subject: Rosetta Space Mission : Got Main Objective Over Years [print this page] Rosetta space mission of the European Space Agency (ESA) whose main objective is to collect data on the composition of the comet nucleus Tchourioumov-Gerasimenko and its behavior when approaching the Sun. The spacecraft, weighing three tons at launch, must be placed in orbit around the comet and then, after an observation period of several months, Philae send a small lander 100 kg, landing on its surface to analyze the composition of the soil. Rosetta is a flagship project for the ESA, which has invested nearly one billion euros, more than 30 of its annual budget. The Scientific Committee decided it was built in 1993, after abandoning a joint project with NASA, hoping it would confirm or refute the models currently on the process of formation of the Solar System Comets are relics.
After a delay of one year due to a failure of the launcher which required to waive the initial target, Comet Wirtanen, Rosetta was launched by an Ariane 5G + March 2, 2004 [1]. The probe should reach near the comet in 2014 after using four times the gravity fields of Earth and Mars to arrive to place themselves on a trajectory parallel to the comet with an identical speed. Along the way the probe has crossed a short distance the asteroid (2867) dye in 2008 (21) Lutetia July 10, 2010: observation of these two bodies is a secondary objective of the mission.
Rosetta will be the sixth probe to observe a comet at close range, but it will be the first to enter orbit for a long period of observation and to be a lander onto its core. The mission is in many ways a technical challenge. The distance between the Earth and the comet requires that the probe is self during critical phases. The lander must be able to succeed to land on a comet nucleus, the composition and behavior are unknown. Finally, the probe must survive the thermal and energy to large amplitude variations of solar lighting imposed by its trajectory.
Scientists have known for some years that the study of comets can provide important clues about the formation process of the solar system, but only one space mission in situ can provide detailed knowledge of the nature of these celestial bodies. The research on comets will be one of the few areas of space exploration where the European Space Agency is ahead of his American counterpart.
The first wave of space missions to comets occur with the passage of Comet Halley in 1986, while NASA, which faces serious financial problems, must renounce to launch a probe, ESA built the spacecraft Giotto who will fly but Halley Comet Grigg-Skjellerup (1996). The first European spacecraft made several techniques including a passage distance of a nucleus of a comet is the source of major scientific discoveries including the presence of organic compounds in the comet nucleus. Comet Halley is studied more or less distance by other space probes launched at the same time that it is sometimes not the main mission: Japanese probes Sakigake and Suisei and Soviet probes Vega 1 and Vega 2.
The U.S. space agency NASA is launching several missions later, with very different characteristics, dedicated to the study of comets:
-Deep Space 1, which flies over the comet Borrelly in 2001;
-Stardust, launched in 1999, passes near the comet Wild 2 in 2004 and captures particles in the tail of it. A capsule containing samples collected landed on Earth in 2006. The content is now being analyzed. The probe is currently continuing its journey to Comet Tempel 1 by Deep Impact struck;
-CONTOUR probe, launched in 2002, had to fly over the nuclei of comets Encke and 73P/Schwassmann-Wachmann but suffered an engine failure which was injected on its interplanetary trajectory;
- Deep Impact, launched in 2005, dropped the same year a 350 kg impactor on the nucleus of comet Tempel 1 raised several thousands of tons of dust and ice: analysis by onboard instruments and space telescopes allows to determine its composition.
After the success of the Giotto mission, the international scientific community in 1991 proposed the launch of a dedicated mission to comets, one of whose goals is to return to Earth a sample of the comet nucleus. NASA and ESA are pooled to give birth to the mission CNSR (Comet Nucleus Sample Return), based on the Cassini spacecraft and capable of bringing 10 kg of samples; ESA must provide the return capsule and launcher . After two years of work, NASA withdraws from the program, the ESA can not provide a single mission of this scale, then develop a less ambitious mission without sample return , Rosetta.
The new mission, approved in 1994, must file two landers to study the comet, one developed by Germany (Roland gear), the other produced by a combination CNES / NASA (Champollion lander). Eighteen months after the beginning of studies, NASA again abandoned his participation in this project. A new lander then arises from the union of eight countries, including Italy, Germany and France, and is finally delivered on the date agreed for its integration on the orbiter in 2002. The sensor is built in a clean room according to the rules of COSPAR to avoid contamination of the comet .
The name chosen for the mission refers to the Rosetta Stone which allowed Jean-Francois Champollion deciphering Egyptian hieroglyphics in 1822. The Philae lander is called (which can be spelled Philae) by reference to the obelisk of Philae, which provides the keys to complete the decoding of Champollion. Indeed, scientists hope the mission will provide many answers about the history of the solar system .
