Rosetta closes in on Earth

This artist’s impression shows the orbits of Earth (blue) and Rosetta (white) as the comet chaser swings by our planet. Rosetta is on its way to its second close encounter with Earth on 13 November.

This month’s Earth swing-by is Rosetta’s third major step on its 10-year journey to comet 67/P Churyumov-Gerasimenko. A trajectory correction manoeuvre successfully performed last month prepared ESA’s comet chaser for the upcoming encounter, and now Rosetta is right on track.

In swinging by Earth, the spacecraft will gain the right amount of energy from Earth’s gravity and precious save fuel for later on.
Closest approach will take place on 13 November 2007 at 21:57 CET, at which time Rosetta will speed past at 45 000 km/h (about 12.5 km/s) relative to Earth. At this time, Rosetta will be 5301km above the Pacific Ocean, south-west of Chile, at 63° 46’ south and 74° 35’ west.

The first Earth swing-by took place on 4 March 2005. On 25 February 2007 Rosetta made its closest approach to Mars, to use its gravity. The swing-by this month will be followed by the third and last swing-by, using Earth’s gravity, on 13 November 2009.

This second Earth swing by will help Rosetta gain enough energy to reach the outer Solar System through the asteroid belt and observe asteroid Steins, one of its science targets.