OPALS: An optical communications technology demonstration from the International Space Station

Optical communication using space borne lasers has long promised to increase the amount of science data transmitted down to Earth. A first step in achieving operational capability is demonstrating the fundamentals of the optical link in an equivalent environment. The International Space Station, with its vast capability, is well suited to accommodate payloads aimed at advancing the readiness of such technologies. The Optical PAyload for Lasercomm Science (OPALS), to be launched to and operated on the ISS in late 2013, will attempt to downlink a short video to an optical ground station in California using a 1550 nanometer, 2.5 watt laser, over the course of a 90 day mission. To achieve this, in addition to designing and building the ISS payload, the OPALS team has increased the capability of the existing ground station, as well as developed the interface to the ISS infrastructure that will allow operators to command it. This paper will discuss the drivers and constraints created by designing to existing interfaces (ISS flight, ISS operational, ground system) while following a Class D payload implementation (NASA NPR 8705.4). The paper will also provide some specific examples of programmatic and technical areas that have been shaped by these drivers and constraints.