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Command and Data Handling

Scope and Description

This topic page covers the testing of command and data handling (C&DH) subsystems for small satellites. The C&DH subsystem is responsible for controlling the spacecraft and managing data flows within the spacecraft and data transmitted to or received from other systems. To carry out these tasks, this subsystem typically includes a processor and associated memory to store and run the flight software, mass memory to store data for downlink, and digital and analog interfaces to communicate with other devices on the spacecraft. The digital electronic components of a C&DH subsystem are susceptible to radiation effects and must be reliable and resilient for mission success.

Resources under this topic area are primarily case studies for testing of satellite C&DH electronics. Note that this does not include flight and embedded software testing, which is closely related but addressed separately in the Detailed Design section of this knowledge base.

Best Practices and Lessons Learned

Last Updated:

Nov. 1, 2021

Redundancy can hide manufacturing or design defects in the independent devices or circuits. It is essential to design for independent testing of redundant devices or circuits. This requirement should be flowed to vendors or established early in the design process for new systems.

Last Updated:

Nov. 1, 2021

When testing memory devices, exercise the full memory space. Individual workmanship (e.g., solder joint for wirebond) flaws can disable a subset of the address bits without creating any apparent issues in other areas of the memory.

Resources

COSMOS

Software Tool
Ball Aerospace

Last Updated: Oct. 19, 2021

This open-source software tool provides a user interface for command and control of embedded systems. ... It is a suite of applications that can be used across the lifecycle of an embedded system (e.g., a small satellite flight computer) - from test to operations.

Last Updated: Sept. 29, 2021

This thesis discusses the command and data handling (C&DH) subsystems for the Next-Gen Earth Monitoring ... and Observation-High Definition (NEMO-HD) and NorSat-3 microsatellites. It describes the hardware and software design as well as the setup procedures for testing the C&DH subsystems.

This conference paper " introduces a generic methodology of simulating a satellite on-board computer ... within an on-board data-handling network." The resulting simulation capability can be used to emulate individual C&DH components for controller-in-the-loop and hardware/software compatibility testing.

Last Updated: Nov. 11, 2021

This thesis provides a detailed review of the command and data handling (C&DH) system being developed ... at the University of Texas at Austin's Texas Space Laboratory (TSL) for multiple CubeSat missions. Chapter 6 of this resource on C&DH System Testing discusses flight software testing, functional testing, command execution tests, and C&DH software unit tests.

Last Updated: Oct. 19, 2021

This thesis describes the design and testing of a radiation-shielded field programmable gate array (FPGA) ... flight computer. It discusses the FPGA's design justification, general characteristics, and theoretical analysis using Markov calculations and CREME96 simulations. Chapter 7 presents the results of testing to validate the overall reliability of the system.

Last Updated: Nov. 11, 2021

This document details the automated testing process and procedures for the Canadian Space Agency's ORCASat ... project. The automated testing framework was integrated into the on-board computer responsible for the command and data handling (C&DH) of the 2U CubeSat. The system architecture and methodology for testing the C&DH system using a hardware-in-the-loop (HIL) test platform is provided in Sections III and IV, respectively.

Last Updated: Oct. 19, 2021

This article presents "a novel and flexible platform for prototyping flight software and testing with ... hardware-in-the-loop is proposed based on the Basilisk software and the Raspberry Pi hardware." The authors provide context and motivation for autonomous operations of deep space missions and demonstrate testing and analysis of the flight software, C&DH hardware, and simulation models in a closed-loop simulation.

Last Updated: Nov. 11, 2021

This journal paper highlights the Technical University of Munich's MOVE-II CubeSat and the hardware-in-the-loop ... (HIL) and software-in-the-loop (SIL) testing performed to test the attitude determination and control system (ADCS). Additionally, other subsystems including the electrical power system (EPS) and command and data handling (C&DH) computer were validated using HIL testing.