The Space Solar Power System (SSPS) is been watched with keen interest. Japan, along with USA and EU, has been developing SSPS. This paper reports the present and future of the development of the SSPS technologies by each region Attention is paid on the SSPS programs, planned SSPS configurations, and future operational plan of SSPS systems. In addition, technologies used in SSPS, for example photovoltaic for space utilization, microwave transmission technology, large scale on-orbit structure and also safety issues related to microwave exposure are discussed herein.

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The mobile high data rate transmission from ambulance is very useful for early-stage medication. This study consists of 2 part, one is satellite system study and the other is deployable antenna system. In this paper, small satellite system for medical motion picture transmission is described. A 4 hour high eccentricity orbit has been selected for this satellite. Recently, many components for small satellite are getting available all over the world. This small satellite can be designed using off-the-shelf components for small satellite.

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This paper describes the design and production of the experimental model of the deployable mesh type reflector antenna which can be boarded on a small satellite to achieve high data rate communication via small satellite. Recently, many missions using small satellites are proposed under the increase of the availability of the launching as secondary payloads so called piggyback satellites. We are planning to build up this deployable antenna system for high speed and high data rate communications via piggyback satellite.

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Pulsed Plasma Thrusters (PPT) using Teflon as solid propellant has characteristics of simplicity, lightweight, and high durability in recent years. Therefore, PPT propulsion system has the advantages for the small, micro-and nano-satellite attitude control. Tokyo Metropolitan Institute of Technology (TMIT) has started R & D on PPT system with the collaboration of NASDA. This paper describes its present status of the R & D. In the BBM phase, we tested that hood angle and electrode material was changed. In this result, we have researched optimum performance of TMIT-PPT. Now we have shifted from BBM-phase to EM-phase.

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In this paper, attitude behavior of boiled eggs rotating on the table is concerned. After introducing a new paper concerning this item, the author tries different approach which admit inclination of the total angular momentum vector from the zenith. Rising of the egg or elevation of the mass center is explained from the standpoint of attitude dynamics/control technology. A very simple approximate second order equation of attitude motion of spinning tops with small inclination angles is derived. It is pointed out that (1) positional relation between contact points and angular velocity vectors is especially important, (2) the angular momentum vectors change their direction from zenith to several ten degrees down which decrease nutation angles or stand up the spinning axes and so mass centers, (3) a condition to curvature of the spinning axis for sleeping top is derived.

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In order to investigate the lateral stability of parafoil, a series of wind-tunnel tests were made with a downscaled model. First, forces and moments on it were measured by a balance. Sideslip angle was a major parameter of the test. It became clear that parafoil had the lateral stability even when no control was made, which is considered mainly due to the unhedral effect of the canopy shape. Secondly, the dynamic test was made with a one-degree-of-freedom rotating device. If parafoil had a sideslip angle, it would rotate toward the direction of decreasing the angle as long as it has the lateral stability. From these test results, the lateral stability of parafoil was discussed.

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This paper studies a decentralized control for a class of space structures which is constructed on orbit. For general mechanical systems with collocated sensors and actuators, it is known effective to use a symmetric controller. The symmetric controller guarantees robust stability of the closed loop system by virtue of its structure having positive definite or positive semi definite symmetric coefficient matrices. We proposes an optimal design method of the symmetric decentralized controller in the sense of H_∞ norm before and after construction. In the synthesis, the optimal controller is obtained by solving linear matrix inequalities reduced from the bounded real lemma. Then we evaluate its performance by a numerical simulation for a simple LSS model.

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Slush hydrogen is a two-phase solid-liquid cryogenic fluid consisting of solid hydrogen particles in liquid hydrogen. Compared to liquid hydrogen, the density is about 16% greater at a solid mass ratio (solid fraction) of 50%, and the cryogenic heat capacity (enthalpy) is about 18% higher. Various applications are anticipated, including fuel for reusable space shuttles, coolant for cold neutron generation, as well as the transport and storage of hydrogen as a clean energy source. At a solid fraction of within 50%, piped transport can be conducted in the same way as for normal fluids. This paper reports the slush hydrogen technology concerning the developments of densimeter and flowmeter.

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Several bonding and joining methods for envelope materials are proposed and tested. The test envelope materials are polyurethane coated fabric and aluminum foil laminated fabric. Several bonding and joining methods, such as overlap joint, butt joint, sewing, lapping reinforce, are applied to these materials and tested to investigate the creep, tensile strength, and helium permeation characteristics

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We've been investigating large deployable antennas that sizes have 10 to 20 m. As its mechanical scale is getting large, shape measurement and prediction by ground test become difficult. Then the shape analysis is important. The electrical surfaces of these antennas are composed of metallic mesh and cable network. The mesh component has membrane characteristics. In this study, we describe some analysis results of membrane and cable structures for deployable antennas.

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The helium gas of the high pressure is used for the fuel supply in the rocket engine re-ignition or the fuel supply to artificial satellite reaction control system. A high pressure gas storage tank beyond 25MPa is necessary to carry this efficiently. The composite tank which wound CFRP around titanium liner was developed to make this tank light weight. A cost reduces by welding a gas port to thin titanium liner made efficiently by super-plasticity forming, and pressure test, endurance test, environmental test was done, and it was proved that it had the performance which should be necessary. At present, it is being used for the reaction control system of the artificial satellite such as a Mars orbiter "NOZOMI" and the H-IIA rocket.

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An orbital space hotel concept is proposed as one of the commercial space program in the near future. By the beginning of the 21st. century, 2 civilians have visited the International Space Station (ISS) now under construction in the low earth orbit. Some adventure travel promoters disclosed their sub-orbital space travel plans using a high speed and high altitude airplane however, these programs are still under examination. This space hotel concept is prepared to make real space travel developed in the short period, composed by existing space systems including ISS and Russian space transportation systems. Habitation module used for the hotel will be attached to he ISS and has interior fitting to enjoy sight seeing of the earth and gravity-free environment. The hotel interior is designed to make guests feel comfortable making it roomy and flexible in their own use. The facility is also applicable for a studio such as film making and broadcasting. The future hotel concept is also introduced.

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