Excitement is building around the world as the clock counts down to the launch of two powerful new ESA space observatories – Herschel and Planck. The spacecraft will be launched together from ESA’s spaceport in Kourou, French Guiana, at 15:12 CEST on 14 May. Attached to the top of their giant Ariane 5 rocket, the pair will measure about 11 m high and 4.5 m wide, with a combined weight of 5.7 tons.
About 2.5 minutes after lift off, the Ariane 5’s solid fuel boosters will fall away. The satellites’ protective fairing is jettisoned about 50 seconds later. The upper stage then separates and its engine ignites about 9 minutes into the flight. By the time the satellites are due to separate, the stage will be speeding away from Earth at about 10 km/s. Herschel will be the first to be released, roughly 26 minutes after lift off. Planck will follow about 2½ minutes later.
During the early stages of the mission, mission controllers will monitor the satellites 22 hours a day from ESA’s ground stations in Australia, Spain and South America. Both satellites will make their own way to L2, a special point in space that lies 1.5 million km away, on the night side of Earth. L2 is an excellent location, since it allows them to observe the sky without any problems from sunlight while using very little fuel. Planck is expected to start sending back data in July, followed in September by Herschel.
Updates on the launch and the progress of the satellites are provided at www.esa.int/herschelplanck and several other ESA websites. Information is also available on Flickr at www.flickr.com/eurospaceagency and on Twitter at www.twitter.com/eurospaceagency .
