Test validated alignment and stability performance of the JMAPS program focal plane array assembly in a cryogenic vacuum environment

Focal Plane Arrays (FPA) consisting of multiple Sensor Chip Assemblies (SCA) in a precision aligned mosaic are being increasingly used in optical instruments requiring large format detectors. The Joint Milli-Arcsecond Pathfinder Survey Mission (JMAPS) requires very precise positional alignment and stability of its 2 x 2 SCA mosaic at operational temperatures to meet its precision sky mapping mission requirements. Key performance requirements include: detector active area co-planarity, in-plane alignment, and thermal stability. This paper presents an overview of the JMAPS Focal Plane Array Assembly, its alignment and thermal-mechanical stability requirements, and associated test-validated performance in a cryogenic vacuum environment.