This second Double Star spacecraft will join ‘Tan Ce 1’, the first satellite launched on 29 December 2003 to complete the Double Star mission.

Double Star will operate alongside ESA’s Cluster mission and will study closely the interaction between the solar wind and Earth’s magnetic field. Together with Cluster, Double Star will provide the most detailed view of Earth’s magnetosphere ever obtained.

Tan Ce 1 is already returning a wealth of scientific data. In January 2004 it tracked together with Cluster a coronal mass ejection from the Sun and gathered interesting data about the Earth bow shock.