The U.S. Space Force’s Space Development Agency (SDA) has awarded contracts totaling approximately $1.75 billion to defense industry stalwarts L3Harris Technologies and Sierra Space. The contracts fund the development and manufacturing of 36 next-generation missile warning and missile tracking satellites, the agency announced on July 13, 2026.
These spacecraft represent the backbone of the Accelerated Missile Defense Tranche 3 (AMT3) program, an expansion of the Tracking Layer within the military’s larger Proliferated Warfighter Space Architecture (PWSA).
Under the terms of the agreements, both prime contractors are on a strict timeline to make their respective batches of 18 satellites available for launch by the end of 2028.
Shielding Against Hypersonic Threats
The dual awards represent a significant escalation in the Pentagon’s efforts to establish a dense, resilient constellation of low Earth orbit (LEO) satellites. This network is designed to detect, track, and intercept advanced adversaries’ hypersonic glide vehicles and ballistic missile systems.
Crucially, this expanded LEO constellation is expected to serve as a vital sensory anchor for the Trump administration’s proposed “Golden Dome” missile defense initiative. By placing dozens of high-speed infrared trackers in low orbits, the system can continuously “hand off” tracking data across planes, maintaining a constant lock on highly maneuverable hypersonic missiles that traditional ground-based radars struggle to see.
The division of the $1.75 billion funding allocation is structured as follows:
Sierra Space ($798 million): Contracted to construct 18 missile warning and tracking satellites, also distributed across two orbital planes.
L3Harris Technologies ($955 million): Tasked with building 18 missile defense satellites across two orbital planes. These units will carry advanced optical sensors derived from the Missile Defense Agency’s Hypersonic and Ballistic Tracking Space Sensor (HBTSS) program.
Strengthening the Tracking Layer
The Tracking Layer relies on wide-field-of-view infrared sensors to capture the thermal signatures of rocket plumes at launch. Once a missile is in flight, the satellites track its trajectory through the atmosphere and beam high-accuracy targeting data down to interceptor systems via a low-latency communications network.
SDA emphasized that these new AMT3 satellites will be fully interoperable with Tracking Layer spacecraft previously procured under Tranches 1, 2, and 3, and will integrate seamlessly into a common ground operational command system.
“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, Space Force’s Portfolio Acquisition Executive for Missile Warning and Tracking and Director of the SDA
Proven Prime Contractors
Both L3Harris and Sierra Space have established strong track records within the SDA’s vendor ecosystem.
L3Harris has participated in every phase of the program’s evolution. The company delivered four Tranche 0 testbed satellites currently in orbit and holds existing contracts for 14 Tranche 1, 18 Tranche 2, and 18 original Tranche 3 satellites. This latest contract elevates L3Harris’s total PWSA commitment to 72 spacecraft.
Sierra Space made its debut as an SDA prime contractor during Tranche 2 with an award for 18 satellites. This new agreement doubles its order book, bringing Sierra Space’s total PWSA constellation commitment to 36 satellites.