The European Space Agency's unmanned Rosetta probe successfully released a lander toward the surface of comet 67P/Churyumov-Gerasimenko on Wednesday, putting on its final seven-hour journey to a historic rendezvous with the fast-moving lump of dust and ice, AP reported. The audacious landing attempt is the climax of a decade-long mission to study the 4-kilometer (2.5-mile) wide comet. It is also the end of a 6.4 billion-kilometer (4 billion-mile) journey on which Rosetta carried its sidekick lander Philae piggyback. If successful, it will be the first time that a spacecraft has landed on a comet. ESA announced early Wednesday that the 100-kilogram (220-pound) lander's active descent system, which uses thrust to prevent the craft from bouncing off the comet's surface, could not be activated. Instead, the agency is relying on ice screws and a harpoon system to secure the lander. Hours later, mission controllers clapped and embraced as the lander's separation was confirmed.
