These space-based sensors, developed by NNSA's Office of Nonproliferation Research and Engineering, are used to monitor the Limited Test Ban Treaty of 1963, and to deter proliferant nations from conducting nuclear tests. NNSA develops and provides a wide variety of technologies to stem the proliferation of weapons of mass destruction and its sensors. These technologies have been monitoring space and atmospheric nuclear explosions for over 40 years and are currently secondary payloads on both the DSP and Global Positioning System (GPS) satellites.

The U.S. Air Force launched the first DSP satellite on Nov. 6, 1970. This constellation of satellites operates in geosynchronous orbit to provide early warning of missile launches, space launches and nuclear explosions.

The last DSP satellite, scheduled for launch in 2005, will mark the end of the present nuclear detection sensor package design, but will also carry the demonstration experiment for the next generation of high altitude sensors -- the Space and Atmospheric Burst Reporting System (SABRS) -- that NNSA is currently developing. Continuing research and development programs have made the sensor packages both smaller and more robust, while greatly increasing the ability to detect clandestine nuclear tests.

NNSA is a semi-autonomous agency of the Department of Energy. It enhances U.S. national security through the military application of nuclear energy, maintains the U.S. nuclear weapons stockpile, promotes international nuclear nonproliferation and safety, reduces global danger from weapons of mass destruction, provides the U.S. Navy with safe and effective nuclear propulsion, and oversees its national laboratories to maintain U.S. leadership in science and technology.