The ESA has succeeded in humanity’s first ever attempt to land a man-made probe on a comet after Philae touched down on the surface of Comet 67P/Churyumov-Gerasimenko.
“Yes, yes, YES!” said Andrea Accamazzo, Rosetta flight director. “We see the lander sitting on the ground!”
After a tense build-up, the European Space Agency’s operations control erupted in cheers when they got the confirmation that Philae had managed its passive landing on the surface of the space-rock, currently hurtling through space over 500 million kilometres from Earth.
It was all out of the scientists’ hands after 7am GMT this morning, when the last checks were done and the time-lagged commands were uploaded to both Rosetta and Philae to go ahead with the separation and the landing attempt.
The agency decided to try for the effort despite the failure of the cold gas system, which was supposed to fire the thruster on top of Philae to counteract the recoil from the firing of the craft’s harpoons. In the event, Philae managed to harpoon the space-rock anyway, drawing itself in to land on its three ice-stem feet, which then drilled in to further anchor it in position.
"Philae is talking to us, the first thing he told us is that the harpoons fired and the landing gear has been retracted. He’s there and Philae is talking to us!” Philae lander manager Dr Stephan Ulemac of Germany's space agency DLR added.
The historic feat is the culmination of decades of planning, including ten years spent just getting Rosetta to reach the comet in the first place.
Cheers and hugs in operations control quickly calmed as the boffins got back to work, since the Philae lander now has just 64 hours to deploy its ten scientific instruments into getting as much data as possible from the space-rock before its batteries run down. The fridge-sized bot is equipped with solar cells, but scientists are unsure if the cells will be able to charge or if conditions on the surface will stop the lander from soaking up any rays.
For that reason, Philae will try to fit as much exploration and discovery as it can into its few days on Comet 67P, analysing the surface, drilling down 23cm for samples and hopefully helping boffins to answer the question of whether life on Earth was seeded by comets from space.
“We know that comets produce organic molecules, such as amino acids and peptides. The big question is whether they formed inside the nucleus of the comet and then evaporated, or formed through photochemical reactions on dust in the tail,” Professor John Plane of the atmospheric and planetary chemistry group at the University of Leeds explained.
“If the former, then these relatively fragile molecules could have survived entry to the Earth’s atmosphere inside comets that made glancing impacts. If the latter, they would probably have been destroyed as shooting stars on entry.
“The really big result will be if Rosetta’s landing probedetects ‘chiral amino acids’ - amino acid molecules of identical composition but mirror images of each other - of which only one chiral form is found in biological systems on Earth.”
Even if Philae manages to recharge its batteries, a deadlier trial awaits the plucky bot sometime between March and August next year, when the comet makes its closest approach to the Sun, which could toast both the lander and its Rosetta satellite companion. If either of the pair survive this brush with fiery doom – and assuming the comet doesn’t break up in the mean time - the mission will end in December next year. ®