The Space Development Agency (SDA) has awarded $1.75 billion in contracts to L3Harris and Sierra Space to construct 36 satellites for the Pentagon’s “Golden Dome” missile defense shield. This expansion, known as the Accelerated Missile Defense Tranche 3 (AMDT3), brings the total constellation to 104 satellites designed to track advanced hypersonic and ballistic missile threats from low Earth orbit.
Expanding the Missile Defense Constellation
The new contracts represent a significant scale-up for the Space Force’s tracking layer. L3Harris and Sierra Space will each build 18 satellites, with delivery scheduled to support a potential launch in late 2028. According to SDA Director GP Sandhoo, these satellites are designed to provide “global, persistent” detection and warning capabilities for both U.S. forces and allies.
This award follows initial contracts granted last December to Lockheed Martin, Rocket Lab, Northrop Grumman, and L3Harris for 72 satellites. By adding the 32 satellites of the AMDT3 batch, the Pentagon is accelerating its path toward a fully operational tracking layer. The initiative is part of a broader push to prioritize “proven capabilities that are ready now,” as noted in a report accompanying recent defense legislation.
Did you know?
The Pentagon’s Golden Dome program, overseen by Director Michael Guetlein, recently received a $10 billion budget increase specifically to accelerate space-based sensing elements within the U.S. missile defense architecture.
The design strategy for these satellites relies on previously demonstrated sensor technology. L3Harris confirmed that its 18 satellites will be based on the Hypersonic and Ballistic Tracking Space Sensor (HBTSS) design. The company previously developed an HBTSS prototype for the Missile Defense Agency, which successfully completed on-orbit demonstrations.
Sierra Space is utilizing its “Horizon” spacecraft bus for its portion of the order. The company is already under contract to provide 18 satellites for Tranche 2 of the SDA tracking layer. CEO Dan Jablonsky stated that the company’s approach focuses on “systems integration expertise” to manage risk and deliver hardware at a faster pace than traditional procurement cycles.
Strategic Priorities for Space-Based Defense
The push for a 104-satellite constellation reflects a shift in military acquisition strategy. Rather than relying on a handful of massive, expensive satellites, the Space Force is moving toward a distributed, resilient network in low Earth orbit. A committee has directed the Space Force to prioritize the deployment of at least 45 vehicles equipped specifically with proven HBTSS payloads to ensure the network remains functional against evolving global threats.
Pro Tip:
When tracking defense procurement, look for the distinction between “prototypes” and “tranche” production. Tranche awards indicate that a design has moved from experimental demonstration to mass-production phase.
Frequently Asked Questions
What is the primary purpose of the AMDT3 satellites?
The satellites are designed to provide global, persistent tracking and warning against advanced missile threats, including hypersonic and ballistic missiles, for the U.S. homeland and deployed forces.
How many satellites will make up the total tracking layer?
When are these satellites expected to be ready?
The SDA has set a delivery schedule intended to support a potential launch in late 2028.
Who are the primary contractors for this project?
The current contracts for the 36 AMDT3 satellites were awarded to L3Harris and Sierra Space. Previous tranches included Lockheed Martin, Rocket Lab, and Northrop Grumman.
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