Today we’re very happy to report on the completion of a long-term project that Dr. Wu worked on during his previous gig at the NASA Jet Propulsion Laboratory: the Optical PAyload for Lasercomm Science (OPALS) mission, on which Dr. Wu served as chief telecommunications engineer. In this mission, we modulated a 1550 nm laser with on-off keying to downlink video from the International Space Station to the Table Mountain Observatory at Wrightwood, California. This demo presented many formidable technical challenges, such as designing encoding schemes to adequately protect our transmission against the effects of atmospheric turbulence and gimbal jitter, and using feedback control to precisely aim the laser at the ground station given noisy imagery from an on-board camera. The first successful downlink was reported in early June, and all transmissions since then have also been reported as working flawlessly.
Dr. Wu responsibilities included the design and implementation of efficient digital communications software for the encoder and decoder, including video source coding, channel coding, frame synchronization, and pseudorandomization, and providing analysis for the link budget and computer vision problem. It was also great fun to work with some especially talented engineers on this project, such as Dr. Kenneth S. Andrews and Dr. Baris I. Erkmen.
Below are links to some media releases related to the project for further reading, along with a teaser slide showing our tongue-in-cheek summarization of the project.