The objective of this work is the development of 3 - 5 micron sensors operating at temperatures from 30C to 70C, for use in Space-Based Surveillance Systems without the use of Cryo-coolers, or uncooled. It is based on a major breakthrough achieved at Xacton. This has led to the fabrication of wafers of Mercury Cadmium Telluride with a very high level of crystalline perfection, very low defect density and extremely uniform in composition, wavelength and other properties. This has resulted in the fabrication of sensors with unmatched performance at elevated temperatures, including room temperature operation. Some of the disadvantages of the Cryo-coolers are that they have only a limited lifetime, are not very reliable, and are heavy and expensive. Therefore, their elimination in the space-based surveillance systems can make the system much simpler to design and fabricate, with increased reliability and lifetime, and also result in considerable cost reduction. In Phase I, we plan to fabricate and deliver 3 - 5 micron detectors with excellent performance at elevated temperatures, e.g., 30C to -70C. In Phase II, it will lead to the fabrication of sensors that can be used in actual Space-Based Surveillance Systems without the use of cryo-coolers or uncooled.