CubeSat laser infrared crosslinK mission status

Abstract

Constellations of CubeSats will benefit from high data rate communications links and precision time transfer and ranging. The CubeSat Laser Infrared CrosslinK (CLICK) mission intends to demonstrate low size, weight, and power (SWaP) laser communication terminals, capable of conducting full-duplex high data rate downlinks and crosslinks, as well as high precision ranging and time transfer. A joint project between the Massachusetts Institute of Technology (MIT), the University of Florida (UF), and NASA Ames Research Center, CLICK consists of two separate demonstration flights: the initial CLICK-A, which will demonstrate a space-to-ground downlink and serve as a risk-reduction mission, and CLICK-B/C, a crosslink demonstration mission.The CLICK payloads each consist of laser transceivers and pointing, acquisition, and tracking (PAT) systems, and will fly on 3U CubeSat buses from Blue Canyon Technologies to perform their optical downlink and crosslink experiments in low Earth orbit (LEO). We present an update on the status of both the CLICK-A and CLICK-B/C payloads. At the time of writing, the final assembly and testing of the CLICK-A payload has been completed and the payload has been delivered for integration with the spacecraft bus. The final testing included the validation of the transmitter and the PAT system, the performance of both of which was characterized under various environmental test conditions and shown to meet their requirements for operation on orbit. On CLICK-B/C, the payload electronics have been designed and are under test. The optical bench of the payload has been assembled, the characterization of which is ongoing.

A Review of Mechanical Fine-Pointing Actuators for Free-Space Optical Communication

“…Detector-operable bandwidth varies due to received signal power. According to Serra et al ( 2019) [43], the detector onboard the CLICK satellite works at a 200 Hz refresh rate when it receives 100 nW of optical power on the Quad-cell from the ground beacon. In the early study phase, an FSM with a bandwidth of approximately 220 Hz, a diameter of 5 mm, and a mechanical deflection angle of ±3.8 degrees was selected for this mission [19].…”

Transmitter and fine pointing system development and testing for the CubeSat Laser Infrared CrosslinK (CLICK) B/C mission

“…The receive chain can select between a time-to-digital converter (TDC)-based approach and an analog-to-digital converter (ADC)-based approach. The latter uses a matched filter and provides a higher signal-to-noise ratio at the expense of digital processing complexity, while the former provides high timing accuracy with less digital processing 8,9 The payload control electronics include a Raspberry Pi Compute Module 3-based CPU board. Running Linux, this module manages the payload command and data handling and interfaces with the spacecraft bus.…”

Performance Analysis of Passive Retro-Reflector Based Tracking in Free-Space Optical Communications With Pointing Errors

“…During the fine tracking stage, the system requires more precise and fast compensation of pointing errors to keep both transceivers within the field of view. For this reason, quadrant detector (QD) and fast steering mirror (FSM) are widely used in this stage [6]. Based on the conventional fine tracking method using QD and FSM, we propose a fine tracking method that reduces outage probability and saves the power budget of the UAV.…”