Boston Chapter of the IEEE Photonics Society

Abstract:  CubeSats are nanosatellites that typically weigh less than 5 kg and are the size of a toaster oven, only with about 100 times less available power. CubeSat communications systems are typically RF, from 1200 baud FSK to >200 Mbps; higher rates are usually commercial CubeSats at higher frequencies and with more capable ground systems. Due to size, weight, and power (SWaP) limits and regulatory constraints, most CubeSats transmit at ~2 Watts with relatively low gain antennas. With the rapid growth in number of CubeSats on orbit, RF licensing for CubeSats has become a challenge. Free space optical (FSO) or laser communications (lasercom) systems have some performance advantages over RF and access to vast amounts of currently unregulated bandwidth. With demonstrated improvements in pointing capabilty, CubeSats in Low Earth Orbit (LEO) can now track a ground station telescope or track to crosslink to another CubeSat optical terminal, enabling FSO at hundreds of Mbps to Gbps while still supporting operation of instrument payloads. Low-cost, compact FSO terminals can support the vision of large constellations or swarms of CubeSat sensors (from hundreds to thousands of nodes) collecting terabytes or petabytes of remote sensing data daily (e.g. hyperspectral imagery, video). Lasercom downlinks and crosslinks within constellations and swarms can also enable exchanges of large volumes of data for autonomous onboard processing toward intelligent system planning and scheduling. We discuss the initial CubeSat FSO missions from research and industry, including MIT's Nanosatellite Optical Downlink Experiment and its corresponding Portable Telescope for Lasercom (PorTeL), MIT's CubeSat Lasercom Infrared CrosslinK mission (CLICK) with University of Florida's Miniature Optical Communications Transceiver (MOCT), and NASA’s Optical Communications and Sensor Demonstration (OCSD) CubeSats.

Biography:  Kerri L. Cahoy, Associate Professor of Aeronautics and Astronautics at MIT, received her B.S. (2000) in Electrical Engineering from Cornell University, and her M.S. (2002) and Ph.D. (2008) degrees in Electrical Engineering from Stanford University working with the Radio Science Team on Mars Global Surveyor. From 2006 to 2008, she was a Senior Payload and Communication Sciences Engineer at Space Systems Loral in Palo Alto, CA. From 2008 to 2010, Dr. Cahoy was a NASA Postdoctoral Program Fellow in Exoplanet Exploration at NASA Ames Research Center. From 2010 to 2011, she was a Radio Science research scientist on the MIT Gravity Recovery and Interior Laboratory (GRAIL) lunar mission team at NASA Goddard Space Flight Center. Prof. Cahoy currently holds the Rockwell International Career Development Chair.

Dr. Cahoy leads the MIT Space, Telecommunications, Astronomy, and Radiation (STAR) Lab, part of the Space Systems Laboratory

Location:  MIT Lincoln Laboratory Forbes Road