The program forms part of the Proliferated Warfighter Space Architecture, a multi-layered satellite network designed to improve missile warning, tracking and defence coordination for the United States and its allies. The initiative is central to Washington’s push to build a resilient, distributed constellation capable of detecting ballistic, hypersonic and next-generation threats from orbit.
Under the current contract, Sierra Space will deliver two orbital planes comprising 18 satellites in total, each fitted with advanced infrared (IR) sensors capable of detecting and tracking missile launches across multiple threat profiles. Each orbital plane will carry multiple missile warning and tracking sensors, forming a crucial layer of early warning capability within the Space Development Agency’s (SDA) expanding space-based defence network.
Erik Daehler, senior vice president of Sierra Space Defense, said the successful critical design review demonstrated the company’s readiness to move into full-scale production.
“Our successful completion of CDR demonstrates Sierra Space’s ability to deliver innovative solutions at speed to support the nation’s defence initiatives. We’re proud to support the SDA’s vision with space systems purpose-built for protecting against emerging threats,” Daehler said.
With the design phase now complete, Sierra Space is shifting to assembly, integration and testing at its Victory Works advanced manufacturing facility in the United States, where hardware is already arriving for production. The company’s Horizon Class spacecraft are designed for high-rate manufacturing to meet the SDA’s ambitious deployment timelines.
Sierra Space’s involvement in the Tranche 2 Tracking Layer (T2TRK) program underscores its growing role as a next-generation defence and aerospace leader, combining commercial space innovation with deep technical heritage. The company has more than 30 years of flight experience and has contributed to over 500 missions, including satellite platforms, propulsion systems and reusable spaceplane technologies.
The SDA’s Tranche 2 Tracking Layer is part of a wider effort to enhance space domain awareness and strengthen deterrence in an era of rapidly advancing missile technologies, particularly as China, Russia, and North Korea expand their hypersonic and long-range capabilities.
Sierra Space joins a select group of contractors – including Lockheed Martin, Northrop Grumman and L3Harris – supporting the SDA’s Proliferated Warfighter Space Architecture, a cornerstone of the Pentagon’s strategy to deliver fast, affordable and resilient space-based defence systems.
“With the T2TRK program, we’re helping redefine how space technology supports global security,” Daehler added. “This is about ensuring our forces and allies can see, understand and respond to threats faster than ever before.”
Sierra Space’s work on T2TRK further cements its reputation as a key defence partner for both the US and allied governments, delivering cutting-edge capabilities across satellite systems, hypersonic technology, propulsion and space infrastructure.