Kazuki Honda
(Kyushu Institute of Technology, Japan)

Recently, many research organizations at universities and private companies have started the development of small satellites. A molecular gas is generated from the organic materials used in these small satellites when exposed to the high vacuum and heat cycle. Because of the harmful influence this effect has on satellite components, such as blocking out light as this gas adheres to optical instruments, it is necessary to evaluate the intended materials to be used in the spacecraft for outgassing characteristics in advance. The need for outgassing measurement has increased as small satellites development continues to increase. The outgassing measurement system is developed for this need in this study. The methods of measuring TML (total mass loss), CVCM (collected volatile condensable materials), and WVR (amount of water vapor regained) is used in outgassing measurement examination provided in ASTM-E595. The recommended values of the selected materials for a spacecraft is TML<1.0%, and CVCM<0.1%. The weighting and test environments in which the above values can be measured under ASTM are developed in this study. After construction, its performance was examined and the contamination simulator was evaluated.

Kazuya Okada
(Kyusyu Institute of Technology, Japan)

The space satellite has become a vital lifeline in fields such as meteorology, communication, broadcasting, and land surveying, etc. As such an integral part of the infrastructure for these fields, improving the reliability of the spacecraft is an important issue. Electric discharges constitute more than half of all spacecraft accidents. The purpose of this study is to develop an electric potential measurement sensor that can be installed even in a small satellite. By enabling installment in a small satellite, we will have more flight opportunities to test its function in real space environment. In this study, a charging observation device is developed that uses an electrostatic analyzer. The ESA uses two step parallel monotonous electrodes. These parallel electrodes use an electric field to bend a charged particle's path into the analyzer, and the electric potential of the spacecraft is measured from the energy difference of the collected particles in the first second steps. Verification has been made of the principle behind the electrostatic analyzer of two-step parallel monotonous electrodes type. Subsequently, an engineering model for the environmental testing has been developed, and operation in plasma vacuum has been verified. In this paper, the current state of the development is described.

Naoki Matsumoto
(Kyushu Institute of Technology, Japan)

Recently causing high operating voltage defects within the solar array at the same time.This is probably due to the potential difference between insulators and satellite body.A negative potential of the satellite assembly develops and is greatly influenced by the storm magnetosphere plasma environment. If the voltage of satellite can be reduced near 0V and surface voltage of insulators can be smaller than that of satellite structure by emitting electrons from satellite structure, the risk of discharge can be greatly removed. This solution has been attempted by developing the device named Electron-Emitting Film, which is used to increase the electric field near the triple junction and emit the field . And Field Emission Microscopy is developed for ELF development and judges the characteristic of ELF.In this study, the goal is evaluation of the ELF through Field-Emission-Microscopy ; FEM; and improvement of the FEM. To be specific, the ELF is set in the FEM and measurement system is started and the ELF is judged by measurement of surface form, electric field electron current distribution, and electric field multiplication coefficient b.The aim of this project is to use FEM to develop an ELF that emits the most electrons possible.

Kenta Tomida
(Kyushu Institute of Technology, Japan)

Rapid progress has been made to support the fast-paced and low-cost development of a university nano satellite. HORYU-II is being developed as part of systems engineering educational program at the Kyushu Institute of Technology. The main mission of HORYU-II is to safely generate 300V in Low Earth Orbit as a high-voltage technology demonstration. It will be launched during the 2011 fiscal year on a H2-A rocket on 700km sun-synchronous orbit. One requirement is a de-orbit time of less than 25 years to minimize generation of space debris. The area to mass ratio is a important parameter of HORYU-II in considerations of the de-orbit requirements to ensure a natural and timely de-orbit. Therefore, HORYU-II is extremely light with a mass under 7kg, while having a solid shape with all sides roughly 30cm in length. The purpose of this research is to design and verify a satellite structure that can endure the launch environment while maintaining a high area to weight ratio. After the structure was designed, natural frequency and stress analyses were conducted with mathematical models. In addition, vibration and shock tests imitating the launch environment were performed. Any resulting damage to each part was defined, and the analysis was verified.

Hiroaki Shioi
(University of Tokyo, Japan)

In the area of satellite development, improving anomaly detection and monitoring techniques are of significant concerns mainly because satellites are under severe, distant, and uncertain conditions. In order to monitor the state of satellites and detect anomaly, it is important to estimate the normal model. However, it is not possible to acquire the exact estimate of the model because a lot of uncertain factors have influence on the behaviors in addition to the complicated system of the satellite; thus predicting the behavior of the satellite before launching, is also a difficult challenge. In this paper, with regards to this concern we provide the method of monitoring the status of the satellite and detecting anomaly by learning Switching Linear Dynamical Systems from telemetry data. We used EM (Expectation-Maximization) algorithm to estimate parameters of the model. By reducing dimension of telemetry data, we can see its characteristic and cyclic behavior, which has several transition and stationary modes - and this method focuses on these characteristics. We apply this method to the real multi-dimensional continuous time-series data of satellite which were provided by JAXA (Japan Aerospace Exploration Agency) and ISSL (Intelligent Space Systems Laboratory), and evaluate the usefulness of our method.