Defense Meteorological Satellite Program

Artist rendition of a DMSP-5D2 satellite in orbit
Program overview
Country	United States
Organization	United States Space Force
Purpose	Earth monitoring
Status	Ongoing
Program history
First flight	DMSP-1 F2 23 August 1962
Last flight	DMSP 5D-3/F19 3 April 2014
Launch site	Vandenberg Space Force Base

TheDefense Meteorological Satellite Program (DMSP) monitorsmeteorological, oceanographic, and solar-terrestrial physics for theUnited States Department of Defense. The program is managed by theUnited States Space Force with on-orbit operations provided by theNational Oceanic and Atmospheric Administration (NOAA).^[1] The (originally classified) mission of the satellites was revealed in March 1973. They provide cloud cover imagery frompolar orbits that areSun-synchronous at nominal altitude of 830 km (520 mi).^[2]

All data ingestion, processing, and distribution byFleet Numerical Meteorology and Oceanography Center (FNMOC) was set to be permanently terminated as of June 30, 2025 due to a "significant cybersecurity risk." However, the Earth Science Division Director at NASA, Dr. Karen St. Germain, requested that the decommission be delayed due to the short notice provided. FNMOC now expects to continue to ingest and disseminate data until July 31, 2025.^[3]

Early in 1963The Aerospace Corporation recommended that the U.S. Air Force develop a dedicated military meterological satellite, and the Defense Department agreed.^[4] The main emphasis would be on cloud-cover photography, but planners expected to add more sophisticated equipment when it became available. Later, when civilian weather satellites improved their capabilities and could satisfy most military requirements, the Defense Department continued to prefer a separate system responsive to the "dynamic" needs of the military. As a result, the Air Force embarked on the first segment of what became known initially as the Defense Satellite Applications Program (DSAP), or Program 417.

During the 1960s, one of the most important projects that the United States civilspace program was involved in dealt withmeteorology and weather forecasting. Unbeknownst to many, theU.S. military services were also starting up aweather satellite program. This program, the DMSP, would relay important weather andclimate data to the military for more effective operations. From the onset of the DMSP program, knowledge of its existence was limited to "need-to-know" personnel. TheUnited States Congress had assigned a substantial budget towards the civil weather satellite program; if knowledge of a second military program came out, it would have been hard for the military to justify it.^{[citation needed]}

Initial operations of early DMSP systems provided radio return of cloud-cover imagery for planning of U.S. high-resolution photographic reconnaissance and surveillance missions, which utilizedfilm-return systems. DMSP satellites operated in aSun-synchronous orbit; passing over the north and south poles, the satellite would see different strips of theEarth at the same local time each day. The DMSP satellites hadperiods of roughly 101.0 minutes, so they would orbit the Earth 14.3 times in 24 hours. This period combined with the Sun-synchronous orbit would have the satellitepass over the whole surface of the planet twice a day.

The images acquired were relayed to the Earth and received by two command and readout stations^[when?] established at retiredNike missile sites located nearFairchild Air Force Base inWashington State andLoring Air Force Base inMaine.^[5] From these sites, the images were then sent to Air Force Global Weather Central (AFGWC) located atOffutt Air Force Base,Nebraska. Images would then be processed, forming a mosaic representing the cloud patterns that were observed from the orbiting satellites. Meteorologists could then provideflight crews and other commanders with up-to-date observations for their particular missions. Further advancements enabled data to be collected in the visual spectrum, down to a half-moonlit scene.Infrared processing enabled night viewing. Other enhancements increased on-board processing; this includes multiple on-board computers and expanded power requirements.^{[citation needed]}

Now in its fifth decade of service, the DMSP program has proven itself to be a valuable tool in scheduling and protecting military operations on land, at sea, and in the air. Because the Air Force weather satellite program began with the mission of providing weather data for Strategic Air Command and National Reconnaissance Office (NRO), DSAP remained classified until 17 April 1973, when Secretaryof the Air Force Dr. John L. McLucas decided that the Defense Department'sdecision to use satellite weather data in the Vietnam conflict and to provide it toboth the Commerce Department and the general scientific community warranteddeclassification of the DSAP mission and release of some of its performance data. In December 1973 the Defense Department changed the name to the Defense Meteorological Satellite Program (DMSP). On 1 June 1998, the control and maintenance of the satellites were transferred toNational Oceanic and Atmospheric Administration (NOAA) in order to reduce costs.^[6]

DMSP was to be replaced by theDefense Weather Satellite System (DWSS) but that was cancelled in 2012. In 2017, the Air Force awarded a contract to build the first of the new defense weather satellites, theWeather System Follow-on Microwave (WSF-M) satellite.^[7]

In 2004 the USAF weather satellite DMSP Block 5D-2 F-11 (S-12) orDMSP-11, launched in 1991 and retired in 1995, exploded in orbit with debris objects generated. It seems likely the fragmentation was due to either a battery explosion or to residual fuel in the attitude control system.^[8][9] Later, propulsion was identified as the "assessed cause" of DMSP-11 explosion.^[10]

On 3 February 2015, the 13th DMSP satellite —DMSP-F13 launched in 1995 — exploded while in aSun-synchronouspolar orbit leaving adebris field of at least 43 to 100 large fragments and more than 50,000 pieces smaller than 1 millimeter.^[11] TheJoint Space Operations Center atVandenberg Space Force Base,Lompoc, California is monitoring the expanding debris field, and "will issue conjunction warnings if necessary".^[12] The cause of the explosion was the rupturing of an onboard battery due to a design flaw (no collision with another object took place).^[13]

On 11 February 2016, a power failure left both the command-and-control subsystem and its backup without the ability to reach the satellite's processor, according to theU.S. Air Force Space Command investigation released in July 2016 that also announced that DMSP 5D-3/F19 was considered to be 'lost'. The satellite's data can still be used, until it ceases pointing the sensors towards theEarth. The satellite was the most recent on-orbit, having been launched on 3 April 2014.^[14]

The failure only left F16, F17 and F18 – all significantly past their expected 3–5 year lifespan – operational. F19's planned replacement was not carried out because Congress ordered the destruction of the already constructed F20 probe to save money by not having to pay its storage costs. It is unlikely that a new DMSP satellite would be launched before 2023; by then the three remaining satellites should no longer be operational.^[15]

In October 2016, the 12th DMSP satellite -DMSP-F12 launched in 1994 - exploded in orbit. The satellite had similar battery as the one that exploded in the DMSP-13 satellite, thus raising suspicions that DMSP-12 explosion was also caused by battery problems. At the time the cause of DMSP-12's explosion was however unknown, although a collision with another object did not seem to be the cause. Apparently, very little debris (just one trackable piece) was generated in DMSP-12 explosion. DMSP-12 was decommissioned in 2008.^[9]

In January 2017, the Joint Space Operations Center announced that two non-maneuverable satellites would come dangerously close, with a collision probability as high as 44%. DMSP F15 andMeteor 1-26 were considered to be the prime candidates for the encounter.^[16] The operations center, which announced the possible collision, didn't identify the satellites involved but third party observers determined the most likely candidates.^[16] The two did not collide.

TheNOAA-16 andNOAA-17 weather satellites were based on the same technology as DMSP satellites. NOAA-16 broke up in November 2015, and NOAA-17 disintegrated in orbit on 10 March 2021.^[17]

TheDMSP 5D-2/F14 (USA-131), launched 4 Apr 1997 and decommissioned in 2020, exploded in orbit in December 2024.^[18][19]

DMSP was initially known asProgram 35. The first successful launch of a Program 35 spacecraft used aScout X-2 rocket lifting off fromPoint Arguello nearVandenberg Space Force Base on 23 August 1962.^[20][21] This was P35-2, the earlier P35-1 launch on 24 May 1962 had failed to reach orbit.^[22] All five Program 35 launch attempts usingScout launch vehicle, including the two successes, were made from VandenbergSLC-5. Other early launches were conducted usingThor-Burner launch vehicles, withAltair orBurner II upperstages. Program 35 had by this time been renamed theData Acquisition and Processing Program, and theDAPP acronym is sometimes used for these satellites.^[23] Eight satellites were launched usingAtlas E launch vehicles between 1982 and 1995. Three were launched aboardTitan II vehicles between 1997 and 2003. One has been launched on aDelta IV rocket.

The most recent launch of a DMSP satellite, DMSP-F19, occurred on 3 April 2014, from Vandenberg aboard anAtlas V launch vehicle.^[24]

The DSAP-1 (Defense Satellite Application Program Block 1) satellites series, also known as P-35, was the first series of military meteorological satellites of the United States. The project designation P-698BH was used concurrently with P-35 from June 1962 and P-35 became P-417 in October 1962. The designation DMSP-1 (Defense Meteorological Satellite Program Block 1) was retroactively assigned to these satellites.

The DSAP-2 (Defense Satellite Application Program Block 2) satellites series consisted of three modified DSAP-1 satellites, retaining the shape and dimension of the earlier series, featuring improved infrared radiometers. The designation DMSP-2 (Defense Meteorological Satellite Program Block 2) was retroactively assigned to these satellites.

The single DSAP-3 (Defense Satellite Application Program Block 3) was a modified DSAP-2 satellite to provide experimental tactical access to weather data, for which a tactical readout station was built near Saigon. The designation DMSP-3 (Defense Meteorological Satellite Program Block 3) was retroactively assigned to this satellite.

The DSAP-4A (Defense Satellite Application Program Block 4A) satellites series consisted of ten satellites, launched between 1965 and 1967. The designation DMSP-4A (Defense Meteorological Satellite Program Block 4A) was retroactively assigned to these satellites.

The DSAP-5A (Defense Satellite Application Program Block 5A) satellites series consisted of six satellites, launched between 1968 and 1971. The designation DMSP-5A (Defense Meteorological Satellite Program Block 5A) was retroactively assigned to these satellites.

The DSAP-5B (Defense Satellite Application Program Block 5B) satellites series consisted of five satellites, launched between 1971 and 1974. The designation DMSP-5B (Defense Meteorological Satellite Program Block 5B) was assigned to these satellites.

The DSAP-5C (Defense Satellite Application Program Block 5C) satellites series consisted of three satellites, launched between 1974 and 1976. The designation DMSP-5C (Defense Meteorological Satellite Program Block 5C) was assigned to these satellites.

^[41]

The DSAP-5D (Defense Satellite Application Program Block 5D) satellites series consisted of nineteen satellites, launched between 1976 and 2014. The designation DMSP-5D (Defense Meteorological Satellite Program Block 5D) was assigned to these satellites.

In 2015, Congress voted to terminate the DMSP program and to scrap the DMSP 5D-3/F20 satellite, ordering the Air Force to move on to a next-generation system. The Air Force had intended to keep DMSP F20 in climate-controlled storage at a Lockheed Martin clean room in Sunnyvale, California, for a time in case it needed to be called up for launch in the coming years,^[42] and in the aftermath of the failure of DMSP 5D-3/F19, the USAF was reconsidering the future of DMSP-5D3 F-20. However, in late 2016, the USAF began scrapping DMSP-5D3 F-20.

• NPOESS - the National Polar-orbiting Operational Environmental Satellite System
• Space debris

• R. Cargill Hall - A History of the Military Polar Orbiting Meteorological Satellite Program
• National Geophysical Data Center archive of DMSP data
• Air Force Fact Sheet (dead-link)
• The High Ground - DMSP (dead-link)
• Air Force Research Lab Horizons magazine article
• Air Force news article
• SSIES ionospheric instrument data pageArchived 2008-04-04 at theWayback Machine

• Derelict satellites orbiting Earth
• United States Air Force
• Weather satellites of the United States
• Military satellites of the United States
• Military space program of the United States
• 1962 in spaceflight
• 1963 in spaceflight
• 1973 in spaceflight
• Spacecraft launched by Atlas rockets
• Spacecraft launched by Delta IV rockets
• Spacecraft launched by Titan rockets
• Satellite series
• Military equipment introduced in the 1960s
• Spacecraft that broke apart in space

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