WASHINGTON — The Space Development Agency is preparing for a high-stakes series of satellite deployments that could define the future of its national security space architecture. The upcoming launches, set to begin within weeks, will test whether SDA can make good on its vision of a resilient, low-cost satellite network in low Earth orbit (LEO).
“This is make or break,” said Maj. Gen. Stephen Purdy, the acting assistant secretary of the Air Force for space acquisition and integration. Purdy, who leads Space Force acquisitions and oversees SDA, spoke July 22 at the Space Foundation’s “Innovate Space” event.
Purdy said the first of several Tranche 1 launches is expected within the next month. The deployment represents a critical juncture for SDA, which has been developing the Proliferated Warfighter Space Architecture (PWSA) since its establishment in 2019.
“What they’re really focused on now is Tranche 1 delivery,” Purdy said during a fireside chat with retired Space Force Gen. Nina Armagno. Tranche 1 will be the first PWSA deployment expected to provide “warfighting capability,” he added.
The PWSA represents a shift from traditional military satellite architecture. Rather than relying on a small number of large, expensive satellites in higher orbits, SDA is building a mesh network of hundreds of smaller, less expensive satellites in low Earth orbit. The constellation is structured in specialized layers, each providing specific functions such as missile warning and tracking, battle management, and secure data transport.
The agency employs what’s known as a spiral development model, delivering new satellites every two years in batches called “tranches.” SDA said this approach allows for rapid incorporation of new technologies and reduces the risk of obsolescence that has plagued traditional space programs.
Integration challenge
The Tranche 1 deployment consists of two primary components: the Transport Layer, comprising approximately 126 satellites that provide data communications, and the Tracking Layer, composed of about 28 satellites equipped with infrared sensors for missile warning and tracking. The layers are designed to work together, with the Tracking Layer interconnected via laser communications with the Transport Layer.
Purdy said the Tranche 1 deployment will be “about a year long activity” with satellites projected to launch every month. “And so we’re really looking forward to that, to get the missile warning capability up into LEO, to get that comm layer up, to start getting past the testing, and start getting into operations.”
The process of integrating satellites from multiple manufacturers into a cohesive network presents significant technical challenges. “It gets more complex the more of these satellites you have,” Purdy noted, highlighting SDA’s current focus on ensuring all components work together seamlessly.
SDA has already conducted preliminary testing through its Tranche 0 demonstration satellites. “Some things worked, some things didn’t work, but that’s why we do that sort of activity. It’s all about risk reduction,” Purdy said.
Industrial base efforts
Since its inception six years ago, SDA has sought to transform how the Pentagon buys space systems, moving away from traditional procurement models that typically involved a small number of established defense contractors. The agency has worked to attract new suppliers to the defense market through competitive procurements and rapid contracting mechanisms.
“They’ve gotten after the industrial base in a huge way,” Purdy said. “Back when they started six years ago, we were in the traditional buy model, and we knew that proliferation was where we wanted to head … And so they set out to sort of build that basic construct, and they set out to build rapid contracting mechanisms.”
At the same time, SDA has faced supply chain challenges, including shortages of optical terminals and other critical satellite components.
Questions loom
As the first Tranche 1 launch nears, questions loom over SDA’s long-term direction. The Trump administration has directed a halt in funding for the Transport Layer’s Tranche 3 and ordered the Department of the Air Force to conduct an analysis of alternatives to consider other options for providing data relay capabilities in space.
One alternative under consideration is a military network using SpaceX’s Starshield broadband satellites, a move that has drawn criticism from some lawmakers who question the industrial base implications of moving away from SDA’s competitive procurement approach in favor of a system from a single vendor.
Purdy did not address these recent developments during his remarks at the Space Foundation event, focusing instead on the immediate challenge of proving SDA’s concept through the successful deployment and operation of Tranche 1.