Many complex optical and electro-optical systems are currently operating in the space environment, and other more sophisticated systems are being planned for future development and operation. Assurance of the survivability of these systems is typically provided by ground-based testing which simulates those aspects of the space environment considered most serious. Such testing, however, has not prevented occasional anomalous behavior and unexplained failures. To properly explain the degradation mechanisms affecting these systems and to obtain the engineering and testing data necessary for the development of improved systems, in situ testing in the space environment is required. The Long Duration Exposure Facility (LDEF) can provide this capability. Several of the experiments being developed for the first LDEF mission will seek to determine the ef-fects of the space environment on components which will form the key elements of future electro-optical systems, and a considerable number of related experiments have been proposed. The engineering and scientific community is encouraged to be-come aware of this activity and to participate in the planning and experiment development for future LDEF missions.