JAXA Supercomputer System Annual Report February 2025-January 2026

Report Number: R25EU0902

Subject Category: Space and Astronautical Science

PDF (to be added)

• Responsible Representative: Akira Oyama, Professor, Institute of Space and Astronautical Science
• Contact Information: Akira Oyama(oyama.akira@jaxa.jp)
• Members: Kana Arima, Reo Iida, Yusei Iida, Yuya Kuroda, Shoki Kurata, Hikari Mukawa, Ren Momoi, Akira Oyama, Ryutaro Onishi, Kenji Shimizu, Ken Sawada, Ren Takeuchi

Abstract

To conduct fundamental research on high-speed fluid dynamics such as aerodynamic design of Mars drones

Reference URL

Please refer to https://ladse.eng.isas.jaxa.jp/ .

Reasons and benefits of using JAXA Supercomputer System

High-fidelity flow simulations such as the large eddy simulations are required to analyze Mars drones.

Achievements of the Year

Focusing on plume-surface interaction (PSI) during Mars landing, we conducted a study aimed at risk assessment and improved physical understanding through numerical analysis. PSI is a phenomenon in which the supersonic plume from the descent engine impinges on the regolith, causing crater formation and particle ejection. This process may lead to several risks, including degradation of lander stability, reduced visibility, and potential damage to onboard instruments. However, quantitative data and reliable reproduction methods applicable to the Martian environment remain limited. Therefore, developing a better understanding based on high-fidelity numerical simulations and establishing design guidelines is essential. The main achievement of this study is the development of a simulation framework capable of simultaneously resolving compressible flow and particle dynamics at high grid resolution, thereby establishing a computational basis for reproducing PSI phenomena. Specifically, we developed a coupling algorithm between FaSTAR, JAXA's compressible CFD solver, and LIGGGHTS, an open-source DEM solver, and demonstrated the feasibility of performing large-scale PSI simulations. To ensure the validity of the solver, verification and validation (V&V) were performed using fundamental experimental data and theoretical results. The simulations successfully reproduced the flow field generated by jet impingement, the pressure distribution near the surface, and the behavior of particles, demonstrating reasonable agreement with expected physical behavior. Figure 1 shows a visualization example from a PSI test simulation. The results illustrate how the interaction between the jet and surface particles develops and evolves over time. These results provide a foundation for future studies, including extension to Martian environmental conditions (low pressure and low gravity) and systematic parametric investigations. In future work, quantitative evaluations using metrics such as crater morphology and particle dispersion will be conducted to support risk assessment and mitigation strategies for PSI.

Mars airplanes designed for wide-area surface exploration have recently attracted considerable attention. To improve the aerodynamic performance of the main wing of a Mars airplane, a multi-objective aerodynamic optimization of airfoil shapes was conducted (Fig. 2). The results revealed that all Pareto-optimal solutions share a concave geometry on the upper surface near the leading edge, which generates a strong low-pressure region. This feature simultaneously enhances lift while reducing both pressure drag and viscous drag (Fig. 3). These findings indicate that an airfoil with a properly designed concave leading edge can maintain excellent aerodynamic performance over a wide range of angles of attack, demonstrating strong robustness. Such a configuration is therefore a highly promising candidate for future Mars airplane wings, achieving both structural feasibility and superior aerodynamic performance.

Fig.1(video): Test simulation of Plume-Surface Interaction

Fig.2: Performance values of the Pareto-optimal solutions (shown by red squares) obtained through aerodynamic design optimization of the Mars airplane main-wing airfoil.

Fig.3: One of the obtained Pareto-optimal airfoil shapes. The flow field is colored by the streamwise velocity, visualizing the recirculation region formed in the concave leading-edge section.

Publications

- Oral Presentations

Yuki Iida, Akira Oyama, Satoshi Sekimoto, and Makoto Sato, Aerodynamic Optimization of Angular Airfoil for Micro-Scale Mars Airplane, AIAA SciTech 2026 Forum, Orlando, Florida, 12-16 January, 2026.

Usage of JSS

Computational Information

• Process Parallelization Methods: MPI
• Thread Parallelization Methods: OpenMP
• Number of Processes: 144 - 480
• Elapsed Time per Case: 24 Hour(s)

JSS3 Resources Used

Fraction of Usage in Total Resources*1(%): 1.27

Details

Please refer to System Configuration of JSS3 for the system configuration and major specifications of JSS3.

*1: Fraction of Usage in Total Resources: Weighted average of three resource types (Computing, File System, and Archiver).

*2: Fraction of Usage：Percentage of usage relative to each resource used in one year.

ISV Software Licenses Used

*2: Fraction of Usage：Percentage of usage relative to each resource used in one year.

JAXA Supercomputer System Annual Report February 2025-January 2026