Vulcan | SDA Tranche 1 Tracking Layer B

Vulcan Rocket Set to Launch SDA Tranche 1 Tracking Layer B Mission

On June 30, 2026, the United Launch Alliance's (ULA) Vulcan rocket is scheduled to lift off, carrying the Space Development Agency's (SDA) Tranche 1 Tracking Layer B payload. This mission represents a critical step in bolstering the United States Space Force's capabilities to detect and counter emerging missile threats in an increasingly contested orbital environment.

At the heart of the mission are its objectives to enhance global missile defense through the Proliferated Warfighter Space Architecture (PWSA). The Tranche 1 Tracking Layer constellation, of which this is one of five planned launches, aims to provide persistent, low-latency indications, warnings, tracking, and targeting of advanced threats, including hypersonic missiles. These systems travel at speeds exceeding Mach 5, making them difficult to detect with traditional ground-based radars due to their maneuverability and low-altitude flight paths. The payload consists of a cluster of satellites equipped with infrared sensors and optical communication links, enabling real-time data relay to ground stations and other orbital assets. This setup allows for rapid threat identification and cueing of defensive systems, potentially integrating with existing networks like the Missile Defense Agency's infrastructure. By proliferating sensors across low Earth orbit (LEO), the constellation reduces single points of failure, offering resilience against anti-satellite attacks.

The Vulcan rocket itself embodies a blend of innovation and reliability in launch vehicle design. Developed by ULA as a successor to the Atlas V and Delta IV, Vulcan features a modular architecture with two solid rocket boosters (SRBs) from Northrop Grumman, configurable for different payload masses. Its core stage is powered by two BE-4 engines from Blue Origin, which use liquefied natural gas (LNG) and liquid oxygen for propulsion, delivering up to 1.1 million pounds of thrust at liftoff. The upper stage, Centaur V, employs RL10 engines for precise orbital insertion, supporting payloads up to 27,200 kilograms to LEO. Technical specifications include a height of about 202 feet and a diameter of 17.7 feet, with options for up to six SRBs to scale performance. This design emphasizes cost-efficiency, aiming to reduce per-launch expenses through reusable components and domestic sourcing, addressing past dependencies on foreign engines.

Vulcan's performance history, though still emerging, builds on ULA's legacy of over 150 successful launches. Its inaugural flight in January 202