First Sino-European satellite completes mission

One of the two satellites of the Double Star mission was decommissioned on 14 October after its designed orbit lifetime came to an end.

TC-1 - along with its twin TC-2 - was the first satellite built and operated by the Chinese National Space Administration (CNSA) in cooperation with the European Space Agency (ESA). Over the past four years, the Double Star mission has studied the interaction between the Earth's magnetic field and solar winds.

After TC-1, which stands for Chinese 'Tan Che' meaning 'explorer', was launched into an equatorial orbit on 29 December 2003, it played a crucial role in various discoveries. For instance Double Star, together with the four satellites of ESA's Cluster mission, revealed that bubbles of superheated gas are constantly growing and popping where the magnetosphere is hit by the constant stream of gas from the sun.

Furthermore, TC-1 helped find that chorus emissions - waves naturally generated in space close to the magnetic equator - are created further away from Earth during high geomagnetic activity. Chorus emissions are involved in creating killer electrons that can damage solar panels and the electronic equipment of satellites, and are also a danger for astronauts. The information provided by the satellites was a step in the direction of being able to predict the waves' impact.

Data collected by TC-1 also shed light on the effects of space weather on the Earth's magnetic field, when TC-1 and the Cluster satellites were suddenly engulfed by oscillating waves of electrical and magnetic energy. TC-1 has 'brought in new perspectives concerning the boundaries of the magnetosphere and the fundamental processes that are playing a role in the transport of mass, momentum and energy into the magnetosphere', ESA states. 'Its data is essential to understand how the sun activity influences the near-Earth space and induces changes in the 'space weather' through magnetic storms and streams of high-energy particles.'

Initially, the mission was only intended to last one year. However, ESA and CNSA extended it twice until the end of September 2007. 'Double Star has demonstrated mutual benefit and fostered scientific cooperation in space research between China and Europe,' says Phillippe Escoubet from ESA. 'We expect even more results when the final archive of high resolution data will be made available to the worldwide scientific community.'