After 10 years, Rosetta catches up with a comet

Launched back in 2004, the European Space Agency's probe Rosetta has rendezvoused with Comet 67P/Churyumov-Gerasimenko, somewhere between the orbits of Mars and Jupiter.  Sometime in November, Rosetta plans to place the lander Philae on the comet's surface! Until then, she's going to observe the comet from about 100 km, the closest a probe has been to a comet, to find the best spot for Philae.

Comet 67P/Churyumov-Gerasimenko

Back in 1978, the International Sun-Earth Explorer was launched, did its job and then was deactivated.  It was reactivated in September 1985 and diverted through the tail of Comet Giacobini-Zinner, over 4700 miles from the core and then Halley's Comet in 1986 at a distance of 31 million kilometers.  In March 1986, ESA's Giotto flew within 600 km, taking the closest pictures of a comet at that time.