- The clustering of satellites in cooperative fly formation con- stellations produces a lightweight, low cost, highly reliable and supra- performance space system. One way to communicate between the sat- ellites is by a laser beam with a narrow divergence angle. To maintain line of sight between the transmitter and the receiver during the commu- nication time, a steering device has to be incorporated into the commu- nication system. We adopt a 2-D optical phased array (OPA) antenna. An OPA antenna is an attractive option for a steering device as it is light- weight, compact, and provides agile and inertia-free 2-D beam steering. We integrate two fields of study—OPA and laser communication theory—to attain a new perspective on communication system design. We theoretically analyze and model a laser intersatellite link using a 2-D OPA antenna and illustrate the model by a numerical simulation. The microsatellite antenna gain distribution statistics are derived from the OPA theory using the Monte Carlo method. We apply the results to evaluate system performance, particularly the effect of OPA phase er- rors. © 2003 Society of Photo-Optical Instrumentation Engineers.