Recent technology trends of cost reduction of launch and satellite miniaturization are leading cutting-edge applications such as earth observation and communication with satellite constellation. Miniaturization of the communication terminal, light weight and low power consumption are required to the communication terminal on small satellites. Free space optical communication is expected approach to realize high data rate communication system on small satellites. Sony and Japan Aerospace Exploration Agency (JAXA) have experimentally verified the fundamental functions of the small optical communication terminal with optical disk technology for small satellites since 2016. Following this basic study, Sony Computer Science Laboratories, Inc. (Sony CSL) has jointly studied in orbit experiment of the small optical communication terminal with JAXA. To verify its functions in-orbit promptly, we have tried to utilize IVA-replaceable Small Exposed Experiment Platform(i-SEEP) attached to Japanese Experiment Module (JEM) on International Space Station (ISS). The developed small optical communication terminal (SOLISS) is connected to i-SEEP and SOLISS is designed to verify bi-directional communication with free-space optical technology capable of 100 Mbps Ethernet frame data transfer between SOLISS and the optical ground station. For the optical ground station connecting with SOLISS, Sony CSL also conducts a joint research project with National Institute of Information and Communications Technology (NICT). To establish the optical communication link, telemetry and commanding through ISS, controlling of the optical ground station and SOLISS are designed. This article discusses the system architecture for in-orbit experimentation of bi-directional optical communication between SOLISS and the optical ground station.
Small optical inter-satellite communication system to be installed into small and micro satellites flying on LEO are designed and experimentally verified of its fundamental functions. Small, light weighted, power efficient as well as usable data transmission rate optical inter-satellite communication system is one of promising approach to provide realtime data handling and operation capabilities for micro and small satellite constellations which have limited conditions of payload. Proposed system is designed to connect satellites with 4500 (km) long maximum to be able to talk with ground station continuously by relaying LEO satellites even when they are in their own maneuvers. Connecting satellites with 4500 (km) long with keeping steady data rate, accurate pointing and tracking method will be one of a crucial issue. In this paper, we propose a precious pointing and tracking method and system with a miniature optics and experimentally verified almost 10 (μrad) of pointing accuracy with more than 500 (mrad) of angular coverage.