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Part Selection

Scope and Description

This topic page covers electrical, electronic, and electromechanical (EEE) part selection for space flight hardware. Selection of EEE parts is driven primarily by circuit design and performance, but is often significantly constrained by reliability and radiation tolerance requirements. This is a rich and complex subject within the smallsat community, and one where the design team's approach can significantly impact cost, schedule, and mission confidence.

Resources under this topic area primarily include traditional space part selection guides, presentations with smallsat-specific guidance, and EEE part radiation test databases.

Best Practices and Lessons Learned

  • The likelihood of other issues is much greater that a part issue. Workmanship, design, or analysis issues are often the culprit when a failure seems to indicate a "parts issue". Multiple engineering development units (EDUs) and robust design and test leads to more confidence in the end-product than what part levels are in a design.
  • Smallsat schedule, budget, size, mass, and other resource constraints dictate that the traditional NASA EEE parts paradigm is inappropriate (and in many cases impossible) for smallsats. An alternative EEE parts selection approach based on risk trades at the systems and component level should be explored.
  • Watch out for common mode failure mechanisms in COTS parts - redundancy doesn’t help if all parts are susceptible to the same failure mechanism! For example: (1) Don’t abuse COTS capacitors - choose conservative values. Hand Soldering can damage ceramic chip caps. (2) Be aware of risky materials - tin whiskers like COTS connectors. (3) Relays, switches, connectors (electromechanical parts) are problematic. Testing parts here offers good return on investment.
  • COTS EEE parts usage requires more risk and value assessment. For reliability in COTS-based systems, rely on circuit design, thorough review of parts datasheets, extensive prototyping and test, use of COTS versions of space-rated parts, selective use of space-rated parts, circuit and software-level radiation effects mitigation, shielding, and design to do-no-harm to other systems.

Resources

These workshop slides give a general overview of Radiation Hardness Assurance from a newspace/smallsat ... point of view. Summary information and advice is presented with references to other helpful resources. This is a good introductory resource.

Website
NASA

This is a database of EEE component radiation test data. Search for candidate parts to determine their ... performance under and susceptibility to radiation effects.

Website
ESA

This is a database of EEE component radiation test data. Search for candidate parts to determine their ... performance under and susceptibility to radiation effects.

Article
Michael Campola et al.

Mission environment and complexity for small satellites is becoming increasingly varied. Different missions ... will be more amenable to different risk and cost tradeoffs. These slides provide detailed information, considerations, and advice for EEE parts to be used specifically in smallsat missions. RHA, COTS use, and more are discussed.

This website is a crowd-sourced encyclopedic parts, materials, and processes (PMP) knowledge repository ... for "alternate grade products." Smallsat developers and stakeholders can use this website to find and share part selection and testing guidance, search for EEE component test data and participate in PMP-related discussions in the forum.

This is a database of EEE component radiation test data. Search for candidate parts to determine their ... performance under and susceptibility to radiation effects. --- At the time of writing this description, the link to the database is broken. Please provide feedback through one of the Knowledge Base topic page forms if an updated link becomes available or if you have an update on the status of this database.

This is a database of EEE component radiation test data. Search for candidate parts to determine their ... performance under and susceptibility to radiation effects.

Article
Dave Petrick et al.

SpaceCube is a family of NASA processors that combine radiation-hardened and commercial components to ... create a hybrid-processing architecture. This presentation from the SpaceCube team provides a high level overview of their design approach, the reliability spectrum, relevant lessons learned, and the value of reconfigurability.

Article
Kuok Ling

These slides from NASA Ames Research Center discuss the use of Consumer Off The Shelf (COTS) parts for ... Class D missions. Their philosophy on COTS use, selection strategy, design approach, and more are given. Trades between mission risk and mission cost are discussed. The author argues that careful COTS EEE part use can maintain reliability with major cost savings - a valuable combination for smallsats.

These slides offer a discussion of EEE parts within the context of small spacecraft. Cost and reliability ... trade offs are at the core of this discussion, particularly in relation to parts screening and qualification methods. Alternate risk-mitigation approaches and the concept of "over-design" are also examined. Examples are provided.

White Paper
NASA

This NASA Handbook is an extremely detailed source of technical knowledge regarding high reliability ... electrical and electronic component parts. Cost factors, screening techniques, radiation effects, derating, failure mechanisms, and much more is discussed.

This NASA standard is intended to increase reliability and mitigate risk in flight hardware and ground ... support equipment "by managing the selection, acquisition, traceability, testing, handling, packaging, storage, and application of EEE parts."

This document provides established instructions and requirements for the selection, screening, qualification, ... and derating of EEE parts for use in space missions. It aims to allow development teams to meet mission reliability and performance objectives while staying within their allotted budget and schedule - making this resource particularly helpful to smallsat teams. EEE-INST-002 processed parts are screened to three different levels to support missions ranging from high reliability to those where the use of high-risk components is acceptable but where a purely COTS approach is insufficient.

Article
Doug Sinclair et al.

This white paper provides a "Careful COTS" approach to component selection and testing as they both relate ... to radiation effects and smallsat missions. The presented approach is particularly applicable to LEO missions that leverage COTS components.

Article
Kenneth LaBel et al.

These slides provide detailed information on the unique operational environment for electronics in space ... and provides guidance on risk mitigation in part selection. It includes an approachable and concise discussion of radiation, vibration, and vacuum - with a particular focus on radiation effects for EEE parts.

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