NASA and SpaceX put Starship’s lunar shape through a wind tunnel

NASA and SpaceX have sent a small version of the next Starship launch stack into two wind tunnels to measure how it handles high-speed air. The 1.2%-scale model represented the Super Heavy Version 3 booster expected to launch the Starship human landing system.

The test article was not the lunar lander by itself. It was the first-stage booster configuration tied to the Starship architecture that NASA plans to use for lunar missions, and the measurements focused on the booster’s return through Earth’s atmosphere.

The model represented a redesigned Super Heavy

SpaceX’s complete Starship launch system consists of a Super Heavy first stage and the Starship upper stage. NASA’s July 31 account says Version 3 introduces significant changes to the booster, giving engineers reason to collect a fresh aerodynamic data set.

The changes include Raptor 3 engines, the removal of the former engine-section skirt and large integrated base heat shield, and an integrated hot stage. Version 3 also switches from four grid fins to three, with each fin about 50% larger. Grid fins help steer the booster during its descent back toward the launch site.

Two tunnels covered different speed regimes

Engineers tested the model at NASA’s Ames Research Center in California. A transonic tunnel exposed it to flows from Mach 0.2 through Mach 1.4, spanning the difficult region around the speed of sound. A smaller supersonic tunnel covered Mach 1.55 through Mach 2.5.

Using separate facilities let the team characterize the booster across several phases of atmospheric flight. Flow near Mach 1 is especially complex because subsonic and supersonic regions can exist around the same vehicle, producing shocks and rapidly shifting pressures. Supersonic testing extends the picture to conditions where those shock structures are fully developed.

Steady loads and buffeting require different measurements

Some aerodynamic forces change smoothly and can be represented as steady forces and moments. Others fluctuate as flow separates or buffets parts of the vehicle. Those unsteady pressures can drive vibration and create local loads that a simple average would conceal.

The late-2025 campaign measured both types of behavior across the model’s surface. Steady-force data can help predict how the booster responds during reentry and improve the flight software that guides it. Unsteady-pressure measurements feed structural load analysis, helping engineers identify locations that may experience persistent or rapidly changing stress.

Scale models still require careful interpretation

A 1.2% model is small enough to fit specialized tunnels, but geometric similarity alone does not recreate every aspect of full-scale flight. Engineers account for Reynolds number, surface detail, support hardware and the tunnel’s own flow limits when translating measurements to a real rocket. Computational models and flight data can then fill gaps that a ground facility cannot reproduce.

Wind tunnels remain valuable because they provide controlled, repeatable conditions. The same orientation can be tested many times while pressure sensors isolate particular regions. Engineers can change speed and angle methodically, building a map of aerodynamic behavior before committing hardware to a flight environment that allows far fewer measurements and no easy repetition.

The booster test supports a lunar landing system

NASA is working with SpaceX on a Starship Human Landing System intended to transport astronauts between lunar orbit and the Moon’s surface. The Human Landing System program relies on commercial partners while NASA supplies technical expertise and facilities for work including aerodynamics, propulsion environments and mission integration.

Super Heavy does not travel to the lunar surface. Its job is to launch the Starship stage from Earth, making booster reliability part of the chain that must work before a lunar lander can perform its mission. Reuse also raises the importance of controlled reentry, since the booster is meant to return toward its launch site for refurbishment and another flight.

The new data will shape software and structures

NASA has experience translating wind-tunnel results into hardware changes. The agency noted that similar work at Ames contributed to adding strakes to the Space Launch System for Artemis II. For Super Heavy Version 3, the immediate products are aerodynamic databases used in guidance, load prediction and structural assessment.

The campaign also shows why an architecture can be visually familiar yet aerodynamically new. Larger fins, altered engine packaging and a different hot-stage arrangement change the surfaces that direct and disturb airflow. Even if the overall rocket still resembles earlier Starship vehicles, those local differences can shift pressure and vibration.

NASA’s announcement attached the tests to Artemis planning, but wind-tunnel results do not establish a launch date or guarantee mission readiness. They answer a narrower and essential question: how the revised booster is likely to behave in air. That measured foundation gives flight software and structural analysis something firmer than extrapolation from the previous version.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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