Deep space optical communications (DSOC) beam expander design and engineering

Maintaining a stable and high quality laser wavefront is pivotal for efficient laser communications in deep space networks. In this presentation, we describe the design and expected optical and structural performance of the afocal beam expanding telescope for the NASA DSOC mission. This 22 cm aperture, 11x magnification telescope must survive the stresses of launch and maintain alignment through solar illumination, laser irradiance, thermal transients, and temperature extremes during the DSOC mission life from Earth to Mars. Structural-Thermal-OPtical (STOP) analysis predict very stable downlink wavefront error (< 122 nm RMS) and beam divergence (< 14.5 microradians). Furthermore, we present additional telescope link loss contributions that will be minimized through particulate contamination control, high spectral throughput, and polarization purity. Successful performance of this telescope will support NASA's ongoing efforts to extended high data rate communications into deep space.