SpaceX Launches 21 Satellites for U.S. Military Satellite Network

A SpaceX Falcon 9 rocket launched 21 satellites into low Earth orbit on September 10, 2025, as part of an ambitious effort to build a military satellite network for the U.S. Space Development Agency (SDA). The mission, which took off at 10:12 a.m. Eastern from Vandenberg Space Force Base in California, marks the first deployment of satellites for SDA's Tranche 1 Transport Layer.

The launch is part of SDA’s development of the Proliferated Warfighter Space Architecture (PWSA), a global network designed to relay secure data and communications across military forces. Acting SDA Director Gurpartap "GP" Sandhoo described the launch as "a great day for SDA and, more importantly, for the warfighter."

Enhancing Global Military Connectivity

The newly deployed satellites form the backbone of the Transport Layer, a mesh network designed to provide secure, beyond-line-of-sight communications. This system expands the capabilities of the Link 16 tactical data network, the U.S. military's primary battlefield communication system. By integrating satellite relays, the Transport Layer will enable real-time, secure data sharing across forces stationed on land, at sea, or in the air.

Before this launch, Link 16 radios were limited to a range of a few hundred miles. With the addition of satellite relays, the network now offers global coverage, enabling seamless communication in remote regions. The first users of this enhanced connectivity will be U.S. Indo-Pacific Command forces, who require persistent data coverage for operations across the vast Pacific theater.

A Step Toward a Broader Constellation

The satellites launched in this mission represent the first of 10 planes planned for Tranche 1 of the Transport Layer. Each plane consists of satellites arranged in the same orbital path, ensuring continuous regional coverage. The satellites launched today are in polar orbit, allowing them to cover all points on Earth, including high-latitude regions previously inaccessible with equatorial orbits.

In total, Tranche 1 will comprise 126 Transport Layer satellites and 28 additional satellites for missile warning and tracking. This initial launch is just one of six planned launches for the Transport Layer, with four additional launches scheduled for the Tracking Layer over the coming year.

The 21 satellites deployed in this mission were constructed by York Space Systems, who secured a $382 million contract for their development in February 2022. Other key contractors contributing to Tranche 1 include Lockheed Martin and Northrop Grumman, who are scheduled to deliver additional satellites in future launches. The satellites feature advanced optical inter-satellite communication terminals, provided by Tesat-Spacecom, enabling rapid and secure data exchanges across the network.

Innovation in Military Space Infrastructure

SDA, established in 2019, was created to move away from the Pentagon’s traditional reliance on large, costly satellites. Instead, the agency aims to deploy networks of smaller, more resilient spacecraft built with commercial components and streamlined acquisition practices. This approach allows for faster deployment and more adaptable solutions to evolving military needs.

"This launch represents a major milestone", said Sandhoo, emphasizing the importance of the Transport Layer for military operations. With this first step complete, the SDA is on track to deliver a transformative communication network designed to enhance the capabilities and reach of U.S. forces worldwide.

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