8 November 2007
Comets are the building blocks from which planets formed and hold vital clues to how life appeared on Earth
Philae, the Rosetta mission’s lander, will hunt for such clues when it touches down and analyses the composition of its target comet in 2014.
To accomplish its mission, Philae is carrying a science instrument called SD2 capable of drilling down to 40 cm beneath the comet’s surface.
Drilling below the surface will allow Philae to reach the pristine materials inside the comet, where they will have been altered much less by solar radiation.
Scientists are therefore hoping that retrieved samples of cometary material will be extremely well preserved.
Philae’s drill ready for action
To collect these samples, Philae’s “drill” will need to be in perfect shape after a 10-year odyssey in the ice-cold vacuum of space.
So, from 24 to 30 September, the Rosetta Science Operations and Navigation Centre at the Toulouse Space Centre put the drill through its paces.
According to Philippe Gaudon, project leader in charge of Rosetta/Philae activities at CNES, “Everything went to plan when we switched on and revved up SD2’s drill after more than 3 years in space. Tests confirmed that the instrument is capable of withstanding very low temperatures (–100°C) without seizing up and that we will be able to collect and compare samples of comet material from different depths.”
On course for comet rendezvous
The European Space Operations Centre (ESOC) in Darmstadt, Germany, performed a minor trajectory correction manoeuvre on 18 October to give Rosetta a maximum boost from its Earth swingby on 13 November.
Rosetta and Philae will make their closest approach to Earth on 13 November at 21:57 CET, flying over the Pacific Ocean at an altitude of 5,300 km and a relative speed of 45,000 kph.
Rosetta’s OSIRIS camera is set to record the event and take pictures of the Earth-Moon system.
After the flyby, Rosetta will continue its journey toward the asteroid belt where it will pass within 800 km of asteroid Steins on 5 September 2008, before returning to Earth for a final gravity assist in November 2009.