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Electronics Manufacturing

Scope and Description

This topic page covers manufacturing of spacecraft electronics. This includes printed circuit board (PCB) procurement/specification, soldering, and polymeric applications (e.g., conformal coating, staking, bonding, etc.). The density of components in modern electronics, diversity of packaging, and general complexity of the assemblies create many opportunities for workmanship flaws in electronics manufacturing. Following traditional standards and processes for electronics manufacturing is often too slow and costly for smallsat developers. This leads many to either have their systems manufactured to commercial specifications or to complete a subset of the manufacturing processes themselves. In either case, it is important to understand and learn from the traditional manufacturing standards and processes.

Resources in this topic area are primarily standards and related implementation documents for electronics manufacturing.

Best Practices and Lessons Learned

  • Always test electronics manufacturing procedures (especially polymeric applications) on spare hardware or a non-flight unit. Document the findings from the technician regarding the quality and clarity of the procedure and the results of any follow up inspection or testing. If possible, this qualification run through the procedure should not be conducted by the author. Review findings and iterate if necessary.
  • Polymerics for space applications have notoriously long lead times and, in may cases, short shelf lives. Regardless of shelf life, buy more than you need and regularly check your inventory for shelf life vs lead time. Account for substantial schedule margin because lead times can be highly variable.
  • Quality assurance inspections should be carried out by a different individual than the one completing a manufacturing task.
  • Set up and clearly label work areas for flight hardware and keep these areas well organized and clean to prevent contamination and potential foreign object debris (FOD) from landing on flight electronics.
  • Do not stake components (unless they are otherwise fragile) or conformal coat a circuit card assembly until it has passed a full functional test. Reworking after polymeric application is significantly more difficult.
  • Use selectively but do not discount the use of the space variant of standards for workmanship and printed circuit boards. When using higher or more stringent standards maintain flexibility. When going to a fab house, board manufacturer, or assembly house, ask for cost and schedule quotes for each of the progressive quality classes (1, 2, 3, “S”) and whether they might recommend a mix or “best effort” depending on the features of the boards or assemblies. In particular have discussions with vendors about relaxing certain specs that might drive risky/challenging features such as microvias, via-in-pad, or multiple additional board layers just to meet the specifications.
  • Recognize that the more stringent printed circuit board specs may help produce more robust boards with extensive internal margins, but there is no established reliability improvement in space applications based on more stringent specs. It is important to note that the extra margins in the more stringent specs can be in conflict with current high density interconnect (HDI) technology, such as typical reconfigurable FPGAs, high density SRAMs, and densely populated boards. Forcing compliance to the specs with such features will significantly increase the time to receive the product and likely reduce the reliability of the board.

Resources

This NASA lesson briefly describes best practices and guidelines for designing and manufacturing space ... flight power supplies to improve reliability and reduce component failures. Special attention is given to corona discharge.

This addendum to IPC J-STD-001E of the Space Applications Electronic Hardware Handbook replaces specific ... requirements for soldered electrical and electronic assemblies. The standard describes materials, processes, and verification criteria to ensure electronic assemblies will survive the thermal and vibration environments of space flight.

This resource on space applications electronic hardware is the latest addendum to the IPC standard from ... the Wiring Harness Manufacturer's Association (WHMA). It provides further detail into the original standards' requirements related to cable and wire harness assemblies to ensure they survive the thermal and vibration environments of space flight.

This IPC handbook provides detailed information on the requirements for soldered electrical and electronic ... assemblies. Soldering procedures, requirements, and tools and techniques are discussed in relation to space and military applications.

White Paper
NASA

This NASA training program provides step-by-step procedures for hand soldering of spacecraft electronic ... components. Examples and practice procedures are provided to help train individuals on a number of tasks, including maintaining electrostatic discharge (ESD) environments, soldering components on printed circuit boards (PCBs), and wire stripping.

This NASA standard provides the electronic hardware requirements for staking, conformal coating, bonding, ... and encapsulation. There is detailed information for each process as well as the required training, certification, and the applicable tools and materials. The staking figures are particularly useful for reference and inspection.

Connectors and harnessing scales such that it can consume a disproportionate volume of small spacecraft. ... This NASA standard provides detailed information on the proper techniques for wire crimping, connections, and harnesses.

This NASA standard "sets forth termination and cabling requirements for optical fiber and cable ...
assemblies" on spacecraft hardware. From fiber optic splicing to cable assemblies, connectors, and cleaning, this document is a detailed resource for smallsat teams implementing fiber cabling in electronic components.

This NASA standard provides detailed requirements for training, facilities, electrostatic discharge control, ... polymeric applications, soldering, cable harness assembly, and fiber optic cable assembly. Many of these requirements simply reference industry standards, however there is still a significant volume of valuable information here to inform smallsat electronics manufacturing processes.

Standard
NASA

This NASA standard provides the requirements for hand and machine soldering of surface mount electrical ... connections. These components are ubiquitous in modern electronics, including the majority of smallsat systems. It is difficult to reliably solder and thoroughly inspect the connections on many surface mount components, making workmanship of the manufacturing as outlined in this document an important consideration for smallsat developers. This figures in this standard are a particularly useful reference for training and inspection.

Standard
ESD Association Standard

This Electrostatic Discharge Association (ESA) standard details the requirements necessary to stand up ... and maintain an electrostatic discharge (ESD) control program and environment. Ensuring a proper ESD environment while developing electronic assemblies for spacecraft is essential to mission success.

This guide provides the procedures and requirements for applying conformal coating, potting and staking ... material specifically intended for Space Dynamics Laboratory (SDL) personnel, although the procedures and best practices provided in this document are relevant for all smallsat projects. Recommended resin formulations for each process are shown along with the ingredients, function, and the recommended amounts.

This conference paper discusses the Cal Poly Picosatellite Project (PolySat). Sections 4 and 5 cover ... integration and construction of PolySat with a level of detail that could be used to inform manufacturing, assembly, and integration processes for other smallsat developers.

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