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1.
In the past, space life sciences has focused on gaining an understanding of physiological tolerance to spaceflight, but, for the last 10 years, the focus has evolved to include issues relevant to extended duration missions. In the 21st century, NASA's long-term strategy for the exploration of the solar system will combine the assurance of human health and performance for long periods in space with investigations aimed at searching for traces of life on other planets and acquiring fundamental scientific knowledge of life processes. Implementation of this strategy will involve a variety of disciplines including radiation health, life support, human factors, space physiology and countermeasures, medical care, environmental health, and exobiology. It will use both ground-based and flight research opportunities such as those found in current on-going programs, on Spacelab and unmanned biosatellite flights, and during Space Station Freedom missions.  相似文献   

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介绍国内外项目成本管理的现状及规范化情况,分析我国航天项目成本管理存在的问题,并从标准化的角度提出我国航天项目成本管理规范化方案,对航天项目成本管理标准体系框架的建立进行了研究。  相似文献   

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引言如何能够使一项工作从计划的制订开始就处于一个可控的、持续改进的环境中,从而取得理想的执行效果是我们一直探讨的问题。西北空管局网络中心针对工作计划从制订到最后的执行反馈过程中的一系列问题,从一个新的角度通过自主研发的软件平台对其进行了统一的、无间断的实时管理,取得了较好的效果。  相似文献   

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This paper deals with the determination of optimal trajectories for the aeroassisted flight experiment (AFE). The intent of this experiment is to simulate a GEO-to-LEO transfer, where GEO denotes a geosynchronous Earth orbit and LEO denotes a low Earth orbit. Specifically, the AFE spacecraft is released from the Space Shuttle and is accelerated by means of a solid rocket motor toward Earth, so as to achieve atmospheric entry conditions identical with those of a spacecraft returning from GEO. During the atmospheric pass, the angle of attack is kept constant, and the angle of bank is controlled in such a way that the following conditions are satisfied: (a) the atmospheric velocity depletion is such that, after exiting, the AFE spacecraft first ascends to a specified apogee and then descends to a specified perigee; and (b) the exit orbital plane is identical with the entry orbital plane. The final maneuver, not analyzed here, includes the rendezvous with and the capture by the Space Shuttle. In this paper, the trajectories of an AFE spacecraft are analyzed in a 3D space, employing the full system of 6 ODEs describing the atmospheric pass. The atmospheric entry conditions are given, and the atmospheric exit conditions are adjusted in such a way that requirements (a) and (b) are met, while simultaneously minimizing the total characteristic velocity, hence the propellant consumption required for orbital transfer. Two possible transfers are considered: indirect ascent (IA) to a 178 NM perigee via a 197 NM apogee; and direct ascent (DA) to a 178 NM apogee. For both transfers, two cases are investigated: (i) the bank angle is continuously variable; and (ii) the trajectory is divided into segments along which the bank angle is constant. For case (ii), the following subcases are studied; 2, 3, 4 and 5 segments; because the time duration of each segment is optimized, the above subcases involve 4, 6, 8 and 10 parameters, respectively. It is shown that the optimal trajectories of cases (i) and (ii) coalesce into a single trajectory: a two-subarc trajectory, with the bank angle constant in each subarc (bang-bang control). Specifically, the bank angle is near 180° in the atmospheric entry phase (positive lift projection phase) and is near 0° in the atmospheric exit phase (negative lift projection phase). It is also shown that, during the atmospheric pass, the peak values of the changes of the orbital inclination and the longitude of the ascending node are nearly zero; hence, the peak value of the wedge angle (angle between the instantaneous orbital plane and the initial orbital plane) is nearly zero. This means that the motion of the spacecraft is nearly planar in an inertial space.  相似文献   

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引言直升机以其机动灵活、快捷、便利、适应能力强等特点广泛地应用于各个领域。随着国民经济的飞速发展以及我国低空空域管理改革的逐步深入,通用航空市场的需求量将越来越大,以直升机为  相似文献   

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The field of disaster risk management is relatively new and takes a structured approach to managing uncertainty related to the threat of natural and man-made disasters. Disaster risk management consists primarily of risk assessment and the development of strategies to mitigate disaster risk. This paper will discuss how increasing both Earth observation data and information technology capabilities can contribute to disaster risk management, particularly in Belize. The paper presents the results and recommendations of a project conducted by an international and interdisciplinary team of experts at the 2009 session of the International Space University in NASA Ames Research Center (California, USA). The aim is to explore the combination of current, planned and potential space-aided, airborne, and ground-based Earth observation tools, the emergence of powerful new web-based and mobile data management tools, and how this combination can support and improve the emerging field of disaster risk management. The starting point of the project was the World Bank’s Comprehensive Approach to Probabilistic Risk Assessment (CAPRA) program, focused in Central America. This program was used as a test bed to analyze current space technologies used in risk management and develop new strategies and tools to be applied in other regions around the world.  相似文献   

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公务飞行市场是中国民航业中一个新兴的细分市场,该细分市场目前正方兴未艾,虽然现在刚刚起步,但随着中国经济的不断发展其发展潜力不可小觑。可以预测,民航未来发展最快的就将是公务飞行市场。  相似文献   

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飞行器多学科设计优化概述   总被引:12,自引:3,他引:12  
王书河  何麟书 《宇航学报》2004,25(6):697-701
针对飞行器多学科设计优化进行了概述。提出多学科设计优化的综合性定义,介绍了国内外发展现状。指明多学科设计优化的组成要素和存在学科耦合、计算耗时两个难点,并认为其关键问题是离散设计变量和非数值型综合设计变量处理、工程综合评估、数据流管理等。阐述了可用于多学科设计优化的各种方法及其优缺点。并提出了多学科设计优化的研究重点。  相似文献   

10.
The Liquid Structure Facility (LSF) is presently under development under ESA contract. It will be able to perform a wide range of fluid science experiments taking use of the determination of the velocity, temperature, concentration fields and the interface shape deformation. This facility will be activated by telecommands and/or manually by the crew. The key points of the LSF are the different diagnostic configuration capabilities, the modularity of the facility, and the accuracy of the control at the boundary conditions (and thus of the stimuli). The LSF is structured around four different modules:

• —the cell module which is exchangeable and is dedicated to an experiment or to a group of experiments, it allows to achieve a high accuracy level for the boundary conditions

• —the temperature control module using a liquid cooling loop which can impose a good thermal stability to the cell module

• —the diagnostic module

• —the electronic and data handling module.

The capabilities of the facility are described in terms of stimuli and diagnostic performances.  相似文献   


11.
小型固体运载器一级飞行段姿态控制方案研究   总被引:1,自引:0,他引:1  
为降低结构质量、提高运载能力,某小型固体运载器采用复合材料箭体结构设计方案和静不稳定气动设计方案,运载器具有较大的挠性,一级飞行过程中,由于稠密大气的影响,结构和控制耦合现象明显,对控制系统设计提出巨大挑战;同时,控制系统还面临发动机结构引起的干扰、风干扰、质量质心时变特性以及气动参数不确定性等问题。针对这些问题,设计了带有主动振动补偿和漂移控制的Backstepping控制器,通过滑模观测器估计低频弹性振动的影响,并给予补偿,采用反演控制技术设计非线性鲁棒控制器,以适应系统中存在的较强的不确定性,确保在一级飞行过程中的全局渐进稳定,提供可选择的漂移控制通道,修正由于风干扰引起的横向、法向漂移。通过运载器飞行仿真环境验证了控制器性能。Montr Carlo仿真结果表明,在各种干扰影响下,所设计的非线性鲁棒控制器的姿态跟踪误差不超过2°,控制舵偏角不超过5,°满足总体方案要求。  相似文献   

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The mission's success fully depends on the Payload Operations conducted during the space flight. The Ground Team has to be trained to assist the Space Crew, to replan the cosmonaut's activities when contingengies occurr onboard and to change or cancel Payload activities when required. In order to act efficiently during the mission, the Ground Team must be prepared in advance of the flight and able to operate special tools for tracking the mission's progress, anticipating problems and taking decisions in realtime.

This document sets out the approach for conducting such a preparation for Ground Operation. It will be focused on the Altaïr mission performed in July 1993 onboard the Russian Mir space station.  相似文献   


14.
Flight and calibration results are presented for the Ares I-X 5-hole probe. The probe is calibrated by using a combination of wind tunnel, CFD, and other numerical modeling techniques. This is then applied to the probe flight data and comparisons are made between the vanes and 5-hole probe. Using this and other data it is shown the probe was corrupted by water rendering that measurement unreliable.  相似文献   

15.
The design and parameters of the antenna feed unit in the ranges of 6, 18, and 92 cm are described. The unit was designed and manufactured for the RadioAstron space telescope with a diameter of 10 m. The parameters and test results are presented.  相似文献   

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Analysing Interferometer for Ambient Air (ANITA) is a flight experiment as precursor for a permanent continuous trace gas monitoring system on the International Space Station (ISS). For over 10 years, under various ESA contracts the flight experiment was defined, designed, breadboarded and set up. For the safety of the crew, ANITA can detect and quantify quasi on-line and simultaneously 32 trace gases with ppm or sub-ppm detection limits. The self-standing measurement system is based on Fourier Transform Infrared Spectrometer (FTIR) technology. The system represents a versatile air monitor allowing for the first time the detection and monitoring of trace gas dynamics of a spacecraft atmosphere. It is envisaged to accommodate ANITA in a Destiny (US LAB) Express Rack on the ISS. The transportation to the ISS is planned with the first ATV 'Jules Verne'. The options are either the Space Shuttle or the Automated Transfer Vehicle.  相似文献   

18.
A major paradigm shift in space exploration is at hand. While great discipline must be exercised, we can reinstitute the exploration of the Moon and Mars through use of current systems and technology. These early initiatives will require coupling available or growth boosters with evolving upper stages and spacecraft that employ new emerging technologies and subsystems to characterize the resources, topography, gravity and sites for future manned expeditions. We have the opportunity to perform first-rate scientific research while also serving the needs of the unfolding Space Exploration Initiative. These early programs can be pursued within limited budgets if management techniques, best described as “fast track”, are applied. Examples of such efforts that met all federal regulations, yet achieved significant returns in 1- to 2-year spans, are given.  相似文献   

19.
引言2011年11月3日,在以民航华东管理局副局长唐伟斌为组长的验证试飞领导小组领导下,厦门高崎国际机场PBN飞行程序验证试飞获得了圆满成功。基于性能的导航(PBN)代表  相似文献   

20.
为提升掠飞攻顶弹箭较高转速下的飞行稳定性,运用数值计算方法研究了弹体-扭曲尾翼组合体在飞行过程中的马格努斯效应气动机理,并应用标准尾翼弹(BFM)模型的实验数据对数值方法进行了验证。分别研究了带有平板尾翼和扭曲尾翼弹体模型的马格努斯力和力矩随攻角的变化规律,并针对弹体弹翼组合体产生马格努斯效应的机理深入分析。结果表明,扭曲尾翼可有效改善翼面的压力分布,并降低弹体对翼面马格努斯效应的干扰,在大攻角时其表现更胜一筹;弹体所受马格努斯力较大,主要集中在受到涡对称畸变的尾锥部;尾翼主要由于弹体干扰以及几何外形的影响马格努斯力集中在尾部,两者产生的马格努斯力矩数值相差不大,但方向相反。  相似文献   

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