DSP provides ballistic missile early warning and is a key part of North American and theater early warning systems. It is capable of detecting missile launches and nuclear detonations and was initially meant to watch the Soviet military. It was used extensively in the 1991 Gulf War to detect Iraqi theater missile launches against coalition forces and allies in the region. The 23rd and final DSP satellite launched in December 2007 but malfunctioned and began drifting outside its intended orbit in 2008.
Block 5 is the latest variant and is more survivable than predecessors. It includes a medium wavelength IR sensor for more mission utility and accommodates 6,000 detectors. The constellation hosts X-ray, optical, and radiation sensors that form a key part of the Radiation Detection Capability (RADEC) supporting the U.S. Nuclear Detonation Detection System (USNDS). USNDS is capable of near-real-time atmospheric and near-space detection and location of nuclear blasts supporting tactical warning, nuclear forces, space control, treaty monitoring, and classified missions. Nine Block 5 satellites were deployed between 1989 and 2007. SBIRS is integrated with DSP, augments its role, and is designed to eventually replace the constellation on orbit. The constellations jointly enabled early detection of ballistic missiles launched by Iran against U.S. forces at Al Asad AB, Iraq, on Jan. 7, 2020, reducing casualties. When Iran launched two waves of drones and missiles against Israel in April and October 2024, systems like DSP and SBIRS gave critical warnings to U.S. forces.
Defense Support Program Technical Data
Contractors: Northrop Grumman (formerly TRW); Aerojet.
Operator/Location: USSF CFC, Mission Delta 4 (DEL 4), 2nd Space Warning Squadron; Buckley SFB, Colo.; Joint Tactical Ground Stations (JTAGS) located in Japan, Italy, South Korea, and Qatar.
First Launch: November 1970.
IOC: Circa 1972.
Design Life: Three-year requirement and five-year goal.
Launch Vehicle: Titan IV with inertial upper stage; Delta IV Heavy NSSL.
Constellation: 23 deployed/five operational.
Active Satellites: •DSP-18. Launched in 1997, on orbit and operational. •DSP-19. Launched in 1999, on orbit and operational. •DSP-20. Launched in 2000, on orbit and operational. •DSP-21. Launched in 2001, on orbit and operational. •DSP-22. Launched in 2004, on orbit and operational. •DSP-23. Launched in 2007, on orbit and nonoperational.
Dimensions: Diameter 22 ft, height 32.8 ft, with paddles deployed.
Weight: Approx. 5,200 lb.