Client
The CSL (Centre Spatial de Liège) is a research centre of the University of LIEGE. The activities of CSL are international: collaborations with ESA and NASA, with most of the European space industries and laboratories and with many large US laboratories. Through its space activities, CSL has accumulated high-level instrumentation which is regularly set to the disposal of the industry.
Project
SWAP (Sun Watcher using Active Pixel System detector and image Processing) is an Extreme UV (EUV) telescope. This telescope is designed by CSL (Centre Spatial de Liège) for the European Space Agency and will be embarked on the PROBA-2 satellite. SWAP will take pictures of the sun every minute to help identify disturbance sources that affect the space weather and the Sun-Earth relationships.
CSL wished to outsource the development of the complete electronics associated with this telescope to a specialist, with the exception of the power supplies and some control electronics.
This should include 2 boards. The first one should control the image sensor and perform the picture capture and temporary storage. The other board should implement a mass storage that directly connects to the first capture board on one side and to the satellite telemetry system on the other. It is used to store pictures acquired by the telescope, before and after their processing by the satellite main computer. It also integrates a CompactPCI interface and controls the download of processed pictures through the earth link of the satellite.
Challenges
The main challenges in this design are traditional in embarked space designs: radiation hardness, extreme temperature ranges, high reliability... However they are significantly increased by the high requirements in terms of memory storage and integration that are not usual in the space domain. Particularly, the memory storage module should be built around high-density SDRAM memories. The image sensor is a brand new High Accuracy Star Tracker CMOS APS. This design is the first one integrating this sensor in a space application. Another very challenging aspect is the mechanical integration of the electronics inside the telescope enclosure. Last, but not the least, the integration of the memory storage into the flight computer introduces huge constraints in terms of power consumption, available space and reliability.
Solution
DELTATEC developed a complete open solution based on a PC client/server architecture. DELTATEC has an impressive track record of developments in digital video. Thanks to its great system expertise, DELTATEC was able to propose a solution that was both compact and complete, meeting all customer requirements.
The image sensor controller board includes the image sensor, a multi-chip SRAM memory module and a FPGA to control the operations. It also includes complex analog electronics that works under extreme conditions.
The mechanical integration inside the telescope has been solved using a flexible PCB technology.
The memory storage uses multi-chip modules for SDRAM and an Actel FPGA to build an extremely compact and low power memory storage (considering the space domain referential). More specifically, the board carries a 4 Gbits array of memory, with 50% redundancy