Rosetta

Rosetta launched into space on March 2nd, 2004 and has now completed its mission. Its primary destination was Comet 67P/Churyumov-Gerasimenko, which it arrived at on August 6th, 2014 . Wherever Rosetta goes, it carries its trusty cameras, comet dust analyzers, plasma sensors, radio receiver and transmitters, and spectrometers. Rosetta often chats with humans from ESA.

Rosetta is a space probe orbiting Comet 67P/Churyumov-Gerasimenko, witnessing how it changes as it orbits the Sun. The Rosetta orbiter was launched carrying the Philae lander which semi-successfully landed on Comet 67P in 2014, becoming the first space probe to ever land on a comet. Philae bounced twice before landing at an angle in the shadow of a cliff and soon after powered down due to the lack of sunlight. Philae later gained enough sunlight to power back on, do a few science experiments and send a few communications to Earth before succumbing to a suspected transmitter failure. Meanwhile, Rosetta continues to study the comet and its role in the evolution of the solar system. On board Rosetta is a micro-etched nickel disk containing an archive of 1500 human languages compiled by the Long Now Foundation.

Worth Exploring:

amazing photographs of the comet on Rosetta's Instagram
a model of Comet 67P for 3D printing
an adorable cartoon about Rosetta and Philae preparing for the comet landing
an interactive map of where Rosetta is in the solar system
the Rosetta team's blog

(top image: a mosaic of Comet 67P taken by Rosetta, ESA/Rosetta/NAVCAM)