Many of the most important European missions which seek to push back the frontiers of knowledge about our solar system and the wider universe have started their space adventures on-board Ariane rockets.
The Hipparcos space astrometry mission, built by Airbus Defence and Space (then Matra) launched by Ariane 4 in 1989 on Flight 33, created the first all-sky map during its three and a half year lifetime. The satellite measured the position of over a hundred thousand stars with high precision and more than one million stars with a lower precision. The Hipparcos Catalogue and Tycho Catalogue of star position and motion are invaluable tools used by astronomers to this day.
At the time of its launch in 1999 by Ariane 5 on Flight 119, XMM Newton was the largest science satellite built in Europe. Designed and built by Airbus Defence and Space (then DaimlerChrysler Aerospace) for ESA, XMM-Newton has detected more X-ray sources than any previous satellite and is helping to solve many cosmic mysteries of the violent Universe, from what happens in and around black holes to the formation of galaxies in the early Universe. The mission was designed to return data for a minimum of two years but has been so successful that the current mission extension will take the telescope to 13 years of operations.
The Airbus Defence and Space-primed Rosetta mission is on a 10-year journey of more than five billion kilometres to rendezvous with the comet Churyumov-Gerasimenko. The Rosetta orbiter carries a suite of instruments that will study the comet from close range. Launched on 2 March 2004 on Flight 158, Rosetta will reach its destination in 2014. It will begin a global mapping and science phase and take six months to close the gap enough to deploy a lander, Philae, which will anchor itself to the surface of the comet for in situ analysis. Rosetta will then follow the comet on its inward journey towards the sun. The Rosetta launch mission undertaken by Ariane 5 was a very special one, since, for the first time, the launcher was required to reach escape speed – i.e. a velocity of around 40,000km/h – to fly its passenger into deep space. To do this, the Ariane 5 upper stage was modified and equipped with larger tanks to carry more propellants, then re-qualified. Instead of re-igniting immediately after separation from the main stage as is the case for ‘usual’ satellite missions to geostationary orbit, the EPS upper stage, together with its Rosetta payload embarked on a 105-minute coasting phase first. Then the upper stage re-ignited its own engine to achieve escape speed to leave the Earth’s gravity field and enter heliocentric orbit. The Rosetta probe was released 18 minutes later.