Lunar Reconnaissance Orbiter (LRO): Observations for Lunar Exploration and Science

The Lunar Reconnaissance Orbiter (LRO) was implemented to facilitate scientific and engineering-driven mapping of the lunar surface at new spatial scales and with new remote sensing methods, identify safe landing sites, search for in situ resources, and measure the space radiation environment. After its successful launch on June 18, 2009, the LRO spacecraft and instruments were activated and calibrated in an eccentric polar lunar orbit until September 15, when LRO was moved to a circular polar orbit with a mean altitude of 50 km. LRO will operate for at least one year to support the goals of NASA’s Exploration Systems Mission Directorate (ESMD), and for at least two years of extended operations for additional lunar science measurements supported by NASA’s Science Mission Directorate (SMD). LRO carries six instruments with associated science and exploration investigations, and a telecommunications/radar technology demonstration. The LRO instruments are: Cosmic Ray Telescope for the Effects of Radiation (CRaTER), Diviner Lunar Radiometer Experiment (DLRE), Lyman-Alpha Mapping Project (LAMP), Lunar Exploration Neutron Detector (LEND), Lunar Orbiter Laser Altimeter (LOLA), and Lunar Reconnaissance Orbiter Camera (LROC). The technology demonstration is a compact, dual-frequency, hybrid polarity synthetic aperture radar instrument (Mini-RF). LRO observations also support the Lunar Crater Observation and Sensing Satellite (LCROSS), the lunar impact mission that was co-manifested with LRO on the Atlas V (401) launch vehicle. This paper describes the LRO objectives and measurements that support exploration of the Moon and that address the science objectives outlined by the National Academy of Science’s report on the Scientific Context for Exploration of the Moon (SCEM). We also describe data accessibility by the science and exploration community.     

Conversations: with Carl Pilcher [interview by Johan Benson

An interview with Carl Pilcher, science program director for solar system exploration at NASA, examines NASA's past, present, and planned missions to explore the solar system. Specific questions relate to the status of current and planned missions, science results of the Pathfinder mission to Mars, cooperation with the Japanese space agency, the status of the search for extraterrestrial life in solar system meteoroids and asteroids, mission size for more in-depth exploration, reports of water on the moon, and the exploration of near-Earth objects.     

通过全球专利分析看深空探测 自主导航与控制技术发展

深空探测作为人类航天活动的重要方向,是人类探索宇宙奥秘和寻求长久发展的必然途径,也是衡量一个国家综合国力和科学技术发展水平的重要标志.作为深空探测中的一类重要技术,自主导航与控制技术越来越多地受到关注并得到应用,成为各国深空探测技术研究和发展的热点之一.以深空探测自主导航与控制技术为对象,通过专利检索分析,研究国内外发展现状,试图获得技术趋势.     

Imaging of the outer planets and satellites

Imaging is the most widely applicable single means of exploring the outer planets and their satellites and also complements other planet-oriented instruments. Imaging generally is more effectively carried out from a three-axis stabilized spacecraft than from a spinning one.Both specific experimental and broader exploratory goals must be recognized. Photography of Jupiter from terrestrial telescopes has revealed features which were neither predictable or predicted. Close-up imaging from fly-bys and orbiters affords the opportunity for discovery of atmospheric phenomena on the outer planets forever beyond the reach of terrestrial laboratories and intuition. On the other hand, a large number of specific applications of close-up imaging to study the giant planets are suggested by experience in photography from Earth and Mars orbit, and by ground-based telescopic studies of Jupiter and Saturn. Photographic observations of horizontal and vertical cloud structure at both global and finer scale, and motions and other time changes, will be essential for the study of atmospheric circulation. Size and composition of cloud particles also is a credible objective of fly-by and orbiter missions carrying both imaging and photo-polarimeter experiments.The satellites of the outer planets actually constitute three distinct classes: lunar-sized objects, asteroidal-sized objects, and particulate rings. Imaging promises to be the primary observational tool for each category with results that could impact scientific thinking in the late 70's and 80's as significantly as has close-up photography of Mars and the Moon in the last 10 yr.Finally, it should be recognized that photography occupies a unique role in the interaction between science and the popular mind. This popular, educational aspect of imaging constitutes a unique aspect of 20th Century culture. Imaging therefore is not only a primary basis for scientific discovery in the exploration of the outer planets, but an important human endeavor of enduring significance.Contribution No. 2163 of the Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91109.This is one of the publications by the Science Advisory Group.     

ARTEMIS Mission Design

The ARTEMIS mission takes two of the five THEMIS spacecraft beyond their prime mission objectives and reuses them to study the Moon and the lunar space environment. Although the spacecraft and fuel resources were tailored to space observations from Earth orbit, sufficient fuel margins, spacecraft capability, and operational flexibility were present that with a circuitous, ballistic, constrained-thrust trajectory, new scientific information could be gleaned from the instruments near the Moon and in lunar orbit. We discuss the challenges of ARTEMIS trajectory design and describe its current implementation to address both heliophysics and planetary science objectives. In particular, we explain the challenges imposed by the constraints of the orbiting hardware and describe the trajectory solutions found in prolonged ballistic flight paths that include multiple lunar approaches, lunar flybys, low-energy trajectory segments, lunar Lissajous orbits, and low-lunar-periapse orbits. We conclude with a discussion of the risks that we took to enable the development and implementation of ARTEMIS.     

STEREO Ground Segment, Science Operations, and Data Archive

Vitally important to the success of any mission is the ground support system used for commanding the spacecraft, receiving the telemetry, and processing the results. We describe the ground system used for the STEREO mission, consisting of the Mission Operations Center, the individual Payload Operations Centers for each instrument, and the STEREO Science Center, together with mission support from the Flight Dynamics Facility, Deep Space Mission System, and the Space Environment Center. The mission planning process is described, as is the data flow from spacecraft telemetry to processed science data to long-term archive. We describe the online resources that researchers will be able to use to access STEREO planning resources, science data, and analysis software. The STEREO Joint Observations Program system is described, with instructions on how observers can participate. Finally, we describe the near-real-time processing of the “space weather beacon” telemetry, which is a low telemetry rate quicklook product available close to 24 hours a day, with the intended use of space weather forecasting.     

Overview of Nighttime Ionospheric Instabilities at Low- and Mid-Latitudes: Coupling Aspects Resulting in Structuring at the Mesoscale

We present a review of the current state of understanding regarding two classes of irregularities causing mesoscale structuring (hundreds of kilometers) in the nighttime ionosphere at low- and mid-latitudes. Additionally, current state of understanding of equatorial plasma bubbles at low latitudes, and medium-scale traveling ionospheric disturbances at mid latitudes and their relationship to possible seeding from lower altitudes are described. In each case, well-developed linear theories exist to explain the general properties of the irregularities. However, these linear theories have growth rates too low to explain the actual observations, giving rise to the need to invoke seeding mechanisms. We describe the observational databases that have been compiled over the decades and discuss possible coupling and seeding mechanisms that would overcome the low growth rate and explain the observed structuring at the mesoscale. Future research directions are also briefly discussed.     

Communicating across the solar system

The next chapter in our ongoing quest for discovery began in the last half of the 20th century, with the initiation of robotic exploration of our solar system. In less than fifty years, we have broken free of Earth's gravity and flown spacecraft to every planet in the solar system except Pluto. The ultimate goal of this exploration is to establish a virtual (and, perhaps, someday, an actual) human presence throughout the solar system. Clearly, communications is one of the central elements of creating such a virtual presence, and also one of the biggest technical challenges in planetary exploration. Transmit performance is characterized by the product of antenna gain and transmitter power, while receive performance scales with the ratio of aperture effective area to system noise temperature. A number of key communications technology advances have enabled our planetary exploration to date, and future technology will open the door to new vistas in space exploration     

深空探测器自主技术发展现状与趋势

深空探测器距离地球远、所处环境复杂、苛刻,利用地面测控站进行深空探测器的遥测和遥控已经很难满足探测器控制的实时性和安全性要求。深空探测器自主技术即通过在探测器上构建一个智能自主管理软件系统,自主地进行工程任务与科学任务的规划调度、命令执行、星上状态的监测与故障时的系统重构,完成无人参与情况下的探测器长时间自主安全运行,自主技术已经逐渐成为深空探测领域未来发展的一项关键技术。本文首先分析了传统测控模式对深空探测的约束,回顾了深空探测器自主技术发展的现状,分析了实现深空探测器自主运行的关键技术,包括在轨自主管理系统设计技术、自主任务规划技术、自主导航与控制技术、自主故障处理技术和自主科学任务操作技术。然后结合深空探测工程实施和技术发展需求,提出未来深空探测器自主技术发展的趋势和重点。     

The Jupiter Energetic Particle Detector Instrument (JEDI) Investigation for the Juno Mission

The Jupiter Energetic Particle Detector Instruments (JEDI) on the Juno Jupiter polar-orbiting, atmosphere-skimming, mission to Jupiter will coordinate with the several other space physics instruments on the Juno spacecraft to characterize and understand the space environment of Jupiter’s polar regions, and specifically to understand the generation of Jupiter’s powerful aurora. JEDI comprises 3 nearly-identical instruments and measures at minimum the energy, angle, and ion composition distributions of ions with energies from H:20 keV and O: 50 keV to >1 MeV, and the energy and angle distribution of electrons from <40 to >500 keV. Each JEDI instrument uses microchannel plates (MCP) and thin foils to measure the times of flight (TOF) of incoming ions and the pulse height associated with the interaction of ions with the foils, and it uses solid state detectors (SSD’s) to measure the total energy (E) of both the ions and the electrons. The MCP anodes and the SSD arrays are configured to determine the directions of arrivals of the incoming charged particles. The instruments also use fast triple coincidence and optimum shielding to suppress penetrating background radiation and incoming UV foreground. Here we describe the science objectives of JEDI, the science and measurement requirements, the challenges that the JEDI team had in meeting these requirements, the design and operation of the JEDI instruments, their calibrated performances, the JEDI inflight and ground operations, and the initial measurements of the JEDI instruments in interplanetary space following the Juno launch on 5 August 2011. Juno will begin its prime science operations, comprising 32 orbits with dimensions 1.1×40 RJ, in mid-2016.     

深空探测器自主技术发展现状与趋势简

 深空探测器距离地球远、所处环境复杂、苛刻,利用地面测控站进行深空探测器的遥测和遥控已经很难满足探测器控制的实时性和安全性要求。深空探测器自主技术即通过在探测器上构建一个智能自主管理软件系统,自主地进行工程任务与科学任务的规划调度、命令执行、星上状态的监测与故障时的系统重构,完成无人参与情况下的探测器长时间自主安全运行,自主技术已经逐渐成为深空探测领域未来发展的一项关键技术。本文首先分析了传统测控模式对深空探测的约束,回顾了深空探测器自主技术发展的现状,分析了实现深空探测器自主运行的关键技术,包括在轨自主管理系统设计技术、自主任务规划技术、自主导航与控制技术、自主故障处理技术和自主科学任务操作技术。然后结合深空探测工程实施和技术发展需求,提出未来深空探测器自主技术发展的趋势和重点。     

基带滤波调制技术深空测控应用性能分析

深空测控的下行链路包括测控和数传2种典型的传输信道,其中数传信道一般具有发射功率大和数据传输速率高的特点,其带外辐射容易对测控信道产生干扰。以典型月球探测器为例,分析比较了数传信道采用常规BPSK（二进制相移键控）调制和基带滤波BPSK调制时,对测控信道的带外辐射影响,并对基带滤波BPSK调制的误码率性能进行了仿真分析,相应结论对未来深空探测任务测控系统总体设计具有十分重要的参考意义。     

中国电推进技术发展及展望

为了促进国内电推进技术的发展,简要介绍了国际上主要电推力器的种类和特点,并结合国外电推进技术的研究及在轨应用情况,介绍了中国电推进技术发展过程和应用现状,总结了国内外电推进技术的发展趋势。在此基础上,根据国内深空探测、商业航天、重力场测量、引力波探测等空间任务对推进器的高比冲、长寿命、宽调节范围、低成本、高精度等需求,提出了国内电推进技术应该将小型离子推力器、大型霍尔推力器、脉冲等离子体推力器以及无拖曳控制推力器作为重点发展方向的建议。     

The Swedish Small Satellite Program for Space Plasma Investigations

The success of the Swedish small satellite program, in combination with an active participation by Swedish research groups in major international missions, has placed Sweden in the frontline of experimental space research. The program started with the development of the research satellite Viking which was launched in 1986, for detailed investigations of the aurora. To date, Sweden has developed and launched a total of six research satellites; five for space plasma investigations; and the most recent satellite Odin, for research in astronomy and aeronomy. These fall into three main categories according to their physical dimension, financial cost and level of ambition: nano-satellites, micro-satellites, and mid-size satellites with ambitious scientific goals. In this brief review we focus on five space plasma missions, for which operations have ended and a comprehensive scientific data analysis has been conducted, which allows for a judgement of their role and impact on the progress in auroral research. Viking and Freja, the two most well-known missions of this program, were pioneers in the exploration of the aurora. The more recent satellites, Munin, Astrid, and Astrid-2 (category 1 and 2), proved to be powerful tools, both for testing new technologies and for carrying out advanced science missions. The Swedish small satellite program has been internationally recognized as cost efficient and scientifically very successful.     

Engineering test beds on the International Space Station

The International Space Station is a unique multi-faceted orbiting laboratory supporting research, development, test and evaluation of new innovative space and Earth-based applications. While NASA sponsored investigations on the ISS are focused largely on enabling future long duration human space exploration missions, Congress designated the US portion of the space station as a National Laboratory making its facilities available to other Federal agencies and private entities for non-exploration related ventures. RDT&E activities on the ISS encompass a number of technical areas including environmental control and life support, communications, materials science, guidance, navigation and control, propulsion, electrical power, and thermal control systems.     

2013 年国外载人航天发展综合分析

2013年,各主要航天国家依据本国具体国情,以审慎务实的态度持续推进载人航天活动。基于此背景,综述了2013年国外载人航天领域发展动态,梳理了国际空间站及深空探索领域的系列成果,分析了重型运载火箭、新型飞船、空间商业运输能力的发展趋势。     

A new online modelling method for aircraft engine state space model

To overcome the drawbacks of current modelling method for aircraft engine state space model, a new method is introduced. The form of state space model is derived by using Talyor series to expand the nonlinear model that is implicit equations and involves many iterations. A partial derivative calculation method for iterations is developed to handle the influence of iterations on parameters. The derivative calculation and the aerothermodynamics calculations are combined in the component level model with fixed number Newton-Raphson (N-R) iterations. Mathematical derivation and simulations show the convergence ability of proposed method. Simulations show that comparing with the linear parameter varying model and centered difference based state space model, much higher accuracy of proposed online modelling method is achieved. The accuracy of the state space model built by proposed method can be maintained when the step amplitudes of inputs are within 2%, and the responses of the state space model can match those of the component level model when each input steps larger amplitudes. In addition, an online verification was carried out to show the capability of modelling at any operating point and that state space model can predict future outputs accurately. Thus, the effectiveness of the proposed method is demonstrated.     

航天材料工程学内涵及其体系构建

为应对空间特殊服役环境,航天材料研制、保证和使用单位已在材料设计、材料加工、材料评价和材料使用方面开展了大量工作。在此基础上,本文首先对我国航天材料的选型要求进行了分析,接着对航天材料、航天材料飞行试验、空间材料科学、航天材料空间环境适应性等概念进行了辨析,并提出了航天材料工程学的概念,进而对航天材料工程的各个组成部分的关联性进行了阐述。最后,为满足未来空间技术发展需求,在总结和借鉴国内外航天材料工程发展经验的基础上,从规划、研发、试(实)验、评价、选用、数据服务等角度,设计构建了具有航天领域特色的航天材料工程体系。     

New technology starts new era of space exploration

In this report the author describe the plans of the United States and other governments for developing deep space exploration programs. The latest energy conversion, power generation, and energy storage developments, described in the IECECs 80 engineering presentations, make these plans achievable.