Optomechanical and wavelength alignments of CubeSat laser communication Systems

Abstract

While the introduction of CubeSats has enabled the scientific, commercial, and governmental communities to launch space missions more quickly at lower costs, the communication subsystems of the platform are limited by a heavily regulated and overcrowded RF spectrum. Scientific instruments with increasing capabilities on CubeSats are generating massive amounts of data and are quickly pushing the boundaries of the data rates of current RF communication systems. An alternative to the traditional RF communication system is the free space optical (FSO) communication system. With higher power efficiency, FSO communication, or lasercom, can potentially provide higher data rates using less power and also avoid the RF spectrum regulatory process. MIT's Nanosatellite Optical Downlink Experiment (NODE) is an effort to demonstrate low cost and high speed optical downlink from LEO for CubeSats, and this thesis focuses on alignments in the optomechanical system and transmitter system of the NODE payload. First, simulation and analyses are performed on an optomechanical model of NODE to study the effects potential misalignments of hardware components can have on the overall system. Second, we present an autonomous optimization algorithm that monitors the conditions of the transmitter system and compensates for wavelength misalignments between the transmitter optical components caused by variations in the thermal environment.