WASHINGTON, D.C. — The Space Development Agency awarded L3Harris Technologies and Sierra Space contracts worth a total of $1.75 billion to develop 36 satellites for the Pentagon’s Golden Dome missile defense architecture. The satellites, scheduled for launch in 2028, will enhance global missile warning, tracking, and targeting capabilities as part of an accelerated defense initiative.

The contracts specifically cover the Accelerated Missile Defense Tranche 3 (AMDT3) space vehicles, which are designed to detect and track advanced missile threats, including hypersonic and ballistic weapons. L3Harris received a contract worth up to $955 million to build 18 Hypersonic and Ballistic Tracking Space Sensor (HBTSS)-like missile defense variant satellites, while Sierra Space was awarded up to $798 million to produce 18 missile warning and missile tracking variant satellites. Both companies will deploy their satellites across two orbital planes in low-Earth orbit.

Gurpartap “GP” Sandhoo, the SDA director and Space Force portfolio acquisition executive for missile warning and tracking, said the awards mark a critical step in expanding space-based defense. “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,” Sandhoo said.

The AMDT3 satellites will integrate into the broader Golden Dome missile shield architecture, a program mandated by former President Donald Trump to be operational by 2028. Trump issued an executive order in 2025 directing the development of Golden Dome and calling for the accelerated deployment of missile warning and tracking satellites, including the HBTSS and PWSA programs. The Golden Dome office, led by General Michael Guetlein, received a $10 billion budget increase in March to expedite space-based capabilities, with funds allocated to develop airborne moving target indication (AMTI) technology and the Space Data Network.

Sierra Space will base its AMDT3 satellites on its Horizon spacecraft platform. The company has invested $1.5 billion in missile defense capabilities prior to this award and is working with subcontractor Leidos to develop systems featuring 8K focal plane arrays for missile warning, tracking, and defense. Dan Jablonsky, CEO of Sierra Space, said the contract validates the company’s approach.

“By combining cutting-edge design and manufacturing systems with industrial depth and systems integration expertise, we’re able to move faster, manage risk better, and deliver more cost-effective solutions. AMDT3 is proof that our approach is working, and we’re just getting started,” he said.

L3Harris’s role builds on its prior work developing the original HBTSS prototype for the Missile Defense Agency, alongside Northrop Grumman. Those prototypes were launched in 2024 with SDA’s demonstration tranche of missile warning and tracking satellites. The new AMDT3 satellites will carry medium field-of-view cameras, distinct from the wide field-of-view infrared cameras used on missile warning and tracking variants.

According to Josh Lovejoy, general manager for missile warning and defense, spectral solutions at L3Harris, the technical progression from warning to defense involves increasingly precise data requirements. “The ‘missile warning, missile tracking, missile defense’ monikers denote a ‘spectrum of technical requirements’: first ‘seeing’ the incoming missile; second, generating its position, velocity and trajectory; and lastly producing ‘actionable information’ with ‘high confidence’ that the ‘spatial and the temporal resolution’ of the data is up to ‘fire control quality’ that can enable a hit,” Lovejoy said.

The AMDT3 award adds to a layered satellite architecture already under development. In January 2024, L3Harris, Sierra Space, and Lockheed Martin received a $2.5 billion contract for Tranche 2 of the Tracking Layer, which includes 18 satellites per contractor—16 for missile warning/tracking and two for missile defense—scheduled for launch no later than April 2027. Additionally, in December, the SDA awarded $3.5 billion in contracts for the standard Tranche 3 Tracking Layer to L3Harris, Lockheed Martin, Northrop Grumman, and Rocket Lab for 72 satellites set to launch in 2029. With the addition of the 36 AMDT3 satellites, the total number of spacecraft in Tranche 3 will reach 104.

The AMDT3 contracts represent a acceleration of the Pentagon’s space-based missile defense timeline, aligning with the 2028 operational goal for Golden Dome set by executive order. By deploying specialized satellites with enhanced tracking and fire-control-quality data capabilities, the U.S. aims to counter emerging threats from hypersonic and advanced ballistic missiles that could otherwise evade traditional defense systems.

This expansion builds on a multi-tranche architecture already in production, demonstrating a sustained investment in layered, resilient space sensing. The integration of industry-developed platforms like L3Harris’s HBTSS derivatives and Sierra Space’s Horizon spacecraft reflects a strategy of leveraging commercial innovation to meet urgent national security requirements, with implications for U.S. defense posture and allied interoperability.