comet until the end of next year.