Stratolaunch Completes First, Full-Scale Preburner Test on PGA Engine

PGA Engine preburner test (Credit: Stratolaunch)

SEATTLE (Stratolaunch PR) — Stratolaunch is proud to announce the successful initiation of full-scale development testing of the PGA Engine preburner, marked by the completion of the first hot-fire test of the preburner on November 2.

Fully designed and developed by Stratolaunch, the PGA Engine is a high-performing, liquid rocket engine that, once completed, will produce 200,000 lbf of thrust. The hydrogen-oxygen engine will have the highest specific impulse of any rocket engine propellant and will release only water as a byproduct.

Designed, fabricated, assembled and tested in less than one year, the full-scale hydrogen preburner will be one of the fastest engine development programs to-date. The team has successfully completed propellant cold flows, igniter activation, and hot-fire sequence development, all culminating to the hot-fire tests.

“I am excited to share that Stratolaunch has completed our first successful hot-fire test of the PGA Engine fuel preburner,” said Jeff Thornburg, vice president of propulsion at Stratolaunch. “This is the first step in proving the performance and highly-efficient design of the PGA engine. The hot-fire test is an incredible milestone for both the propulsion team and Stratolaunch.”

Not only is the PGA Engine the first U.S. hydrogen-staged combustion engine since the Space Shuttle Main Engine, the Stratolaunch propulsion team has also prioritized the use of additive manufacturing for the development of the engine, enabling rapid prototyping on a much faster scale than traditional methods. This process has resulted in 100 percent additive manufacturing of the preburner. 

Once completed, the PGA Engine will support multiple configurations of Stratolaunch’s in-house launch vehicles enabling convenient, reliable, and routine access to space.

Preburner testing will continue over the coming months, with increases in both the duration and power-levels of the hot-tests. For the latest news and updates, please check out @Stratolaunch and