APPLICATION NOTES FOR AS22759

1. Flammability properties of these wires are controlled by the applicable specifications.  However, applications in Space Transportation System (STS) payloads may require that the specific STS flammability hazards be addressed. Users are advised to consult the appropriate project systems safety officer.
2. Due to the cold flow phenomena of teflon insulation, the designer is advised NOT to route teflon insulated wires over sharp edges and tight turns, or apply tight stitches and tie wraps to cable assemblies.
3. Silver coated copper is susceptible to cuprous oxide corrosion ("Red Plague") when produced, stored, or used in a moist or high humidity environment.  The environment for this type of wire must be controlled.
4. Some ETFE insulated wire has been found to fail flammability testing in a 30% oxygen environment.
5. For cable bundles of 51 to 139 wires, refer to MIL-STD-681 for additional color designators.
6. Use of conductor sizes of 24 and larger are preferred in interconnecting cable and harness assemblies.  When smaller conductors are necessary, high strength copper alloy shall be used, (REF:  NASA NTS8739.(3G-2) Workmanship Standard for Crimping, Interconnecting Cables, Harnesses, and Wiring [Formerly NHB 5300.4(3G)]).  Refer to NTS8739.(3G-2) for design practice assistance.
7. The insulation material table linked HERE is provided for application assistance.
8. CAUTION!!! Some fluoropolymer insulation materials such as Ethylene-Tetrafluoroethylene (ETFE) may outgas trace amounts of fluorine over time. NASA GSFC Advisory NA-GSFC-2003-03 (Dec. 2002) addresses corrosion concerns for metal shell connectors (especially microminiature and nanominiature types) and contacts that are terminated with fluoropolymer insulated wire AND stored in sealed plastic/metal bags for several months or longer. In sealed packages, Fluorine that is outgassed may react with moisture to form highly corrosive hydrofluoric acid. This acid is capable of corroding metals such as Nickel and Gold which are commonly used finishes for spaceflight connectors and contacts.

As a precaution for all flight hardware with pre-wired connector assemblies, the following mitigations are recommended by NA-GSFC-2003-03:

• Projects should inspect the connectors upon receipt (both the shell and contacts) using appropriate magnification to
  verify that there is no corrosion. The existing inventory of pre-wired connector assemblies should be reinspected. In
  addition, all assemblies should be inspected before use. Inspect for darkening of the shiny metal surfaces. All
  connector interfaces should be covered with protective dust covers. For assemblies that have already been integrated
  into flight hardware and that were inspected and found to be acceptable before mating, there should be no concern for
  subsequent malfunction.
• The pre-wired connector assemblies should be removed from sealed bags and stored in open packages that will allow
  any reactive fluorine compound (s) to escape. Connector assemblies should be stored in a controlled humidity
  environment. The preferable storage area for pre-wired connector assemblies would be in a dry nitrogen atmosphere.