NASA and its industry partners are preparing for next year’s Artemis III demonstration mission by completing new wind tunnel tests on SpaceX’s Super Heavy Version 3 rocket booster. The tests, conducted at NASA’s Ames Research Center in California’s Silicon Valley, focused on better understanding the extreme aerodynamic forces the rocket can experience during re-entry. The recent test series builds on previous testing completed at NASA Ames in 2024.
NASA is working with SpaceX to develop the company’s Starship Human Landing System (HLS) to safely carry astronauts from lunar orbit to the Moon’s surface and back. The upgraded Super Heavy rocket booster is part of SpaceX’s Starship launch system. Version 3 of Starship and Super Heavy is expected to be the basis for the Starship HLS for Artemis III in 2027 and a later crewed lunar landing in 2028.
Although Starship HLS is a lunar lander designed and built by SpaceX, NASA collaborates with commercial companies to provide access to specialized testing facilities, like the wind tunnels at NASA Ames, and technical expertise, such as the team that set up the wind tunnel testing and helped analyze the results.
“NASA has a lot of experience with unsteady aerodynamics,” said Manish Mehta, discipline lead engineer for the HLS Plume and Aero Environments team, NASA’s Marshall Space Flight Center in Huntsville, Alabama. “We used the agency’s broad experience base of conducting wind tunnel tests for the space shuttle, the SLS (Space Launch System) rocket, and Orion spacecraft to efficiently set up and analyze the wind tunnel testing for the Super Heavy Version 3. In fact, similar testing at the Ames Unitary Plan Wind Tunnel resulted in adding strakes to SLS for Artemis II, so what we learned for Artemis II is helping us get to Artemis III and beyond.”
SpaceX’s Starship consists of a 33-engine first-stage Super Heavy rocket, or booster, and the second-stage Starship. Version 3 of Super Heavy incorporates many new and upgraded systems, including:
- New propulsion systems and new Raptor 3 rocket engines
- No engine section skirt, individual engine shrouds, or integrated large-scale base heat shield
- Three gridfins on the Super Heavy booster instead of four, with each fin now 50% larger
- An integrated hot stage replacing the previous single-use protective interstage
With significant changes to Super Heavy, NASA and SpaceX engineers wanted more information about the steady and unsteady aerodynamic forces the rocket will experience during atmospheric re-entry as it returns to the launch site for refurbishment and re-use.
“When a rocket, or an airplane, flies through air at high speed, it’s subjected to steady aerodynamic forces and moments, and unsteady aerodynamic forces and moments,” explained Jayanta Panda, unsteady aerodynamics subject matter expert at NASA Ames and part of the Human Landing System Plume and Aero Environments team. “An example of a steady aerodynamic force would be when air smoothly flows over the surface of the rocket as it ascends. An unsteady aerodynamic force would be air ‘buffeting,’ or hitting, certain areas the rocket at less predictable times and potentially causing vibrations.”
NASA and SpaceX used a 1.2% scale model of the Super Heavy Version 3 in the transonic wind tunnel and the supersonic wind tunnel at NASA Ames for testing. The transonic tunnel blasts scale models of rockets or aircraft with air at speeds ranging from Mach 0.2 to Mach 1.4 (Mach 1 is the speed of sound, or about 761 miles per hour). The smaller supersonic tunnel fires winds at higher speeds, from Mach 1.55 to Mach 2.5. The wind tunnel tests on Super Heavy Version 3, conducted in late 2025, used both tunnels to measure steady and unsteady air flows on the surfaces of Super Heavy.
“Resulting wind tunnel data on steady forces and moments helps predict how the rocket will react to forces in the atmosphere during re-entry so the flight software can effectively guide the rocket during flight,” Mehta said. “The unsteady pressure data helps engineers understand the environment around the rocket as it re-enters Earth’s atmosphere. Engineers use that information as one input into software that analyzes loads on the rocket.”
Through the Artemis program, NASA is returning humans to the Moon for scientific discovery, economic opportunity, to establish an enduring human presence on the lunar surface, and build the foundation for the first crewed missions to Mars – for the benefit of all.
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