Northrop Grumman has delivered 21 satellites to Vandenberg Space Force Base as the US moves to expand a low Earth orbit network for military communications and missile tracking.
The satellites are part of the Space Development Agency’s (SDA) Tranche 1 Transport Layer, which is designed to provide secure, low-latency data links for military forces and connect with satellites in the Proliferated Warfighter Space Architecture (PWSA) Tracking Layer.
Northrop is producing the satellites using a manufacturing approach intended to support larger constellations.
Several dozen additional satellites built by the company are expected to launch over the next six months, covering both data transport and missile defense missions.
“We are embedding mission understanding into every phase of development, enabling us to strike the right balance of speed and mission utility, meeting the needs of the warfighter,” Northrop senior director of proliferated systems Lou Christen said.
Proliferated Warfighter Space Architecture
The PWSA is a US military satellite network designed to provide low-latency communications and space-based missile warning and tracking through a large constellation in low Earth orbit.
SDA is building the architecture in successive tranches, allowing new spacecraft and technologies to be added roughly every two years. The approach is intended to increase resilience and make the network easier to upgrade as requirements change.
The network’s Transport Layer provides the communications and data-routing infrastructure, while the Tracking Layer adds infrared sensors for detecting and tracking missile threats.
In September, L3Harris Technologies completed the preliminary design review for 18 missile-tracking satellites for the Tranche 3 Tracking Layer.
Earlier, in December 2025, the SDA awarded about $3.5 billion in agreements to L3Harris, Lockheed Martin, Rocket Lab, and Northrop Grumman for 72 Tracking Layer satellites. Each company is building 18 spacecraft, with launches planned for fiscal 2029.
