SwRI expands facility to support hypersonic, supersonic technology testing

SAN ANTONIO — July 20, 2026 — Southwest Research Institute (SwRI) has expanded the capabilities of its High Energy Annex Test (HEAT) facility to advance hypersonic and supersonic technology. The SwRI HEAT Facility, which was created in 2016 to support gas turbine combustor testing, can now simulate the extreme conditions experienced at hypersonic speeds. These upgrades make it possible for SwRI to test hypersonic systems technologies, such as scramjets, ramjets, small gas turbines, and rocket thrusters in a controlled environment. The work supports a project that seeks to address a critical gap in hypersonic vehicle development.

Hypersonic and supersonic vehicles regularly experience extreme conditions, including temperatures exceeding 1400 degrees Fahrenheit, high altitudes, and low-pressure environments. Achieving and maintaining these conditions in test facilities requires stable and uniform high airflow velocities, which are challenging to generate and control to a degree that allows for accurate testing.

“Testing in actual high-speed flight is expensive and risky, which is why accurate simulated testing is important,” said SwRI Research Engineer Austin Jones, who led the project. “The new facility capabilities allow us to simulate these extreme conditions in a lab setting while allowing for adjustments and improvements to be incorporated before real-world testing.”

The HEAT facility has added a new ejector system that allows it to simulate high-altitude conditions. It works by using high-pressure air to create a fast-moving jet that draws surrounding air through a nozzle, lowering the pressure and creating a vacuum. This low-pressure environment closely resembles the thin atmosphere at high altitudes in which scramjets, jet engines that can propel vehicles at hypersonic speeds, would typically operate.

“Simulating a scramjet isolator system requires very hot supersonic flow through a duct,” Jones said. “To achieve that, we added the ejector and used an existing high pressure electrically heated upstream air system. The ejector creates a vacuum downstream in the duct, allowing for a significant pressure differential across a nozzle to produce the high temperature supersonic flow.”

The HEAT facility can now simulate supersonic speeds and high-altitude, low-pressure conditions as low as 2.5 PSI, which is ideal for supersonic testing. The project is ongoing, and the researchers have achieved temperatures up to 1400 degrees Fahrenheit and successfully generated scramjet isolator conditions matching flight speeds up to Mach 4.

For more information, visit https://www.swri.org/markets/energy-environment/machinery/propulsion-technologies .