- The basic free-space optical communication system includes atleast two satellites. To communicate between them, the transmitter satellitemust track the beacon of the receiver satellite and point the informationoptical beam in its direction. Optical tracking and pointing systems for freespace suffer during tracking from high-amplitude vibration because ofbackground radiation from interstellar objects such as the Sun, Moon, Earth,and stars in the tracking field of view or the mechanical impact from satelliteinternal and external sources. The vibrations of beam pointing increase thebit error rate and jam communication between the two satellites. One way toovercome this problem is to increase the satellite receiver beacon power.However, this solution requires increased power consumption and weight, bothof which are disadvantageous in satellite development. Considering thesefacts, we derive a mathematical model of a communication system that adaptsoptimally the transmitter beam width and the transmitted power to the trackingsystem performance. Based on this model, we investigate the performance of acommunication system with discrete element optical phased array transmittertelescope gain. An example for a practical communication system between a LowEarth Orbit Satellite and a Geostationary Earth Orbit Satellite is presented.From the results of this research it can be seen that a four-element adaptivetransmitter telescope is sufficient to compensate for vibration amplitudedoubling. The benefits of the proposed model are less required transmitterpower and improved communication system performance.