The NASA Optical Communication and Sensor Demonstration Program: An Update Siegfried W. Janson and Richard P. Welle The Aerospace Corporation Mail Stop M2/241, P.O. Box 92957, Los Angeles, CA 90009-2957; 310.379.7060 siegfried.w.janson@aero.org

The Optical Communication and Sensor Demonstration Program was one of three projects selected by the NASA Small Spacecraft Technology Program in 2012. This effort will demonstrate a 5 to 50 Mbps optical downlink in a 1.5U CubeSat based on a 10-W modulated fiber laser with a 0.35o full width half-maximum angular beamwidth. To fully utilize the laser, the spacecraft requires equivalent or better pointing accuracy. We’ve developed miniaturized sun, Earth Nadir, and Earth-horizon sensors, plus a cm-scale star tracker, to provide the required attitude references for our attitude control system. The secondary goal is to demonstrate proximity operations using two identical spacecraft. In the spring of 2015, two 1.5U AeroCube-OCSD CubeSats will be ejected from the same P-POD and brought within 200-meters of each other using on-board GPS measurements for position and velocity determination, variable drag for cooperative orbit rephasing, and a steam thruster for proximity maneuvering. Each satellite has deployed wings that allow varying the ballistic coefficient by at least a factor of 4 by changing spacecraft orientation with respect to the flight direction. High-fidelity orbit ephemerides will be generated on the ground using multiple GPS measurements per orbit, and relative range will be measured on-orbit using a laser rangefinder