NASA Develops Efficient Dynamic Simulations for Large Displacements and Rotations

New reduced-order modeling approach enables computationally efficient nonlinear dynamic analyses for complex systems like the Space Launch System

Published on Mar. 12, 2026

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NASA researchers have developed a novel approach using nonlinear dynamic substructures (NDS) that enables computationally efficient dynamic simulations involving large displacements and rotations. This capability has been integrated into the Space Launch System (SLS) coupled loads analysis (CLA) framework, allowing for the inclusion of complex umbilical models to more accurately capture system flexibilities, dynamic responses, and clearances during launch.

Why it matters

Accurately modeling the nonlinear dynamic behavior of complex systems like the SLS is critical for ensuring safety and mission success. The new NDS approach developed by NASA provides a computationally efficient solution that can be seamlessly integrated into large-scale system-level analyses, overcoming the limitations of traditional finite element models for capturing large displacements and rotations.

The details

The NDS approach builds upon the use of reduced-order dynamic math models (DMMs) in linear system-level dynamic analyses. By incorporating quaternions to track large rotations and modifying solution algorithms to allow for equilibrium iterations, the residual flexibility mixed boundary (RFMB) transformation is transformed into a nonlinear dynamic substructure. This enables DMMs to be used for computationally efficient nonlinear dynamic simulations involving large displacements and rotations.

  • The NDS approach was developed and integrated into the SLS CLA framework in 2026.

The players

Dexter Johnson

A NASA researcher who can be contacted for more information about the NDS approach.

Space Launch System (SLS)

NASA's heavy-lift launch vehicle that is being used for the Artemis program to return humans to the Moon.

Interim Cryogenic Propulsion Stage (ICPS)

An upper stage of the SLS that is connected to the vehicle via an umbilical system.

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What they’re saying

“The power of the reduced-order models does not end with linear dynamics. It is possible to introduce large displacements and rotations into reduced-order models to enable seamless integration into large substructured integrated system dynamic analyses such as a CLA.”

— Dexter Johnson (nasa.gov)

What’s next

NASA plans to continue refining and expanding the NDS approach to enable even more accurate and computationally efficient nonlinear dynamic simulations for future space systems.

The takeaway

NASA's development of the NDS approach represents a significant advancement in the field of computational dynamics, allowing for the efficient modeling of complex systems with large displacements and rotations. This capability will be crucial for ensuring the safety and success of future space missions.