Development of balloon-borne reel-down and -up winch system

Balloon-borne winches, which can reel down and up scientific instruments repeatedly, have been developed since 1981 in order to observe stratospheric vertical microstuctures. The instrument is suspended by a kevler wire through a traverse-cum ropeguide, and its depth is accurately measured by counting numbers of spool rotations and ropeguide turns. Battery consumption is minimized by utilizing an efficient deccelerator and a hysteresis brake. In 1983 we have successfully performed to reel up and down a 12 kg payload through 1 km for three cycles at 24 km altitude. We are improving the capability of the winch, and have succeeded (May 1984) to reel down a 22 kg payload up to 3 km from a balloon.     

Spaceports and new industrialized areas in the Pacific Basin

This article analyses the rapid economic advancement of the Pacific Basin area, and discusses its future potential. Common efforts in space utilization can integrate the area, and overcome the wide diversity of political, economic and social structures. Aspects of communications, space remote sensing and space-based materials processing are examined and forecasts are made for the future role of the Pacific Basin in these areas. A populated Orbital Space City will be necessary to further space utilization. To support future activities in space, a Pacific Spaceport and a Pacific Space Centre are proposed, which would lead to the development of several ‘New Industrialized Areas’ in the age of the Solar Power Satellite. Estimates are made of the amount of electricity which will be required.     

Laboratory simulation of space weathering: Changes of optical properties and TEM/ESR confirmation of nanophase metallic iron

Reflectance spectra of S-type asteroids are different from those of ordinary chondrites. This spectral mismatch is explained by space weathering processes, where high-velocity dust particle impacts change the optical properties of the uppermost regolith surface of asteroids. S-type asteroids exhibit more overall depletion and reddening of spectra, and more weakening of absorption bands relative to ordinary chondrites. Nanophase metallic iron particles, which are formed through vapor deposition from dust impact heating, are considered as the most essential cause of space weathering. In this study, we describe the spectral changes of olivine and pyroxene using nanosecond pulse laser irradiation and the presence of nanophase metallic iron particles in laser-irradiated materials by transmission electron microscopy (TEM) and electron spin resonance (ESR).

The irradiated spectra of the samples show a reduction of the overall spectra (250–2600 nm) and a reddening with weakened absorption bands. Nanophase metallic iron particles were found not only in laser-irradiated olivine samples, but also in laser-irradiated pyroxene samples by TEM. Strong ESR signals, which derive from nanophase iron particles, are observed in the irradiated olivine samples. Moreover, ESR intensities increase with the space weathering degree simulated as laser irradiation time. One possible application of space weathering is the estimation of the relative age of asteroids using the relation between optical effects and quantities of produced nanophase iron particles.     

Influence of acoustic fields on drop dynamics in an acoustic resonator

Capillary waves on a liquid sphere may be excited by acoustic fields, especially due to the higher harmonics of the resonant acoustic fields. The growth of the capillary waves has been analytically discussed. For a manipulation of weightless molten material without contacts, rotation of a liquid drop by acoustic waves is important. Approximate solutions to govern the dynamics of capillary waves on a rotating liquid drop has been analytically derived. Instabilities of multi-lobed waves due to a rotational flow in the perturbed flow field and due to the acoustic fields have been discussed.