— Ch. 1 · Mission Genesis And Launch —
Philae (spacecraft).
~4 min read · Ch. 1 of 6
The European Space Agency launched the Philae lander from French Guiana on the 2nd of March 2004 at 07:17 UTC. This Ariane 5G+ rocket carried both the Rosetta orbiter and the Philae probe into space for a journey lasting 3,907 days. The original target was comet 46P/Wirtanen, but a launch failure in 2003 forced mission planners to switch targets. They selected 67P/Churyumov, Gerasimenko instead, which required significant engineering changes to the landing gear due to its larger mass. Scientists hoped the new target would allow them to study cometary material up close without destroying it like previous impact missions. The spacecraft traveled through deep space for over ten years before reaching their destination in August 2014.
The Bouncing Landing Event
Philae touched down on the 12th of November 2014 at 15:34:04 UTC SCET after a twenty-eight-minute signal delay reached Earth. The anchoring harpoons failed to deploy because the nitrocellulose charge inside them proved unreliable in vacuum conditions. A thruster designed to hold the probe against the surface also did not fire as planned. The lander rebounded off the ground and rose to an altitude of approximately one kilometer before falling back. It struck a surface prominence during the first bounce, slowing rotation from every thirteen seconds to once every twenty-four seconds. The craft bounced twice more before coming to rest at 17:31:17 UTC SCET. Final analysis showed the initial impact was softer than expected but left Philae wedged in rough terrain at a thirty-degree angle.