After traveling for a decade aboard the Rosetta spacecraft, the small Philae lander detached and descended onto comet 67P/Churyumov-Gerasimenko, achieving humanity's first controlled landing on a comet nucleus. Anchoring harpoons failed to fire, causing Philae to bounce before settling in a shadowed crevice, but the mission still gathered unprecedented data about a primordial building block of the solar system.
Rosetta and Philae launched in 2004 on a journey so long and circuitous—using multiple gravitational slingshots around Earth and Mars—that the mission spent much of its transit in hibernation to conserve power. When Philae finally separated from its mothership and descended toward comet 67P, mission controllers in Darmstadt, Germany watched with an anxiety born of genuine uncertainty about whether landing on a comet was even possible.
The landing did not go as planned. Philae's harpoons, meant to anchor it to the comet's low-gravity surface, failed to deploy, and the lander bounced twice before finally coming to rest in a crevice shadowed from sunlight, which starved its solar panels of power. Scientists worked frantically over the following days, extracting as much data as possible before batteries died.
Despite the rough landing, Philae's brief operational window yielded a wealth of data on the comet's composition, including organic molecules, before falling silent. It remains one of the most audacious feats of precision spaceflight ever attempted, comparable to landing a washing machine on a moving mountain from millions of miles away.