NASA’s MODerate resolution Imaging Spectroradiometer (MODIS) is an across-track wide-field-of-view scanner that images the entire Earth with 36 spectral bands once every day or two. The first MODIS was launched from Vandenberg AFB, California on the Terra satellite platform on 18 Dec 1999. As the initial flagship of the Earth Observing System, Terra is a polar orbiting platform with a 10:30 equatorial crossing time. A second MODIS was launched on board the Aqua satellite on 4 May 2002. Aqua is also on a polar orbit with a 1:30 PM crossing time.