The Space Fence is a second-generation

space surveillance Space domain awareness is the study and monitoring of satellites orbiting the Earth. It involves the detection, tracking, cataloging and identification of artificial objects, i.e. active/inactive satellites, spent rocket bodies, or fragmentatio ...

system operated by the

United States Space Force The United States Space Force (USSF) is the space force branch of the United States Department of Defense. It is one of the six United States Armed Forces, armed forces of the United States and one of the eight uniformed services of the Unite ...

in order to track artificial satellites and

space debris Space debris (also known as space junk, space pollution, space waste, space trash, space garbage, or cosmic debris) are defunct human-made objects in spaceprincipally in Earth orbitwhich no longer serve a useful function. These include dere ...

in Earth orbit. It was constructed and designed by

Lockheed Martin The Lockheed Martin Corporation is an American Arms industry, defense and aerospace manufacturer with worldwide interests. It was formed by the merger of Lockheed Corporation with Martin Marietta on March 15, 1995. It is headquartered in North ...

Northrop Grumman Northrop Grumman Corporation is an American multinational Aerospace manufacturer, aerospace and Arms industry, defense company. With 97,000 employees and an annual revenue in excess of $40 billion, it is one of the world's largest Arms industry ...

, and

Raytheon Raytheon is a business unit of RTX Corporation and is a major U.S. defense contractor and industrial corporation with manufacturing concentrations in weapons and military and commercial electronics. Founded in 1922, it merged in 2020 with Unite ...

starting in 2009, with it being declared operational in March 2020. The budget is (FY15). The main facility is located at

Kwajalein Atoll Kwajalein Atoll (; Marshallese language, Marshallese: ) is part of the Marshall Islands, Republic of the Marshall Islands (RMI). The southernmost and largest island in the atoll is named Kwajalein Island, which its majority English-speaking re ...

in the

Marshall Islands The Marshall Islands, officially the Republic of the Marshall Islands, is an island country west of the International Date Line and north of the equator in the Micronesia region of the Northwestern Pacific Ocean. The territory consists of 29 c ...

.Indian anti-satellite test proves early test for Space Fence
by Debra Werner — April 11, 2019, SpaceNews.com, ''...Still in testing mode, the U.S. Air Force Space Fence on Kwajalein Atoll detected India’s March 27 anti-satellite test and issued a break-up alert...The Air Force is scheduled to begin initial operation...in the fourth quarter of this year...''

History

The initial plans to upgrade the legacy

Air Force Space Surveillance System The AN/FPS-133 Air Force Space Surveillance System, colloquially known as the Space Fence, was a U.S. government multistatic radar system built to detect orbital objects passing over America. It is a component of the U.S. space surveillance ...

were made in 2009. The USAF 850th Electronic Systems Group, Electronic Systems Center awarded three $30-million study contracts to

General Dynamics General Dynamics Corporation (GD) is an American publicly traded aerospace and defense corporation headquartered in Reston, Virginia. As of 2020, it was the fifth largest defense contractor in the world by arms sales and fifth largest in the Unit ...

, and

on 11 June 2009. The new Space Fence was envisioned to be a system of two or three

S-band The S band is a designation by the Institute of Electrical and Electronics Engineers (IEEE) for a part of the microwave band of the electromagnetic spectrum covering frequencies from 2 to 4 gigahertz (GHz). Thus it crosses the convention ...

ground-based radars designed to perform uncued detection, tracking and accurate measurement of orbiting space objects, and was intended to replace the Air Force Space Surveillance System, or VHF Fence, that was transferred from the

US Navy The United States Navy (USN) is the naval warfare, maritime military branch, service branch of the United States Department of Defense. It is the world's most powerful navy with the largest Displacement (ship), displacement, at 4.5 millio ...

to the

US Air Force The United States Air Force (USAF) is the Air force, air service branch of the United States Department of Defense. It is one of the six United States Armed Forces and one of the eight uniformed services of the United States. Tracing its ori ...

in 2004. The shorter wavelength of the S-band Space Fence will allow for the detection of much smaller satellites and

debris Debris (, ) is rubble, wreckage, ruins, litter and discarded waste, garbage/refuse/trash, scattered remains of something destroyed, or, as in geology, large rock fragments left by a melting glacier, etc. Depending on context, ''debris'' can ref ...

. The 2009 satellite collision of the

Iridium 33 Iridium 33 was a communications satellite launched by Russia for Iridium Communications. It was launched into low Earth orbit from Site 81/23 at the Baikonur Cosmodrome at 01:36 UTC on 14 September 1997, by a Proton-K rocket with a Block DM2 u ...

and

Kosmos 2251 Kosmos-2251 ( meaning ''Cosmos 2251'') was a Russian Strela-2M military communications satellite. It was launched into Low Earth orbit from Site 132/1 at the Plesetsk Cosmodrome at 04:17 UTC on 16 June 1993, by a Kosmos-3M carrier rocket. The ...

communications satellites, which added hundreds more pieces of debris in orbit, highlighted the need for more precise tracking of space objects. , data collected from the new Space Fence's sensors was planned to feed into the

Joint Space Operations Center The Combined Space Operations Center (CSpOC) is a U.S.–led multinational space operations center that provides command and control of space forces for the United States Space Command under the United States Space Force component field command ...

Mission System, which is used to track objects orbiting the Earth, monitor

space weather Space weather is a branch of space physics and aeronomy, or heliophysics, concerned with the varying conditions within the Solar System and its heliosphere. This includes the effects of the solar wind, especially on the Earth's magnetosphere, ion ...

, and assess foreign launches. Used by operators at the USAF 614th Air and Space Operations Center at Vandenberg Air Force Base, Calif., the 614 AOC's 24-hour-a-day, seven-day-a-week support provides vigilance of global and theater operations, and equips the Joint Functional Component Command for space operations with the tools to conduct command and control of space forces. Plans to award the final contract were delayed by the federal government's

budget sequestration Budget sequestration is a provision of United States law that causes an across-the-board reduction in certain kinds of spending included in the federal budget. Sequestration involves setting a hard cap on the amount of government spending with ...

in early 2013 and the AFSSS system was scheduled to be discontinued in October 2013 due to budget cuts. In 2014,

awarded a contract for the Space Fence ground structures to

. The ground structures include the receive array, cooling equipment, radomes and other buildings. The primary Space Fence system is located on

in the

. The U. S. Space Force declared the system operational on March 28, 2020.

Technical characteristics

The Space Fence will use

radar and will track a larger number of small objects than previous space radars: "about 200,000 objects and make 1.5 million observations per day, about 10 times the number" made by existing or recently retired US assets.

Data-sharing agreements

Countries with space situational awareness data-sharing agreements in place with the USAF include Australia, Japan, Italy, Canada, France, South Korea, and the United Kingdom. It also "has agreements with the

European Space Agency The European Space Agency (ESA) is a 23-member International organization, international organization devoted to space exploration. With its headquarters in Paris and a staff of around 2,547 people globally as of 2023, ESA was founded in 1975 ...

and Europe’s Eumetsat weather satellite organization."

Predecessor system

A previous system used by the USAF for the same purpose was the

, which ceased operation in September 2013.

References

{{Lockheed Martin United States Space Surveillance Network 2020 establishments in the Marshall Islands Equipment of the United States Space Force Programs of the United States Space Force Lockheed Martin Raytheon Company