Light-weight, compact SWIR and MWIR imaging interferometer for space

ABSTRACT: We propose a novel SWIR/MWIR imaging system targeted for deployment at geosynchronous orbits. The new system is based on interferometric principles, is scalable, light-weight, and uses easily replicable inexpensive optics. The optics, detectors, and interferometric signal processing principles draw heavily on decades of experience in ground-based astronomical applications designed to yield the highest sensitivity and resolution in the IR with cost-effective optical solutions. The system is designed to fit within a 2 foot cube. Light weight is assured by building the infrastructure from carbon fiber reinforced polymer (CFRP) which has been qualified in space. The same material is employed for the primary mirrors of the interferometric elements in a replication process. Thus, not only are they light weight, but they are cheap, easy to fabricate, and readily produced in quantity. They also demonstrate excellent optical quality. The design allows for up to six interferometer elements to be combined in an arrangement that comes close to providing the sensitivity of a filled aperture while remaining much more compact. Dual imaging cameras behind the interferometer allow broad wavelength coverage in the atmospheric windows across the SWIR and MWIR bands. Beam combination is by conventional glass optics held rigidly in place. Processing of the interferometer signals to remove the instrumental point-spread function uses a light-weight on-board processor that runs in real time. BENEFIT: Anticipated benefits are a light-weight space based sensor for SWIR/MWIR imaging that is inexpensive, easy and rapid to manufacture, and can readily be deployed on commercial buses. The principles developed under this program are easily transferred to airborne platforms to provide larger apertures with greater resolution and sensitivity than current technology without increasing the system size, weight, and power demands. Ground-based platforms for surveillance and security will also benefit from the same advantages.