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SpaceCANArtur ScholzLibreCube Initiative

InterfaceStandardization

Data Interface

?

System Bus / Command and Monitoring Bus

I2C

I2C

Chart created using data from M. Swartwouthttps://sites.google.com/a/slu.edu/swartwout/home/cubesat-database

Jacklin, Stephen A. "Small-Satellite Mission Failure Rates." (2019).

Complexity

Complexity

Simple & Robust

Telecommand

Telemetry

Telecommands- switch unit on/off- change mode/configuration of unit- trigger action- …

Telemetry- status of unit- sensor readings (temp, voltage, current, …)- …

MIL-STD-1553SpaceWire

UART / RS-485CAN Bus

Higher layers

Data link layer

Physical layer

Function Node ID

4 7

… up to 127

Masternode_id = 0

Slavenode_id = 1

Slavenode_id = 2

Bus A (Prime)

Bus B (Redundant)

ServicesRedundancy managementSynchronizationTime distributionTC/TM exchange(Message exchange via ISO-TP)

Redundancy

HB

Synchronization

SYNC

Time distribution

SCET UTC

TC/TM exchange

TC

TM

TM

TM

Data (1 … 8 Bytes)Node ID

Init

TM received? Print

Timer? Send TC

Init

SYNC received? Exec

TCreceived?

Collect & Send TM

Master node Slave node

SYNC (1 Hz)

HB (2 Hz)

Y

Y

N

Y