Thermoelastic modeling of the CubeSat Laser Infrared CrosslinK (CLICK) payloads

Abstract

Radio frequency (RF) communication is the typical way that small satellites transmit data from space to the ground. Laser communication (lasercom) can provide lower size, weight, and power (SWaP) compared with RF communication systems. The CubeSat Laser Infrared CrosslinK (CLICK) mission is a series of three 3U CubeSats with low SWaP lasercom payloads. The mission has two phases: CLICK-A, which is downlink lasercom only, and CLICK-B/C, which will perform both crosslink and downlink lasercom experiments. CLICK-A will provide a 10 Mbps downlink data rate to a 28 cm aperture portable optical ground station. CLICK-B/C will provide at least 20 Mbps crosslink at ranges from 25 km to 580 km and with ranging capability better than 50 cm (optical time precision of 1.6 ns). This thesis focuses on the engineering analysis that has gone into the thermal design of the CLICK lasercom payloads. We first provide an overview of the mechanical design, electrical power consumption, and the concept of operations for each of the payloads, which is used to predict on orbit temperatures. The CLICK-A payload thermal model is described and the results of the model are shown. We also describe thermal vacuum testing of a camera and lens that are used both for the CLICK-A and CLICK-B/C payloads. The CLICK-B/C payloads thermal model is described and the results of the model are shown. Thermoelastic analysis is performed to determine the pointing error induced by the shifting of optics within the CLICK-B/C payloads. The thermal models predict all components will stay within survival temperatures, and that all components will be able to be preheated to within their operational temperature bounds. This work contributes to the development of CLICK payloads and the state of the art for miniaturized free space optical communication technologies.