Micro-Scanning Laser Range Finders and Position-Attitude Determination for Formation Flight

There are several space missions which require a cluster of micro spacecraft with small area of several kilometer. We propose an asteroid mission by means of several micro spacecraft in formation flight. We are in progress to develop a micro-scanning laser range finder (MS-LRF) for navigation system of such cluster missions. The MS-LRF is a LRF which utilized a two-dimensional scanner fabricated by micromachine technology. Also we propose navigation algorithm to determine the relative position and attitude of member spacecraft in the cluster using MS-LRFs

Reducing nonideal to ideal coupling in random matrix description of chaotic scattering: Application to the time-delay problem

We write explicitly a transformation of the scattering phases reducing the problem of quantum chaotic scattering for systems with M statistically equivalent channels at nonideal coupling to that for ideal coupling. Unfolding the phases by their local density leads to universality of their local fluctuations for large M. A relation between the partial time delays and diagonal matrix elements of the Wigner-Smith matrix is revealed for ideal coupling. This helped us in deriving the joint probability distribution of partial time delays and the distribution of the Wigner time delay.Comment: 4 pages, revtex, no figures; published versio

AC resistivity of d-wave ceramic superconductors

We model d-wave ceramic superconductors with a three-dimensional lattice of randomly distributed $\pi$ Josephson junctions with finite self-inductance. The linear and nonlinear ac resistivity of the d-wave ceramic superconductors is obtained as function of temperature by solving the corresponding Langevin dynamical equations. We find that the linear ac resistivity remains finite at the temperature $T_p$ where the third harmonics of resistivity has a peak. The current amplitude dependence of the nonlinear resistivity at the peak position is found to be a power law. These results agree qualitatively with experiments. We also show that the peak of the nonlinear resistivity is related to the onset of the paramagnetic Meissner effect which occurs at the crossover temperature $T_p$, which is above the chiral glass transition temperature $T_{cg}$.Comment: 7 eps figures, Phys. Rev. B (in press

Development of a Super-Small Solid Rocket Motor for OMOTENASHI

Background of the OMOTENASHI Mission. To be launched by NASA’s SLS Artemis 1 in the early 2020s, OMOTENASHI will be one of the 13 CubeSats launched as secondary payloads. With a size of 6U (113×239×366 mm) and a mass of CubeSat, it is the world’s smallest moon lander. Aims to land on the moon

Astrodynamics Science About Itokawa, Gravity and Ephemeris

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76347/1/AIAA-2006-6658-569.pd

The Hayabusa Spacecraft Asteroid Multi-Band Imaging Camera: AMICA

The Hayabusa Spacecraft Asteroid Multiband Imaging Camera (AMICA) has acquired more than 1400 multispectral and high-resolution images of its target asteroid, 25143 Itokawa, since late August 2005. In this paper, we summarize the design and performance of AMICA. In addition, we describe the calibration methods, assumptions, and models, based on measurements. Major calibration steps include corrections for linearity and modeling and subtraction of bias, dark current, read-out smear, and pixel-to-pixel responsivity variations. AMICA v-band data were calibrated to radiance using in-flight stellar observations. The other band data were calibrated to reflectance by comparing them to ground-based observations to avoid the uncertainty of the solar irradiation in those bands. We found that the AMICA signal was linear with respect to the input signal to an accuracy of << 1% when the signal level was < 3800 DN. We verified that the absolute radiance calibration of the AMICA v-band (0.55 micron) was accurate to 4% or less, the accuracy of the disk-integrated spectra with respect to the AMICA v-band was about 1%, and the pixel-to-pixel responsivity (flatfield) variation was 3% or less. The uncertainty in background zero-level was 5 DN. From wide-band observations of star clusters, we found that the AMICA optics have an effective focal length of 120.80 \pm 0.03 mm, yielding a field-of-view (FOV) of 5.83 deg x 5.69 deg. The resulting geometric distortion model was accurate to within a third of a pixel. We demonstrated an image-restoration technique using the point-spread functions of stars, and confirmed that the technique functions well in all loss-less images. An artifact not corrected by this calibration is scattered light associated with bright disks in the FOV.Comment: 107 pages, 22 figures, 9 tables. will appear in Icaru

数値解析による短パルス電解加工特性の検討

金沢大学理工研究域機械工学系電解加工においては，数十nsの超短パルス電圧の使用により極間距離が数μmとなり，マイクロ加工が可能となっている．大面積の加工においても同様な効果が期待できるが，加工面積に比例して流れる総電流が増加するため，加工回路のインピーダンスの影響が大きくなる．そこで本研究では，電気二重層を考慮した極間の電位分布の数値解析と，加工電源の回路方程式を連成解析することで，加工電源のインピーダンスの影響を検討した.出版者照会後に全文公

高硬度粉末の結合特性に関する研究: 可視化による結合メカニズムの解明

金沢大学理工研究域機械工学系In this study, laser irradiation state is visualized by a high-speed camera. The influence of laser condition, such as power and laser scanning speed, on the consolidation of metal powder was investigated. In addition, the aspect of sputtered particles from the melt pool were evaluated. As results, consolidated state was found to be different in spite of same energy density. Scattering direction of sputteringwas found to be related to the scanning speed. Counts of sputtered particles was found to be reduced when the scanning speed increase.粉末結合積層法では、従来の加工法と比べ製品が望ましい品質に達していないといった問題がある。造形条件の各パラメータによる品質への影響を調査した内容は数多く存在するが、粉末が溶融・固化する際の詳細なメカニズムは深く調査されていない。本研究では、高速度カメラを使用して粉末にレーザを照射する様子を観察し、撮影した動画並びに画像を基に結合メカニズムの解明を試みた内容について報告する。出版者照会後に全文公