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141.
Space sustainability is emerging as a core element of national policy and international initiatives. At this time, however, a coherent strategy and supporting policies have not been developed. To initiate a conversation to develop such a strategy, the authors have applied the principles developed by Elinor Ostrom for terrestrial common-pool resource (CPR) governance to near-Earth orbit in space. A concern arises as to whether Ostrom's eight principles are a good “fit” for application to space CPR because of the unique physical characteristics of space and the legal underpinnings of our presence there. This commentary will address selected issues raised by Weeden and Chow, and suggest alternative ways to approach near-Earth orbit sustainability.  相似文献   
142.
The 2007 US National Research Council Decadal Survey for Earth Science and Applications from Space was the first consensus perspective produced by the US Earth Science community of the relative priorities among a sequence of 17 satellite missions over the course of the next decade. However, the Decadal Survey only captured the perspective of the science community, leading to questions about the inclusion of broader priorities from constituent communities and stakeholders. We present a stakeholder value network analysis for the NASA/NOAA Earth Observation Program. The analysis includes a rigorous articulation of the needs and objectives of 13 major stakeholders and a complete stakeholder value network with 190 individual “value flows” that capture the interactions between all the stakeholders. It produces a novel stakeholder map, graphically indicating the outputs most likely to create a lasting Earth Science program. The most important value loops and program outputs are used to derive a set of high-level program goals that suggest what NASA and NOAA should do, as well as how they should conduct business. The analysis concludes that international partnerships represent a strong potential partner for certain science missions with greater potential value delivery than currently-prioritized efforts with defense stakeholders and concludes that weather and land-use missions, in addition to climate missions, should be given highest priority; water, human health, and solid Earth missions should be given lower priority based on each science category's potential for delivering value to the entire stakeholder network.  相似文献   
143.
A correlative analysis has been made between cosmic ray intensity and solar activity (sunspot numbers) during high amplitude days for the period 1991–1995. The high amplitude days with the time of maximum in the corotational/azimuthal direction do not indicate any significant correlation with solar activity. The diurnal amplitude significantly remains constant and high (0.5%) during the entire period. Our observations suggest that the direction of the anisotropy of high amplitude anisotropic wave train events contribute significantly to the short-term behavior of the cosmic ray diurnal anisotropy. The correlation coefficient is found to remain positive during solar activity maximum for all the high amplitude anisotropic wave train events.  相似文献   
144.
The problem of selecting quasi-synchronous orbits of a spacecraft around Phobos is considered. These quasi-synchronous orbits are far (with respect to the Hill’s sphere) quasi-satellite orbits with retrograde rotation in the restricted three body problem. The orbit should pass through a given point at a specified time instant. It should also possess a property of minimum distance from the Phobos surface at every passage above the region of planned landing. The equations of dynamics are represented in the form describing the orbit as a combination of motions in two drifting ellipses, inner and outer ellipses. The center of the outer ellipse is located on the inner ellipse. A formula is derived that relates averaged values of half-axes of the inner and outer ellipses. It is used for construction of the first approximation of numerically designed orbit, which makes it possible to simplify and speed up the computing process. The tables of initial conditions obtained as a result of calculations are presented.  相似文献   
145.
The results of designing the attitude control system of the first Russian nanosatellite TNS-0 no. 1 providing orientation of its longitudinal axis along the local geomagnetic field induction vector are presented. The system consists of a permanent magnet and two sets of hysteresis rods. The magnetic and geometric parameters of the magnet and rods are calculated. The influence of the permanent magnet field on the hysteresis rods and mutual influence of the rods in the case of compact satellite packaging are analyzed. Examples of calculations of transient processes and steady-state angular satellite motion are presented.  相似文献   
146.
Dynamics of planets around other stars that demonstrate a variety of possible characteristics is of interest from the point of view of realization of new scenarios of evolution which have not been realized in the Solar System. We consider the rotational evolution of exoplanets under the action of gravitational perturbations and magnetic disturbances using the methods of quality analysis and theory of bifurcation of multiparametric differential equations that describe evolution of non-resonant rotation of a dynamically symmetric planet magnetized along its symmetry axis. We analyze 64 phase portraits describing the evolution of angular momentum vector L for all possible values of planet parameters. The values of parameters are determined for the case when the direct rotation of a planet is changed for its retrograde rotation.  相似文献   
147.
The Apophis Exploratory and Mitigation Platform (AEMP) concept was developed as a prototype mission to explore and potentially deflect the Near Earth Asteroid (NEA) 99942 Apophis. Deflection of the asteroid from the potential 2036 impact will be achieved using a gravity tractor technique, while a permanent deflection, eliminating future threats, will be imparted using a novel albedo manipulation technique. This mission will serve as an archetypal template for future missions to small NEAs and could be adapted to mitigate the threat of collision with other potential Earth-crossing objects.  相似文献   
148.
A comparison of temporal profiles of low-energy ion intensity and magnetic field magnitude in different periods of solar activity in the outer heliosphere is carried out using the data of the Voyager 1 and Voyager 2 spacecraft. It is shown that temporal, spectral, and statistical characteristics of particle fluxes and magnetic field in the heliospheric regions before and after the terminal shock in 2002–2008 had similar dynamics in different hemispheres. This similarity allowed one to assume that, in the region of the inner heliospheric boundary, a quasistable spatial structure existed moving together with the terminal shock in accordance with the solar wind pressure, as well as, probably, under the action of the interstellar medium. It was revealed that the spatial dimensions of most details of this structure are less on Voyager 2, which, probably, is due to variation of the solar activity level, difference in latitude of spacecraft disposition, and also the influence of the interstellar magnetic field.  相似文献   
149.
With the beginning of space era, a new branch of medicine has arisen and has been developing along with human exploration of outer space. And even though space medicine mainly faces the same problems as traditional medicine--cosmonauts health care and their high efficiency--this branch, has its own features, associated with the unusual factors of space flight, of which weightlessness is the major one. During the development of manned cosmonautics (duration of a human stay in space has reached already 438 days), methods of cosmonauts medical support and monitoring of their condition have been developed, knowledge of human possibilities and methods of process of organism adaptation to various and frequently severe conditions of external environment have increased. All this led to the fact that nowadays space medicine can become useful for improvement of human health care not only in space but also on the Earth. Moreover, the problem of implementation of cosmonautics achievements, and in particular of space medicine, in practice of public health care presents one of the most important issues concerning human health care. It is also connected with public opinion which is more and more concerned about the efficiency of significant expenses on space activities, especially lately. People often are set by the questions: what has space given, what fruits has space research provided to mankind, which results of this research can be used on the Earth already today for improvement of their life, for discussion of many difficult earthly problems? In terms of using cosmonautics possibilities, its achievements for health care and treatment, it is possible to define a few branches, in which purposeful studies are carried out.  相似文献   
150.
本文描述的是研究爆炸成型发射弹(EFP)模型的流场及超高速空气动力特性所用的弹道试验设备;简要报导了记录全尺寸干涉图形的技术;对径向密度分布再现的方法进行了讨论;在零攻角实验时不同模型的空气动力阻力是采用简化方法来计算的;对各种不同EFP型式的气动稳定性提出了定性估计的方法;并阐述了用于组合体超高速飞行特性研究的数值计算技术的基本原理  相似文献   
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