ESA's Rosetta spacecraft will be the first to undertake the long-term exploration of a comet at close quarters. It comprises a large orbiter, which is designed to operate for a decade at large distances from the Sun, and a small lander. Each of these carries a large complement of scientific experiments designed to complete the most detailed study of a comet ever attempted.
After entering orbit around Comet 67P/Churyumov-Gerasimenko in 2014, the spacecraft will release a small lander onto the icy nucleus, then spend the next two years orbiting the comet as it heads towards the Sun. On the way to Comet Churyumov-Gerasimenko, Rosetta will receive gravity assists from Earth and Mars, and will fly past main belt asteroids.
During its 10-year journey to Comet 67P/Churyumov-Gerasimenko, Rosetta will circle the Sun almost four times. It will also cross the asteroid belt twice and gain velocity from gravitational 'kicks' provided by close swing-bys of Mars (2007) and Earth (2005, 2007 and 2009).
During the cruise phase, Rosetta alternates between phases of passive and active operation, depending on mission needs. As a secondary scientific objective, Rosetta observed asteroid Steins in 2008 and will flyby Lutetia in 2010, with closest approach at 800 and 1700 km, respectively. Science data recorded onboard will be transmitted to Earth afterwards.
Following a planned deep-space manoeuvre using the engine to achieve a change in speed of approximately 800 m/s, the spacecraft goes into hibernation between May 2011 and January 2014, due to the very limited power that will be available, which would not allow safe spacecraft operations. Almost all electrical systems are switched off, except for the thermal subsystem, on-board computer, radio receivers, command decoders and power supply.
During this period, Rosetta should record its maximum distance from the Sun, about 800 000 000 km, and Earth, about 1000 000 000 km.
In May 2014, Rosetta's thrusters will brake the spacecraft so that it can match Comet 67P/Churyumov-Gerasimenko's orbit. The spacecraft will arrive in the comet's vicinity a few weeks later.
Over the following six months, it will edge closer to the black, dormant nucleus until it is only a few dozen kilometres away. The way will then be clear for the exciting transition to global mapping, lander deployment and the continuing 'comet chase' toward the Sun.
Mission operations
Monitored and controlled at ESA/ESOC via the Agency's ESTRACK deep space stations at New Norcia, Australia, and Cebreros, Spain.
Rosetta mission operations: Rosetta operations
More information: Rosetta
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