Rosetta is a European Space Agency (ESA) cornerstone mission, launched on 2 March 2004 by Ariane 5. It is designed to rendezvous with comet 67/P Churyumov-Gerasimenko and orbit it, while performing remote sensing investigations as well as carrying a lander to descend to the comet's surface and perform in situ measurements.
During the cruise phase, Rosetta has performed gravity-assist flybys of Earth (March 2005, November 2007) and Mars (March 2007) with a further Earth-assist in November 2009. Flybys of two asteroids on the way to the comet are also planned. After the asteroid flybys the spacecraft will intercept the comet at a distance from the Sun of ~3.6 AU. The rendezvous manoeuvre will occur in May 2014. After global mapping of the comet nucleus a landing site will be chosen and in November 2014 the lander will be released. The lander will relay data via the orbiter for at least the next 84 hours. The orbiter will remain with the comet and make observations through perihelion on 12 August 2015, until the nominal end of the mission in December 2015.
PSSRI plays major roles in two experiments on the lander. Ptolemy
is a gas analysis instrument capable of performing isotopic measurements on individual components from solid samples of the comet's surface. MUPUS
is a multi-purpose system to investigate some of the physical properties of the surface layers of the nucleus. PSSRI members are also co-investigators on the GIADA (Grain Impact Analyser and Dust Accumulator) experiment on the orbiter and SESAME (Surface Electrical, Seismic and Acoustic Monitoring Experiments) on the lander.
The Rosetta mission is named after the 'Rosetta Stone', which proved to be pivotal in the deciphering of Egyptian hieroglyphs. Discovered in 1799, by occupying French forces in Egypt, the stone has an inscription on it in three different scripts: Egyptian Hieroglyphic and Demotic as well as Ancient Greek. Out of these three only the Greek was known, at the time, and it was explained in the text that all three scripts were copies of the same source document. This allowed, for the first time, direct comparison between a translatable document and Egyptian hieroglyphs. Although initially collected by the French the stone came into British hands as part of the surrender terms from the French in 1801. It was brought to England in 1802 and later that year was donated to the British Museum with other recovered artefacts.
The lander itself is named Philae, after the obelisk that was discovered by Sir William John Bankes, a British antiquarian, on Philae Island, south of Cairo in 1815. The obelisk had a bilingual inscription including the names of Cleopatra and Ptolemy in Egyptian hieroglyphs, offering historians further clues to translating the hieroglyphs on the Rosetta Stone. The obelisk can still be viewed at Bankes's Dorset Estate, Kingston Lacy, which is now owned by the National Trust.