Assembly, Optimization and Calibration of the Roman Coronagraph Camera Systems: The Exoplanetary Systems Camera (EXCAM) and the Low Order Wavefront Sensing Camera (LOCAM)

The Nancy Grace Roman Space Telescope (“Roman”) is a 2.4 m flagship astrophysicsmission featuring a secondary coronagraph instrument (CGI) capable of directlyimaging extrasolar planets and debris disks through starlight suppression. CGI will,for the first time, demonstrate a space-based platform for active wavefront controlthrough adaptive optics and the use of photon-counting electron-multiplying chargecoupled devices (EMCCDs). Integral to this demonstration are its two camerasystems, EXCAM and LOCAM, that will enable contrast of up to 10−8 for sciencetargets—a 100-fold improvement over current state-of-the-art technology. We detailthe assembly, calibration, and integration of EXCAM and LOCAM into the CGI. Thecamera subassemblies are introduced with a description of their design, assembly,and functionality, followed by an explanation of the waveforms that specialize eachcamera. Calibration results from both the subsystem and instrument levels arepresented alongside CGI performance requirements and suggestions for optimumperformance across relevant operating scenarios. CGI is a critical step toward futuremissions targeted at direct imaging of Earth-like planets in the habitable zonesof nearby stars. We conclude with recommendations for next-generation camerasystems that can accommodate similar functionality to CGI while offering improvedimaging performance and extended mission lifetime.