このページのトップです。


The University of Tokyo FIRST Program
New Paradigm of Space Development and Utilization Opened by Micro/Nano-satellites with Reasonably Reliable Systems "Hodoyoshi" Concept

Shinichi Nakasuka
Department of Aeronautics and Astronautics, School of Engineering, University of Tokyo
7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, JAPAN nakasuka@space.t.u-tokyo.ac.jp

  • Creation of New Paradigm of Space Utilizations with Low-cost Micro/Nano-satellites
    •  This project aims to accelerate the technology developments and practical utilizations of micro/nano-satellites. Micro/nano-satellites are expected to reduce the cost of satellite development from several hundred million dollars to several million dollars and development period from 5-7 years to 1-2 years, which may open new ways of satellite utilizations in the form of large number of satellite constellations which enables frequent observations of the same places on the Earth or "personal satellite" concept. The following research goals are to be pursued in the project period of 2010-2013 by collaboration of several leading universities and small industries in Japan.
    • Conceptualization and demonstration of novel reliability concept "Reasonable Reliable Systems ("Hodoyoshi" in Japanese)" suitable for micro/nano-satellites.
    • Research and development of all the required components for micro/nano-satellites with advanced concept and technologies, aiming for the world top level "performance per size".
    • Innovation of satellite development process including standardization of interfaces and software, ways of ground test, etc, to further reduce the development cost and period.
    • Construction of all-Japan consortium for R&D, supply chain network, creation of international user communities, and capacity building, etc.
  • Reasonably Reliable Systems Concept
    •  The hearing on design philosophy from successful micro/nano-satellite leading developers showed that they did not pursue such high reliability as required in the conventional governmental satellites. Fig.1 shows the "implicit" cost vs. reliability curve in the experiential knowledge of such successful developers of micro/nano-satellites; cost gets suddenly exploded when a required reliability level exceeds a certain level. "Hodoyoshi" concept tries to model these cost-reliability relationships to find out an appropriate design point which yields "high reliability per cost" such as marked by a circle in Fig.1. Systems engineering study referring to designs of previous satellites, their on-orbit performance data and ground test results, etc. is now under way. Characteristic Curve for Satellite Cost vs. Reliability
      Fig. 1 Characteristic Curve for Satellite Cost vs. Reliability
  • Innovative Subsystem Design Concept
    •  Conventional components for mid/large satellites cannot be utilized because of the limitation of size and power. Innovative concept for each component is pursued to aim at the world top-level “performance per size”. Examples include a new concept of optical system with an on-orbit compensation mechanism, optical communication system, extensible structures, modular type thermal control system and SDK to improve software reusability, etc. The basic idea of these advanced component concepts are under study by collaborating universities with their own specialties, and small industries help them develop actual onboard hardware out of these concepts. Innovative Subsystem Design Concept
  • Satellite Development Plan
    •  Five satellites are planned to be developed within the period of 2010-2013, in order to demonstrate the results of the R&D as well as to facilitate the creation of new user communities. The first satellite “Hodoyoshi-1”, which will be launched in 2012, aims at 5m GSD remote sensing, introducing an innovative design concept for satellite and new onboard optical sensor system. Refractive optics is employed; whose design has the flexibility to customize wavelength bands. The second satellite will aim at space science mission, and No.3 to 5 satellites will be operated in constellation to create and try a new satellite business. Missions for them are now under investigation. Hodoyoshi-1 and Its Optical System
      Fig.2 Hodoyoshi-1 and Its Optical System

TO TOP