Abstract

Altair is an acquisition, tracking, and pointing (ATP) space experiment sponsored by the Strategic Defense Initiative Organization (SDIO) Directed Energy Program Office. The experiment is configured as a free-flying satellite with an electro-optical payload designed to address target acquisition and pointing issues. The payload was designed by a government-led Phillips Laboratory team. The Altair optical tracking system includes visible and IR tracking cameras (4.3 μm) and detectors for laser wavelengths of 532,770, and 830 nm. Various multilayer dielectric beam splitters are used to direct the light to the proper detectors. By considering the interference filter production issues from the start, a design for the optical system was achieved that avoided beam splitters that would be difficult to produce. The guiding principles were as follows: keep the angles of incidence as small as possible (preferably less than 25°); when separating the IR spectrum from the visible, reflect the visible and transmit the IR; maintain an uninterrupted visible spectrum between the laser wavelengths (i.e., avoid laser wavelengths in the middle of the visible spectrum); and arrange the angles of the beam splitters so that the multiple reflections of the alignment beam, which is at one edge of the aperture, "walks" out of the aperture. The conceptual design of the Altair Space Experiment optical system, which includes these features, will be presented.

© 1992 Optical Society of America