Moderate Resolution Imaging Spectroradiometer (MODIS)
MODIS is a key instrument aboard NASA's Terra and Aqua satellites that is often used in disaster management for mapping anything from vegetation to floods or fires. It collects data in 36 spectral bands, twice a day.
The MODIS website publishes technical specifications of the instrument, provides access to data, processed products andf maps. It also hosts a large collection of MODIS images from across the world.