Metrology Trades for Ambient Testing of the James Webb Space Telescope

Abstract

Testing the James Webb Space Telescope at ambient temperature meant measuring flight hardware that could not be touched. The metrology had to be non-contacting, to avoid physical damage and contamination of the mirrors; non-targeting, to avoid adhesives and mechanical attachments; and multi-purpose, because time and budget were limited. Bente Hoffmann Eegholm sets out those constraints, the purpose of the test, the instruments chosen and the set-up built at 16 metres inside the clean room, then the results and what they meant for the trades that had to be made.