European probe set for first-ever comet landing

European probe set for first-ever comet landing

12th November 2014, Comments 0 comments

After a trek of more than a decade, covering 6.

5 billion kilometres (four billion miles), a mini lab called Philae separated on schedule from its mother ship Rosetta.

.

Philae was placed on a trajectory to land on 67P/Churyumov-Gerasimenko, a comet now more than 510 million kilometres (320 million miles) from Earth and racing towards the Sun.

.

"The Philae lander has separated from the Rosetta orbiter, and is now on its way to becoming the first spacecraft to touch down on a comet," the European Space Agency (ESA) said.

.

Scientists faced a seven-hour wait to see if the bet comes off, their nerves stretched by a non-fatal, last-minute glitch.

.

Comets are believed to be clusters of primordial ice and carbon dust left over from the building of the Solar System.

.

They are doomed to circle the Sun in orbits that can range from a few years to millennia.

.

A 100-kilogramme (220-pound) robot lab, Philae was designed to piggyback comet "67P" and probe its chemistry and structure with 10 instruments.

.

If all goes well, Earth will receive a signal at about 1600 GMT Wednesday saying Philae has landed.

.

"The die is cast," ESA director general Jean-Jacques Dordain told journalists.

.

"Philae has to land - we can't do anything more about it.

""Now, it's down to the laws of physics.

We're on the way to the surface," added ESA's senior science advisor, Mark McCaughrean.

.

"I don't have finger nails, so I won't be biting them," he quipped.



Risky landing

Philae is meant to settle down at a gentle 3.

5 kilometres per hour, firing two harpoons into a surface that engineers fervently hope will provide enough grip.

Ice screws at the end of its three legs will be driven into the low-gravity comet to stop the probe bouncing back into space.

.

A final check found an apparent malfunction with a small gas thruster on top of Philae which was supposed to fire at the same time and provide a downward push, said Stephan Ulamec with the German aerospace firm DLR.

.

"We are going to have to depend entirely on the harpoons," which depending on the surface can penetrate to 2.

5 metres (more than eight feet), Ulamec said.

The EUR 1.

3 billion (USD 1.

6 billion) mission was approved in 1993.

.

Rosetta, carrying Philae, was hoisted into space in 2004, and took more than a decade to reach its target in August this year, having used the gravitational pull of Earth and Mars as slingshots to build up speed.

.

Turning slowly around "67P" ever since, Rosetta has made some astonishing observations.

The comet's profile somewhat resembles that of a rubber bath duck - but darker than the blackest coal, and a surface gnarled and battered by billions of years in space.

It has a treacherous, irregular surface, with crags, cliffs and rocks - an extremely difficult target to land on.

.

The big test will be for Philae to settle down safely as Rosetta and 67P zip towards the Sun at a breakneck 18 kilometres per second (11 miles per second).

.

If it comes to grief, scientists will be hugely disappointed although they note that Philae accounts for only about a fifth of the mission's total expected data haul.

.

Rosetta will continue to escort the comet, scanning it with 11 instruments, as it loops around the Sun and makes its closest approach next year.

.

"We know that it's a risky business, but the potential gain is so great," Jean-Pierre Bibring, in charge of Philae's scientific operations, told AFP.

.

According to a leading theory, comets pounded the fledgling Earth 4.

6 billion years ago, providing it with carbon molecules and precious water - part of the tool kit for life.

.

.


© 2014 AFP

0 Comments To This Article