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資料番号: SA1004691000

資料番号: SA1160297000

資料番号: SA1160216000

This study estimates the effect of creases, or plastic wrinkle lines, on the out-of-plane stiffness of solar sails. A method to simulate the crease effects using reduced-order finite-element (FE) models is proposed, and is applied to a practical solar sail architecture. A detailed crease shape is determined by a geometrically nonlinear FE analysis using a simple model first; the effect of creases is then replaced by beam elements. This method substantially reduces the computational effort required for the FE analysis of a solar sail model. The result suggests the significant impact of creases on membrane's out-of-plane stiffness when the tension level in the membrane is small., 資料番号: PA1510010000

Japan Aerospace Exploration Agency (JAXA) are planning an outer solar system exploration and sample return mission from a Jovian Trojan asteroid using a 3000 m2 solar power sail. The difficulty of this mission is a severe restriction on the weight; only 300 kg is allocated for sampling and returning to Earth. In this weight, fuel for trajectory and attitude control, sampling mechanism, re-entry capsule, and other systems required to return to the Earth are included. In this paper, a preliminary analysis of this sample return mission is conducted. Three scenarios for sampling are proposed; sampling with a 3000 m2 solar power sail, with a detachable small solar power sail using electric propulsion systems and with a small probe using chemical propulsion systems. The mission analysis shows that the most feasible configuration is to conduct the sampling with the 3000 m2 solar power sail using an extension mast., 資料番号: PA1510011000

Piecewise Straight Fold is proposed for large solar sail membranes to simultaneously realize the high packaging efficiency and the simple folding. The fold pattern is based on Spiral Fold to reduce the deviation of the fold line, which improve the packaging efficiency. In addition, the fold pattern consists of piecewise straight fold lines, which approximate the Spiral Fold line, in order to simplify the folding. A simple manufacturing process of Piecewise Straight Fold is developed based on the Z-fold membrane. The preliminary experimental results show the feasibility of the Piecewise Straight Fold and its simple manufacturing process, where the high packaging efficiency is also verified. The wrapping fold experiments for the solar power sail membrane is demonstrated by using the Piecewise Straight Fold. In the wrapping fold experiments, the applicability of the Piecewise Straight Fold to the solar power sail membrane is verified., 資料番号: PA1510012000

資料番号: SA1005043000

The small solar power sail demonstrator IKAROS was developed and launched in 2010 by JAXA and deployed its large membrane successfully. Through IKAROS's on-orbit operation, one of the most critical problems was a sail's shape imbalance during the sail deployment sequence. This paper focuses on the evaluation and consideration of the sail's imbalance through high vacuum experiments using a scale-down sail model. The experimental results obtained using the specially designed rotating mechanism and a small scale model lead to a hypothesis of the reason for the IKAROS's imbalanced deployment. The experimental results are extrapolated up to IKAROS's scale, using dimensionless analyses.

資料番号: SA1004852000

資料番号: SA1004855000

資料番号: SA1005035000

Japan Exploration Agency (JAXA) launched a powered solar sail “Interplanetary Kite-craft Accelerated by Radiation Of the Sun (IKAROS)” on May 21, 2010. One of the primal technologies demonstrated at IKAROS is the spin-deployment of the sail whose diameter is 20 m class. After the launch, two-step deployment operation was performed and successful expansion of the sail was confirmed. This paper shows the flight data and observed dynamic motion during the deployment. At the quasi-static first stage deployment, the spin rate of main body shows little oscillation after each step and then damped quickly. The damping ratio of the spin rate after a later step of deployment is estimated by curve-fitting to be 0.0127. At the dynamic second stage deployment, the nutation motion is maintained within ±1.5 deg/s and the spin rate of main body is converged quickly about 60s after the deployment start. These flight result and observed dynamic motion during the deployment are compared with the results of numerical simulations using multi-particle model. These results show that the multi-particle model can simulate the global behavior of membrane sufficiently except the dumping motion of in-plane oscillation between the main body and the expanded membrane.