Rosetta delivered the first spacecraft to orbit a comet and deploy a lander on one.
The European Space Agency launched Rosetta in 2004 and sent it toward comet 67P/Churyumov–Gerasimenko. After a long cruise that included planetary gravity assists and hibernation, Rosetta entered orbit around the comet in August 2014.
In November 2014, Rosetta released the Philae lander, the first probe to make a controlled landing on a comet’s surface. Philae’s anchoring system did not work as planned, and it bounced before coming to rest, but it still returned scientific data.
Rosetta continued observing the comet as it approached the Sun. The mission ended in September 2016 when the orbiter was guided down to the comet. Giotto had earlier flown past Halley’s Comet, but it neither orbited a comet nor deployed a lander.