March 17, 2015

Myriade Platform

The second in CNES's Myriade serie of microsatellites, Parasol uses the same spacecraft bus as the Demeter microsatellite in orbit since 29 June 2004, which is probing electromagnetic disturbances related to Earth tremors. The bus provides generic systems designed for satellites with a launch weight of around 100 kg.

The main structure is a 60-cm cube opening out on each side for easy access to equipment. With its payload, the satellite stands about 80 cm tall and weighs 120 kg at launch.

The attitude control system, precise to within one-tenth of a degree, is built around a star sensor, four reaction wheels and three magnetic torquers. Three Sun sensors and a magnetometer are also used during the satellite positioning phase. Four one-Newton hydrazine thrusters control the satellite's orbit, while onboard data handling is centralised and controlled by a 10-Mips T805 microprocessor. Data can be stored in a mass memory. Telemetry and telecommands use the international standard established by the Consultative Committee for Space Data Systems (CCSDS).

The solar array consists of two hinged panels folded against the platform during launch. When the panels are deployed in orbit, the 1.7-metre array initially provides approximately 180 W of electrical power.

To accommodate large amounts of data and fast transmission, Parasol has a large mass memory (16 Gbits) and a high-speed telemetry system, both derived from Demeter.