CDH ICD

The purpose of this document is to describe the mechanical, electrical, data, and thermal interfaces between the CDH subsystem and other satellite subsystems. 

• CDH receives power from a distributed power bus at unregulated battery voltage (Vbat = 6.4 +/- 0.4 V) through distribution load switches that are operated by the Power module controller.

• Power ON/OFF is controlled by a CAN-Controlled Load Switches and Monitors (CCLSM) through the auxiliary CAN bus, which is commanded and controlled by the Power subsystem

• The CDH subsystem is made of the CDH Circuit Card Assembly (CCA). All parts of the CDH are soldered onto the CCA and the CCA has no detachable parts.

• Position: CDH/AODCS Module

• Mass: 41.89 grams

• Dimensions (L x W x H):  90mm x 90mm x 1.6mm

• Mounting Holes:

  • four corner holes 2.5 mm diameter each for M2 metric screws

  • 81 mm center-to-center distance

• Maximum Component Height: +5.60 mm from board's top and -5.60 mm from board's bottom surface

• Outgassing: All hardware components are compliant and will be conformally coated

• CDH CAD Drawing: To be made

• 1 thermistor to measure CDH processor temperature

• Operational temperature range: -40°C to 85°C. 

• Survival temperature range: -40°C to 85°C. 

• Thermal subsystem, which includes thermistors located throughout the satellite, uses indirect connections to the CDH through other subsystems.

  • • The PLD subsystem provides thermistor information to the CDH over CAN

    • The PWR subsystem provides thermistor information to the CDH over CAN. Information from the thermistors located on the solar arrays is provided to the CDH by PWR through CAN

    • The AODCS subsystem provides thermistor information to the CDH over SPI

    • The COMMS subsystem provides thermistor information to the CDH over RS-485