Laser communication system design for the Google Lunar X-Prize

Laser communications systems offer a significant advantage over traditional radio frequency systems due to the shorter wavelength of laser light. Data can be sent at higher rates for less power with proportionally smaller transmitters and receivers. A laser communications system has never been demonstrated in a moon to Earth link at MBps data rates This paper presents a model of a laser downlink from the moon, developed to rapidly explore various system architectures. Modeling and analysis shows that the target data rates of above 2 Mb/s are possible with 300 mW of transmitter power using a 3.5 mm aperture, a 1.5 m receiver diameter and a minimum gimbal resolution (maximum step size) of 78 μrad. 19.89 Mb/s data rates are possible using a 1 cm transmit aperture but with a much stricter minimum gimbal resolution (maximum step size) of 27 μrad.