Space-based Staring Infrared Sensors

The US, in 1970, launched the first of a series of space-based staring array sensors that detected and located infrared heat signatures. Such signatures, which are associated with measurement of energy and location, are not pictures in the IMINT sense. Currently called the Satellite Early Warning System (SEWS), the program is the descendant of several generations of Defense Support Program (DSP) spacecraft.

Originally intended to detect the intense heat of an ICBM launch, this system proved useful at a theater level in 1990-1991. It detected the launch of Iraqi Scud missiles in time to give early warning to potential targets.