L3Harris will provide technology to support the Accelerated Missile Defense Tranche 3 (AMDT3) mission, designed to accelerate the US ability to defend against emerging threats from hypersonic and ballistic missiles.
By Sandra Erwin,
Published by Space News, 24 September 2026
L3Harris, Rocket Lab and BAE Systems clear design milestones as the military builds out a multilayered sensor network
WASHINGTON — Three missile-tracking satellite programs have cleared key design reviews as the Space Force builds out new sensor constellations in low and medium Earth orbit.
In low Earth orbit, the Space Development Agency is moving ahead with its Tranche 3 Tracking Layer, a 72-satellite procurement worth about $3.5 billion. L3Harris Technologies said Sept. 24 it completed a preliminary design review for the 18 satellites it is building under an $843 million award, while Rocket Lab said Sept. 3 it had passed the same milestone for its own 18-satellite batch under an $805 million contract. Lockheed Martin and Northrop Grumman are also each building 18 spacecraft. The Tranche 3 constellation is scheduled to begin launching in fiscal 2029.
The SDA satellites will use infrared sensors to detect and track ballistic and hypersonic missiles as part of the agency’s proliferated low Earth orbit architecture. Tranche 3 expands on capabilities introduced in earlier SDA tranches.
The Space Systems Command is leading the Resilient Missile Warning and Tracking Medium Earth Orbit Epoch 2 program. BAE Systems said Sept. 21 it completed a critical design review for the 10-satellite constellation, moving the program further into production under a contract worth about $1.2 billion. The review came about six months after the program cleared preliminary design review.
The spacecraft are intended to detect and track threats ranging from intercontinental ballistic missiles to dim, maneuvering hypersonic weapons. BAE said it has already placed long-lead orders and begun producing some components, using its TREK spacecraft bus and infrared payload technologies. MDA Space is supplying antennas and related electronics for the Epoch 2 satellites.
The LEO and MEO programs are part of the Space Force’s broader shift toward a multilayered missile-warning and tracking architecture, with different orbital layers providing overlapping coverage and greater resilience than an architecture centered largely on a small number of satellites in geostationary orbit.
Both are also expected to contribute to Golden Dome, the Pentagon’s planned homeland missile defense system intended to detect and defeat ballistic, hypersonic and cruise missiles and other advanced aerial threats.
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