Collaborative Navigation in an Unfamiliar Environment with People Having Different Spatial Aptitudes

This study addressed the issue of collaborative navigation by examining the types of information communicated in the processes of direction giving and receiving between people who guided each other simultaneously to a destination over the cell phone in a novel environment. When paired with a partner whose sense of direction differed greatly from their own, people found the collaboration difficult and took a longer time to verbally direct the partner to the destination. Landmarks that people used in giving navigational instructions differed depending on sense of direction. People with a good sense of direction adjusted route directions to their partners' wayfinding ability. Results from a detailed qualitative analysis of participants' verbal protocols and implications for personalized navigation tools are discussed.     

Radar beamwidth reduction techniques

It is essential and desirable to get a high resolution echo in a radar image without using a large antenna. On scanning a radar antenna, the target's distribution is smoothed by the antenna beam and a smeared echo appears on the radar display. This paper describes three different types of beam compression radars: subsurface SAR; correlation array radar; and inversion processed radar. The experimental results show that the beamwidth on display was effectively compressed by the signal processing     

The contest for leadership in East Asia: Japanese and Chinese approaches to outer space

Japan and China, as two advanced spacefaring nations in Asia-Pacific region, are often referred to as rivals in space. China's successful manned space launch program in 2003 and ASAT test in 2007 were considered as turning points which potentially introduces a “space race in Asia”. This article argues that there are three defining arenas in a space race: competition for prestige or soft power, competition over military capability or hard power, and competition of international services or public goods. It analyzes the objectives, norms and logics of space policy in Japan and China, and argues that these two countries have quite different thinking over what to do in space, explaining that they are playing different games in the first two arenas. However, Japan and China are competing for leadership and influence over the region. APRSAF and APSCO, two similar regional space organizations, are the vehicles for this competition. It concludes that there is a space race only in the third arena as a competition for leadership in Asia.     

Administrative reforms and the policy logics of Japanese space policy

The Japanese administrative reform which took place in recent years integrated NASDA and ISAS to create a larger space agency. Why was such an agency called for? What was the purpose behind the administrative reform? This article examines the motivations, objectives and responses to the reform process by using policy logic and institutional analysis to examine the evolution of the Japanese space programme. It argues that the reform aimed to rationalize the national administrative system and salvage the government from financial crisis. Thus, the reform was not designed to strengthen space activities in Japan, and as a result, Japanese space policy making is confused.     

Mesospheric nitric oxide and ozone measurements in polar winter at 69°N

Two rocket experiments were carried out just before and after the polar night at Andoya (69°N), Norway to investigate transport of nitric oxide produced by auroral processes into the middle atmosphere and its influence on the ozone chemistry. Nitric oxide densities of (2–5) × 10⁸cm⁻³ found in the 70–90 km region are one to two orders of magnitude larger than those at middle latitudes. The influence on ozone densities in the 70–90 km region due to such enhanced nitric oxide abundance is found to be insignificant as compared to that due to transport in the middle of February. The larger ozone densities found in February (in spite of longer sunlit duration) than in November in the 40–60 km region again support predominance of transport over photochemical loss.     

Transforming Japan's space policy-making

Since its beginning the objective of Japanese space policy has been to ‘catch up’ with advanced spacefaring countries. However, this catching-up strategy is now facing several difficulties, because of the downturn in the economy and changing political and technological circumstances. In such circumstances the Japanese space community has realized the need to change its national space strategy. In 2005 a group of powerful Japanese politicians issued a report on constructing a national space strategy, which recommended that the government establish a new decision-making structure by creating a new Basic Law of Space Activities. These efforts underline the need for Japanese space to shift the focus of its policy from technological development to applications.     

Assessment of space debris collisions against spacecraft with deorbit devices

Deorbit methods have been employed to remove space debris from orbit. One of these methods is to utilize atmospheric drag. In this method, a membrane loaded into the spacecraft is expanded to increase atmospheric drag. Although this method works without requiring fuel, it has the disadvantage of a high risk of collision with other debris owing to its larger area. Area-time product and energy-to-mass ratio have been used as indices to evaluate the risk of collisions between spacecraft and debris. However, the evaluation criteria were uncertain because these two indices are independent. In this paper, we propose a new evaluation index, single-sheet collision factor (SSCF), that comprehensively evaluates the collision risk based on experiments simulating debris collisions. As a result of the hypervelocity collision experiment, we found that the penetration-area mass of the spacecraft affects the severity of debris collisions. In this paper, the product of the exterior-wall thickness, the exterior-wall density, and the space debris cross-sectional area defines the penetration-area mass of the spacecraft. Furthermore, we compare and evaluate various deorbit methods using SSCF. The comparison showed that the penetration-area mass of the SSCF could be quantitatively determined for the debris-collision severity due to difference in structural materials of spacecraft. SSCF will be used to create rules for space-environment conservation with the expansion of the space-development market.     

A balloon-borne very long baseline interferometry experiment in the stratosphere: Systems design and developments

The balloon-borne very long baseline interferometry (VLBI) experiment is a technical feasibility study for performing radio interferometry in the stratosphere. The flight model has been developed. A balloon-borne VLBI station will be launched to establish interferometric fringes with ground-based VLBI stations distributed over the Japanese islands at an observing frequency of approximately 20?GHz as the first step. This paper describes the system design and development of a series of observing instruments and bus systems. In addition to the advantages of avoiding the atmospheric effects of absorption and fluctuation in high frequency radio observation, the mobility of a station can improve the sampling coverage (“uv-coverage”) by increasing the number of baselines by the number of ground-based counterparts for each observation day. This benefit cannot be obtained with conventional arrays that solely comprise ground-based stations. The balloon-borne VLBI can contribute to a future progress of research fields such as black holes by direct imaging.     

Dynamics of the Phase-Locked Loop without a Limiter

The general (nth order) phase-locked loop is analyzed, of which the amplitude is not constant. The input carrier signal is amplitude-modulated by wide-band stationary Gaussian noise, and the signal, superposed with the additive white stationary Gaussian noise, enters the nonlimited phase-locked loop. Under the above assumptions the loop can be shown to constitute an n-dimensional vector Markov process, so that the process satisfies the n-dimensional Fokker-Plank equation. The probability density function depends on the effective loop signal-to-noise ratio and the effective modulation power.     

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.