Laser communications (Lasercom) technology offers the promise of much higher rate data exchanges while reducing the size and weight of the telecommunications package for deep space missions. This improved system performance is due primarily to the narrow transmit signal beamwidth at the optical wavelength, which allows for more efficient delivery of the transmit signal to the receiver. The problem of pointing a laser signal can in general be decomposed into the problems of (i) stabilizing the optical line of sight and (ii) providing the appropriate pointing reference to the receiver location. Optical Physics Company (OPC) has adapted the precision interferometric star tracker it is currently developing under several DoD contracts for deep space lasercom beam pointing applications. The OPC interferometric star tracker can also be used to provide precise attitude measurements to the spacecraft for navigation and orbit determination purposes. The current concept for the beam pointing is for a star tracker to be mounted opposite to the downlink beam boresight. This configuration has the advantage that, for outer planet missions, the sun will almost always be away from the tracker, thus allowing the tracker to have a direct view of the sky.

Application most relevant to this project is the use of star trackers for spacecraft. OPC is building a cubesat star tracker at this time to deliver to a DOD customer. The performance is power dependent - ranging from sub arcsecond to 2 arcsecond accuracy. The package is small - 250 cc in volume. Another visible band star tracker application was proposed to the Navy recently under the SBIR program. This proposal has been selected for award. The application involves space situational awareness, specifically to develop, build and deliver a version of the interferometric tracker capable of detecting and tracking dim objects. Another application is GPS denied navigation which has increasingly become a more acute need in the past few years. Customers are GPS denied navigation systems include virtually the whole armed forces. Our approach is primarily tailored to airborne platforms such as fighter aircraft, ground attack aircraft, next generation bomber, Tier II and Tier II+ UAVs, airborne early warning and control aircraft, ICBMs, and missiles including hypersonic missiles. OPC is currently funded under Navy RIF to build and flight test a stellar inertial navigation system prototype.

The most immediate application of this technology is in deep space optical communications with the main customer in this area being NASA. NASA Draft Communication and Navigation Systems Roadmap Technology Area 05 dated November 2010 states in reference to optical communications that "longer term, reliance on beacons should be eliminated." Our technology offers the ability to communicate from a near Earth or deep space (up to 40 AU) spacecraft platform using a narrow beam aimed precisely at a beaconless receiver. We can consider both near Earth and deep space applications for the proposed technology. For applications in deep space ranges (up to 40 AU- which is the radius of the solar system), we can name the JPL project called deep-space optical terminals (DOT) as our primary customer at this time. This project was initiated in 2009. DOT involves concept and design of terminals that can handle higher data rates with lower mass and power than the Mars Laser Communication Demonstration (MLCD). OPC has also been funded recently for a study by JPL to investigate if its interferometric star tracker can be used for a spinning spacecraft. The study findings have shown the feasibility of adapting the interferometric tracker to provide accurate attitude information for a rapidly spinning spacecraft.