- The basic free space optical communication system includes at least two satellites. In order to communicate between them, the transmitter satellite must track the beacon of the receiver satellite and point the information optical beam in its direction. Optical tracking and pointing systems for free space suffer during tracking from high amplitude vibration due to background radiation from interstellar objects such as sun, moon, earth and stars in the tracking field of view or mechanical impact from satellite internal and external sources. The vibrations of the beam pointing increase the bit error rate and jam communication between the two satellites. One way to overcome this problem is to increase the satellite receiver beacon power. However this solution requires increased power consumption and weight. These two factors are disadvantageous in satellite development. Considering these facts, we derive a mathematical model of a communication system that adapts optimally the transmitter beamwidth and the transmitted power to the tracking system performance. Based on this model, we investigate the performance of a communication system with discrete level optical phased array transmitter telescope gain. An example for a practical communication system between a low earth orbit satellite (LEO) and a geostationary earth orbit satellite (GEO) is presented. From the results of this work it is seen that a four level adaptive transmitter telescope is sufficient to compensate for vibration amplitude doubling. The benefits of the proposed model are less required transmitter power and improved communication system performance.