A nitrogen-cooled Michelson interferometer was fabricated using a unique flexural pivot mirror translation system which allows a proportionally large aperture and is ideally suited for operation at cryogenic temperatures. Cooling the entire interferometer yields a sensitivity sufficient to measure weak atmospheric emissions from an electron-gun induced artificial aurora. The spectral range 2.0 to 5.6 Âµm is scanned at a repetition rate of 1.8 seconds with an apodized resolution of 2 cm-1. Piezoelectric elements in the fixed mirror mount allow realignment at cryogenic temperatures. Laser (sampling) and white light (absolute position) reference channels are run antiparallel to the main channel using the same optics. When launched aboard a Talos Castor rocket as part of the EXCEDE payload the interferometer maintained alignment within 20 percent of launch modulation efficiency.