共查询到20条相似文献,搜索用时 15 毫秒
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Robert C. Singleterry Steve R. Blattnig Martha S. Clowdsley Garry D. Qualls Chris A. Sandridge Lisa C. Simonsen Tony C. Slaba Steven A. Walker Francis F. Badavi Jan L. Spangler Aric R. Aumann E. Neal Zapp Robert D. Rutledge Kerry T. Lee Ryan B. Norman John W. Norbury 《Acta Astronautica》2011,68(7-8):1086-1097
OLTARIS (On-Line Tool for the Assessment of Radiation In Space) is a space radiation analysis tool available on the World Wide Web. It can be used to study the effects of space radiation for various spacecraft and mission scenarios involving humans and electronics. The transport is based on the HZETRN transport code and the input nuclear physics model is NUCFRG. This paper describes the tools behind the web interface and the types of inputs required to obtain results. Typical inputs are mission parameters and slab definitions or vehicle thickness distributions. Radiation environments can be chosen by the user. This paper describes these inputs as well as the output response functions including dose, dose equivalent, whole body effective dose equivalent, LET spectra and detector response models. 相似文献
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This paper makes the attempt to illustrate the need for a detailed operational analysis of future space transportation systems with the help of computer-based simulation models. The basic approach deemed suitable for such a systems simulation is explained in some detail. A reference program (100,000 Mg payload per year during 25 years) for a reference mission (heavy cargo transport to GEO for SPS construction) has been selected. A base-line launch vehicle (fully reusable ballistic all chemical three stage vehicle) has been defined, which is considered a serious applicant for such a mission. It was found that the take-off mass of this type of vehicle should be as large as practical from the viewpoint of cost-effectiveness. The example chosen has a GLOW of 10,000 Mg and lifts more than 100 Mg to GEO.With consideration of the operational parameters the simulation model evaluates the annual production rates, inventory of stages, utilization of facilities and operational cost, which amount within this frame of reference to about 96 $/kg net payload delivered to GEO in terms of 1980 dollars and contribute the main share to the total transportation cost. 相似文献
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J.C. Cretenet 《Acta Astronautica》1985,12(11):949-958
The presence of Europe in the future developments of spatial programs, which are foreseen, for the 1990s and further, needs the availability of vehicles, modules and all related technologies adapted to operational use of low earth orbit station.The manned HERMES vehicle shall be part of the in-orbit infrastructure realized either in the European context or in cooperation between Europe and the United States.The main mission for this vehicle will be to run a shuttle with the station that means transport and change of the crews, its safe return in abort condition and cargo transport of consumable and experimental equipment.Secondary missions could be servicing on automatic platform, making autonomous scientific experiments. Lastly, the vehicle, by means of its on-board propulsion capability, could be used to accomplish in-orbit tow and assembly missions.Studies which are undertaken now about the vehicle are devoted to the aerodynamic shape (research of a compromise between aerothermic and overall fitting), the system (functional architecture, ground and flight configuration); further works dealing with technology are presently on hand in the field of thermal protection, aerodynamics, power generation with a high massic yield. 相似文献
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针对吸气式高超声速飞行器爬升段飞行任务,考虑飞行器气动/推进特性及参数不确定性问题,采用鲁棒优化思路,结合巡航性能指标,优选了飞行器爬升段的关键任务点。首先,由能量状态法结合发动机工作约束,确定了飞行器的爬升起始任务点;其次,依据飞行器巡航性能分析方法,提出了兼顾气动/推进效率的性能指标,优化得到了高超声速飞行器爬升末端任务点;最后考虑飞行器质心位置的不确定性,采用鲁棒优化方法确定了爬升段末端的飞行任务窗口。仿真结果表明,设计的优选流程快速可行,飞行任务窗口能同时满足飞行器的巡航飞行性能要求及不确定性最坏情况的约束,具有较强的鲁棒性。 相似文献
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《中国航天(英文版)》2017,(2)
This paper introduces a launch vehicle scheme for the new generation of cryogenic and quick-launch launch vehicle(LM-6). The main technical innovations of LM-6 launch vehicle include the capability of twenty satellites launched by one vehicle, high-pressure staged combustion cycle engine and oxygen tank self-pressurization, sandwich bulkhead tank with 200 K temperature difference, and 7-day quick-launch using the "three horizontals" test and launch mode with integral transportation and erection. The future development of the quick-launch launch vehicle is predicted based upon the need for vehicle mission coverage improvement, better response speed, and stronger market competiveness. 相似文献
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针对一类包含可变构型在内的高超声速飞行器的难点,分析了工程应用需求,综述了几类典型的非线性控制方法的研究进展。首先针对高超声速飞行器的几类常见研究模型,总结了模型来源及特点;其次,以实际工程需求为出发点,分析了此类飞行器的控制难点及对于控制系统能力提出的需求;再者,总结了高超声速飞行器几种典型非线性控制及智能控制研究的基本情况和进展,并给出了各类控制方案的框架;最后,面向未来任务形式多样化、环境复杂化的飞行器控制,讨论了可以进一步研究的问题和方向。 相似文献
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Optimization of ion-propelled space vehicles is a topic of many aspects. Well known is the Stuhlinger procedure, which results in maximum payload mass fraction, given some mission and vehicle characteristic data. This procedure determines all major vehicle data—specifically, the electric power level. It is described with some refinements in this paper. Furthermore, a novel problem is treated: What set of vehicular data leads to the shortest possible propulsive mission duration, for a given electric power level? This goes beyond the “classic” Stuhlinger treatment; but is built upon this fundament. 相似文献
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An intercept mission with nuclear explosives is the most effective of the practical mitigation options against the impact threat of near-Earth objects (NEOs) with a short warning time (e.g., much less than 10 years). The existing penetrated subsurface nuclear explosion technology limits the intercept velocity to less than approximately 300 m/s. Consequently, an innovative concept of blending a hypervelocity kinetic impactor with a subsurface nuclear explosion has been developed for optimal penetration, fragmentation, and dispersion of the target NEO. A proposed hypervelocity asteroid intercept vehicle (HAIV) consists of a kinetic-impact leader spacecraft and a follower spacecraft carrying nuclear explosives. This paper describes the conceptual development and design of a baseline HAIV system and its flight validation mission architecture for three mission cost classifications (e.g., $500 M, $1 B, and $1.5 B). 相似文献
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再入走廊给出了飞行器满足任务要求、并安全返回地球的再入飞行范围,它是再入轨道优化、再入方案设计、再入飞行任务规划等的重要部分。文章通过再入动力学建模,引入Chapman假设,进行了航天器从外层空间返回的再入走廊的研究,分析了影响再入走廊边界的重要因素,并以航天飞机为例计算了再入走廊,验证了该分析方法的正确性。 相似文献
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近几年,随着小卫星市场的蓬勃发展,小型卫星发射市场持续升温,以飞马座XL和运载器一号火箭为代表的空射火箭完成多次发射任务,将数十颗卫星送入近地轨道。空射运载火箭具备快速响应、机动灵活、发射成本低、任务适应性强等技术特点。运载火箭从空中发射可以充分利用载机的飞行高度和飞行速度,在相同的系统运载能力下,火箭的起飞质量更小;在相同的火箭起飞质量下,系统运载能力更高;同时,对于规模星座快速部署,空中发射的灵活优势显著。围绕空射火箭的上述技术特点,基于空射火箭模型开展仿真分析研究及不同发射方式的结果对比,结果表明空射方式对提升系统效益效果显著。 相似文献
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In the 36 years between June 1965 and February 2001, the US human space flight program has conducted 100 spacewalks, or extravehicular activities (EVAs), as NASA officially calls them. EVA occurs when astronauts wearing spacesuits travel outside their protective spacecraft to perform tasks in the space vacuum environment. US EVA started with pioneering feasibility tests during the Gemini Program. The Apollo Program required sending astronauts to the moon and performing EVA to explore the lunar surface. EVA supported scientific mission objectives of the Skylab program, but may be best remembered for repairing launch damage to the vehicle and thus saving the program. EVA capability on Shuttle was initially planned to be a kit that could be flown at will, and was primarily intended for coping with vehicle return emergencies. The Skylab emergency and the pivotal role of EVA in salvaging that program quickly promoted Shuttle EVA to an essential element for achieving mission objectives, including retrieving satellites and developing techniques to assemble and maintain the International Space Station (ISS). Now, EVA is supporting assembly of ISS. This paper highlights development of US EVA capability within the context of the overarching mission objectives of the US human space flight program. 相似文献
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为降低全生命周期成本,提高航天运载器综合竞争力,提出了基于综合电子方案的某型运载器电气系统设计实现方法。首先对该运载器功能需求进行了分析,建立了基于综合电子的系统分布式集成逻辑架构,然后分别就系统任务规划与操作系统分区结构、基于时间触发以太网(TTE)的一体化机内外总线体制以及系统容错处理机制等关键技术及实现途径开展了分析论证。本方案提出的相关软、硬件设计方法有利于实现系统快速集成与系统内资源共享,同时为实现冗余容错控制、在线任务规划等功能提供了便利。 相似文献
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介绍了目前国外提出的一种三元结构的火星采样返回任务方案,整个方案分3次发射,分别发射漫游车、着陆器和轨道器,每次发射间隔为4年,最终目的是将火星样品带回地球。该方案的优势在于,通过3次发射分别完成漫游车巡视勘察、着陆器现场探测、轨道器数据中继和在轨探测,最终综合完成火星采样返回,能够极大地缓解项目进度和资金压力,充分利用每次发射窗口分步骤完成探测任务。文章重点对方案涉及的关键技术进行了分析,包括样品获取与封装、行星保护、精准着陆、漫游车的危险规避能力和移动性、火星上升器、交会与样品捕获、地球再入器技术等;对方案的前景和优势进行了探讨,并给出几点启示,如精准着陆或成为今后行星探测着陆方式的新趋势,火星采样返回任务将是人类火星探测的里程碑,今后的深空探测任务趋向国际合作模式等。 相似文献
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《Acta Astronautica》2003,52(2-6):211-218
Aladdin, one of five Concept Study winners for NASA's Discovery AO98-OSS-04, was a mission to obtain samples from the two Martian moons using several unique mission design and sample collection techniques. The mission design enabled sample return from two bodies at the relatively low cost of a Discovery-class mission. It featured a phasing orbit, multiple flybys of the Martian moons, and a short overall mission duration. The phasing orbit greatly reduced the post-launch Δv requirement, thus permitting the use of a Delta II launch vehicle. Multiple moon flybys provided ample opportunities for sample collection and science observations. The short overall mission duration reduced program costs. Aladdin's sample collection, unlike traditional sample collection methods, used a “launch-and-catch” technique to obtain samples. Projectiles would be launched to the moon's surface during a close flyby and the ejected particles gathered for Earth return and analysis. This innovative technique, the Aladdin mission, and the possible extension of the technique to other bodies are described. 相似文献