Rosetta's ten-year chase to catch a comet
Earth and Mars flybys, two asteroids, 31 months of hibernation — and the first orbit around a comet.
Published 2026-10-23
Catching a comet is not simple. You cannot fly straight at it — you have to match its speed and path around the Sun. ESA's Rosetta spent ten years doing exactly that.[5][2]
Launch
Rosetta launched on March 2, 2004, on an Ariane 5 rocket from the Guiana Space Centre in Kourou, French Guiana.[5] It was named after the Rosetta Stone, which helped scholars decipher Egyptian hieroglyphs; its lander, Philae, was named after the Philae obelisk, which played a similar role.[5][6]
Gaining speed with gravity
To reach 67P, Rosetta used gravity assists to build up speed:[5]
- Earth flyby, March 4, 2005.
- Mars flyby, February 25, 2007 — at an altitude of only about 250 km, a manoeuvre nicknamed “The Billion Euro Gamble.” It succeeded.
- Earth flyby, November 13, 2007.
- Asteroid 2867 Šteins, September 5, 2008.
- Earth flyby, November 12, 2009.
- Asteroid 21 Lutetia, July 10, 2010, at about 3,168 km.
The long sleep
Far from the Sun, Rosetta's solar arrays could not power everything. On June 8, 2011, almost all of its electronics were switched off for a planned 31 months of hibernation.[5] It woke up in January 2014, and from May 2014 a series of burns slowed it to match the comet.[5]
Arrival
On August 6, 2014, Rosetta reached 67P and became the first spacecraft to orbit a comet.[5] ESA describes it as the first mission to rendezvous with a comet, to follow one around the Sun, and to deploy a lander to a comet's surface.[2] Rosetta was also the first spacecraft to fly out near Jupiter's orbit using solar cells as its main power source.[5]
The finale
After following the comet through its closest approach to the Sun on August 13, 2015,[4] Rosetta ended its mission on September 30, 2016, with a slow, controlled descent onto the comet's Ma'at region, at about walking pace.[5]
Numbered citations link to the sources list on the Comet 67P/Churyumov–Gerasimenko overview page.