An old friend returned home for a flying visit on 13 November. 44 months after its launch from Kourou, French Guiana, ESA’s Rosetta spacecraft swept past the Earth for the second time. Europe’s comet chaser has now flown a little over 3 billion km, but it still has another 4 billion km to travel before it arrives at its destination, comet 67/P Churyumov-Gerasimenko, in 2014.
Rosetta is bouncing around the inner Solar System like a billiard ball as it picks up speed and changes its path during close encounters with Earth and Mars. This latest milestone on the epic voyage marked the third of four planetary swing-bys planned for Rosetta.
After its orbit was fine-tuned by a 42 second firing of its thrusters on 18 October, Rosetta was right on target for the Earth flyby. At 21:57 CET, the 3 tonne spacecraft raced past the planet at a speed of 45,000 km/h (12.5 km/s). As it swooped over the Pacific Ocean, south-west of Chile, Rosetta was only 5,295 km overhead.
Around closest approach, Rosetta took a good look at Earth, making observations of its atmosphere and magnetosphere, imaging urban regions, and looking for meteors from space. It then began a sequence of observations of the Earth-Moon system on its outbound trajectory.
The spacecraft will now be catapulted towards the outer Solar System before coming back to Earth for the last time in November 2009. But before that, as it crosses the asteroid belt, Rosetta will seize the opportunity to study asteroid Steins from close range in September 2008.
