The Missile Defense Agency's Advanced Technology Office is developing advanced passive electro-optical and infrared sensors for future space-based seekers by exploring new infrared detector materials. A Type II strained layer superlattice, one of the materials under development, has shown great potential for space applications. Theoretical results indicate that strained layer superlattice has the promise to be superior to current infrared sensor materials, such as HgCdTe, quantum well infrared photodetectors, and Si:As. Strained layer superlattice-based infrared detector materials combine the advantages of HgCdTe and quantum well infrared photodetectors. The bandgap of strained layer superlattice can be tuned for strong broadband absorption throughout the short-, mid-, long-, and very long wavelength infrared bands. The electronic band structure can be engineered to suppress Auger recombination noise and reduce the tunneling current. The device structures can be easily stacked for multicolor focal plane arrays. The III-V semiconductor fabrication offers the potential of producing low-defect-density, large-format focal plane arrays with high uniformity and high operability. A current program goal is to extend wavelengths to longer than 14 µm for space applications. This paper discusses the advantages of strained layer superlattice materials and describes efforts to improve the material quality, device design, and device processing.