eso9932-en-us — Photo Release
Scouting for ROSETTA
29 June 1999: The launch in early 2003 of the Rosetta spacecraft of the European Space Agency (ESA), the 3rd "Cornerstone" mission of this organisation, will mark the beginning of an exciting scientific endeavour. Following two close passages by the Earth and another by Mars to gain speed, the complex 1.3-tonnes spacecraft will continue towards a rendez-vous with the icy nucleus of Comet Wirtanen , passing two asteroids on the way. Beginning in late 2011, at a time when the comet is close to its aphelion - the most distant point in its elongated orbit, about 770 million km from the Sun - the Rosetta "orbiter" will literally chase Comet Wirtanen for two years, sending back valuable data about the nucleus and its immediate environment. A "lander" will attach itself to this lump of frozen ice and dust, which is travelling through space at over 46,000 kilometres per hour, and analyse samples. A joint team from ESO and ESA's Space Science Department has proposed a short series of ground-based exploratory observations in support of this European space mission. Responding to the challenge, the second 8.2-m VLT telescope (KUEYEN), while undergoing commissioning at Paranal, has just performed a remarkable feat by observing the nucleus of Comet Wirtanen, now near its aphelion, i.e. at the location of the future Rosetta encounter. This is equivalent to viewing a pitch-black golfball, over 20,000 kilometres away!