Support Equipment

Space Fence

Also known as
  • Space Fence radar
  • U.S. Space Fence
  • Space Fence S-band radar
  • Space Fence at Kwajalein

Space Fence is a Lockheed Martin-built, ground-based S-band space-surveillance radar at Kwajalein Atoll. The U.S. Space Force uses the solid-state phased-array system for space domain awareness, cataloging orbital objects and feeding Space Surveillance Network data rather than employing it as a conflict weapon.

Space Fence, Ground-based S-band space-surveillance radar, Support Equipment
Image source: Space Fence site
Operational Context

Space Fence is best read as a space-domain-awareness sensor node: it produces orbital tracking observations, contributes to the Space Surveillance Network, and depends on downstream data systems before its observations can support military decision-making.

AreaDocumented contextSource
Radar missionThe system overview describes a ground-based S-band radar architecture built to detect, track, and catalog small objects across low, medium, and geosynchronous Earth orbit regimes.Space Fence System Overview
Operational siteThe accepted operational site is at Kwajalein Island, where the Space Force uses the radar to track satellites, rocket bodies, and orbital debris.USSF announces initial operational capability and operational acceptance of Space Fence
Data connectionIn 2022, Space Systems Command made Space Fence observation data directly available through the Unified Data Library, establishing the UDL's first direct Space Surveillance Network sensor connection.SSC Unified Data Library and Space Fence establish Direct Sensor Connection
Integration caveatGAO later reported that the UDL had been fielded but was not yet fully incorporated into daily space situational-awareness operations by the 18th and 19th Space Defense Squadrons as of its 2023 review.Space Situational Awareness: DOD Should Evaluate How It Can Use Commercial Data
Profile / Specs

Profile

Origin
United States
Type
Ground-based S-band space-surveillance radar
Service note
2014-present
Designed
2009-2014
Produced
2014-2020 initial fielding
Developed from
Air Force Space Surveillance System (AFSSS)

Specifications

Radar type
Ground-based S-band phased-array space-surveillance radar
Sensor site
Kwajalein Atoll, Republic of the Marshall Islands
Mission
Detects, tracks, and characterizes orbital objects and debris in low, medium, and geosynchronous Earth orbit
Technology
Solid-state gallium nitride (GaN) electronics with element-level digital beamforming
Operational profile
Provides uncued search and long-arc tracking for the Space Surveillance Network
Data integration
Observation data can be ingested directly into the U.S. Space Force Unified Data Library
Mission Software Heritage

Space Fence is a radar site, but Lockheed Martin also identifies a software lineage behind its space situational-awareness mission subsystem.

Compatible itemItem typeCompatibility evidence
iSpace, Space situational awareness and command-and-control software suite, Support EquipmentiSpaceSpace situational-awareness software suite

Lockheed Martin says iSpace expertise was leveraged when developing the Space Fence space situational-awareness mission subsystem.

Sources: German Space Agency Selects Lockheed Martin iSpace System for Space Situational Awareness

Timeline

Space Fence Key Events

  1. First U.S. Space Fence site announced

    The Air Force announced Kwajalein Island in the Republic of the Marshall Islands as the first U.S. Space Fence facility.

    Sources: Basing of first U.S. Space Fence facility announced

  2. Lockheed Martin wins the contract

    Air & Space Forces Magazine reported that the Air Force selected Lockheed Martin to build the Space Fence for a $914.7 million contract.

    Sources: Lockheed Martin Wins Space Fence Contract

  3. Trial period begins

    The Space Fence entered a government-led trial period after developmental and operational testing, with the article describing its solid-state S-band radar and GaN-based architecture.

    Sources: State-of-the-Art Space Fence Radar Enters Government-led Trial Period as it Nears Operational Acceptance

  4. Initial operational capability and acceptance

    The U.S. Space Force formally declared initial operational capability and operational acceptance of the Space Fence radar at Kwajalein Island.

    Sources: USSF announces initial operational capability and operational acceptance of Space Fence

  5. Direct Unified Data Library connection tested

    Space Systems Command completed testing that made Space Fence observation data directly available through the Unified Data Library.

    Sources: SSC Unified Data Library and Space Fence establish Direct Sensor Connection

Media

Space Fence Images

Space Fence, Ground-based S-band space-surveillance radar, Support Equipment - view 1
Source: Space Fence site
Related Weapon Systems
Space-Based Infrared System / SBIRS, Missile-warning satellite constellation, Support EquipmentSupport EquipmentSpace-Based Infrared System / SBIRSMissile-warning satellite constellationSpace-Based Infrared System (SBIRS) is the U.S. Space Force space-based missile-warning constellation that replaced Defense Support Program coverage with geosynchronous satellites, highly elliptical orbit payloads, and consolidated ground processing. Lockheed Martin led the space and ground system, Northrop Grumman supplied infrared payloads, and official reporting says SBIRS provided early warning during Iran's April 2024 missile and drone attack on Israel.
IRST21 Sensor System, Passive long-wave infrared search-and-track sensor system, Support EquipmentSupport EquipmentIRST21 Sensor SystemPassive long-wave infrared search-and-track sensor systemIRST21 is Lockheed Martin's passive long-wave infrared search-and-track sensor family for fighter aircraft, packaged either inside the F/A-18E/F Super Hornet centerline tank or in the modular Legion Pod. It gives aircraft a non-emitting air-to-air detection and tracking channel, has supported F-15C missile-cue testing with AIM-9X and AIM-120 shots, and moved into Navy IRST Block II fielding for the Super Hornet in 2025.

Sources

Space Fence System OverviewPublisher: AMOS Technical Conference / Lockheed Martin | Note: Supports Space Fence system architecture, S-band radar role, digital beamforming, GaN electronics, mission scope, and Lockheed Martin program background. | Accessed: 2026-06-29Lockheed Martin Wins Space Fence ContractPublisher: Air & Space Forces Magazine | Note: Supports the June 2, 2014 contract award, the Kwajalein site selection, the $914.7 million contract value, and the replacement role for the Air Force Space Surveillance System. | Accessed: 2026-06-29Basing of first U.S. Space Fence facility announcedPublisher: United States Air Force | Note: Supports the 2012 Kwajalein basing announcement and the early program timeline. | Accessed: 2026-06-29State-of-the-Art Space Fence Radar Enters Government-led Trial Period as it Nears Operational AcceptancePublisher: United States Space Force / Los Angeles Air Force Base | Note: Supports the trial period, S-band radar description, GaN-based solid-state architecture, and operational context before acceptance. | Accessed: 2026-06-29USSF announces initial operational capability and operational acceptance of Space FencePublisher: United States Space Force / U.S. Space Command | Note: Supports the March 27, 2020 IOC and operational acceptance, the Kwajalein location, the Space Force operator context, and the orbital-object tracking mission. | Accessed: 2026-06-29SSC Unified Data Library and Space Fence establish Direct Sensor ConnectionPublisher: U.S. Space Force Space Systems Command | Note: Supports the April 2022 direct Space Fence-to-Unified Data Library sensor connection, the Space Surveillance Network context, and the space domain-awareness data-integration role. | Accessed: 2026-06-29Space Situational Awareness: DOD Should Evaluate How It Can Use Commercial DataPublisher: U.S. Government Accountability Office | Note: Supports the UDL integration caveat that Space Fence data reached the classified UDL while operational SSA systems were not yet fully using UDL data in daily operations. | Accessed: 2026-06-29German Space Agency Selects Lockheed Martin iSpace System for Space Situational AwarenessPublisher: Lockheed Martin | Note: Supports the relationship between Lockheed Martin iSpace expertise and the Space Fence space situational-awareness mission subsystem. | Accessed: 2026-06-29Space Fence sitePublisher: United States Space Force | Note: Supports public-domain provenance for the aerial gallery image of the Space Fence facility at Kwajalein Atoll. | Accessed: 2026-06-29Space Fence RadarPublisher: United States Space Force | Note: Supports public-domain provenance for the Space Fence radar graphic used in the gallery. | Accessed: 2026-06-29