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Command and Data Handling

Scope and Description

This topic page covers the design of command and data handling (C&DH) subsystems for small satellites. The C&DH subsystem is responsible for controlling the spacecraft, managing internal data flows, and handling the 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 in this topic area are primarily website databases of smallsat COTS components and book chapters on satellite C&DH design.

Best Practices and Lessons Learned

Last Updated:

Nov. 10, 2021

Consider redundancy for critical, yet cheap, electronic components such as mass memory devices (e.g., SD Cards) that are less resilient to the radiation environment.

Last Updated:

Nov. 10, 2021

Design your C&DH to be reused on future missions. This will minimize the amount of new flight software, ground support equipment, and testing - all of which can increase the cost and risk for future missions.

Last Updated:

Nov. 1, 2021

Whenever practical, the ability to reprogram or reconfigure flight software on orbit should be a requirement. Software flaws are a common cause of smallsat failure.

Resources

Last Updated: Nov. 11, 2021

SPOON is an online database of smallsat components such as payloads, flight processors, antennas, propulsion ... systems, equipment for ground stations, and power systems.

Command & Data Handling

Website
CubeSatShop

Last Updated: Aug. 30, 2021

The CubeSatShop provides commercial-off-the-shelf (COTS) components from verified vendors for small satellites. ... This link directs users to the command and data handling page where COTS hardware components can be purchased.

This annual state-of-the-art report from NASA provides "a survey of small spacecraft technologies sourced ... from open literature" with an introduction to each technology, development status and performance metrics for procurable systems, and descriptions of new technologies with reference missions. Section 8 of this report covers avionics and flight software technologies.

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.

This annual state-of-the-art report from NASA provides "a survey of small spacecraft technologies sourced ... from open literature" with an introduction to each technology, development status and performance metrics for procurable systems, and descriptions of new technologies with reference missions. Section 11 of this report covers ground data systems & mission operations technologies.

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 paper describes the approach taken by the ION-F student team in designing a common Command and ... Data Handling (C&DH) subsystem for three different nanosatellites. It outlines the requirements of the satellites and reasons behind the decision to develop a custom board. The design is based upon industrial-grade components and centered on a Hitachi SuperH RISC Processor. The C&DH subsystem contains a 16 MB telemetry buffer, a digital and analog interface subsystem, and a DMA-oriented CMOS camera framebuffer." This is a dated case study for C&DH design, but it effectively captures requirements and design approaches that are still relevant today.

Last Updated: Oct. 19, 2021

This site provides cubesat requirements, guidance, and available product offerings related to payload ... processors for satellites. It provides an overview of the payload system, payload processor, and a list of payload processors available on the global marketplace.

Last Updated: Oct. 19, 2021

This site provides background on satellite on-board computers (OBCs), requirements, and a list of OBCs ... available on the global market.

Last Updated: Oct. 18, 2021

SMAD is a practical handbook for space mission engineering covering all aspects of a space system - from ... orbit and constellation design to operations. This section titled "Command and Data Handling" (C&DH) provides an introduction to C&DH, system sizing, and the basics for determining C&DH requirements.

Last Updated: Oct. 19, 2021

SMAD is a practical handbook for space mission engineering covering all aspects of a space system - from ... orbit and constellation design to operations. This section titled "Spacecraft Computer Systems" addresses computer system specifications, computer resource estimation, and computer system design for a notional satellite mission.

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.