Abstract: Stray light in a metering structure is controlled by surrounding with a rigid shield an elongated length of a strut and supporting on the rigid shield a surface finish which is highly absorptive of light. The strut is thermally decoupled from the rigid shield using a plurality of insulating web layers comprising a multi-layer insulation (MLI) system disposed between the strut and the rigid shield. The MLI in such scenarios (1) thermally isolates the strut from the shield (2) serves as a support structure to support the rigid shield on the strut, and (3) absorbs thermally induced mechanical stresses as between the rigid shield and the strut.

Abstract: Metering structure includes a rigid strut configured to support an optical element. A rigid shield mounted on the strut has a shield length which is substantially coextensive with the elongated length of the rigid strut such that rigid shield substantially encloses the strut along the entire shield length. The rigid shield has a surface finish which is highly absorptive of electromagnetic radiation in the optical spectrum. One or more thermal insulating material layers comprise a multi-layer insulation (MLI) system disposed between the rigid strut and the rigid shield. Rigid and flexure brackets secure the rigid shield to the strut.