| |  | | | Ariane-5 launch |
The long trek
Rosetta's ten-year expedition began in February 2004, with an Ariane-5 launch from Kourou in French Guiana.
The three-tonne spacecraft was first inserted into a parking orbit, before being sent on its way towards the outer Solar System.
The cosmic billiard ball
Unfortunately, no existing rocket, not even the powerful European-built Ariane-5, has the capability to send such a large spacecraft directly to Comet 67P/Churyumov-Gerasimenko.
Instead, Rosetta will bounce around the inner Solar System like a ‘cosmic billiard ball’, circling the Sun almost four times during its ten-year trek to Comet 67P/Churyumov-Gerasimenko.
Along this roundabout route, Rosetta will enter the asteroid belt twice and gain velocity from gravitational ‘kicks’ provided by close fly-bys of Mars (2007) and Earth (2005, 2007 and 2009).
| | Rosetta: Earth fly-by | |
Earth fly-bys (2005, 2007 and 2009)
Rosetta first travels away from its home planet and then encounters Earth again, a year after launch, in March 2005.
Rosetta remains active during the cruise to Earth. The fly-by distance is between 300 and 14 000 kilometres. Operations mainly involve tracking, orbit determination and payload check-out. Orbit correction manoeuvres take place before and after each fly-by.
After the first fly-by of Earth in March 2005, Rosetta heads to Mars and then returns to Earth twice in November 2007 and November 2009 for its second and third fly-bys of our planet.
| | | Rosetta swings by Mars |
Mars fly-by (February 2007)
Rosetta flies past Mars in February 2007 at a distance of about 200 kilometres, obtaining some science observations.
An eclipse of Earth by Mars lasts for about 37 minutes, causing a communication black-out.
| | Asteroids come in many shapes and sizes | |
Asteroids fly-bys
The spacecraft goes into passive cruise mode on the way to the asteroid belt. Rosetta observes the asteroids from a distance of a few thousand kilometres. Science data recorded on board are transmitted to Earth after the fly-by.
| | | Deep-space hibernation before comet rendezvous |
Deep-space hibernation (May 2011 - January 2014)
After a large deep-space manoeuvre, the spacecraft goes into hibernation. During this period, Rosetta records its maximum distances from the Sun (about 800 million kilometres) and Earth (about 1000 million kilometres).
| | Rosetta approaching the comet's nucleus | |
Arrival
The spacecraft will eventually arrive in the comet’s vicinity in May 2014. Rosetta’s thrusters will then brake the spacecraft, so that it can match Comet 67P/Churyumov-Gerasimenko’s orbit.
Over the next 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 comet chase towards the Sun.
Last update: 1 November 2004 | |
