International Space Station Uses Cordierite Ceramic Mirror for Optical Communication

Kyocera
Kyoto, Japan
https://global.kyocera.com/

Sony Computer Science Laboratories, Inc.
Tokyo, Japan
https://www.sonycsl.co.jp/

Kyocera Corporation’s “Fine Cordierite” ceramic mirror was chosen for use in experimental equipment to conduct optical communication between the International Space Station (ISS) and a mobile optical station on Earth. This is the first time a mirror made of cordierite ceramic was selected for use in experimental optical communications equipment in the ISS.

The ceramic mirror has been adopted in the optical communication antenna — Quantum-Small Optical Link (QSOL) — developed by Sony Computer Science Laboratories, Inc. Developed following a commission from Japan's Ministry of Internal Affairs and Communications, QSOL is an optical communication antenna component for the Secure Laser Communications Terminal for Low Earth Orbit (SeCRETS) for on-orbit technology demonstration.

SeCRETS was launched toward the ISS on August 2, 2023, and installed on the external experiment platform of the “Kibo” Japanese Experiment Module (Intermediate Space Environment Experiment Platform [i-SEEP]). Subsequently, secret key sharing was carried out using 10GHz clock optical communication from the ISS in low orbit to a portable optical ground station on the ground, and further successfully demonstrated secure communication between the ISS and the ground station using one-time pad encryption with the key.

The current method for two-way data communication between Earth observation satellites in space and ground stations involves using optical wireless communication with either radio waves or visible light. This communication is essential for acquiring image data for weather forecasting, disaster response, and infrastructure monitoring.

Advancements in the sensors installed on Earth observation satellites have resulted in an increased volume of obtainable observation data. However, there is a pressing need to rapidly transmit large amounts of observation data to ground stations. Achieving high-speed and high-capacity data communication has posed a challenge for space infrastructure. To address this issue, the implementation of laser-light optical communication is expected to enable data transmission and reception at speeds over 100 times faster than radio wave communication with significantly higher capacity.

Additionally, to transmit data from satellites to specific ground stations by optical communication, it is necessary to adjust the light to the optimal angle using optical mirrors. Conventionally, metal or glass mirrors have been used, but nanoscale precision is required for adjusting light. Therefore, mirrors with long-term stable dimensional accuracy and the ability to withstand thermal expansion and temperature changes in the harsh space environment are needed.

In this experiment, Kyocera’s Fine Cordierite ceramic mirror was installed in QSOL due to its unique thermal and mechanical properties, such as low thermal expansion and long-term dimensional stability. With the success of this experiment, the company believes its products can contribute to the construction of space infrastructure aimed at achieving high-speed and high-capacity data communication in satellite optical communication in the future.

This demonstration was conducted jointly by the National Institute of Information and Communications Technology, the School of Engineering, the University of Tokyo, the Next Generation Space System Technology Research Association, SKY Perfect JSAT Corporation, and Sony CSL.

This article was contributed by Kyocera (Kyoto, Japan). For more information, visit here .

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