May 15, 2017

The spacecraft bus

Here are the main features of the Myriade spacecraft bus:

CAD representation
DEMETER platform

  • Structure:
    • typical technological structure (aluminium, NIDA, etc.),
    • passive thermal control (paint, insulation blankets, heaters, etc.).

  • Power supply:
    • 2-pannel solar array with 24.5% efficiency (up to 180 W with maximum sun exposure) complete with drive mechanism to ensure continuous rotation
    • 13.5 Ah Li-ion battery
    • power regulation and distribution unit

  • Satellite orientation control:
    • sensors: solar tracker, magnetometer, star tracker, gyrometer
    • actuator: magnetorquers, reaction wheels, hydrazine propulsion system
    • a coarse pointing mode (accurate to 5 to 10°) and a fine pointing mode (0.1°)
    • different pointing types available: Earth, Solar, inertial, etc.

  • Computing and telemetry/remote control link:
    • CNES-designed computer (T805 processor + microcontrollers) with 1 Gb storage
    • 400 kbps telemetry and 20 kbps remote control unit operating with CCSDS protocol, 2 GHz RF S-band link
    • onboard time-keeping (accurate to 0.1 s)
    • storage (8 to 16 Gb) and high-speed downlink (16.8 Mb/s) for scientific telemetry, X-band RF link (8 GHz)
    • payload capacity of up to 55 kg and 55 W.