The Defense Meteorological Satellite Program maintains four satellites with a near-polar orbit. These satellites carry both visible and infrared sensors, and are able to provide images of the earth during the day and at night.
The DMSP began in the 1970s as a way of providing the military with detailed weather information. The four satellites currently in operation fly 830 km above the earth and have a 101-minute, sun synchronous orbit.
GINA receives DMSP data.
For more on the DMSP visit NOAA’s Earth Observation Group pages.