Mission to Catch a Comet!

Comets have inspired awe and wonder since the dawn of history. Many scientists today believe that comets crashed into Earth in its formative period spewing organic molecules that were crucial to the growth of life. Comets may have formed about the same time as the giant planets of our solar system (Jupiter, Saturn, Uranus, and Neptune) - about 4.6 billion years ago. Some scientists think that comets and planets were both made from the same clumps of dust and ice that spewed from our Sun’s birth; others think that these roving time capsules are even older than that, and that they may contain grains of interstellar stuff that is even older than our solar system!

Attempting New “Firsts” in Space

Rosetta is a spacecraft on a ten-year mission to catch the comet "67P/Churyumov-Gerasimenko" (C-G) and answer some of our questions about comets. Rosetta will be the first spacecraft to soft-land a robot on a comet! Rosetta will also be the first spacecraft to accompany a comet as it enters our inner solar system, observing at close range how the comet changes as the Sun’s heat transforms it into the luminous apparition that has frightened and inspired people for centuries.

Named after the Rosetta Stone

The Rosetta spacecraft is named after the ancient Rosetta Stone that you can visit today in London’s British Museum. The Philae lander is named after the Philae Obelisk which, together with the Rosetta Stone, provided the key to our first understanding of Egyptian hieroglyphs, or “picture words.” Scientists hope that the Rosetta spacecraft will enable us to translate the even older language of comets, as expressed by their thermal signatures, into new knowledge about the origins of our solar system and, perhaps, life on Earth.

An International Mission with U.S. Support

This daring international mission is spearheaded by the European Space Agency (ESA), with key support and instruments from NASA. NASA contributed three of the orbiter's instruments (ALICE, MIRO, and IES) and part of the electronics package for the Double Focusing Mass Spectrometer - one of two detectors on the Swiss ROSINA instrument. NASA is also providing science investigators for selected non-U.S. instruments. In all, NASA is involved to a greater or lesser degree in Alice, MIRO, IES, OSIRIS, Radio Science, ROSINA, and VIRTIS experiments. NASA's Deep Space Network provides support for ESA's Ground Station Network for spacecraft tracking and navigation.

Schedule of Events

ESA’s Science Programme Committee approved the International Rosetta Mission in November 1993 as a Cornerstone Mission in ESA's Horizons 2000 science program.

On March 2, 2004, Rosetta was launched into an orbit that enabled it to chase Earth around the Sun for about a year.

  • On March 4, 2005, Rosetta caught up with Earth and executed the first of its four gravity assists (three from Earth and one from Mars). This first gravity assist hurled Rosetta toward Mars for its meeting in 2007.
  • En route to Mars, Rosetta's instruments analyzed the collision between Deep Impact's impactor and comet Tempel-1 on July 4, 2005.
  • In February 2007, Rosetta executed a close flyby of Mars, which provided the gravity assist it needed to loop back toward Earth for a second flyby in November 2007.
  • In November 2007, Rosetta executed its second Earth flyby, gaining the gravity assist it needed to pass Mars' orbit and reach the asteroid belt.
  • On September 5, 2008, Rosetta passed within 1700 km of asteroid Steins, enabling its instruments to closely observe the flying rock.
  • In November, 2009, Rosetta swung back for a final boost from Earth’s gravity to return again to the asteroid belt.
  • On July 10, 2010, Rosetta flew within 3000 km of asteroid Lutetia, and again used its instruments to observe at close range this asteroid, ten times larger than Steins.
  • By May, 2011, Rosetta was coasting through areas in the outer solar system where the sun is almost a billion km away. At that distance, Rosetta’s solar panels are not able to gather much energy from the Sun, so the spacecraft shut down most electrical activities and will hibernate until comet C-G returns from its long transit in the outer solar system.
  • In January 2014, Rosetta will fire its engine to position itself next to comet C-G in May 2014 as it comes hurtling by. Rosetta will release the Philae for a controlled soft landing on the comet. The Philae will then transmit critical data from the comet’s surface for relay back to Earth. Philae will use harpoons to anchor itself to the comet.
  • After escorting comet C-G past its perihelion (closest point to the Sun), Rosetta will terminate its mission.