To Fly to the Sun: Solar Probe Mission & Technology Challenges

To fly close to the Sun (to a perihelion of 4 solar radii) represents many unique challenges to a mission and spacecraft design. The solar probe design is a result of over two decades of studies that have allowed the evolution of both the mission and trajectory design, as well as the spacecraft configurations. During these studies some of the most significant design challenges have been the trajectory design, the spacecraft shield design, the spacecraft configuration, the telecommunications near perihelion, science instrument accommodations, and minimizing mission cost. This latter challenge (minimum cost) permeates all other design issues suggesting specific solutions consistent with this constraint. This presents the evolution and rationale that have taken place to arrive at the current design for this challenging mission.     

The Scientific Measurement System of the Gravity Recovery and Interior Laboratory (GRAIL) Mission

The Gravity Recovery and Interior Laboratory (GRAIL) mission to the Moon utilized an integrated scientific measurement system comprised of flight, ground, mission, and data system elements in order to meet the end-to-end performance required to achieve its scientific objectives. Modeling and simulation efforts were carried out early in the mission that influenced and optimized the design, implementation, and testing of these elements. Because the two prime scientific observables, range between the two spacecraft and range rates between each spacecraft and ground stations, can be affected by the performance of any element of the mission, we treated every element as part of an extended science instrument, a science system. All simulations and modeling took into account the design and configuration of each element to compute the expected performance and error budgets. In the process, scientific requirements were converted to engineering specifications that became the primary drivers for development and testing. Extensive simulations demonstrated that the scientific objectives could in most cases be met with significant margin. Errors are grouped into dynamic or kinematic sources and the largest source of non-gravitational error comes from spacecraft thermal radiation. With all error models included, the baseline solution shows that estimation of the lunar gravity field is robust against both dynamic and kinematic errors and a nominal field of degree 300 or better could be achieved according to the scaled Kaula rule for the Moon. The core signature is more sensitive to modeling errors and can be recovered with a small margin.     

Modelling of the MICROSCOPE Mission

The French space mission MICROSCOPE aims at testing the Equivalence Principle (EP) up to an accuracy of 10^?15. The experiment will be carried out on a satellite which is developed and produced within the CNES Myriade series. The measuring accuracy will be achieved by means of two high-precision capacitive differential accelerometers that are built by the French institute ONERA, see Touboul and Rodrigues (Class. Quantum Gravity 18:2487–2498, 2001). At ZARM, which is a member of the science team, the data evaluation process is prepared. Therefore, a comprehensive simulation of the real system including the science signal and all error sources is built for the development and testing of data reduction and data analysis algorithms to extract the EP violation signal. Currently, the ZARM Drag-Free simulator, a tool to support mission modelling, is adapted for the MICROSCOPE mission in order to simulate test mass and satellite dynamics. Models of environmental disturbances like solar radiation pressure are considered, also. Additionally, detailed modelling of the on-board capacitive sensors is done. The actual status of the mission modelling will be presented. Particularly, the modelling of disturbances forces will be discussed in detail.     

Theory and Modeling for the Magnetospheric Multiscale Mission

The Magnetospheric Multiscale (MMS) mission will provide measurement capabilities, which will exceed those of earlier and even contemporary missions by orders of magnitude. MMS will, for the first time, be able to measure directly and with sufficient resolution key features of the magnetic reconnection process, down to the critical electron scales, which need to be resolved to understand how reconnection works. Owing to the complexity and extremely high spatial resolution required, no prior measurements exist, which could be employed to guide the definition of measurement requirements, and consequently set essential parameters for mission planning and execution. Insight into expected details of the reconnection process could hence only been obtained from theory and modern kinetic modeling. This situation was recognized early on by MMS leadership, which supported the formation of a fully integrated Theory and Modeling Team (TMT). The TMT participated in all aspects of mission planning, from the proposal stage to individual aspects of instrument performance characteristics. It provided and continues to provide to the mission the latest insights regarding the kinetic physics of magnetic reconnection, as well as associated particle acceleration and turbulence, assuring that, to the best of modern knowledge, the mission is prepared to resolve the inner workings of the magnetic reconnection process. The present paper provides a summary of key recent results or reconnection research by TMT members.     

直升机任务能力评估

首先介绍了直升机任务能力的主要内容及其应用领域,然后建立了一种适用于直升机任务能力评估的对数法,并对其评估的具体项目进行了说明。最后给出了一些机型的评估算例,计算结果表明用该方法对直升机的任务能力进行评估是合理的。     

Impact Cratering Theory and Modeling for the Deep Impact Mission: From Mission Planning to Data Analysis

The cratering event produced by the Deep Impact mission is a unique experimental opportunity, beyond the capability of Earth-based laboratories with regard to the impacting energy, target material, space environment, and extremely low-gravity field. Consequently, impact cratering theory and modeling play an important role in this mission, from initial inception to final data analysis. Experimentally derived impact cratering scaling laws provide us with our best estimates for the crater diameter, depth, and formation time: critical in the mission planning stage for producing the flight plan and instrument specifications. Cratering theory has strongly influenced the impactor design, producing a probe that should produce the largest possible crater on the surface of Tempel 1 under a wide range of scenarios. Numerical hydrocode modeling allows us to estimate the volume and thermodynamic characteristics of the material vaporized in the early stages of the impact. Hydrocode modeling will also aid us in understanding the observed crater excavation process, especially in the area of impacts into porous materials. Finally, experimentally derived ejecta scaling laws and modeling provide us with a means to predict and analyze the observed behavior of the material launched from the comet during crater excavation, and may provide us with a unique means of estimating the magnitude of the comet’s gravity field and by extension the mass and density of comet Tempel 1.     

The Operational Environment of the Hipparcos Mission

We investigate links between the observational environment as experienced by the Hipparcos satellite and the performance of the spacecraft and payload instrumentation, with particular emphasis on finding out whether some of these effects may have been inadequately represented in instrument calibrations and could thus have affected the scientific results of the mission. Scan-coverage and radiation effects are primarily random effects with only some long-term systematics. However, long- (days to weeks) and short-term (hours) temperature variations reflected in the performance of some of the spacecraft instrumentation. It is shown that only a small sign of some long-term thermal variations could be detected in the payload instrumentation. These findings further limit the scope left for the occurrence of large-scale correlated errors in the Hipparcos astrometric data. On the other hand, a number of great circles were identified which showed a highly significant drift of the basic angle, which had not been detected in the preparation of the published data. The data from these circles may have, in some cases, led to, very localised, slightly anomalous results, in particular where stars are accidentally affected by two or more of such circles. This revised version was published online in August 2006 with corrections to the Cover Date.     

载人小行星探测的飞行模式简

基于载人小行星探测的任务背景,根据其基本的飞行阶段及任务特点,对其探测任务的飞行模式进行分析,其中包括探测器逃逸地球的飞行方式、小行星表面探测方式、返回与再入的飞行方式,重点研究小行星表面探测方式.对运载能力、技术难度、探测器质量规模进行了分析与比较,得出基于着陆对接口概念的近地＋对接着陆＋直接再入的较优的飞行模式,并将该模式进一步划分为9个飞行节点及6个主要飞行阶段,对其飞行过程进行了详细的描述.     

舰载直升机任务航电系统及建模

介绍了美国海军舰载直升机的发展,着重阐述了海鹰直升机的发展,概述了其先进的任务航电系统,还对海鹰直升机的建模进行简单说明。     

导弹集群协同作战任务规划系统

以领弹/攻击弹等新概念作战方式为例,讨论基于C4ISR系统下的导弹集群协同作战的总体框架,对信息融合系统、态势评估系统、任务规划系统、战毁评估系统及数据链系统等进行了分析,并对任务规划的主要算法,如A*,D*,Voronoi图法等进行了分析比较,最后设计了任务规划系统的硬件体系框架和软件结构模块.     

基于BDD的航天测控系统任务可靠性分析

针对航天测控系统任务可靠性分析问题,提出了基于二值决策图（BDD）的航天测控系统任务可靠性分析模型和算法。将航天测控系统视为一个多阶段任务系统,采用任务剖面描述任务时序逻辑关系。根据各阶段的可靠性逻辑结构建立了单阶段的BDD,依次对各阶段的BDD进行运算得到系统的BDD,据此计算系统的可靠度。最后给出了一个算例,验证了算法的有效性。     

The Plasma Ion and Electron Instruments for the Genesis Mission

The Genesis Ion Monitor (GIM) and the Genesis Electron Monitor (GEM) provide 3-dimensional plasma measurements of the solar wind for the Genesis mission. These measurements are used onboard to determine the type of plasma that is flowing past the spacecraft and to configure the solar wind sample collection subsystems in real-time. Both GIM and GEM employ spherical-section electrostatic analyzers followed by channel electron multiplier (CEM) arrays for detection and angle and energy/charge analysis of incident ions and electrons. GIM is of a new design specific to Genesis mission requirements whereas the GEM sensor is an almost exact copy of the plasma electron sensors currently flying on the ACE and Ulysses spacecraft, albeit with new electronics and programming. Ions are detected at forty log-spaced energy levels between ∼ 1 eV and 14 keV by eight CEM detectors, while electrons with energies between ∼ 1 eV and 1.4 keV are measured at twenty log-spaced energy levels using seven CEMs. The spin of the spacecraft is used to sweep the fan-shaped fields-of-view of both instruments across all areas of the sky of interest, with ion measurements being taken forty times per spin and samples of the electron population being taken twenty four times per spin. Complete ion and electron energy spectra are measured every ∼ 2.5 min (four spins of the spacecraft) with adequate energy and angular resolution to determine fully 3-dimensional ion and electron distribution functions. The GIM and GEM plasma measurements are principally used to enable the operational solar wind sample collection goals of the Genesis mission but they also provide a potentially very useful data set for studies of solar wind phenomena, especially if combined with other solar wind data sets from ACE, WIND, SOHO and Ulysses for multi-spacecraft investigations. This revised version was published online in August 2006 with corrections to the Cover Date.     

UCAV任务规划系统的研究进展及发展趋势

分析了无人作战飞机任务规划系统的特点，按照规划范围和时段对无人作战飞机任务规划系统进行分层研究，讨论和分析了各个层次的作用及发展现状。最后，展望了无人作战飞机任务规划系统的发展趋势。     

飞机任务简报技术研究与实现

传统的机载数据记录系统只是将数据记录下来,在地面站下载后分析回放。由于机载设备记录的数据量巨大,地面下载、检索数据非常耗时,这大大降低了飞机的故障诊断速度及快速出动能力。本文提出了一种任务简报技术,在飞机飞行或执行任务过程中建立索引文件、事件文件,当飞行结束后,通过事件文件、索引文件快速下载与事件相关的数据片段。该技术能够显著提高数据下载、检索速度,对任务简报功能设计有一定参考价值。     

浅谈新时期航空企业标准化工作的特点和挑战

论述了新标准的数量和应用范围空前扩大,标准化工作内容更加深化、细化;信息标准化的崛起:国外民机标准的借鉴等6个方面的企业标准化工作在新时期的特点和挑战,指出应注意这些新特点,把握机遇,发展创新,使企业标准化工作跃上一个新台阶.     

Challenges of education in engineering

The article discussed the present challenges of engineering education and the role it plays in the society. It tackled some important issues in engineering education including the decreasing interest of American High School graduates in engineering program and solution to this problem by promoting engineering education via the Internet.     

The Global-Scale Observations of the Limb and Disk (GOLD) Mission

The Earth’s thermosphere and ionosphere constitute a dynamic system that varies daily in response to energy inputs from above and from below. This system can exhibit a significant response within an hour to changes in those inputs, as plasma and fluid processes compete to control its temperature, composition, and structure. Within this system, short wavelength solar radiation and charged particles from the magnetosphere deposit energy, and waves propagating from the lower atmosphere dissipate. Understanding the global-scale response of the thermosphere-ionosphere (T-I) system to these drivers is essential to advancing our physical understanding of coupling between the space environment and the Earth’s atmosphere. Previous missions have successfully determined how the “climate” of the T-I system responds. The Global-scale Observations of the Limb and Disk (GOLD) mission will determine how the “weather” of the T-I responds, taking the next step in understanding the coupling between the space environment and the Earth’s atmosphere. Operating in geostationary orbit, the GOLD imaging spectrograph will measure the Earth’s emissions from 132 to 162 nm. These measurements will be used image two critical variables—thermospheric temperature and composition, near 160 km—on the dayside disk at half-hour time scales. At night they will be used to image the evolution of the low latitude ionosphere in the same regions that were observed earlier during the day. Due to the geostationary orbit being used the mission observes the same hemisphere repeatedly, allowing the unambiguous separation of spatial and temporal variability over the Americas.     

Science Objectives and Rationale for the Radiation Belt Storm Probes Mission

The NASA Radiation Belt Storm Probes (RBSP) mission addresses how populations of high energy charged particles are created, vary, and evolve in space environments, and specifically within Earth’s magnetically trapped radiation belts. RBSP, with a nominal launch date of August 2012, comprises two spacecraft making in situ measurements for at least 2 years in nearly the same highly elliptical, low inclination orbits (1.1×5.8 RE, 10^°). The orbits are slightly different so that 1 spacecraft laps the other spacecraft about every 2.5 months, allowing separation of spatial from temporal effects over spatial scales ranging from ～0.1 to 5 RE. The uniquely comprehensive suite of instruments, identical on the two spacecraft, measures all of the particle (electrons, ions, ion composition), fields (E and B), and wave distributions (d E and d B) that are needed to resolve the most critical science questions. Here we summarize the high level science objectives for the RBSP mission, provide historical background on studies of Earth and planetary radiation belts, present examples of the most compelling scientific mysteries of the radiation belts, present the mission design of the RBSP mission that targets these mysteries and objectives, present the observation and measurement requirements for the mission, and introduce the instrumentation that will deliver these measurements. This paper references and is followed by a number of companion papers that describe the details of the RBSP mission, spacecraft, and instruments.     

The Radio Frequency Subsystem and Radio Science on the MESSENGER Mission

The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) Radio Frequency (RF) Telecommunications Subsystem is used to send commands to the spacecraft, transmit information on the state of the spacecraft and science-related observations, and assist in navigating the spacecraft to and in orbit about Mercury by providing precise observations of the spacecraft’s Doppler velocity and range in the line of sight to Earth. The RF signal is transmitted and received at X-band frequencies (7.2 GHz uplink, 8.4 GHz downlink) by the NASA Deep Space Network. The tracking data from MESSENGER will contribute significantly to achieving the mission’s geophysics objectives. The RF subsystem, as the radio science instrument, will help determine Mercury’s gravitational field and, in conjunction with the Mercury Laser Altimeter instrument, help determine the topography of the planet. Further analysis of the data will improve the knowledge of the planet’s orbital ephemeris and rotation state. The rotational state determination includes refined measurements of the obliquity and forced physical libration, which are necessary to characterize Mercury’s core state.