Massachusetts Institute of Technology

Kathleen Michelle Riesing

Kerri Cahoy

David O Caplan

Tam Nguyen Thuc Nguyen

Ryan Wallace Kingsbury

Don M Boroson

Bryan Shawn Robinson

Jamie W Burnside

Hyosang Yoon

Jade Wang

Curt Schieler

Bryan C Bilyeu

Jessica Chang

Communication systems and methods for high-data-rate, high-efficiency, free-space communications are described. High-speed optical modems and automatic repeat request can be employed to transmit large data files without data errors between remote devices, such as an earth-orbiting satellite and ground station. Data rates over 100 Gb/s can be achieved.

Free-space optical communication system and methods for efficient data delivery

Communication bottlenecks, particularly in the downlink direction, are a common problem for many CubeSat developers. As described herein, a CubeSat module for a CubeSat comprises an optical transmitter to transmit data to a remote terminal, a receiver to acquire an optical beacon from a remote terminal, and a fine-pointing module operably and directly coupleable to a coarse-pointing module of the CubeSat. The fine-pointing module is configured to point the optical transmitter toward the remote terminal with an accuracy range that overlaps with an accuracy range of the coarse-pointing module of the CubeSat so as to establish a communications link between the CubeSat and the remote terminal over a low-Earth-orbit (LEO) distance.

Free-space optical communication module for small satellites

A portable optical ground station can track a satellite with an amateur telescope mounted on a two-axis gimbal. The telescope is aligned with respect to an inertial, Earth-fixed frame using a wide field of view star camera. Star cameras are accurate to the arcsecond level and have the advantage of providing orientation with a single measurement. Using multiple star sensor measurements at different gimbal angles, it is possible to calculate the alignment of the gimbals in the Earth-fixed frame and the alignment of the star sensor in the gimbal frame. Once the alignment is obtained, satellite tracking can be achieved with a known orbit and precise Earth rotation model, such as the International Earth Rotation and Reference System Service (IERS). This alignment procedure can be carried out in less than one hour, making it practical to move and deploy the portable ground station.

Satellite tracking with a portable telescope and star camera

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Cambridge, MA, United States of America

Kathleen Michelle Riesing