The primary load-carrying structure for the Optical Bench Assembly is the graphite-epoxymatched set that includes the Aft Optics Platform (AOP) and the Afocal Telescope Bench (ATB).
The AOP provides optically accurate positioning of the four objective assemblies and the dichroic assembly. It also provides the mounting plane for the Passive Radiative Cooler using three titanium anchors.
The ATB provides accurate registration of the primary, secondary, and fold telescope mirrors to each other, and a close-tolerance three-point mount for the AOP, which aligns the aft optics to the telescope. Optical alignments are in the order of 25µm. The combined weight of the Optical Bench Assembly is 22 kg.