On Monday, July 13, 2026, the Space Development Agency (SDA) awarded two firm-fixed-price Other Transaction Authority (OTA) rapid prototyping agreements totaling approximately $1.75 billion to expand its space-based missile tracking capabilities.
The contracts select L3Harris Technologies and Sierra Space Corporation to manufacture and deliver a combined total of 36 satellites. Operating as part of the Tracking Layer for Tranche 3 of the Proliferated Warfighter Space Architecture (PWSA), the spacecraft will directly support the U.S. Space Force’s “Golden Dome for America” layered defense initiative to defend against hypersonic and advanced ballistic missile threats.
Program Structure and Constellation Expansion
The newly structured procurement—designated by the agency as the Accelerated Missile Defense Tranche 3 (AMDT3) program—serves as an expansion layer to accelerate orbital sensor deployments over high-threat zones. Under the terms of the allocation, L3Harris received a $955 million agreement, while Sierra Space was awarded $798 million.
The AMDT3 framework expands upon the foundational Tranche 3 Tracking Layer contracts finalized by the SDA in December 2025, which originally allocated $3.5 billion across Lockheed Martin, Rocket Lab, Northrop Grumman, and L3Harris to build an initial batch of 72 satellites. This accelerated 36-satellite addition expands the total volume of the Tranche 3 tracking constellation to 104 space vehicles distributed across multiple orbital planes.
Orbital Deployment and Technical Variations
The 36 incoming AMDT3 satellites will be deployed across four distinct low-Earth orbit (LEO) planes, split into balanced technical configurations:
- L3Harris Fleet: Responsible for delivering 18 missile defense variants distributed across two orbital planes. These platforms utilize a design derived from the company’s Hypersonic and Ballistic Tracking Space Sensor (HBTSS) and feature medium-field-of-view infrared payloads engineered to generate fire control-quality targeting coordinates.
- Sierra Space Fleet: Tasked with providing 18 missile warning and tracking variants across the remaining two orbital planes. These vehicles will be constructed using the company’s standardized “Horizon” spacecraft bus architecture, which was developed to fulfill its prior SDA Tranche 2 Tracking Layer prime contract awarded in January 2024.
All 36 spacecraft will integrate optical inter-satellite links to communicate directly with the PWSA Transport Layer, allowing for rapid routing of sensor alerts directly to tactical military networks.
Executing Accelerated Spatial Defense Vows
The contract acceleration directly addresses federal mandates to field a functional homeland missile defense layer by the conclusion of the decade. By utilizing proliferated, smaller satellite platforms rather than traditional, high-cost single spacecraft, the Space Force aims to reduce tracking revisit times and enhance systemic orbital resilience.
“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,” stated Gurpartap “GP” Sandhoo, SDA Director and Space Force Portfolio Acquisition Executive for Missile Warning and Tracking.
Integration and Launch Windows
Both prime contractors will handle full-stack vehicle integration, assembly, and checkout operations within their respective defense manufacturing complexes. According to the milestone schedule provided by the Space Force, all 36 accelerated space vehicles must be completed, tested, and ready for launch manifest integration by the end of 2028.
