World’s First Demonstration of a Radio Interferometer on a Flexible Membrane Structure: The HELIOS-R Interferometry Mission under Innovative Satellite Technology Demonstration-4

March 30, 2026.
Japan Aerospace Exploration Agency (JAXA)
Space Exploration Innovation Hub Center

 Japan Aerospace Exploration Agency (President YAMAKAWA Hiroshi, JAXA) Space Exploration Innovation Hub Center (TansaX) has successfully conducted on‑orbit test operations of the HELIOS‑R Interferometer payload aboard the lightweight deployable membrane structure HELIOS‑R, marking the world’s first demonstration of microwave interferometry on a flexible membrane structure (*1).

 HELIOS-R was jointly developed by JAXA TansaX, JAXA Institute of Space and Astronautical Science (ISAS), Sakase Adtech Co., Ltd., Institute of Science Tokyo and National Defense Academy of Japan (*2). The payload was launched aboard the small satellite RAISE‑4 (RApid Innovative payload demonstration SatellitE‑4), part of JAXA’s Innovative Satellite Technology Demonstration‑4 (*3), from New Zealand on December 14, 2025. Following confirmation of membrane deployment on February 13, 2026, the interferometer was commissioned with an experimental radio signal transmission on March 6, 2026. The test successfully demonstrated nominal operation of the HELIOS‑R Interferometer, including microwave interferometric observations using membrane‑mounted antennas. The photograph below shows the HELIOS-R membrane after deployment. (The HELIOS-R Interferometer antenna can be seen near the center-right).

 We will continuously observe interferometric variations corresponding to the orientation of membrane‑mounted antennas caused by minute deformations of the flexible membrane structure, while quantitatively evaluating performance degradation resulting from long term operation in the space environment, particularly due to thermal cycles and radiation exposure.

 Through this test, we have demonstrated successfully the feasibility of converting an entire lightweight, deployable membrane structure into a large‑aperture antenna. Expected future applications include meter‑class, large-aperture antennas deployable on small satellites for high‑resolution remote sensing (Earth observation and outer‑planet exploration), high-throughput MIMO communications, and relative navigation sensors for spacecraft operating in deep space missions.

 TansaX will apply the outcomes of this research to related collaborative projects, including　RFP10, “Development of millimeter‑wave devices and integrated systems for high‑efficiency, long‑distance wireless power transmission for both space and terrestrial applications,” and RFP12, “Research on switching converters, high-efficiency receiving antenna arrays, and maximization of combined received power for a 24GHz high-efficiency, high-power wireless power transfer system” (*4) . TansaX will continue to contribute to the development of future lunar infrastructure, including lightweight, high-power, and high-efficiency wireless power transmission systems.

 

*1 As of March 31, 2026
*2 This research originated from the development of a radio interferometer following the successful “Hayabusa2 Capsule Recovery Mission,” which served as a ground‑based demonstration under the collaborative research project “Research on a High‑Performance Exploration Radar for Next‑Generation Information and Communication Systems.” This project was conducted within the framework of the “Innovation Hub Construction Support Program” commissioned by JAXA from the Japan Science and Technology Agency (JST), entitled “Open Innovation Hub for Expanding Humanity’s Habitable and Activity Domains through Solar System Frontier Exploration.” Based on these achievements, development of the interferometer was initiated with the intention of mounting it on a multifunctional lightweight membrane structure being developed by JAXA’s Institute of Space and Astronautical Science (ISAS) and Sakase Adtech Co., Ltd. As an opportunity to demonstrate this multifunctional membrane technology in space, a proposal was submitted to the “Demonstration Themes for Innovative Satellite Technology Demonstration‑3,” and was successfully selected.
Following this selection, a joint research agreement was established in 2021 among the Space Exploration Innovation Hub Center (TansaX), JAXA ISAS, Sakase Adtech Co., Ltd., and Tokyo Institute of Technology. In 2024, the National Defense Academy of Japan joined the collaboration, and the project has since been jointly developed by all participating institutions.
*3 Innovative Satellite Technology Demonstration Program(Japanese only)
HELIOS-R (Japanese only)
*4 Research on switching converters, high-efficiency receiving antenna arrays, and maximization of combined received power for a 24GHz high-efficiency, high-power wireless power transfer system. (Japanese only）