For more than six decades, the United States military has relied on a quiet workhorse on orbit: the Defense Meteorological Satellite Program (DMSP). Designed during the Cold War and first launched in 1962, the satellite constellation has far outlived its expected lifespan, continuing to provide crucial weather intelligence for military planners even as newer systems slowly begin to take its place.
Originally intended to provide global weather imagery to support military operations, DMSP satellites monitor cloud cover, ocean conditions and atmospheric activity from sun-synchronous polar orbits about 830 kilometers above Earth. Their sensors capture visible, infrared and microwave data used to forecast weather patterns and plan aviation missions, missile tests and naval deployments.
The satellites have proved remarkably durable. The most recent DMSP spacecraft launched in 2014, and two remain operational today, surveying the entire Earth multiple times each day. But longevity comes with limits.
Analysts say the aging constellation no longer can meet the growing demands of modern military operations. For example, to maintain a one-hour refresh rate — capturing updated imagery or data for a specific geographical location — upward of a dozen satellites would be required in low Earth orbit, Col. Patrick Williams, director of weather for the U.S. Air Force, said during a November 2023 webinar at the Mitchell Institute for Aerospace Studies, a nonpartisan research organization.
With two DMSP satellites still functioning, “It’s just not enough, so it might as well be a dead constellation at this point,” Williams said.
Even so, the satellites remain indispensable. The U.S. Navy’s Fleet Numerical Meteorology and Oceanography Center has repeatedly extended the distribution of DMSP data to other agencies, including the National Oceanic and Atmospheric Administration, whose hurricane forecasting models rely heavily on the information. A Navy spokesperson explained that officials decided to continue providing the data after feedback from government partners.
“The center had planned to phase out the data as part of a [War] Department modernization effort,” the spokesperson told the Military Times in July 2025. “But after feedback from government partners, officials found a way to meet modernization goals while keeping the data flowing until the sensor fails or the program formally ends in September 2026.”
The U.S. Space Force already has begun fielding replacements, including the ML-1A Weather System Follow-on–Microwave, which launched in 2024 and can measure ocean surface winds, sea ice, soil moisture and tropical cyclone intensity with far greater precision.
Officials say the future likely will rely on a “family of systems” approach, combining new satellites with data from international partners and civilian weather networks. As then-Lt. Col. Joseph Maguadog of Space Systems Command noted during the Mitchell webinar, the remaining DMSP satellites likely have only a few more years of life.
For now, the spacecraft continue to do what they have done for decades — quietly circling the planet and delivering vital weather intelligence.
Mission
The DMSP has been collecting weather data for U.S. military operations for more than five decades and provides assured, secure global weather and space weather data to support Department of War operations.
Features
Two primary operational DMSP satellites are in sun-synchronous low Earth polar orbits at about 450 nautical miles. The main weather sensor is an optical system, which provides continuous visual and infrared imagery of cloud cover for an area about 1,600 nautical miles wide. Complete global coverage of weather features is accomplished every 14 hours, providing essential data over data-sparse and data-denied areas. Additional satellite sensors measure atmospheric vertical profiles of moisture and temperature. Military weather forecasters can detect developing weather patterns and track existing weather phenomena over remote areas, including the presence of fog, severe thunderstorms, dust and sandstorms, and tropical cyclones.
Other DMSP sensors measure space weather parameters such as charged particles, electromagnetic fields and ionospheric characteristics to assess the impact of the natural environment on ballistic-missile early warning radar systems, long-range communications and satellite communications. Also, data is used to monitor global auroral activity and predict the effects of the space environment on satellite operations. DMSP spacecraft can store data onboard as well as transmit data directly to ground terminals.
U.S. SPACE FORCE, Ball Aerospace & Technologies Corp.
Background
The first DMSP satellite, known at the time as the Defense Satellite Applications Program, was launched in 1962. DMSP initially was classified and run by the National Reconnaissance Office in support of the Corona Earth surveillance program. Corona satellites had limited film onboard, and it was essential to have timely and accurate weather forecasts to ensure cloud-free pictures were taken of high-interest areas. DMSP data also is critical to the forecast process. Declassified in 1972, DMSP data was made available to civilian and scientific communities.
In May 1994, the president directed the Department of Commerce (DOC) and Department of Defense (DOD) to converge their separate polar-orbiting weather satellite programs. A tri-agency organization consisting of the DOC, DOD and NASA was formed. As part of the convergence plan, DMSP operations were transferred from the DOD to the DOC in June 1998, while funding responsibility remains with the U.S. Air Force.
In December 2019, oversight of the DMSP was transferred to the Space Force under the 2020 National Defense Authorization Act.
General Characteristics
Primary Function: Collect cloud, atmospheric, space weather and Earth surface data
Weight: 1,236.4 kilograms, including 351-kilogram sensor payload
Orbit Altitude: About 830 kilometers
Dimensions: 7.62 meters long with solar panels deployed
Date Deployed: August 1962