The Autonomous System Architecture of the Small SAR Satellite Operation System and On-Orbit Autonomous Operation Experiences

We are developing a small SAR (Synthetic Aperture Radar) satellite for our commercial solution business. Our goal is to deploy at least 30 small SAR satellites in orbit and enable frequent and persistent observations until the Mid 2020s. We launched the satellite on 15th December 2020 by Rocket Lab\u27s Electron. We waited for a month until we took the first image to confirm the complete evacuation of the residual air and contaminations to prevent any hazardous electrical discharge. We took the first image on 8th February. The satellite is now operating in a fine state and acquiring images requested by the customers. We will make six satellite constellation until 2023. We also describe our system architecture including our solution business and the satellite development. Our business development team and the satellite development team are communicating with each other for adequate system architecture and agile satellite development. Our business development team acquires many novel needs from our customers. One of our goals is an agile reflection of the user\u27s needs for the satellite development. We are now establishing a process and an organization to extract those business needs, analyze them and identify the key requirements for the satellite performances and functions. We believe that one important challenge is to achieve application layer integration from a customer business system to a satellite on-board software through solution platform, data platform, satellite control ground system, and the satellite itself. We try to harmonize the software and information processes of the application layer, although the platform where the application is located, the organization where staffs belong, and their culture are different. We wish our activities contribute to our small satellite community or ecosystem and a system architecture including component suppliers, communication service providers, and data processing service providers

Oki-Dozen Dike Swarm: Effect of the Regional Stress Field on Volcano-Tectonic Orientations

This article presents new field, geochronological, and geochemical data for the Late Miocene Oki-dozen dike swarm (ODS), southwest Japan. This swarm is part of a volcanic suite comprising mafic and silicic dikes, sills, and pyroclastic cones from which we obtained structural measurements at a various genetic orders and scales. The mafic magmas generated three dike swarms with dikes oriented to NW-SE, N-S, and NE-SW. In comparison, the silicic intrusions do not have a preferred orientation but instead appear to radiate from the center of the volcanic suite. Comparison of the maximum thickness of 37 dikes with SiO2 content (wt%) yielded a critical thickness (T cr ) value of T cr = 0.2 × (SiO2 − 40). These data indicate that the orientations of dikes were controlled by the magnitude of dike tip pressure and magma overpressure, both of which positively correlate with SiO2 concentrations. The silicic units yield estimated pressures (up to 15–60 MPa) that are large enough to have counteracted the regional stress field, whereas the mafic dike swarm only yielded lower pressures. This result suggests that comparative analysis at a range of scales is essential for the accurate determination on the tectonic stress field by igneous rocks