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Mechanical Assembly

Scope and Description

This topic page covers mechanical assembly of spacecraft hardware up to the subsystem-level of integration, including staking and other mechanical or thermal polymeric applications. Establishing and following good mechanical assembly practices will ensure reliability through the rigorous low Earth orbit thermal cycling environments and launch vibration environments experienced by most smallsats. The importance of establishing good practices is particularly important for smallsat hardware, where, in many cases, inexperienced technicians (e.g., members of the engineering team) are completing mechanical assembly.

Resources under this topic area are primarily workmanship standards and example quality assurance documents and procedures for mechanical assembly of space hardware.

Best Practices and Lessons Learned

  • Always test mechanical assembly 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.
  • Tools and materials should be labeled with unique IDs for clear identification in assembly procedures, calibration traceability (e.g., for torque drivers), and inventory tracking.
  • 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.
  • Engineers and technicians should collaborate to improve assembly procedures, tools, and facilities as needed to make assembly easier. These improvements can be expensive, but will often deliver return on investment by reducing labor cost. In addition, easier assembly is correlated to fewer workmanship flaws and increased reliability in the final product.

Resources

This appendix provides a smallsat manufacturing quality assurance document example.

Article
Jeff Juranek

This conference presentation includes "key recommendations" on how to improve the efficiency of space ... hardware assembly, integration, and test. The recommendations are supported by examples and data.

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.

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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