East meets West in near-earth space

Since their dual launches in July and August 2000, ESA's four Cluster spacecraft have been flying in formation around the Earth, sending back the first detailed, three-dimensional information about the magnetosphere and its interaction with the solar wind. This unique examination of the magnetic bubble that surrounds our planet is about to be enhanced by Double Star, a groundbreaking collaboration involving ESA and the Chinese National Space Administration (CNSA). The Double Star programme involves the launching of two satellites - the first already placed in orbit on 29 December 2003 and the second scheduled for launch in July 2004 - each carrying experiments provided by European and Chinese institutes. This will enable scientists to analyse data sent back simultaneously from no fewer than six spacecraft, each located in different regions of near-Earth space. The simultaneous, six-point study should provide new insights into the mysterious mechanisms that trigger magnetic storms and the brilliant auroral displays in Earth's polar skies.