Philae had traveled for ten years aboard the Rosetta spacecraft before separating for a seven-hour descent. Its harpoons failed to fire, and it bounced twice before coming to rest in the shadow of a cliff.
With little sunlight for its solar panels, Philae sent back about 64 hours of data before its battery ran out. Rosetta finally spotted it in a photo in September 2016, wedged in a crack, shortly before the mission ended.
Source: Wikipedia