This paper presents a nonlinear dynamic model of a powered paraglider (PPG). The PPG is composed of a canopy and a payload with a propelling unit. The canopy is connected with the payload at two points. The model has been derived as a state vector equation under the assumption that the canopy has six degrees of freedom (DOF) and the payload has two DOF of pitching and yawing motions relative to the canopy. Friction at the connecting points between the canopy and the payload is taken into account. Time responses of the PPG without thrust have been computed using the model and the results are compared with flight experiment data. Simulation of a level flight with thrust has also been conducted.

View full abstract

This paper has studied the optimal formations for the Interferometric Synthetic Aperture Radar (InSAR) missions with multiple satellites. InSAR is one of the most attracting technologies currently in space observation field. It utilizes two or more images of the same target, enabling the construction of the 3D images of the globe. InSAR can be performed in real time with multiple satellites flying nearby. Such missions have been already proposed in some previous studies. These studies, however, have just proposed apparently balanced designs of formation, such as N-regular polygon formation with N satellites, without giving the details on optimal formation strategies. In order to give simple formation designing strategies for multiple-satellite InSAR missions, this paper discusses the optimization of a satellite formation, based on mathematics and numerical simulation. This report, or the first report, shows the simplified evaluation function for formations of InSAR missions first. Using this function, this study conducted formation optimization without taking into account satellites' relative motion, such as the rotation in a centrifugal stabilized formation. The optimal formation designing strategies with such relative motions have been described in the second report following this report.

View full abstract

This paper describes optimal formation designing strategies for Interferometric Synthetic Aperture Radar (InSAR) missions with multiple satellites. The 1st report has presented the strategies disregarding satellites' relative motion. Alternatively, the 2nd report has taken into account the relative motion among satellites. Such relative motion includes elliptical rotating motion induced by the orbital motion of satellites, and circular rotating motion in centrifugal stabilized formations. The results of this study were intuitive: with either elliptical or circular rotational motion, all the satellites should be distributed equally with the same phase interval next to each other in order to make the height (3D) profile of an image most reliable.

View full abstract

We have constructed a high-accuracy structural shape reconstruction system for global structural monitoring of large-scaled composite structures. The remarkable point of the algorithm is that we use high-resolution distributed strain data obtained by one of optical fiber strain sensing systems; pulse-prepump Brillouin optical time domain analysis (PPP-BOTDA) system. In this paper, a displacement reconstruction algorithm is constructed with the consideration of characteristics of distributed strain data, such as the influence of the spatial resolution and the measurement error distribution. In response, we adopted weighted least-square method to estimate strain distribution functions with adjusting weights for each sampling points corresponding to the reliability of data. The algorithm was applied to the estimation of beam bending deflections. Several strain data under different loading conditions were obtained by a beam bending test using a composite beam specimen with an embedded optical fiber. And then, the deflections under each loading condition were predicted appropriately.

View full abstract

The purpose of the study is to investigate the relevance between the shape of a separated region and phenomena such as transition to turbulence and unsteadiness in hypersonic ramp-induced shock-wave/boundary-layer interaction on the assumption that the latter are influenced by the former. Parametric dependence of the shape based on comparisons between an analytical model and experiments is presented. It is found that the transition threshold value of the flow incidence angle with a ramp surface is reduced as both Reynolds numbers Re_xs and Re_l increase, where x_s and l  denote the distance from the leading edge of a flat plate to that of upstream influence and the length of a separated boundary layer, respectively. High speed schlieren images show that the minimum ramp angle at which flowfield unsteadiness is noticed depends on the deviation from the analytical model in shape of a separated region, being slightly larger than the ramp angle where the deviation occurs. It is also shown that the spatial scale of the unsteadiness increases along with an increase in the deviation.

View full abstract

The Hinode (Solar-B) was launched by M-V rocket on 22 September 2006 UT. The telemetry data of the Hinode X-ray Telescope (XRT) showed that the X-ray count rate detected with the XRT had decreased rapidly since the operational heaters on the XRT telescope tube were turned on. This is attributed to the fact that molecular contaminants accumulated onto the CCD with the temperature of −60ºC resulting in the degradation of the XRT sensitivity. We baked the CCD at the temperature of 35ºC in order to remove the contaminants from the CCD surface. However many contaminant spots appeared on the surface. We found that major contaminant source existed in the telescope tube, and identified the contaminants as diethylhexyl phthalate (DEHP) or DEHP-like organics. The mechanisms to yield the contaminant spots were discussed.

View full abstract

The Hinode (Solar-B) Solar Optical Telescope (SOT) is sensitive to molecular contaminant deposition resulting from its organic materials outgassing on orbit. It was launched by M-V rocket on 22 September 2006 UT. The SOT telemetry data showed that temperature of the Heat Dump Mirror (HDM) rose rapidly during first two months, and that the SOT throughput at shorter wavelength decreased linearly over one year. These are attributed to the facts that molecular contamination deposition degrades a solar absorptance of the HDM, the reflectance of the Primary Mirror and the Secondary Mirror, and the transmittance of the Collimating Lens. The numerical analyses of molecular contamination deposition were conducted in order to identify a major contaminant source and contaminated optics. We found that a major contaminant source was silicone sealant DC6-1104 which was used in the Collimating Lens Unit.

View full abstract