垂直返回重复使用运载火箭技术分析

结合SpaceX公司近期进行的多次猎鹰火箭一子级垂直着陆返回技术试验,对比分析垂直返回重复使用运载火箭两种返回方式的工程应用价值。首先,建立运载火箭一子级动力返回段弹道设计动力学模型。随后,提出基于H-V飞行剖面分段返回弹道设计方法。然后针对“返回原场”（RTLS）和“不返回原场”(NRTLS)两种垂直返回方式,构建综合考虑上升段与返回段的推进剂耦合作用的一体化弹道优化设计策略。最后,通过数值仿真,对比分析了两种返回方式下的火箭运载能力。结果表明,采用“不返回原场”方式的运载能力损失仅占“返回原场”方式的一半,具有较好的工程应用价值。     

针对海南文昌发射场的载人航天器盐雾效应试验及防护方法

空间站工程大吨位载人航天器均在海南文昌发射场发射,面临盐雾效应这个新的环境要素。文章针对海南文昌发射场盐雾环境对载人航天器的影响开展分析和验证工作,研究文昌发射场盐雾水平,分析盐雾效应产生机理和常规盐雾模拟试验方法,针对载人航天器测发流程特点提出主动盐雾防护与盐雾效应摸底试验相结合的工程方法。基于盐雾效应机理总结提出的盐雾效应筛查表格可指导开展沿海地区发射航天器的盐雾防护设计和敏感因素筛查。     

Ensuring an acceptable reliability and safety level for a launch complex

Some key aspects and criteria tasks for ensuring an acceptable reliability and safety level for complex technical systems are discussed in the view of successful operation of a launch complex, at the stage of Launch Vehicle (LV) preparation. The standards and principles of adequate characteristics for launch site core technological systems are defined. The tasks for evaluation the probability of faultless operation for the systems, their reliability a posteriori, and safety barriers formation are described. The model of the pre-launch phase is presented as a random process, in the form of “simple Poisson flow”.     

多径效应对DS/SS非相干延迟锁定环的影响

基于工程背景,结合实际应用中遇到的多径问题,首先从理论上进行分析,而后在systemvue2006仿真环境下对多径信道进行建模,着重仿真分析了多径效应对伪码跟踪环路的影响,给出了不同多径参数的情况下,非相干延迟锁定环路的鉴相特性曲线,对实际应用具有一定的指导意义。分析和计算结果表明多径效应对DSSS非相干延迟锁定环的影响主要与多径系数、多径时延和载波周期的倍数关系两个因素有关,并且呈现出一定的规律。     

中国运载火箭测试发射模式发展思路研究

运载火箭的测试发射模式对火箭和发射场总体方案起着重要作用,目前各国常用的测发模式主要有一平两垂、三垂和三平模式。研究和总结国内外运载火箭测发模式及其特点,从任务适应性、环境适应性、可靠性和安全性、经济性这4个指标中细化出13项影响因素,在此基础上开展了3种测发模式影响因素对比分析。结合我国发射场环境地质条件和现有建设条件,提出一种运载火箭测发模式定量分析方法,完成了我国小型、中型、大型及重型运载火箭在现有4个发射场最优测发模式分析,为我国运载火箭未来测发模式发展提供重要参考。     

文昌发射场通信卫星塔架电缆设计方案及测试验证

海南文昌发射场的高温、高湿、盐雾等环境问题给通信卫星塔架电缆设计提出挑战。为此，文章在借鉴西昌发射场塔架电缆设计的基础上，提出塔架电缆由A1段、A2段和B段3个电缆分支组成；继而针对文昌发射场环境特点详述了塔架电缆在设计、铺设和使用方面关键点；最后对塔架电缆进行了测试验证，给出了测试内容和注意事项。所设计的塔架电缆已在3颗通信卫星正样星上得到验证，测试流程已基本固化，并形成了相应的操作性文件。     

海运及沿海发射期间航天产品的腐蚀风险与应对策略

海南发射场投入运行在即,在此发射的航天器在海运和发射场期间将面临着腐蚀的风险。文章对比了海南发射场与酒泉、西昌、太原等内陆发射场的腐蚀环境差异,例举了NASA肯尼迪航天中心在海运和发射场期间航天产品的腐蚀案例,分析了我国未来航天器在海运和海南发射场期间的腐蚀风险,并根据NASA、ESA对沿海发射场航天器腐蚀的应对策略,提出了相应的防腐蚀建议与措施。     

Nuclear waste disposal in space: Implications of advanced space transportation

Previous studies have shown that the disposal of nuclear waste in space is promising as a practical and economically plausible option, based on use of the first generation space shuttle. The promise brightens if we consider use of more effective second generation systems such as fully reusable single-stage-to-orbit transports. These vehicles, with simpler more reliable flight characteristics and with operational economics at least twenty times more favorable than the first shuttle, can become available in the early 1990s when the nuclear waste problem will have grown to truly serious proportions. This paper surveys both vertical and horizontal-takeoff vehicles as they could be used for the Earth-to-orbit phase of nuclear waste disposal mission. The international nature of the nuclear waste issue is emphasized, and the suggestion is made that an international equatorial launch site be established. This launch center, apart from its inherent safety features, would serve as a focus for an international solution of the truly worldwide problem of nuclear waste disposal.     

中国运载火箭地面系统发展方向研究

地面系统用于支持和保障火箭的发射与试验,对火箭的使用性能、发射能力、发射场配置及工作流程等有重要的影响。调研了国外运载火箭地面系统发展现状,总结了国外运载火箭地面系统发展趋势。从快速发射、简易发射、安全发射、自动发射和通用发射等方面提出了地面系统发展思路和主要关键技术,为我国后续运载火箭地面系统发展提供参考。     

从角闪烁观点对被动测向中多径效应的讨论

多径效应是被动测向过程中客观存在的现象,基于其产生的物理机理可从角闪烁的观点出发来加以讨论。首先介绍了角闪烁的两种物理解释,其次对被动测向中的多径效应进行了一般的数学分析,说明了相应的统计模型,重点对低仰角时被动测向中的多径效应进行了特例分析,并进行了数字仿真。     

The Rockot launch system

EUROCKOT Launch Services GmbH has been founded by Daimler-Benz Aerospace of Germany and Khrunichev State Research and Production Space Center of Russia to offer world-wide cost effective launch services on the Rockot launch system. The Rockot commercial program is described. Rockot can launch satellites weighing up to 1850 kg into polar and other low earth (LEO) orbits. The Rockot launch vehicle is based on the former Russian SS-19 strategic missile. The first and second stages are inherited from the SS-19, the third stage named Breeze is newly developed and has multiple ignition capability. The Rockot launch system is flight proven. In addition to the currently adapted Rockot launch site Plesetsk for high inclinations, EUROCKOT is in the process to also adapt the Baykonur cosmodrome as their complementary Rockot launch site for lower inclinations. The wide range of Rockot performance is provided. The first commercial launch is foreseen in the middle of 1999. The expected launch capacity for Plesetsk and Baykonur will exceed 10 launches per year. The complete Rockot system including performance is presented.     

Modified Rake architecture for GNSS receiver in a multipath environment

Multipath is one of the major error sources in satellite-based navigation systems. This paper proposes a new anti-multipath architecture, named Modified Rake (MRake), for Global Navigation Satellite System (GNSS) receiver. The architecture derives from RAKE receiver in communication system. It can track direct-path and multipath components separately from the received signal without consumption of much hardware resources or complex calculation. The MRake architecture uses an Amplitude Estimation Unit (AEU) to estimate the amplitude of each component, and a noncoherent DLL to adaptively control its time-delay. Since the receiver only uses the direct-path signal to calculate the user's position, the tracked multipath components are subtracted from the composite signal to reduce the multipath effect, and thus to reduce tracking error. MRake receiver shows better performance or consumes much fewer resources than traditional anti-multipath techniques.     

大型低温液体火箭“零窗口”发射技术

我国大型低温液体运载火箭组成系统多、各系统耦合关联程度大、射前流程复杂，实现“零窗口”发射难度大。基于大型低温液体运载火箭的系统特点和射前约束条件，提出了实现“零窗口”发射的技术方案。通过能力挖潜主动拓展了任务故障适应性和窗口宽度，并辅以科学的测试发射策略，将技术和流程相结合，共同实现大型低温运载火箭“零窗口”发射目标。这对全面提升大型运载火箭和发射场“零窗口”发射能力、适应未来航天发展需求具有十分重要的意义。     

高空飞行环境中液体运载火箭底部热环境研究

采用数值模拟和飞行测试验证相结合的方法对液体运载火箭高空对流/辐射耦合换热问题开展系统深入研究。基于燃气多组分输运Navier-Stokes方程、热辐射方程、Realizable k-ε两方程湍流模型，建立了高空含自由流的运载火箭燃气喷流流动模型。辐射模型采用离散坐标法(DOM)，空间离散采用二阶迎风TVD格式，对多个典型飞行高度火箭底部热流进行大型并行计算，将数值结果与试验数据进行广泛对比，验证了计算模型的精度和有效性。数值研究表明，火箭底部辐射热流在刚起飞阶段达到最大值，随着飞行高度上升，辐射热流逐渐降低，火箭底部对流热流表现为先升高后降低的趋势，并在20 km高空达到峰值。本文的预测分析方法对液体运载火箭底部热防护设计具有重要的理论意义和工程应用价值。     

The impact of launch vehicle type and size on development cost

The technical development trend of future launch vehicle systems is towards fully reusable systems, in order to reduce space transportation cost. However, different types of launch vehicles are feasible, as there are

• —winged two-stage systems (WTS)

• —ballistic single-stage vehicles (BSS)

• —ballistic two-stage vehicles (BTS)

The performance of those systems is compared according to the present state of the art as well as the development cost, based on the “TRANSCOST-Model”. The development costs are shown versus launch mass (GLOW) and pay-load for the three types of reusable systems mentioned above.It is shown that performance optimization and cost minimization lead to different results. It is more economic to increase the vehicle size for achieving higher performance, instead of increasing technical complexity.Finally it is described that due to the essentially lower launch cost of reusable vehicles it will be feasible to recover the development cost by an amortization charge on the launch cost. This possibility, however, would allow commercial funding of future launch vehicle developments.     

A preliminary study of pulse-laser powered orbital launcher

An air-breathing pulse-laser powered orbital launcher has been proposed as an alternative to conventional chemical launch systems. The aim of the present study is to assess its feasibility through the estimation of its achievable payload mass per unit beam power and launch cost. A transfer trajectory from the ground to a geosynchronous Earth orbit (GEO) is proposed, and the launch trajectory to its geosynchronous transfer orbit (GTO) is computed using the realistic performance modeled in the pulsejet, ramjet, and rocket flight modes of the launcher. Results show that the launcher can transfer 0.084 kg of payload per 1 MW beam power to a geosynchronous earth orbit. The cost becomes a quarter of existing systems if one can divide a single launch into 24,000 multiple launches.     

The transcost-model for launch vehicle cost estimation and its application to future systems analysis

The first part of the paper describes the structure of the analytical cost estimation model (1982 edition) for launch vehicle development, fabrication and launch operations cost. Especially the new approach for a cost assessment of operations cost including refurbishment (in case of reusable vehicles), direct and indirect operations is presented for discussion and subsequent improvements by introduction of more reference values. The model uses the Man-Year (MY) as cost unit which is independent from inflation and currency exchange rate changes.

The second part of the paper deals with its application to future systems analysis and cost comparison with the example of a potential future European launcher (Post-Ariane-4) with 15 tons LEO payload capability: ten different two-stage launch vehicle concepts (expendable, semi-reusable and fully reusable) with storable and cryogenic propellants are analysed with respect to development cost and cost per launch.

The key problem for a future European launch vehicle is the optimum solution between the (limited) development effort and the desired minimum launch cost. More advanced (partially) reusable systems could provide an essential reduction in cost per launch, require, however, a higher development effort.

In such a case an analytical cost model based on realistic reference data can provide important data for the vehicle concept selection process.     

一种基于小波变换的伪码跟踪环路多径抑制方法

多径效应是GPS等卫星导航系统的重要误差源之一,严重影响导航系统的性能。针对多径效应,在分析了多径信号模型和伪码自相关函数特征的基础上,提出了一种基于小波变换的多径抑制方法。该方法利用自相关函数曲线斜率突变点位置不受多径信号影响的特性,通过小波变换检测其斜率突变点位置,进而利用得到的鉴相误差调整码相位,达到多径抑制的目的。仿真结果表明,该方法不受多径条数的影响,鉴相结果更准确,多径抑制能力得到显著提高。
     

运载火箭多体动力学建模与仿真技术研究

针对新一代运载火箭结构动力学与控制系统耦合强烈、严重影响火箭的飞行稳定问题,提出一种基于多体动力学虚拟样机建模与仿真的方法,有效解决运载火箭姿态动力学模型地面难以验证的困难。首先阐述了在运载火箭姿态动力学分析中应用多体虚拟样机的基本思路;然后对多体动力学模型与传统火箭姿态动力学模型在建模原理上的差异进行分析,指出引入多体仿真技术的意义;最后针对新一代火箭,提出并实现一种多体虚拟样机建模方法,仿真并验证了新一代火箭姿态控制模型与控制参数设计的正确性。本文的研究表明,航天器系统设计中常遇到复杂的动力学耦合问题,采用多体动力学虚拟样机仿真是一种行之有效的方法。     

中国航天固体火箭技术的发展

叙述了20世纪50年代以来中国航天固体火箭推进技术的发展历程，介绍了9种最具代表性的固体火箭发动机的技术特征、研制过程、地面试验和飞行情况，这些发动机分别应用于中国的探空火箭、运载火箭上面级和应用卫星变轨系统。文中还简要地评述了中国固体推进各单项技术的发展水平。