Wiring and Cabling
Solder sleeves nickel plated stranded copper wire

Manufacturing problem: NAS1744-03 solder sleeve used to solder nickel plated stranded copper wire to the nickel plated shield of a twisted pair. The stranded wire was tinned; the shield was not. NAS1744-03 is designed for use with tinned or silver plated wire, not nickel plated. It is important to verify compatibility of materials to be soldered prior to the soldering operation. In addition, only solder sleeves specifically approved for spaceflight application are permitted due to outgassing requirements.

Reference :
NASA-STD-8739.3 7.2 - Preparation of Connectors
5. Tinning of Conductors.
The portion of stranded or solid conductors or part leads that will eventually become a part of the finished solder connection shall be tinned with solder and cleaned prior to attachment.