EUROPE GOES TO VENUS: THE JOURNEY OF VENUS EXPRESS

摘要

On November 9~(th) 2005, a Russian Soyuz-Fregat launcher boosted Venus Express into space from the Baikonur cosmodrome, in Kazakhstan. The spacecraft reached its final destination 5 months later, on April 11th 2006, after a journey of 440 millions of kilometres in the solar system. It fired its main engine during 49 minutes and slowed down to be captured into orbit around the planet. A series of manoeuvres then led the spacecraft to its operational orbit, circling the poles with a period of 24h along a highly elliptical orbit, with an altitude between 250 km and 66 000 km. Conducted by ESA, Venus Express is the first European mission to the "morning star", two years after Mars Express that was the first ESA mission to Mars. It has undertaken the most comprehensive study ever of the Venusian atmosphere, over a period of at least 2 Venus sidereal days (486 days). 7 science instruments, most of them inherited from Rosetta and Mars Express, probe the atmosphere in great detail with the goal to answer many of the unresolved questions about Venus. They study its complex dynamics and chemistry, interactions between the atmosphere and the surface, as well as interactions with the solar wind. Developed by Astrium as prime contractor, Venus Express spacecraft is a near copy of Mars Express. However, several changes were necessary to accommodate the science instruments and to cope with Venus hot environment. In particular, a new Solar Array was developed, and thermal control was adapted. Thanks to an efficient cooperation between all European partners, the development was however achieved in a very short time, less than 4 years from concept to launch, which makes it the fastest ESA Science mission ever done. The global budget of the mission is 220 millions Euro, covering development of the spacecraft, launch and operations. Main events of the journey to Venus are presented, as well as spacecraft in-orbit performances.