The tilt of this telescope relative to the turntable could be changed on command and was equipped with 27 lead sulfide IR detectors using filters to scan different parts of the spectrum. The W-17 payload consisted of a turntable rotating at two RPM with a Bouwers-concentric telescope attached.

A few balloon flights were flown during the second half of 1959 to begin gathering the needed data on natural backgrounds. IR scanners to test the concept and gather data on natural backgrounds from aircraft and balloons would be built by Baird-Atomic, Inc. At the forward end of the Agena was mounted the W-17 IR detector payload subcontracted to Aerojet-General Corporation. Like the Agena used in the reconnaissance satellite, the Agena would provide the final impulse needed to achieve orbit after booster burnout as well as provide support functions for the payload once there. Like the reconnaissance satellite in WS-117L, this early warning payload would be integrated with the Agena upper stage being developed at Lockheed. Over the years that followed, Knopow (now appointed the subsystem manager and later would become the program manager) and others went out to convert most of the skeptics generating almost unbounded enthusiasm among some in the USAF in the process.Īs broader support for the program was being sought, design work for the actual satellite moved forward. A system that generated an inordinate number of false alarms was essentially as useless as no system at all.

Many believed that while in theory a missile plume could be detected by IR sensors, the complex natural background structure of the warm Earth and its atmosphere would overwhelm the system’s ability to differentiate a true threat from a false alarm. While Subsystem G was included in the WS-117L contract when the USAF selected Lockheed as the prime contractor in June of 1956, there were still a host of skeptics that needed convincing. Knopow was able to convince his superiors about IR sensor’s ability to detect missile launches from orbit and in March of 1956, it was incorporated into the firm’s WS-117L proposal to the USAF as Subsystem G. Also included under the WS-117L umbrella was an elint (electronic intelligence) capability designed to detect Soviet Bloc radars and intercept their communications. On the top of the list was a reconnaissance satellite capable of returning detailed pictures from behind the Iron Curtain (see “ The First Discoverer Missions: America’s Original (Secret) Satellite Program”). At this time, WS-117L was a catch all for the varied USAF satellite proposals with direct military applications. Among its early programs was the development of WS-117L (Weapon System 117L) and the Agena upper stage that it would use. In June of 1955, Knopow joined Lockheed’s new Missile and Space Division (now part of the aerospace giant, Lockheed Martin) that was setting up shop in Palo Alto, California. Knopow who developed the concept of a satellite-based early warning system. While this was found to be possible in principle, the detection of the bright plume generated by an ascending missile (potentially the most dangerous of these weapons) proved to be easiest with the technology available.Ī portrait of Joseph J. Working for the Operations Analysis Office in the Directorate of Operations at the USAF Headquarters, Knopow studied the ability of the then new generation of infrared (IR) sensors to detect turbojet powered bombers and transports as well as long range missiles. The beginning of the United States’ space-based early warning system can be traced back to studies performed during the early 1950s by Joseph J. With the memory of Pearl Harbor still fresh in the minds of the public and the military establishment, a better solution giving even more warning time was needed. While a formidable line of defense, this system at best provided only 15 minutes of warning before a rocket-launched nuclear warhead would strike. Back then the country’s first line of defense against missile attack was a string of radar installations across the North American Arctic frontier, known as BMEWS (Ballistic Missile Early Warning System), supplemented by radar equipped aircraft. At the dawn of the Space Age such a system was just a dream. (Lockheed-Martin)īut this reliable early warning capability is a product of decades of effort by scientists and engineers across the country. An artist rendering of a SBIRS GEO satellite in Earth orbit.

Lockheed agena spacecraft