WASHINGTON — The Space Development Agency announced Dec. 19 it awarded about $3.5 billion in contracts to four companies to build 72 missile-tracking satellites for the next phase of a low Earth orbit constellation designed to detect and follow advanced missile threats.
The contracts cover the Tracking Layer Tranche 3 segment of the Proliferated Warfighter Space Architecture (PWSA), a growing network of military satellites intended to provide faster, more resilient missile warning and tracking than legacy space systems.
L3Harris Technologies, Lockheed Martin, Rocket Lab USA and Northrop Grumman will each build 18 satellites. Lockheed Martin received the largest award at $1.1 billion, followed by L3Harris at $843 million, Rocket Lab at $805 million and Northrop Grumman at $764 million, the agency said.
The satellites are projected to launch in fiscal year 2029.
The Tracking Layer is designed to detect missile launches shortly after liftoff and maintain custody of targets throughout flight, including hypersonic glide vehicles that can maneuver unpredictably.
“The Tracking Layer of Tranche 3, once integrated with the PWSA Transport Layer, will significantly increase the coverage and accuracy needed to close kill chains against advanced adversary threats,” said Gurpartap “GP” Sandhoo, acting director of SDA. “The constellation will include a mix of missile warning and missile tracking, with half the constellation’s payloads supporting advanced missile defense missions.”
Each Tranche 3 satellite will carry an infrared sensor, optical communications terminals, Ka-band communications payloads and an S-band backup telemetry, tracking and command system. The 72 satellites will be deployed across eight orbital planes.
The Tracking Layer does not operate on its own. Using laser-based crosslinks, the satellites pass tracking data through SDA’s Transport Layer, a mesh network that moves information directly to missile defense systems, combatant commands and weapons platforms. The aim is to compress the timeline from detection to decision.
SDA, which operates under the U.S. Space Force, is building the architecture in “tranches,” with new generations launched roughly every two years to incorporate updated technology and add capacity.
The Tranche 3 awards follow earlier contracts for the Tracking Layer. In January 2024, SDA awarded three contracts for 54 Tranche 2 satellites to L3Harris, Lockheed Martin and Sierra Space. Tranche 1 contracts for 28 satellites were awarded in July 2022 to Northrop Grumman and L3Harris.
The Tracking Layer is expected to play a central role in the Pentagon’s planned Golden Dome missile defense system, which is intended to link sensors, command-and-control systems and interceptors into a single, integrated network. Space-based tracking provides the sensing backbone for that architecture, enabling early detection and continuous tracking needed for missile defenses to respond in time.
