The European Space Agency (ESA) and the Chinese National Space Administration (CNSA) launched the two Double Star Programme (DSP) satellites six months apart in December 2003 (TC-1) and July 2004 (TC-2) from launch sites in China.
The purpose of the DSP mission is to extend our knowledge of the magnetosphere using the two Tan Ce (Chinese for explorer) satellites. TC-1 was launched from the Xi Chang spaceport into an equatorial orbit and TC-2 was launched from the Tai Yuan spaceport into a polar orbit, with both satellites flying in highly elliptical orbits so that they sample many key regions of the magnetosphere.
Each satellite had eight instruments on board sampling the plasma environment around the Earth. They studied magnetic reconnection, located the trigger mechanism for magnetic storms, and studied physical processes such as particle acceleration, diffusion, injection and up-flowing ions in magnetic storms. Five of the instruments are common to both satellites, with eight of the instruments built in Europe and eight in China. Most of the European instruments have a heritage from ESA's Cluster mission and DSP coordinates its activities with Cluster. The nominal end of mission for Double Star was initially July 2005, but the mission was extended until the end of 2009.
Instruments on Double Star
*Instrument originated in China
Double Star in orbit
FGM: Fluxgate Magnetometer (TC-1 and TC-2), located on a 3.5 metre boom measures the magnetic fields along the orbit.
NUADU: Neutral Atom Detection Unit (TC-2) monitors energetic neutral atoms in the magnetosphere particularly imaging the Earth's ring current.
HIA: Hot Ion Analyser (TC-1) analyses the distribution functions of ions in the nearby (magnetosphere) space plasma and in the solar wind.
PEACE: Plasma Electron and Current Experiment (TC-1 and TC-2) studies electrons in the space plasma.
ASPOC: Active Spacecraft Potential Control (TC-1) prevents a build-up of positive electrical charge on the satellite, using the measurements from PEACE.
STAFF / DWP: Spatio-Temporal Analysis of Field Fluctuations/Digital Wave Processor (TC-1) at the end of a 3.5 metre boom, studies waves (rapid variations in the magnetic fields) particularly in regions where the charged particles of the solar wind interact with the magnetosphere.
LFEW *: Low Frequency Electromagnetic Wave Detector (TC-2)
LEID *: Low Energy Ion Detector(TC-2)
HID *: Heavy Ion Detector (TC-1 and TC-2)
HEPD *: High Energy Proton Detector (TC-1 and TC-2)
HEED *: High Energy Electron Detector (TC-1 and TC-2)