The two Double Star spacecraft store the data from all instruments on their solid-state recorders and then dump them when visible from the Chinese receiving ground stations in Beijing and Shanghai (China). In addition, to increase the data return, the ESA ground station in Villafranca (Spain) is used to acquire 4 hours of data per day. These data are then sent to China via a dedicated link for processing and further distribution to the principal investigators.
The European Payload and Operations Service (EPOS) at Rutherford Appleton Laboratory in the UK co-ordinates the science operations. Its main task is to merge all commands coming from the 7 European instruments (NUADU on board TC-2 will be commanded by the Double Star operation center in China) into an overall command schedule, which is then sent to the Double Star Operation and Management Centre in China. EPOS also collects and processes the data needed to plan the instrument operations and will develop the quicklook plot system.
The vast amount of scientific information sent back by the two spacecraft is handled by the Double Star Science Data System (DSDS). This comprises four national data centres - three in Europe (Austria, France, United-Kingdom) and one in China. The main interface with the Chinese data centre is the Austrian data centre at IWF in Graz. The Austrian data centre distributes the raw data from the spacecraft to the Principal Investigator teams in Europe. The DSDS supports scientific data processing and distributes the summary and prime parameter data in physical units.
The coordinated spacecraft and ground-based observation
The cooperation between the DSP and the 'Meridian Chain Projection', a key scientific programme to be implemented by the Chinese government, will consist of national monitoring system of the space environment. Moreover, the cooperation among DSP, Cluster, and other international scientific satellites can help with the coordinated multi-satellite and ground-based observation of the 23-year solar cycle activities. It will play an important role in the development of space physics research and space environment detecting technology.