Next-generation space telescope (NGST) and space-based optical SETI

Many new space observatory projects are now being discussed and planned. With the primary goals of useful astronomical research, including detection and characterization of extrasolar planetary systems, the larger of such prospective observatories include the Next-Generation Space Telescope (NGST), Terrestrial Planet Finder (TPF), Darwin, Life Finder (LF), and Planet Imager (PI). Several of these seem particularly useful for SETI searches at optical wavelengths, as do also some smaller proposed space observatories such as Eclipse, Kepler, and GAIA. The new space observatories offer the following capabilities of particular interest to SETI: (1) single, calibrated instruments providing continuous extended time observing a particular planetary system or a wide-angle region containing many possible systems; (2) sensitivity in wavelength regions difficult to observe through the earth's atmosphere due to absorption or to scattered light; (3) very high photometric accuracy to detect small variations in signal from a planetary system; (4) decreased scattered light from our solar system's zodiacal light, depending on observatory orbit location; and (5) the potential of blocking (nulling) most of a star's light, thereby increasing greatly the signal-to-noise ratio (SNR) for detecting light from objects close to the star. We offer some suggestions as to how these new space observatories might be employed or adapted to offer optical SETI capabilities, and provide estimates of their potential performance for that mission.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.