 The US, in 1970, launched the first of a series of space-based staring array sensors that detected and located infrared heat signatures, typically from rocket motors but also from other intense heat sources.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.