  Large-area surveys operating at mid-infrared wavelengths have proven to be a
valuable means of discovering and characterizing minor planets. Through the use
of radiometric models, it is possible to derive physical properties such as
diameters, albedos, and thermal inertia for large numbers of objects. Modern
detector array technology has resulted in a significant improvement in spatial
resolution and sensitivity compared with previous generations of space-based
infrared telescopes, giving rise to a commensurate increase in the number of
objects that have been observed at these wavelengths. Space-based infrared
surveys of asteroids therefore offer an effective means of rapidly gathering
information about small body populations' orbital and physical properties. The
AKARI, WISE/NEOWISE, Spitzer, and Herschel missions have significantly
increased the number of minor planets with well-determined diameters and
albedos.
