SwRI and the NPSS Consortium release new version of NPSS® software with improved functionality

SAN ANTONIO — March 2, 2026 — Southwest Research Institute (SwRI), on behalf of the Numerical Propulsion System Simulation (NPSS®) Consortium, has released a new version of the NPSS software, the industry-leading aerospace software package for simulating and designing propulsion systems. NPSS 3.3 adds new functionalities, data types, and communication interfaces that provide improved flexibility and software compatibility while reducing model and component development times.

NPSS allows the aerospace industry to model turbomachinery, air-breathing propulsion systems, liquid rocket engines, engine control systems, and systems integration. It also supports modeling for refrigeration cycles, multi-phase heat transfer systems, vehicle emission analyses, supercritical carbon dioxide (sCO ₂ ) power cycles, and more.

NPSS was developed in the 1990s by NASA’s Glenn Research Center. Since 2013, SwRI has managed the NPSS Consortium to support the user community with new software capabilities, improved usability, and technical support. NPSS supports numerous applications ranging from creating new engine models to developing digital twin models of spacecraft. Beyond aerospace applications, NPSS has been used to simulate solar power systems, industrial gas turbines, and hybrid electric systems.

Key features of NPSS 3.3 include electric port support that allows users to model hybrid turbo-electric propulsion systems, including electric vertical takeoff and landing systems. Complex numerical functions enhance electric system modeling, allowing users to tackle hybrid propulsion problems more effectively.

“NPSS incorporates the Functional Mock-up Interface industry standard, allowing NPSS to interface with other engineering tools,” said SwRI’s Griffin Beck, who oversees the NPSS consortium. “For example, a gas turbine performance model created in NPSS can now communicate with an external engine control model, enabling co-simulations that combine performance and external control models at the same time.”

NPSS 3.3 features a foreign function interface (FFI) to allow integration with specific external functions rather than full software packages.

“The FFI provides users with greater flexibility and enables more detailed modeling,” Beck explained. “For example, you could integrate your NPSS model with a high-fidelity combustion function. This would significantly enhance the accuracy of combustion modeling beyond what NPSS can do on its own.”

The software now includes built-in support for exporting and reading data in a .CSV file format, making it easier to handle engine performance data directly within the software.

For more information or to purchase an NPSS license, visit SwRI’s NPSS webpage at npssconsortium.org .