LAUSR

Abstract. The Coronagraph Instrument (CGI) onboard the Nancy Grace Roman Space Telescope is a technology demonstration instrument that will enable direct imaging of exoplanets with the ability to observe exoplanets almost a billion times fainter than their host star. To accomplish this breakthrough imaging capability, an advanced optical design is required that includes deformable mirrors, alignment mechanisms, optical masks, mirrors, and electron-multiplying charge-coupled device detectors. This advanced optical design necessitated the development of a comprehensive contamination control program including material selection, environmental monitoring, surface inspections and sampling, instrument venting design, and use of molecular absorbers inside the CGI optical bench. To verify CGI’s contamination control requirements, detailed analyses of both molecular and particulate contamination were performed including contamination transport modeling, wavelength-dependent optical degradation, molecular absorber saturation, optical mask blockage due to particulates, and simulations of instrument thermal vacuum testing. We describe the development of the CGI contamination control program including case studies on the implementation of the plan and analysis performed to verify the mission requirements.