NASA GlennICE Advances 3D Aircraft Icing Simulation Software

NASA Unveils GlennICE: A Digital Leap for Aviation Safety

NASA has officially introduced GlennICE, a next-generation software code designed to revolutionize how the aviation industry predicts and prevents ice accumulation on aircraft. Developed at the Glenn Research Center in Cleveland, Ohio, this new tool addresses the limitations of decades-old legacy systems, offering high-fidelity 3D simulations critical for the safety of emerging aircraft designs, including eVTOL vehicles and sustainable commercial jets.

According to an announcement from the agency on December 4, 2025, GlennICE, short for the Glenn Icing Computational Environment, enables engineers to “flight test” designs digitally with extreme precision. By simulating how ice forms on complex surfaces like rotating propeller blades, engine interiors, and truss-braced wings, the software aims to reduce the reliance on expensive and time-consuming physical wind tunnel testing.

From 2D Legacy to 3D Precision

For over 20 years, the aviation industry relied primarily on LEWICE, a 2D coding standard also developed by NASA. While LEWICE proved effective for traditional “tube-and-wing” aircraft, it struggles to model the intricate geometries of modern Advanced Air Mobility (AAM) vehicles. NASA officials state that GlennICE was built specifically to bridge this gap.

Christopher Porter, the lead developer for GlennICE at NASA, emphasized the necessity of this evolution in the agency’s press release:

“The legacy codes are well formulated to handle simulations of traditional tube-and-wing shaped aircraft. But now, we have new vehicles with new designs that present icing research challenges. This requires a more advanced tool, and that’s where GlennICE comes in.”

Advanced Physics and Droplet Tracking

The core advancement in GlennICE is its use of Lagrangian droplet tracking. Unlike previous methods that utilized simple 2D strips, GlennICE simulates the trajectories of individual water droplets as they approach an aircraft. According to NASA technical reports, the software can track millions of droplets to calculate exactly which ones impact the surface and which are swept away by airflow.

Validation data indicates the software has demonstrated the ability to simulate over 134 million trajectories to ensure safety-critical accuracy. This capability allows it to model various hazardous icing conditions, including:

• Rime Ice: Rough, opaque ice that forms instantly upon impact.
• Glaze Ice: Clear, heavy ice that can run back along the wing before freezing, altering aerodynamics significantly.
• Supercooled Large Droplets (SLD): Freezing rain or drizzle, which poses a severe threat to flight control surfaces.
• Ice Crystals: High-altitude particles that can melt and refreeze inside turbine engines.

Industry Adoption and Strategic Partnerships

The transition to GlennICE is already underway across the aerospace sector. NASA reports that “dozens of industry partners” are currently utilizing the tool to certify next-generation aircraft. Key collaborations highlighted in recent reports include:

• Boeing: Engineers are using GlennICE to predict ice formation on the Transonic Truss-Braced Wing (TTBW) concept, known as the X-66A. The software helps model ice buildup on the aircraft’s unique support struts, a task difficult to achieve with legacy 2D tools.
• Wisk Aero: As a subsidiary of Boeing focused on autonomous air taxis, Wisk utilizes the software to simulate icing on complex rotors and lifting surfaces, a critical step for AAM certification.
• Honeywell Aerospace: The company employs GlennICE to research “ice crystal icing” inside engines, a phenomenon linked to power loss events in commercial aviation.

AirPro News Analysis

The release of GlennICE represents a pivotal moment for the Advanced Air Mobility (AAM) sector. As manufacturers of eVTOLs and delivery drones push toward commercial certification, they face stringent safety requirements regarding flight into known icing (FIKI) conditions. Physical testing for every potential icing scenario is financially prohibitive and logistically difficult given the limited availability of specialized facilities like the NASA Icing Research Tunnel.

By providing a validated “digital twin” capability, NASA is effectively lowering the barrier to entry for sustainable aviation startups. If regulators accept GlennICE data as a partial substitute for physical testing, similar to how CFD is used in aerodynamics, it could significantly accelerate the timeline for bringing autonomous air taxis to market.

Validating the Digital Twin

To ensure the software’s predictions match reality, NASA validated GlennICE using data from the Icing Research Tunnel (IRT), the world’s oldest and largest refrigerated wind tunnel. This process ensures that the digital simulations align with physical physics, allowing engineers to trust the software for scenarios that are difficult to replicate physically.

Porter noted the importance of this capability in the official release:

“Some environments we need to test in are impractical with wind tunnels because of the tunnel size required and complex physics involved. But with GlennICE, we can do these tests digitally.”

Version 5.1.0 of the software, released in early 2025, introduced standardized verification frameworks, further solidifying its role as the new industry standard for icing research.

Sources

• NASA: NASA Software Raises Bar for Aircraft Icing Research
• NASA Technical Reports Server: GlennICE Verification and Validation v5.1.0