海南发射场盐雾环境对航天器结构材料的影响

文章在分析海南发射场的盐雾环境及成因并对大气中氯离子含量进行统计和对比的基础上,阐述了盐雾环境与航天器结构材料的作用机理,并对航天器结构用典型材料进行1年的库内暴露试验,详细考查了在海南发射场盐雾环境下,这些材料的腐蚀后微观形貌、腐蚀产物表面成分和物相,以及ZK61M镁合金的热控功能退化情况,并针对航天器在发射场测试与发射期间海洋大气盐雾环境影响给出评估分析。结果表明:航天器测试发射周期(按3个月计算)内,上述材料不会发生宏观腐蚀现象;发射后氯离子等盐雾成分在航天器表面附着并进入空间后,不会继续腐蚀或扩展。     

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。     

海洋环境下载人航天器电子设备防护技术

海南文昌发射场高温、高湿、高盐雾的气候条件以及由天津到海南长距离的海上运输给航天器电子设备的三防性能带来了挑战。文章首先对运输过程中高湿、盐雾和霉菌对航天器电子设备的影响进行了分析,然后对航天器电子设备的三防工艺及运输技术进行了研究,并提出了具有普遍适用性的三防措施,能够有效降低环境因素带来的不利影响。     

航天器发射场安全保障技术措施

要提高航天器发射的成功率,就必须重视运载器研制质量及发射场的安全。 30多年来在航天器、运载器研制生产方面已经获得了很大成绩,但发射成功率还达不到百分之百。例如,西方的运载器其平均发射成功率只达到91.7％。发射场设备虽不断完善,自动化水平也不断提高,但仍存在不安全因素,由此可引起大火、爆炸事故、推进剂中毒等。 发射工作尽管有风险,但只要防范措施周密,遇险就有备无患。现谈谈航天器发射场的不安全因素及安全防护措施。     

知识资料窗

知识资料窗航天器发射场航天器发射场就是发射航天器的特定区域。场区内有整套试验设施和设备，用以装配、贮存、检测和发射航天器，测量飞行轨道，发送控制指令，接收和处理遥测信息。场址选择航天器发射场的位置根据航天器发射试验技术的特点和安全要求选定。运载火箭发...     

NASA准备发射深空原子钟提高导航技术

据NASA网站2012年4月9日报道，NASA正为发射一个深空原子钟（DSAC）演示验证而做准备。它使用单向导航技术——通过实现航天器实时估算自己的授时与导航数据，可对目前使用的双向导航系统做出改进。在双向导航系统中，信息要送回地面，需要地面小组评估授时与导航，然后再传回航天器。在执行时间起到关键作用的事件时，星载实时导航能力是提高NASA能力的关键，例如在行星着陆或行星飞越期间，对地面与航天器互动而言，信号延迟太长。在未来NASA任务中使用深空原子钟，     

航天器撞击解体碎片的短期危害评估

讨论了航天器与短期碎片云碰撞概率的计算流程。基于碎片云中碎片的数量、航天器的横截面积和碰撞概率风险阈值,提出了“风险区域判据”的方法,用于快速判断筛选航天器是否存在与碎片云碰撞的风险。推导了基于NASA标准解体模型的碎片分离速度概率密度函数,建立了计算航天器与单颗碎片碰撞概率的时间积分算法。针对在计算航天器与整个碎片云碰撞概率时的数据量无限制增长问题,提出了近似简化的“准平均概率”方法,有效地解决了计算速度的瓶颈问题。分析讨论了航天器与碎片云的轨道误差对计算碰撞概率的影响。最后,采用仿真算例进行计算分析与验证。     

归因于空间环境的航天器故障与异常

天然空间环境对航天器设计、研制和运行的影响是NASA马歇尔空间飞行中心系统分析和集成实验室电磁与航空宇宙环境部组织编写的一系列NASA RP报告的主题。其中,NASA RP-1390详细概述了天然空间环境7个主要环境因素,包括它们的简单定义、相关的型号计划事项以及对各种航天器分系统的影响。该报告提供100多个从1974～1994年间发生的归因于天然空间环境的航天器故障和异常的案例,统计分析天然空间环境及其对航天器的影响。文章是对这篇报告的介绍与点评。     

我国航天发射场面临的形势与未来发展探讨

<正>引言习主席指出:"发展航天事业,建设航天强国,是我们不懈追求的航天梦"。作为航天系统工程的重要组成部分,航天发射场是航天器进入外层空间的前提和基础,承担着航天器测试发射和首区测量控制等重要任务。航天事业的迅猛发展,需要建设与之相适应的技术先进、功能完备的航天发射场。航天强国都在根据世情国情制定包括航天发射场在内的航天发展战略。我们必须准确把握国外航天发射场发展的重要趋势,清醒认识与航天强国之间的现实差距,合理规划我国     

动态新闻

海南航天发射场开工建设 预计2013年投入使用 2009年9月14日，中国海南航天发射场开工仪式在海南省文昌市龙楼镇举行。至此，规划已久的海南航天发射场正式破土动工。     

NanoSail-D: A solar sail demonstration mission

In the early to mid-2000s, NASA made substantial progress in the development of solar sail propulsion systems. Solar sail propulsion uses the solar radiation pressure exerted by the momentum transfer of reflected photons to generate a net force on a spacecraft. To date, solar sail propulsion systems were designed for large robotic spacecraft. Recently, however, NASA has been investigating the application of solar sails for small satellite propulsion. The NanoSail-D is a subscale solar sail system designed for possible small spacecraft applications. The NanoSail-D mission flew on board the ill-fated Falcon Rocket launched August 2, 2008, and due to the failure of that rocket, never achieved orbit. The NanoSail-D flight spare is ready for flight and a suitable launch arrangement is being actively pursued. This paper will present an introduction solar sail propulsion systems and an overview of the NanoSail-D spacecraft.     

中国空间技术成就斐然——纪念东方红1号卫星发射成功30周年

从1970年至1999年,中国已用长征系列运载火箭进行了68次航天发射,累计发射了84颗人造地球卫星(其中国产卫星52颗、国外卫星32颗)和1艘无人状态的试验飞船,发射成功率约85％。现今,中国对空间技术体系的认识已得到深化,中国的航天器进入太空技术已位居世界前列,中国的航天信息应用技术已取得显著效益。     

The Mars Sample Return Project.

The Mars Sample Return (MSR) Project is underway. A 2003 mission to be launched on a Delta III Class vehicle and a 2005 mission launched on an Ariane 5 will culminate in carefully selected Mars samples arriving on Earth in 2008. NASA is the lead agency and will provide the Mars landed elements, namely, landers, rovers, and Mars ascent vehicles (MAVs). The French Space Agency CNES is the largest international partner and will provide for the joint NASA/CNES 2005 Mission the Ariane 5 launch and the Earth Return Mars Orbiter that will capture the sample canisters from the Mars parking orbits the MAVs place them in. The sample canisters will be returned to Earth aboard the CNES Orbiter in the Earth Entry Vehicles provided by NASA. Other national space agencies are also expected to participate in substantial roles. Italy is planning to provide a drill that will operate from the Landers to provide subsurface samples. Other experiments in addition to the MSR payload will also be carried on the Landers. This paper will present the current status of the design of the MSR missions and flight articles.     

Dual attitude and parameter estimation of passively magnetically stabilized nano satellites

The attitude determination capability of a nano satellite is limited by a lack of traditional high performance attitude sensors, a result of having small budgets for mass and power. Attitude determination can still be performed on a nano satellite with low fidelity sensors, but an accurate model of the spacecraft attitude dynamics is required. The passive magnetic stabilization systems commonly employed in nano satellites are known to introduce uncertainties in the parameters of the attitude dynamics model that cannot easily be resolved prior to launch. In this paper, a batch estimation problem is formulated that simultaneously solves for the attitude of the spacecraft and performs parameter estimation on the magnetic properties of the magnetic materials using only a measurement of the solar vector. The estimation technique is applied to data from NASA Ames Research Center's O/OREOS nano satellite and the University of Michigan's RAX-1 nano satellite, where clear differences are detected between the magnetic properties as measured before launch and those that fit the observed data. To date this is the first known on-orbit verification of the attitude dynamics model of a passively magnetically stabilized spacecraft.     

Inflatable composite habitat structures for lunar and mars exploration

Recent advances in materials technology have improved the performance capabilities of inflatable, flexible composite structures, which have increased their potential for use in numerous space applications. Space suits, which are comprised of flexible composite components, are a good example of the successful use of inflatable composite structures in space. Space suits employ inflatables technology to provide a stand alone spacecraft for astronauts during extra-vehicular activity. A natural extension of this application of inflatables technology is in orbital or planetary habitat structures. NASA Johnson Space Center (JSC) is currently investigating flexible composite structures deployed via inflation for use as habitats, transfer vehicles and depots for continued exploration of the Moon and Mars.

Inflatable composite structures are being investigated because they offer significant benefits over conventional structures for aerospace applications. Inflatable structures are flexible and can be packaged in smaller and more complex shaped volumes, which result in the selection of smaller launch vehicles which dramatically reduce launch costs. Inflatable composite structures are typically manufactured from materials that have higher strength to weight ratios than conventional systems and are therefore lower in mass. Mass reductions are further realized because of the tailorability of inflatable composite structures, which allow the strength of the system to be concentrated where needed. Flexible composite structures also tend to be more damage tolerant due to their “forgiveness” as compared to rigid mechanical systems. In addition, inflatables have consistently proven to be lower in both development and manufacturing costs.

Several inflatable habitat development programs are discussed with their increasing maturation toward use on a flight mission. Selected development programs being discussed include several NASA Langley Research Center habitat programs that were conducted in the 1960s, the Lawrence Livermore National Laboratory inflatable space station study, the NASA JSC deployable inflatable Lunar habitat study, and the inflatable Mars TransHab study and test program currently ongoing at NASA JSC. Relevant technology developments made by ILC Dover are also presented.     

Rosetta: The ESA comet rendezvous mission

Rosetta was selected in November 1993 for the ESA Cornerstone 3 mission, to be launched in 2003, dedicated to the exploration of the small bodies of the solar system (asteroids and comets). Following this selection, the Rosetta mission and its spacecraft have been completely reviewed: this paper presents the studies performed the proposed mission and the resulting spacecraft design.

Three mission opportunities have been identified in 2003–2004, allowing rendezvous with a comet. From a single Ariane 5 launch, the transfer to the comet orbit will be supported by planetary gravity assists (two from Earth, one from Venus or Mars); during the transfer sequence, two asteroid fly-bys will occur, allowing first mission science phases. The comet rendezvous will occur 8–9 years after launch; Rosetta will orbit around the comet and the main science mission phase will take place up to the comet perihelion (1–2 years duration).

The spacecraft design is driven (i) by the communication scenario with the Earth and its equipment, (ii) by the autonomy requirements for the long cruise phases which are not supported by the ground stations, (iii) by the solar cells solar array for the electrical power supply and (iv) by the navigation scenario and sensors for cruise, target approach and rendezvous phases. These requirements will be developed and the satellite design will be presented.     

Piloted operations at a near-Earth object (NEO)

In late 2006, NASA's Constellation Program sponsored a study to examine the feasibility of sending a piloted Orion spacecraft to a near-Earth object. NEOs are asteroids or comets that have perihelion distances less than or equal to 1.3 astronomical units, and can have orbits that cross that of the Earth. Therefore, the most suitable targets for the Orion Crew Exploration Vehicle (CEV) are those NEOs in heliocentric orbits similar to Earth's (i.e. low inclination and low eccentricity). One of the significant advantages of this type of mission is that it strengthens and validates the foundational infrastructure of the United States Space Exploration Policy and is highly complementary to NASA's planned lunar sortie and outpost missions circa 2020. A human expedition to a NEO would not only underline the broad utility of the Orion CEV and Ares launch systems, but would also be the first human expedition to an interplanetary body beyond the Earth–Moon system. These deep space operations will present unique challenges not present in lunar missions for the onboard crew, spacecraft systems, and mission control team. Executing several piloted NEO missions will enable NASA to gain crucial deep space operational experience, which will be necessary prerequisites for the eventual human missions to Mars.Our NEO team will present and discuss the following:

• •new mission trajectories and concepts;
• •operational command and control considerations;
• •expected science, operational, resource utilization, and impact mitigation returns; and
• •continued exploration momentum and future Mars exploration benefits.

     

Success criteria and risk management for the new millennium program

The National Aeronautics and Space Administration (NASA) New Millennium Program (NMP) is a technology development and validation program that will flight-validate advanced, new technologies with space flight applications. NMP's purpose is twofold. First, it will develop technologies that will enable future spacecraft to be smaller, more capable and reliable, and to be launched more frequently. Second, it will validate the technologies in flight to reduce the risks to future science missions that fly these technologies for the first time. To measure the program's success, NMP has devised a set of criteria that stresses the relevance of technologies selected for flight validation to NASA's 21st-century science mission needs. Also, NMP has instituted a ‘risk management’ policy, where, through a combination of adequate resources and early risk assessment and risk mitigation plans for the technologies, the overall risk of the NMP flights can be rendered acceptable.     

Study on passive momentum exchange landing gear using two-dimensional analysis

This paper discusses a landing response control system based on the momentum exchange principle for planetary exploration spacecraft. In the past, landing gear systems with cantilever designs that incorporate honeycomb materials to dissipate shock energy through plastic deformation have been used, but once tested before launch, the system cannot be used in a real mission. The sky crane system used for the Mars Science Laboratory by NASA can achieve a safe and precise landing, but it is highly complex. This paper introduces a momentum exchange impact damper (MEID) that absorbs the controlled object׳s momentum with extra masses called damper masses. The MEID is reusable, which makes it easy to ensure the landing gear׳s reliability. In this system, only passive elements such as springs are needed. A single-axis (SA) model has already been used to verify the effectiveness of MEIDs through simulations and experiments measuring the rebound height of the spacecraft. However, the SA model cannot address the rotational motion and tipping of the spacecraft. This paper presents a two-landing-gear-system (TLGS) model in which multiple MEIDs are equipped for two-dimensional analysis. Unlike in the authors׳ previous studies, in this study each MEID is launched when the corresponding landing gear lands and the MEIDs do not contain active actuators. This mechanism can be used to realize advanced control specifications, and it is simply compared with previous mechanisms including actuators, in which all of the MEIDs are launched simultaneously. If each MEID works when the corresponding gear lands, the rebound height of each gear can be minimized, and tipping can be prevented, as demonstrated by the results of our simulations.