In the present day, both MODIS and VIIRS have
multiple midwave and thermal infrared bands providing twicedaily
global coverage at coarse spatial resolutions (1 km), and the
Advanced Spaceborne Thermal Emission and Reflection Radiometer
(ASTER) delivers five thermal infrared bands at 90 m spatial resolution
with a 16-day repeat cycle, but a narrow field of view that
does not permit global coverage. There is no current thermal infrared
sensor that combines multiple bands needed for temperatureemissivity
separation, a sub-100 m spatial resolution, and a frequent
repeat interval with global coverage, which are necessary to answer
a wide range of Earth science studies related to surface composition,
hydrology, and volcanology.