L3Harris, Sierra Space to build 36 satellites to expand U.S. missile-tracking network

The U.S. Space Force's Space Development Agency has awarded contracts worth about $1.75 billion to L3Harris Technologies and Sierra Space to build the next group of missile warning and missile defense satellites for its proliferated low Earth orbit constellation, the agency said July 13.

The awards cover 36 satellites for the Accelerated Missile Defense Tranche 3 program, an expansion of the Tracking Layer of the Proliferated Warfighter Space Architecture, or PWSA. The satellites are scheduled to be available for launch by the end of 2028.

The contracts mark another step in the Pentagon's effort to build a large network of low Earth orbit satellites capable of detecting, tracking and helping defend against ballistic and hypersonic missile threats. The constellation is expected to support the Trump administration's proposed Golden Dome missile defense initiative by providing space-based missile warning and tracking data.

L3Harris was awarded a contract worth about $955 million to build 18 missile defense satellites equipped with sensors similar to the Missile Defense Agency's Hypersonic and Ballistic Tracking Space Sensor, or HBTSS, across two orbital planes.

Sierra Space received a contract valued at about $798 million to build 18 missile warning and missile tracking satellites across two orbital planes.

"With these awards, SDA is accelerating the deployment of the Tracking Layer to provide the homeland, our deployed forces, and allies with global, persistent indications, detection, identification warning, tracking, and defense against advanced and evolving missile threats," Gurpartap "GP" Sandhoo, the Space Force's Portfolio Acquisition Executive for Missile Warning and Tracking and director of the Space Development Agency, said in a statement.

The new satellites will be interoperable with Tracking Layer spacecraft already procured under Tranches 1, 2 and 3 and will operate through a common ground system, SDA said.

The Tracking Layer consists of infrared sensor satellites designed to detect missile launches, track missiles through flight and provide targeting data through a low-latency communications network in low Earth orbit.

Both companies are already part of SDA's Tracking Layer supplier base. L3Harris has participated in every generation of the constellation, delivering four Tranche 0 satellites now in orbit and winning contracts for 14 Tranche 1 satellites, 18 Tranche 2 satellites and 18 of the original Tranche 3 spacecraft. Sierra Space joined the program as a prime contractor in Tranche 2 with an award for 18 satellites. The latest agreements bring L3Harris's total across the Tracking Layer to 72 satellites and Sierra Space's to 36.

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Published: 2026-07-14 08:10

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