Osamu Mori

Mission Report on The Solar Power Sail Deployment Demonstration of IKAROS

Hirokata Sawada Japan Aerospace Exploration Agency, Kanagawa, 252-5210, JAPAN Osamu Mori 2 Japan Aerospace Exploration Agency, Kanagawa, 252-5210, JAPAN Nobukatsu Okuizumi Japan Aerospace Exploration Agency, Kanagawa, 252-5210, JAPAN Yoji Shirasawa University of Tokyo, Tokyo, JAPAN Yasuyuki Miyazaki Nihon University, Chiba, 274-8501, JAPAN Michihiro Natori Waseda University, Tokyo, 169-8555, JAPAN Saburo Matunaga Tokyo Institute of Technology, Tokyo, 152-8552, JAPAN Hiroshi Furuya Tokyo Institute of Technology, Tokyo, 152-8552, JAPAN Hiraku Sakamoto Tokyo Institute of Technology, Tokyo, 152-8552, JAPAN

Overview of IKAROS Mission

The Japan Aerospace Exploration Agency (JAXA) makes the world’s first solar power sail demonstration of photon propulsion and thin film solar power generation during its interplanetary cruise by IKAROS (Interplanetary Kite-craft Accelerated by Radiation Of the Sun). It deployed and spans a membrane of 20 m in diameter taking the advantage of the spin centrifugal force. It accelerates and controls the orbit using solar radiation pressure successfully. This is the first actual solar sail flying an interplanetary voyage. This paper presents the summary of development and operation of IKAROS.

4R and 5R parallel mechanism mobile robots

We have proposed a self-reconfigurable parallel robot, which can be configured to 4R and 5R closed kinematic chains. This paper proposes a parallel mechanism mobile robot by mounting it on a crawler mechanism. The combined mobile robot gains some useful functionalities other than just locomotion as an advantage of its parallel mechanism, such as getting over a bump by controlling its center of gravity and carrying an object by making use of its shape. Furthermore, the robot can form three-dimensional structures with other such robots and reach a certain height which the single one cannot. We have developed two such robots that are self-contained. This paper analyzes the motions of the functionalities and verifies them experimentally using the robots.

Manufacturing and Folding of Solar Sail "IKAROS"

The Solar Sail “IKAROS” (Interplanetary Kite-craft Accelerated by Radiation Of the Sun) , which is the first solar sail on orbit, consists of 20m diagonal length square membrane made of 7.5μm thickness polyimide film. The sail membrane is deployed by centrifugal force due to spinning motion of the spacecraft. The wrapping fold is applied to realize stable deployment property. The manufacturing process of the large membrane with the folding techniques are described in detail.

Evaluation of Sail Mechanics of IKAROS on its Slow-Spin and Reverse-Spin Operation

In the post operational phase of spin type solar sail “IKAROS”, a slow-spin operation and a reverse-spin operation were conducted to acquire basic knowledge of mechanics of sail membrane. The flight data indicates that the sail membrane kept its shape against the solar radiation pressure even with low centrifugal force.

Repeatability of Stored Configuration of a Large Solar Sail with Non-negligible Thickness

Hiraku Sakamoto∗, Shogo Kadonishi, Yasutaka Satou, Hiroshi Furuya, Tokyo Institute of Technology, Tokyo 152-8552, Japan Yoji Shirasawa, Nobukatsu Okuizumi, Osamu Mori, Hirotaka Sawada, Japan Aerospace Exploration Agency, Kanagawa 252-5210, Japan Jun Matsumoto, University of Tokyo, Tokyo 113-8656, Japan M. C. Natori, Waseda University, Tokyo 169-8555, Japan Yasuyuki Miyazaki Nihon University, Chiba 274-8501, Japan and Masaaki Okuma Tokyo Institute of Technology, Tokyo 152-8552, Japan

Modeling of Spinning Solar Sail by Multi Particle Model and Its Application to Attitude Control System

In this paper, the attitude motion and attitude control strategy of spinning solar sail are discussed. As the spinning type solar sail does not have any rigid structure to support its membrane, the impulsive torque by the RCS can introduce oscillatory motion of the membrane. Thus, an “oscillation free” attitude controller is needed, which takes into account the flexibility of the membrane and avoid unnecessary oscillatory motion. First, the dynamics model and numerical model were introduced, and the validity of these models and dominant out-of-plane membrane vibration mode is examined by membrane vibration experiment and comparison between both models. Then, based on the analysis of the dynamics of torque-free motion, it was shown that a spinning solar sail has three oscillation modes of nutation, one of which is equal to the spinning rate of the spacecraft. The dominancy of each nutation mode was analytically and numerically discussed. Then, we discussed the spin axis maneuver control using conventional RCS. It was analytically shown that continual impulsive torque synchronizing the spin rate can excite nutation velocity and that a controller is needed to damp the nutation while controlling the spin axis at the same time. The authors proposed new controller named Flex-RLC and improved one. Their effectiveness was verified by numerical simulations using precise multi-particle numerical model which can express higher order oscillatory motion of the flexible membrane, and it was found that the proposed method can control the attitude of spinning solar sail while drastically reduces the nutation velocity compared with conventional control logic. So, it can be said that the proposed method is promising fast and stable controller for spinning solar sail.© 2009 ASME

Dynamics of Large Membrane for Solar Sail-Craft

This paper discusses dynamics of large membrane for achieving spinning solar sail-craft proposed by the Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA). For comprehending the dynamics, firstly, two types of grand-scale experiments were conducted. One was an ice rink experiment. The other was a balloon experiment. In the both experiments, we succeeded in deploying 10m and 20m diameter membrane and observing the motion. Secondly, we constructed a numerical model using a multi-particle method, and numerical simulations were conducted. We drew a comparison between results of experiments and numerical simulations. The effectively of the multi-particle model was then indicated in this paper.Copyright

Attitude and Orbit Prediction of IKAROS in Actual Flight Operation

The world’s first solar sail IKAROS (Interplanetary Kite-craft Accelerated by Radiation Of the Sun) which is operated by Japan Aerospace Exploration Agency (JAXA) lost communication with the ground station due to the power short-age on December 24, 2011. In order to acquire IKAROS again after the power comes back, we immediately initiated to predict the attitude and orbit for the spacecraft.