From Supercomputers to Wind Tunnels: NASA’s Road to Artemis II

 

By Jill Dunbar

Of the many roads leading to successful Artemis missions, one is paved with high-tech computing chips called superchips. Along the way, a partnership between NASA wind tunnel engineers, data visualization scientists, and software developers verified a quick, cost-effective solution to improve NASA’s SLS (Space Launch System) rocket for the upcoming Artemis II mission. This will be the first crewed flight of the SLS rocket and Orion spacecraft, on an approximately 10-day journey around the Moon. 

A high-speed network connection between high-end computing resources at the NASA Advanced Supercomputing facility and the Unitary Plan Wind Tunnel, both located at NASA’s Ames Research Center in California’s Silicon Valley, is enabling a collaboration to improve the rocket for the Artemis II mission. During the Artemis I test flight, the SLS rocket experienced higher-than-expected vibrations near the solid rocket booster attach points, caused by unsteady airflow between the gap.

One solution proposed for Artemis II was adding four strakes. A strake is a thin, fin-like structure commonly used on aircraft to improve unsteady airflow and stability. Adding them to the core stage minimizes the vibration of components.

The strake solution comes from previous tests in the Unitary Plan Wind Tunnel, where NASA engineers applied an Unsteady Pressure Sensitive Paint (uPSP) technique to SLS models. The paint measures changes over time in aerodynamic pressures on air and spacecraft.

This supercomputer simulation peers down at a close-up of the SLS rocket during ascent. The force of friction is represented in greens, yellows, and blues. A six-foot-long strake flanking each booster’s forward connection point on the SLS intertank smooths vibrations induced by airflow, represented by purples, yellows, and reds. The white streams represent a contour plot of density magnitude, highlighting the change of density in the air.

Credit: NASA/NAS/Gerrit-Daniel Stich, Michael Barad, Timothy Sandstrom, Derek Dalle

It is sprayed onto test models, and high-speed cameras capture video of the fluctuating brightness of the paint, which corresponds to the local pressure fluctuations on the model. Capturing rapid changes in pressure across large areas of the SLS model helps engineers understand the fast-changing environment. The data is streamed to the NASA Advanced Supercomputing facility via a high-speed network connection.

“This technique lets us see wind tunnel data in much finer detail than ever before. With that extra clarity, engineers can create more accurate models of how rockets and spacecraft respond to stress, helping design stronger, safer, and more efficient structures,” said Thomas Steva, lead engineer, SLS sub-division in the Aerodynamics Branch at NASA’s Marshall Space Flight Center in Huntsville, Alabama.

For the SLS configuration with the strakes, the wind tunnel team applied the paint to a scale model of the rocket. Once the camera data streamed to the supercomputing facility, a team of visualization and data analysis experts displayed the results on the hyperwall visualization system, giving the SLS team an unprecedented look at the effect of the strakes on the vehicle’s performance. Teams were able to interact with and analyze the paint data.

"NASA’s high-end computing capability and facilities, paired with unique facilities at Ames, give us the ability to increase productivity by shortening timelines, reducing costs, and strengthening designs in ways that directly support safe human spaceflight.

Kevin Murphy

NASA's Chief Science Data Officer

“NASA’s high-end computing capability and facilities, paired with unique facilities at Ames, give us the ability to increase productivity by shortening timelines, reducing costs, and strengthening designs in ways that directly support safe human spaceflight,” said Kevin Murphy, NASA’s chief science data officer and lead for the agency’s High-End Computing Capability portfolio at NASA Headquarters in Washington. “We’re actively using this capability to help ensure Artemis II is ready for launch.”

Leveraging the high-speed connection between the Unitary Plan Wind Tunnel and NASA Advanced Supercomputing facility reduces the typical data processing time from weeks to just hours.

For years, the NASA Advancing Supercomputing Division’s in-house Launch, Ascent, and Vehicle Aerodynamics software has helped play a role in designing and certifying the various SLS vehicle configurations.

“Being able to work with the hyperwall and the visualization team allows for in-person, rapid engagement with data, and we can make near-real-time tweaks to the processing,” said Lara Lash, an aerospace engineering researcher in the Experimental Aero-Physics Branch at NASA Ames who leads the uPSP work.

This video shows two simulations of the SLS (Space Launch System) rocket using NASA’s Launch Ascent and Vehicle Aerodynamics solver. For the Artemis II test flight, a pair of six-foot-long strakes will be added to the core stage of SLS that will smooth vibrations induced by airflow during ascent. The top simulation is without strakes while the bottom shows the airflow with strakes. The green and yellow colors on the rocket’s surface show how the airflow scrapes against the rocket’s skin. The white and gray areas show changes in air density between the boosters and core stage, with the brightest regions marking shock waves. The strakes reduce vibrations and improves the safety of the integrated vehicle.

NASA/NAS/Gerrit-Daniel Stich, Michael Barad, Timothy Sandstrom, Derek Dalle

This time, NASA Advanced Supercomputing researchers used the Cabeus supercomputer, which is the agency’s largest GPU-based computing cluster containing 350 NVIDIA superchip nodes. The supercomputer produced a series of complex computational fluid dynamic simulations that helped explain the underlying physics of the strake addition and filled in gaps between areas where the wind tunnel cameras and sensors couldn’t reach.

This truly was a joint effort across multiple teams.

“The beauty of the strake solution is that we were able to add strakes to improve unsteady aerodynamics, and associated vibration levels of components in the intertank,” said Kristin Morgan, who manages the strake implementation effort for the SLS at Marshall.

A team from Boeing is currently installing the strakes on the rocket at NASA’s Kennedy Space Center in Florida and are targeting October 2025 to complete installation.

Through Artemis, NASA will send astronauts to explore the Moon for scientific discovery, economic benefits, and build the foundation for the first crewed missions to Mars.

To learn more about Artemis, visit: https://www.nasa.gov/artemis

Source: From Supercomputers to Wind Tunnels: NASA’s Road to Artemis II - NASA