Rosetta spacecraft

Trajectories of the Rosetta probe

Rosetta European Space Agency, was launched from the Space Center in Kourou, French Guiana, March 2, 2004, for a very long journey of 6 billion km. The main objective is to reach the periodic comet (6.59 years) Churyumov-Gerasimenko, to analyze the composition and structure of its core, its degassing to the approach of the Sun and put down, the robot lander Philae 100kg, on its surface.
The Rosetta mission has already provided extensive data collected during flybys of Mars in February 2007, the small asteroid (2867) Steins (≈ 5 km) 5 September 2008 and the large asteroid Lutetia (95.8 km) 10 July 2010. Rosetta was in hibernation since June 2011, to more than 800 million km from the Sun, near the orbit of Jupiter, and its automatic wake was scheduled after 957 days. January 20, 2014, 9 million km from the comet, the probe was warmed his navigational instruments, stopped its rotation and pointed his main radio antenna toward Earth to transmit a signal of life. The signal was received by the two ground stations Goldstone and Canberra NASA January 20, 2014 at 18:18 UTC, from the first window of opportunity that the probe had to communicate with Earth. Immediately confirmed by the Space Operations Centre of ESA in Darmstadt and the success of the awakening been announced as follows: "Hello World" via twitter account.
From January 20, scientists have made essential health checks on the satellite, on the eleven instruments of the orbiter and ten instruments of lander will be lit and prepared for the study of the comet 67P/Churyumov-Gerasimenko. The first images of Churyumov-Gerasimenko are expected in May 2014, when the probe will be 2 million km from the comet. For two months, Rosetta will conduct a detailed mapping of the surface as well as precise measurements of gravity, mass, shape and gas from its dusty atmosphere or coma of the comet. Then scientists will choose a landing site for Philae, the robot lander 100 kg. The perilous landing of Philae is scheduled for November 11, 2014. Gravity on the surface of the comet is so low that Philae will use harpoons that will hang in the ice to prevent bounce in space after landing.

We then receive photos in high resolution ice surface of the comet. The robot will drill up to 23 cm soil depth and analyze samples in its laboratory. The comet will reach its closest distance from the Sun (185 million km) August 13, 2015, it will be between the orbits of Earth and Mars. Rosetta will follow the comet for the rest of 2015. Comets are the guardians of the past, vagabonds of the sky, messengers from space that carry the keys to our origin, which is why scientists are deploying so much imagination to go collect messages of primordial matter. Rosetta will reach the comet Churyumov-Gerasimenko in August 2014 (see the full itinerary and detailed trajectories the Rosetta probe with gravity assists by clicking on the note at right).
Already in 1986 a probe went to photograph Halley's Comet closely (600 km) bringing extraordinary kernel images. Comets date from a time when the primitive solar system had not yet formed the planets. There are 5 billion years ago, a supernova explodes. The cloud of gas and dust condensed to form the Sun at the center and around a gaseous disk, flattened in rotation, is filled of bodies, that circulate in all directions. Some of the bodies stick together and form the planets but others too far from the center, orbit random disturbances, in the polar regions of the solar system. Some of these icy objects leave one day the cloud to plunge towards the Sun. Heated by the sun their gas evaporates, a long hair deploys, they become comets. That is why comets hold the oldest organic molecules of the solar system.
Rosetta will be the first spacecraft to go into orbit around a comet and to depose a science lab, the robot Philae lander on its surface.

Image: The long journey of 6 billion km of the Rosetta probe with all its trajectories and its various rendezvous. Credits: CNES, Sébastien Rouquette.