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1
Doschek, G. A. "Recent Advances in EUV Solar Astronomy." International Astronomical Union Colloquium 152 (1996): 503–10. http://dx.doi.org/10.1017/s0252921100036460.
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I discuss recent advances in EUV solar astronomy. The new work is primarily a result of current solar space missions such as the Yohkoh high energy solar physics mission, as well as upcoming space missions such as the ESA Solar and Heliospheric Observatory (SOHO). I discuss spectroscopic and atomic physics work, and new results concerning solar flares that are directly relevant to stellar research.
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Hudson, Hugh S. "Spatial Resolution of Solar Total Irradiance Variability: The YOHKOH White-Light Observations." International Astronomical Union Colloquium 143 (1994): 196–205. http://dx.doi.org/10.1017/s0252921100024696.
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The observations from the ACRIM instrument on board the Solar Maximum Mission, and other recent experiments, have allowed us to study the time variations of solar irradiance. These observations identified several mechanisms, ranging from sunspots to global oscillations produced by waves trapped in the solar interior (the p-modes) that cause variations in the total irradiance. In all cases the variations have small amplitudes in integrated light from the visible photosphere. The SXT instrument on board Yohkoh has provided a new data set that can resolve some of these variations spatially. Most of these data are in the form of whole-Sun images: rate about 5 per day; effective pixel size of 4.92 arc sec; passband 28Å centered at 4310Å; data interval beginning in September, 1991 and ending in October, 1992. These observations have several advantages over ground-based observations for the characterization of solar global variability, namely the lack of atmospheric effects and the long-term stability of the instrumentation. We present an assessment of these data in the context of the existing total irradiance data, and also discuss their application to determination of the figure of the Sun, particularly measurements of the variations of the solar radius.
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Turck-Chieze, S., R. Bocchia, P. Boumier, M. Cantin, J. Charra, B. Cougrand, J. Cretolle, et al. "The spatial Golf project." International Astronomical Union Colloquium 147 (1994): 532–36. http://dx.doi.org/10.1017/s0252921100026543.
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AbstractThis spatial experiment is under construction and has been defined as a 2 years mission on board SOHO, a satellite dedicated to the Sun which will be launched in mid 95. The main objectives are the detection of solar low degree acoustic modes and solar gravity modes for improving our knowledge of the solar nuclear region.
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Ali, Essam, Mohamed Fanni, and Abdelfatah M. Mohamed. "Design and task management of a mobile solar station for charging flying drones." E3S Web of Conferences 167 (2020): 05004. http://dx.doi.org/10.1051/e3sconf/202016705004.
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This paper provides design and task management of the first stage of a project entitled “Fall-Army Worm (FAW) insect killer”. The project has three main stages: design and energy management stage, flying control of drone stage and detecting and killing FAW stage. The goal of this project is to detect and kill; without chemical methods; a harmful FAW insect which is rapidly spreading in Africa and Asia. This paper focuses on design of the first stage of the system, getting maximum power and controlling the energy of the system. A Photo Voltaic system with energy storage devices is proposed to be the source of power. A new algorithm to control the time scheduling of the killing and detection mission is proposed and its effects on the system’s energy and mission period are studied. A comparison between different methods for tracking the maximum power from PV panels is performed to choose the best (less time and high accuracy) method. The results of simulation indicate the effectiveness of the proposed maximum power tracking and task management system.
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Buzasi, Derek L. "Building a Large Solar Analog Sample Using K2." Proceedings of the International Astronomical Union 13, S340 (February 2018): 233–34. http://dx.doi.org/10.1017/s1743921318001230.
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AbstractWe have begun a project aimed at providing a large consistent set of well- vetted solar analogs in order to address questions of stellar rotation, activity, dynamos, and gyrochronology. We make use of the K2 mission fields to obtain precise photometric time series, supplemented by ground-based photometric and spectroscopic data for promising candidates. From this data we will derive rotation periods, spot coverages, and flare rates for a well- defined and well-calibrated sample of solar analogs.
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Neukum, G. "The Planetenteleskop Mission." International Astronomical Union Colloquium 123 (1990): 286. http://dx.doi.org/10.1017/s0252921100077149.
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AbstractThe scientific focus of the Planetenteleskop project will be on time-variable solar system phenomena (planet-magnetosphere-satellite interactions, active processes of cometary nuclei, atmospheric circulation and dynamics), on time-invariant solar system phenomena (geochemical provinces on planetary and satellite surfaces, global characteristics of primitive bodies), on planetary environments of other stars, and on general astronomical and astrophysical applications. The proposed Planetenteleskop in elliptical 24 h earth orbit will combine near-simultaneous, high-resolution spectroscopic observations, diffraction-limited imaging quality, long integration times (< 10 h) and excellent target tracking accuracy (nominally 0.05 arc sec/10 h, up to 0.02 arc sec). The excellent tracking accuracy and stability on extended objects and features is provided by a novel real-time on-board image correlation scheme. The Planetenteleskop has been studied in prephase A and phase A by industry and the involved science community in Germany in cooperation with American colleagues.
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da Silva, José Roberto Cândido, and Gefeson Mendes Pacheco. "An Extended Methodology for Sizing Solar Unmanned Aerial Vehicles: Theory and Development of a Python Framework for Design Assist." Sensors 21, no. 22 (November 12, 2021): 7541. http://dx.doi.org/10.3390/s21227541.
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There is a growing interest in using unmanned aerial vehicles (UAVs) in the most diverse application areas from agriculture to remote sensing, that determine the need to project and define mission profiles of the UAVs. In addition, solar photovoltaic energy increases the flight autonomy of this type of aircraft, forming the term Solar UAV. This study proposes an extended methodology for sizing Solar UAVs that take off from a runway. This methodology considers mission parameters such as operating location, altitude, flight speed, flight endurance, and payload to sizing the aircraft parameters, such as wingspan, area of embedded solar cells panels, runway length required for takeoff and landing, battery weight, and the total weight of the aircraft. Using the Python language, we developed a framework to apply the proposed methodology and assist in designing a Solar UAV. With this framework, it was possible to perform a sensitivity analysis of design parameters and constraints. Finally, we performed a simulation of a mission, checking the output parameters.
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A’Hearn, Michael F. "The Deep Impact Project." Highlights of Astronomy 13 (2005): 746–48. http://dx.doi.org/10.1017/s1539299600017007.
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AbstractThe Deep Impact mission aims at understanding the third dimension of a cometary nucleus, the physical and chemical properties as a function of depth below the surface. General wisdom holds that comets, because they are small and spend most of their lives far from the sun, hold primordial ices in their interiors. However, it is universally agreed that the surface layers have evolved, whether from cosmic rays while residing in the Oort cloud or from solar heating during previous perihelion passages. Clearly, in order to interpret surface observations and outgassing, we must understand how the surface layers differ from the interior. Deep Impact is the first mission to carry out a macroscopic experiment on a planetary body since the Apollo program dropped a lunar module on the moon and measured the seismic response.
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Longwe, B., M. Mganga, and N. Sinyiza. "Review of sustainable solar powered water supply system design approach by Water Mission Malawi." Water Practice and Technology 14, no. 4 (November 20, 2019): 749–63. http://dx.doi.org/10.2166/wpt.2019.079.
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Abstract Water Mission's extensive experience in designing, constructing and supporting solar-powered pumping solutions demonstrates the technological viability and cost effectiveness for delivering safe water to people, particularly in rural areas. Water Mission follows a unique design approach that uses conventional but relatively unique engineering specifications in terms of hydraulics, power requirement, water treatment and distribution, having tested them in different geographical environments. Water Mission incorporates a community-managed sustainability model into the design to ensure a longer life span for the project by promoting a well-defined maintenance and sustainability plan. This approach was applied to ten projects in 2015 in Kasungu, Lilongwe and Blantyre districts where installation, monitoring and evaluation were done and subjected to Water Mission's standards for qualification to hand them over to the beneficiary communities at the end of one year post installation. The paper is a review and discussion of the steps that Water Mission follows in its design process to come up with a sustainable project with solar energy. The paper also illustrates the non-compromise stand by Water Mission when it comes to the hand-over criteria for its projects by following and respecting the results of the prescribed evaluation test. It highlights detailed advantages and disadvantages of the design approach and presents recommendations. It is concluded that the approach can be replicated elsewhere in Malawi as a solution to water supply.
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Lindegren, Lennart. "Gaia: Astrometric performance and current status of the project." Proceedings of the International Astronomical Union 5, S261 (April 2009): 296–305. http://dx.doi.org/10.1017/s1743921309990548.
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AbstractThe scientific objectives of the Gaia mission cover areas of galactic structure and evolution, stellar astrophysics, exoplanets, solar system physics, and fundamental physics. Astrometrically, its main contribution will be the determination of millions of absolute stellar parallaxes and the establishment of a very accurate, dense and faint non-rotating optical reference frame. With a planned launch in spring 2012, the project is in its advanced implementation phase. In parallel, preparations for the scientific data processing are well under way within the Gaia Data Processing and Analysis Consortium. Final mission results are expected around 2021, but early releases of preliminary data are expected. This review summarizes the main science goals and overall organisation of the project, the measurement principle and core astrometric solution, and provide an updated overview of the expected astrometric performance.
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Stuhlinger, Ernst. "Future Deep Space Propulsion Systems." International Astronomical Union Colloquium 123 (1990): 355–62. http://dx.doi.org/10.1017/s0252921100077289.
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AbstractAmong several potential future deep space propulsion systems, the two which are closest to realization are selected for closer consideration: solar-electric, and nuclear-electric propulsion. In particular, the paper describes a manned Mars mission using a particle bed reactor and Brayton cycle converter as power source. Technical details of the design and the mission profile of a 4-astronaut expedition to Mars, and a proposed course of action for project implementation are presented.
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Meftah, Mustapha, Luc Damé, Philippe Keckhut, Slimane Bekki, Alain Sarkissian, Alain Hauchecorne, Emmanuel Bertran, et al. "UVSQ-SAT, a Pathfinder CubeSat Mission for Observing Essential Climate Variables." Remote Sensing 12, no. 1 (December 26, 2019): 92. http://dx.doi.org/10.3390/rs12010092.
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The UltraViolet and infrared Sensors at high Quantum efficiency onboard a small SATellite (UVSQ-SAT) mission aims to demonstrate pioneering technologies for broadband measurement of the Earth’s radiation budget (ERB) and solar spectral irradiance (SSI) in the Herzberg continuum (200–242 nm) using high quantum efficiency ultraviolet and infrared sensors. This research and innovation mission has been initiated by the University of Versailles Saint-Quentin-en-Yvelines (UVSQ) with the support of the International Satellite Program in Research and Education (INSPIRE). The motivation of the UVSQ-SAT mission is to experiment miniaturized remote sensing sensors that could be used in the multi-point observation of Essential Climate Variables (ECV) by a small satellite constellation. UVSQ-SAT represents the first step in this ambitious satellite constellation project which is currently under development under the responsibility of the Laboratory Atmospheres, Environments, Space Observations (LATMOS), with the UVSQ-SAT CubeSat launch planned for 2020/2021. The UVSQ-SAT scientific payload consists of twelve miniaturized thermopile-based radiation sensors for monitoring incoming solar radiation and outgoing terrestrial radiation, four photodiodes that benefit from the intrinsic advantages of Ga 2 O 3 alloy-based sensors made by pulsed laser deposition for measuring solar UV spectral irradiance, and a new three-axis accelerometer/gyroscope/compass for satellite attitude estimation. We present here the scientific objectives of the UVSQ-SAT mission along the concepts and properties of the CubeSat platform and its payload. We also present the results of a numerical simulation study on the spatial reconstruction of the Earth’s radiation budget, on a geographical grid of 1 ° × 1 ° degree latitude-longitude, that could be achieved with UVSQ-SAT for different observation periods.
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Zhang, Peng, Naimeng Lu, Chuanrong Li, Lei Ding, Xiaobing Zheng, Xuejun Zhang, Xiuqing Hu, et al. "Development of the Chinese Space-Based Radiometric Benchmark Mission LIBRA." Remote Sensing 12, no. 14 (July 8, 2020): 2179. http://dx.doi.org/10.3390/rs12142179.
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Climate observations and their applications require measurements with high stability and low uncertainty in order to detect and assess climate variability and trends. The difficulty with space-based observations is that it is generally not possible to trace them to standard calibration references when in orbit. In order to overcome this problem, it has been proposed to deploy space-based radiometric reference systems which intercalibrate measurements from multiple satellite platforms. Such reference systems have been strongly recommended by international expert teams. This paper describes the Chinese Space-based Radiometric Benchmark (CSRB) project which has been under development since 2014. The goal of CSRB is to launch a reference-type satellite named LIBRA in around 2025. We present the roadmap for CSRB as well as requirements and specifications for LIBRA. Key technologies of the system include miniature phase-change cells providing fixed-temperature points, a cryogenic absolute radiometer, and a spontaneous parametric down-conversion detector. LIBRA will offer measurements with SI traceability for the outgoing radiation from the Earth and the incoming radiation from the Sun with high spectral resolution. The system will be realized with four payloads, i.e., the Infrared Spectrometer (IRS), the Earth-Moon Imaging Spectrometer (EMIS), the Total Solar Irradiance (TSI), and the Solar spectral Irradiance Traceable to Quantum benchmark (SITQ). An on-orbit mode for radiometric calibration traceability and a balloon-based demonstration system for LIBRA are introduced as well in the last part of this paper. As a complementary project to the Climate Absolute Radiance and Refractivity Observatory (CLARREO) and the Traceable Radiometry Underpinning Terrestrial- and Helio- Studies (TRUTHS), LIBRA is expected to join the Earth observation satellite constellation and intends to contribute to space-based climate studies via publicly available data.
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Lindegren, L., C. Babusiaux, C. Bailer-Jones, U. Bastian, A. G. A. Brown, M. Cropper, E. Høg, et al. "The Gaia mission: science, organization and present status." Proceedings of the International Astronomical Union 3, S248 (October 2007): 217–23. http://dx.doi.org/10.1017/s1743921308019133.
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AbstractThe ESA space astrometry mission Gaia will measure the positions, parallaxes and proper motions of the 1 billion brightest stars on the sky. Expected accuracies are in the 7–25 μas range down to 15 mag and sub-mas accuracies at the faint limit (20 mag). The astrometric data are complemented by low-resolution spectrophotometric data in the 330–1000 nm wavelength range and, for the brighter stars, radial velocity measurements. The scientific case covers an extremely wide range of topics in galactic and stellar astrophysics, solar system and exoplanet science, as well as the establishment of a very accurate, dense and faint optical reference frame. With a planned launch around 2012 and an (extended) operational lifetime of 6 years, final results are expected around 2021. We give a brief overview of the science goals of Gaia, the overall project organisation, expected performance, and some key technical features and challenges.
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Escoubet, C. P., M. Fehringer, and M. Goldstein. "<i>Introduction</i>The Cluster mission." Annales Geophysicae 19, no. 10/12 (September 30, 2001): 1197–200. http://dx.doi.org/10.5194/angeo-19-1197-2001.
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Abstract. The Cluster mission, ESA’s first cornerstone project, together with the SOHO mission, dating back to the first proposals in 1982, was finally launched in the summer of 2000. On 16 July and 9 August, respectively, two Russian Soyuz rockets blasted off from the Russian cosmodrome in Baikonour to deliver two Cluster spacecraft, each into their proper orbit. By the end of August 2000, the four Cluster satellites had reached their final tetrahedral constellation. The commissioning of 44 instruments, both individually and as an ensemble of complementary tools, was completed five months later to ensure the optimal use of their combined observational potential. On 1 February 2001, the mission was declared operational. The main goal of the Cluster mission is to study the small-scale plasma structures in three dimensions in key plasma regions, such as the solar wind, bow shock, magnetopause, polar cusps, magnetotail and the auroral zones. With its unique capabilities of three-dimensional spatial resolution, Cluster plays a major role in the International Solar Terrestrial Program (ISTP), where Cluster and the Solar and Heliospheric Observatory (SOHO) are the European contributions. Cluster’s payload consists of state-of-the-art plasma instrumentation to measure electric and magnetic fields from the quasi-static up to high frequencies, and electron and ion distribution functions from energies of nearly 0 eV to a few MeV. The science operations are coordinated by the Joint Science Operations Centre (JSOC), at the Rutherford Appleton Laboratory (UK), and implemented by the European Space Operations Centre (ESOC), in Darmstadt, Germany. A network of eight national data centres has been set up for raw data processing, for the production of physical parameters, and their distribution to end users all over the world. The latest information on the Cluster mission can be found at http://sci.esa.int/cluster/.
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Suresh, R. "Design And Anayisis Of Lander Cum Rover For Mars Mission." Journal of University of Shanghai for Science and Technology 24, no. 02 (February 19, 2022): 273–90. http://dx.doi.org/10.51201/jusst/22/0236.
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For the past two decades, Mars, the closest planet to the Earth in the solar system, has been investigated for its climate, thermal state, and resources. Space landers are vessels that assist in the landing of the rover that is used to investigate Mars. The design, modelling, soft landing, planet atmosphere analysis, and prototype of a 2-in-1 lander and rover used to explore Mars were all utilized in this project. Ion thrusters which are our radio frequency (RIT) to produce thrust are used for orbital insertion. Because Mars has an atmosphere and gravity, we can use RC motors as a hovering mechanism to study the planet’s environment. CATIA V5 is used to design the 2-in-1 lander rover, Ion thruster, and hovering system, while ANSYS is used to analyse the static, thermal, and flow results of the model. From this analysis, we can find whether the designed model can sustain mars’ atmospheric condition and thermal condition. MATLAB is being used to simulate a soft landing and space exploration. Many sensors are utilized to investigate Mars and determine weather and temperature conditions. The whole operating and performance of the two-in-one lander and rover is estimated in this project.
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Ali, Essam, Mohamed Fanni, and Abdelfatah M. Mohamed. "A New Battery Selection System and Charging Control of a Movable Solar-Powered Charging Station for Endless Flying Killing Drones." Sustainability 14, no. 4 (February 11, 2022): 2071. http://dx.doi.org/10.3390/su14042071.
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This paper provides a design, a charging control, and energy management of a movable Photo Voltaic (PV) charging station with an Automatic Battery Replacement (ABR) system to enable drones for ongoing missions. The paper represents the first stage of a three-staged project titled Fall Armyworm (FAW) insect killer. The other two stages involve the flight control of drones and detecting and killing FAW insects. Without chemical methods, the project aims to eliminate harmful FAW insects that are rapidly spreading in Africa and Asia. The power source is a hybrid PV system with energy storage devices (batteries and supercapacitors). The maximum power from PV panels is tracked using three different online methods (PSO, IC, and P&O), and the best method with the highest accuracy is selected. The experimental and simulation results approved that PSO is the recommended method used in this project among the studied methods because of its high target reach (about 97%) and low steady-state oscillation (maximum 2.15%). An intelligent energy management system is investigated and designed to efficiently utilize solar power with a constant-current constant-voltage charger for LiPo batteries. A new Battery Selection System (BSS) is designed and verified to efficiently utilize the harvested energy and increase the mission time. The BSS targets to manage the selection of the appropriate battery to charge and control its charging rate. The system performance is tested using MATLAB software. Then, an experimental setup for the system is built to validate simulation results. The results of simulations and experiments proved the reliability of BSS in different operating cases with an efficiency higher than 97%.
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do Nascimento, Clair, and Tadashi Yokoyama. "Variation of the Equator due to a Highly Inclined and Eccentric Disturber." Mathematical Problems in Engineering 2009 (2009): 1–10. http://dx.doi.org/10.1155/2009/467865.
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The New Horizons project is currently in progress, but until recently years ago, a mission to Neptune-Triton System predicted in the mid term 2008–2013 was one of the priorities of NASA's Solar System Exploration theme. Any way, it is important to increase our knowledge on the dynamics of the inner satellites of Neptune, since according to some authors, this was a key question in the mission to Neptune-Triton system. In a previous work, we presented the expansion of the disturbing function for the dynamics of this system. Here we derive the averaged classical equations of the precession of the equator for this problem. The highly inclined and retrograde orbit of Triton makes this problem very unusual. Therefore, the classical truncations in the inclinations are not acceptable, so that the precession equations must be obtained in closed form for the inclination. With a significant mass and due to its distance from Neptune, which is continuously decreasing, Triton should exert in the future, important precession on Neptune's equator. The effects of this precession on the inner satellites are shown, including some resonant cases predicted in the future. Although Triton's orbit is almost circular, no expansion in the eccentricity is needed.
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Scaioni, M., P. Giommi, M. T. Brunetti, C. Carli, P. Cerroni, G. Cremonese, G. Forlani, et al. "THE ‘MOON MAPPING’ PROJECT TO PROMOTE COOPERATION BETWEEN STUDENTS OF ITALY AND CHINA." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B6 (June 17, 2016): 71–78. http://dx.doi.org/10.5194/isprs-archives-xli-b6-71-2016.
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The research project ‘Moon Mapping’ has been established in 2014 between the Italian and Chinese Governments to promote cooperation and exchange between undergraduate students from both countries. The operational phase of the project started in early 2015, and will end in 2017, for a total length of three years. The main aim is to train new scholars to be able to work on different kinds of remotely-sensed data collected over the Moon surface by the Chinese space missions Chang’E-1/2. The project coordination has been assigned to the Italian Space Agency for the Italian side and to the Center of Space Exploration, China Ministry of Education, for the Chinese side. Several Chinese universities and Italian national research institutes and universities have been officially involved in this project. Six main research topics have been identified: (1) map of the solar wind ion; (2) geomorphological map of the Moon; (3) data preprocessing of Chang’E-1 mission; (4) map of element distribution; (5) establishment of 3D digital visualization system; and (6) compilation and publication of a tutorial on joint lunar mapping.
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Scaioni, M., P. Giommi, M. T. Brunetti, C. Carli, P. Cerroni, G. Cremonese, G. Forlani, et al. "THE ‘MOON MAPPING’ PROJECT TO PROMOTE COOPERATION BETWEEN STUDENTS OF ITALY AND CHINA." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B6 (June 17, 2016): 71–78. http://dx.doi.org/10.5194/isprsarchives-xli-b6-71-2016.
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The research project ‘Moon Mapping’ has been established in 2014 between the Italian and Chinese Governments to promote cooperation and exchange between undergraduate students from both countries. The operational phase of the project started in early 2015, and will end in 2017, for a total length of three years. The main aim is to train new scholars to be able to work on different kinds of remotely-sensed data collected over the Moon surface by the Chinese space missions Chang’E-1/2. The project coordination has been assigned to the Italian Space Agency for the Italian side and to the Center of Space Exploration, China Ministry of Education, for the Chinese side. Several Chinese universities and Italian national research institutes and universities have been officially involved in this project. Six main research topics have been identified: (1) map of the solar wind ion; (2) geomorphological map of the Moon; (3) data preprocessing of Chang’E-1 mission; (4) map of element distribution; (5) establishment of 3D digital visualization system; and (6) compilation and publication of a tutorial on joint lunar mapping.
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Vauclair, S. "Helioseismic Constraints on the Solar Structure: Evidences of Element Segregation and Mild Mixing Below the Convection Zone." Symposium - International Astronomical Union 185 (1998): 135–40. http://dx.doi.org/10.1017/s007418090023845x.
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The study of the internal structure of the Sun entered a new age with helioseismology. Several ground based networks, as well as the space mission SoHO, continuously observe the solar oscillations. In particular GONG, the “Global Oscillation Network Project”, gathers six sites around the world with six identical Doppler instruments. These instruments observe the phase shift of the Ni 676.8nm line with 3 images every minute, 1.8 sites observing simultaneously. Millions of solar p-modes have been detected. The inversion of the measured frequencies yields accurate and detailed information about the sound velocity in the Sun's interior, which in turn leads to constraints on the equation of state, opacities, chemical composition. Precise informations on the differential rotation inside the Sun have also been obtained. (See the special Science issue on GONG, vol 272, 31 May 1996).
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Kay, W. D. "Where No Nation Has Gone Before: Domestic Politics and the First International Space Science Mission." Journal of Policy History 5, no. 4 (October 1993): 435–52. http://dx.doi.org/10.1017/s0898030600007545.
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The history of the U.S. space program can be rather neatly divided into two distinct periods. The first, which begins with the launch of Sputnik in 1957 and runs through the end of Project Apollo in 1972, is sometimes referred to as the “golden age” of space exploration. This period was characterized not only by its impressive scientific and technical successes but also by the fact that it possessed a highly supportive social, economic, and political environment. Buoyed by fears and rumors of Soviet achievements in space, the National Aeronautics and Space Administration (NASA) of the 1950s and 1960s usually had little trouble securing an annual budget sufficient to maintain an ambitious set of projects (both manned and unmanned) that stretched from near-earth orbit to the outer reaches of the solar system.
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Wedler, Armin, Martin J. Schuster, Marcus G. Müller, Bernhard Vodermayer, Lukas Meyer, Riccardo Giubilato, Mallikarjuna Vayugundla, et al. "German Aerospace Center's advanced robotic technology for future lunar scientific missions." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 379, no. 2188 (November 23, 2020): 20190574. http://dx.doi.org/10.1098/rsta.2019.0574.
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The Earth's moon is currently an object of interest of many space agencies for unmanned robotic missions within this decade. Besides future prospects for building lunar gateways as support to human space flight, the Moon is an attractive location for scientific purposes. Not only will its study give insight on the foundations of the Solar System but also its location, uncontaminated by the Earth's ionosphere, represents a vantage point for the observation of the Sun and planetary bodies outside the Solar System. Lunar exploration has been traditionally conducted by means of single-agent robotic assets, which is a limiting factor for the return of scientific missions. The German Aerospace Center (DLR) is developing fundamental technologies towards increased autonomy of robotic explorers to fulfil more complex mission tasks through cooperation. This paper presents an overview of past, present and future activities of DLR towards highly autonomous systems for scientific missions targeting the Moon and other planetary bodies. The heritage from the Mobile Asteroid Scout (MASCOT), developed jointly by DLR and CNES and deployed on asteroid Ryugu on 3 October 2018 from JAXA's Hayabusa2 spacecraft, inspired the development of novel core technologies towards higher efficiency in planetary exploration. Together with the lessons learnt from the ROBEX project (2012–2017), where a mobile robot autonomously deployed seismic sensors at a Moon analogue site, this experience is shaping the future steps towards more complex space missions. They include the development of a mobile rover for JAXA's Martian Moons eXploration (MMX) in 2024 as well as demonstrations of novel multi-robot technologies at a Moon analogue site on the volcano Mt Etna in the ARCHES project. Within ARCHES, a demonstration mission is planned from the 14 June to 10 July 2021, 1 during which heterogeneous teams of robots will autonomously conduct geological and mineralogical analysis experiments and deploy an array of low-frequency antennas to measure Jovian and solar bursts. This article is part of a discussion meeting issue ‘Astronomy from the Moon: the next decades'.
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Sreesawet, Suwat, Seksan Jaturat, and Sittiporn Channamsin. "Orbit Design for Thai Space Consortium Satellite." Proceedings 39, no. 1 (December 27, 2019): 1. http://dx.doi.org/10.3390/proceedings2019039001.
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Currently, Geo-Informatics and Space Technology Development Agency (GISTDA), National Astronomical Research Institute of Thailand (NARIT) and Synchrotron Light Research Institute (SLRI) have a co-operation on a project of developing a satellite for scientific research called Thai Space Consortium (TSC). The project is aiming at Earth remote sensing mission by a small satellite about 100 kg. The main payload of the satellite is an optical instrument with the secondary payload of energetic particle detector for space weather. The satellite is designed to be in a Sun Synchronous orbit due to requirement of same light condition throughout the operational lifetime. In the meantime, there is another project by GISTDA named THEOS-2. This project consists of two remote-sensing satellites, THEOS-2 MainSAT and THEOS-2 SmallSAT, under the development in Europe. The SmallSAT does not have the propulsion subsystem. So it cannot perform station-keeping maneuvers or maintain constellation with others. Therefore, in this paper, we analyze two scenarios that the TSC satellite flies as constellations with the MainSAT of THEOS2 project. The constellation is in the sense that the TSC satellite flies on the same ground track path with the MainSAT satellite with slightly differences in local solar time. The ground track sequencing is presented with a methodology for obtaining orbital parameters with a discussion on accuracy relating to Keplerian assumption.
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Céspedes, Jorge Enrique Salamanca, and Roberto Ferro Escobar. "Diseño e Implementacion de un Modulo de Gestion de Energia para un Pico-Satelite Tipo Cubesat." KnE Engineering 3, no. 1 (February 11, 2018): 913. http://dx.doi.org/10.18502/keg.v3i1.1512.
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This article briefly describes the development of Power Module for Experimental picosatellite CubeSat UD Colombia 1 following CubeSat standard requirements. Whether the Power Module project consists of four stages of development: study, design, implementation and testing. In the study phase to review the theoretical framework and preliminary designs made in the Universidad Distrital and other CubeSat developed in the world, also investigates existing components and technologies in the market. The design phase involves analysis of the system and using a computer program designed to generate the necessary hardware. The implementation consists in making the printed circuit board and the component assembly. And electrical type tests to certify the proper operation of the module. The development of the power module of the CubeSat standard requirements and mission picosatellite, and depends on the state and information available from other modules picosatellite. The ultimate goal is to obtain a power module that is functional and working conditions of the space environment in which the picosatellite fulfill its focused on telemedicine, with a payload that would become the telecommunications system mission. Keywords: Power Module, CubeSat UD Colombia 1, Standard CubeSat, DC-DC converters, Solar Panels, Batteries, Power Management.
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Chesley, Steve, Daniela Lazzaro, Andrea Milani, Yoshikawa Makoto, Shinsuke Abe, Alan Gilmore, Mikael Granvik, et al. "TRIENNIAL REPORT." Proceedings of the International Astronomical Union 11, T29A (August 2015): 340–64. http://dx.doi.org/10.1017/s1743921316000831.
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This triennium has seen progress in a number of directions related to Commission 20 objectives. Foremost, the growth in the number of astrometric observations of small solar system bodies continues to accelerate and the total number of measurements recorded by the Minor Planet Center now exceeds 135 million. Currently the Pan-STARRS project and the Catalina Sky Survey (CSS) dominate detection and discovery efforts, while the NEO-WISE space mission contributes infrared detections valuable for understanding the size distribution of populations. Looking forward, the Large Synoptic Survey Telescope (LSST) is now funded and in construction on Cerro Pachon in Chile. LSST has the potential to revolutionize the field by conducting a multi-color, ten-year, all-sky survey with a limiting magnitude ~24.5 in the r-band. Survey operations are set to begin in 2022.
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Castelli, C., R. Hagood, H. Mapson-Menard, and B. Winter. "The Carbon Fibre Structure for the Extreme Ultraviolet Imaging Spectrometer on the Solar-B Satellite." Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 219, no. 3 (July 1, 2005): 177–86. http://dx.doi.org/10.1243/146442005x10373.
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The Extreme Ultraviolet Imaging Spectrometer (EIS) is a core instrument on the Japanese Solar-B mission and is due for launch in the summer of 2006. EIS is a 3.2 m long telescope employing grating optics and a pair of charge coupled device imaging cameras working in the extreme ultraviolet (EUV) region in two separate wavelength bands between 170-210 and 240-290 Å. To house all the telescope subsystems, a novel carbon fibre reinforced plastic structure was developed in collaboration with McLaren Composites Limited (UK) to meet a set of the demanding performance requirements in terms of dimensional stability, rigidity, and structural cleanliness as well as being able to survive the harsh launch environment of the Japanese M-V rocket. The final design was based on a honeycomb panel structure using stiff carbon fibre laminates. This case study describes some of the design challenges that were overcome for this project to produce the engineering, mechanical, and thermal models. Particular attention is given to the cleanliness control strategy to preserve the EUV optical throughput, the method of attachment to the spacecraft, and of optical subsystems as well as the instrument thermal design.
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Swartz, William, Steven Lorentz, Stergios Papadakis, Philip Huang, Allan Smith, David Deglau, Yinan Yu, Sonia Reilly, Nolan Reilly, and Donald Anderson. "RAVAN: CubeSat Demonstration for Multi-Point Earth Radiation Budget Measurements." Remote Sensing 11, no. 7 (April 3, 2019): 796. http://dx.doi.org/10.3390/rs11070796.
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The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) 3U CubeSat mission is a pathfinder to demonstrate technologies for the measurement of Earth’s radiation budget, the quantification of which is critical for predicting the future course of climate change. A specific motivation is the need for lower-cost technology alternatives that could be used for multi-point constellation measurements of Earth outgoing radiation. RAVAN launched 11 November 2016, into a nearly 600-km, Sun-synchronous orbit, and collected data for over 20 months. RAVAN successfully demonstrates two key technologies. The first is the use of vertically aligned carbon nanotubes (VACNTs) as absorbers in broadband radiometers for measuring Earth’s outgoing radiation and the total solar irradiance. VACNT forests are arguably the blackest material known and have an extremely flat spectral response over a wide wavelength range, from the ultraviolet to the far infrared. As radiometer absorbers, they have greater sensitivity for a given time constant and are more compact than traditional cavity absorbers. The second technology demonstrated is a pair of gallium phase-change black body cells that are used as a stable reference to monitor the degradation of RAVAN’s radiometer sensors on orbit. Four radiometers (two VACNT, two cavity), the pair of gallium black bodies, and associated electronics are accommodated in the payload of an agile 3U CubeSat bus that allows for routine solar and deep-space attitude maneuvers, which are essential for calibrating the Earth irradiance measurements. The radiometers show excellent long-term stability over the course of the mission and a high correlation between the VACNT and cavity radiometer technologies. Short-term variability—at greater than the tenths-of-a-Watt/m2 needed for climate accuracy—is a challenge that remains, consistent with insufficient thermal knowledge and control on a 3U CubeSat. There are also VACNT–cavity biases of 3% and 6% in the Total and SW channels, respectively, which would have to be overcome in a future mission. Although one of the black bodies failed after four months, the other provided a repeatable standard for the duration of the project. We present representative measurements from the mission and demonstrate how the radiometer time series can be used to reconstruct outgoing radiation spatial information. Improvements to the technology and approach that would lead to better performance and greater accuracy in future missions are discussed.
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Harasani, W., M. Khalid, N. Arai, K. Fukuda, and K. Hiraoka. "Initial conceptual design and wing aerodynamic analysis of a solar power-based UAV." Aeronautical Journal 118, no. 1203 (May 2014): 540–54. http://dx.doi.org/10.1017/s0001924000009350.
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Abstract King Abdul Aziz University of Saudi Arabia (KAU) and Tokai University in Japan have collaborated to design and manufacture a solar powered unmanned air vehicle (UAV), Sun Falcon, which has capability of continuous one day fight with intended design extension towards night flight. The project is a student-driven endeavour involving some 30 students. Both universities are equally involved in the actual design studies of the performance characteristics, aerodynamic design, propulsion and structural analysis. Tokai University is in charge of the actual on-site supervision and examination of on-going manufacturing processes and ultimate fabrication of the prototype model. The conceptual design of the Sun Falcon was meticulously worked out in consideration of the operational mission, which included such flight characteristics as the cruising velocity, flight altitude, payload, flight time, rate of climb, power requirements and so on. The weather condition patterns in Saudi Arabia, which remained fairly supportive of the solar cell performance, were also deemed crucial in the design process. However, the design of a solar plane had other challenges in terms of power unit accommodation and payload consideration in comparison to other conventional UAVs. In this paper, an outline of the design features of the Sun Falcon is presented and other notable design features particular to solar UAVs are discussed. It was learnt in this exercise that the selection of the base aerofoil is perhaps one of the most important design items, as the Reynolds number for such UAVs understandably drops notably lower than conventional aeroplanes and such features as the camber curvature and wing area must cater for the installation of solar panels whose size, strength and quantity must respect local weather conditions. For the Sun Falcon, the actual design process examined two candidate aerofoils FX74-CL5-140 (FX74) and SD7037-092-88(SD7037) both of which were abundantly suitable for furnishing the required aerodynamic characteristics. SD7037 was ultimately chosen as it provided the best geometry and camber line in terms of accommodation and placement of the solar panels. Further scrutiny demonstrated that this latter aerofoil provided better take-off performance and superior L/D behaviour under cruise conditions. In order to check out the aerodynamic performance in general and overall stability and control characteristics, a preflight test under battery power (a 2,500 mAh li-po 4-cell 14·8v) was achieved on 4 June 2013. Other solar powered based tests are currently under way at present.
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Boakes, P. D., R. Nakamura, M. Volwerk, and S. E. Milan. "ECLAT Cluster Spacecraft Magnetotail Plasma Region Identifications (2001–2009)." Dataset Papers in Science 2014 (August 12, 2014): 1–13. http://dx.doi.org/10.1155/2014/684305.
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The European Space Agency’s four-spacecraft Cluster mission has been observing the Earth’s dynamical magnetotail region since early 2001. The magnetotail, and in particular the hot trapped plasma sheet, is a critical region in the coupled Sun-Earth system. Changes in the solar wind have direct influence on the properties and dynamical processes occurring in this region, which in turn directly influence operational near-Earth space, the upper atmosphere, and even induce large-scale currents in the ground. As part of the European Cluster Assimilation Technology (ECLAT) project, a magnetotail plasma region dataset has been produced to facilitate magnetospheric research and further our understanding of the important processes linking the solar wind-magnetospheric-ionospheric system. The dataset consists of a comprehensive list of plasma regions encountered in the nightside magnetosphere of the Earth by each of the four Cluster spacecraft in the years 2001–2009. The regions identified are those where major energy transport/conversion processes take place and are important regions for system level science. Characteristic averaged parameters describing the behavior of each region are provided for further understanding. The dataset facilitates the use of the large repository of Cluster data by the wider scientific community.
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Schneider, Andreas, Tobias Borsdorff, Joost aan de Brugh, Haili Hu, and Jochen Landgraf. "A full-mission data set of H<sub>2</sub>O and HDO columns from SCIAMACHY 2.3 µm reflectance measurements." Atmospheric Measurement Techniques 11, no. 6 (June 12, 2018): 3339–50. http://dx.doi.org/10.5194/amt-11-3339-2018.
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Abstract. A new data set of vertical column densities of the water vapour isotopologues H2O and HDO from the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) instrument for the whole of the mission period from January 2003 to April 2012 is presented. The data are retrieved from reflectance measurements in the spectral range 2339 to 2383 nm with the Shortwave Infrared CO Retrieval (SICOR) algorithm, ignoring atmospheric light scattering in the measurement simulation. The retrievals are validated with ground-based Fourier transform infrared measurements obtained within the Multi-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water (MUSICA) project. A good agreement for low-altitude stations is found with an average bias of −3.6×1021 for H2O and −1.0×1018 molec cm−2 for HDO. The a posteriori computed δD shows an average bias of −8 ‰, even though polar stations have a larger negative bias. The latter is due to the large amount of sensor noise in SCIAMACHY in combination with low albedo and high solar zenith angles. To demonstrate the benefit of accounting for light scattering in the retrieval, the quality of the data product fitting effective cloud parameters simultaneously with trace gas columns is evaluated in a dedicated case study for measurements round high-altitude stations. Due to a large altitude difference between the satellite ground pixel and the mountain station, clear-sky scenes yield a large bias, resulting in a δD bias of 125 ‰. When selecting scenes with optically thick clouds within 1000 m above or below the station altitude, the bias in a posteriori δD is reduced from 125 to 44 ‰. The insights from the present study will also benefit the analysis of the data from the new Sentinel-5 Precursor mission.
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Shestov, S. V., A. N. Zhukov, B. Inhester, L. Dolla, and M. Mierla. "Expected performances of the PROBA-3/ASPIICS solar coronagraph: Simulated data." Astronomy & Astrophysics 652 (July 30, 2021): A4. http://dx.doi.org/10.1051/0004-6361/202140467.
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Context. The Association of Spacecraft for Polarimetric and Imaging Investigation of the Corona of the Sun (ASPIICS) is a novel externally occulted solar coronagraph that will be launched on board the Project for On-Board Autonomy (PROBA-3) mission in 2023. The external occulter will be placed on the first satellite ∼150 m ahead of the second satellite, which will carry an optical instrument. During 6 hours per orbit, the satellites will fly in a precise formation and will constitute a giant externally occulted coronagraph. The large distance between the external occulter and the primary objective will allow observations of the white-light solar corona starting from extremely low heights of ∼1.1 R⊙. Aims. Developing and testing of algorithms for the scientific image processing requires understanding of all the optics-related and detector-related effects of the coronagraph, development of appropriate physical and numerical models, and preparation of simulated images that include all these effects. At the same time, an analysis of the simulated data gives valuable information about the performance of the instrument, the suitable observation regime, and the amount of telemetry. Methods. We used available physical models of the instrument and implemented them as a software to generate simulated data. We analyzed intermediate and complete simulated images to obtain a better understanding of the performance of ASPIICS, in particular, to predict its photometric sensitivity, effect of noise, suitable exposure times, etc. Results. The proposed models and algorithms are used not only to create the simulated data, but also to form the basis for the scientific processing algorithms to be applied during on-ground ASPIICS data processing. We discuss the possible effect of noise and the uncertainty of the calibration factors on the accuracy of final data, and propose suitable exposure times.
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Schmidtke, G., Ch Jacobi, B. Nikutowski, and Ch Erhardt. "Extreme ultraviolet (EUV) solar spectral irradiance (SSI) for ionospheric application – history and contemporary state-of-art." Advances in Radio Science 12 (November 11, 2014): 251–60. http://dx.doi.org/10.5194/ars-12-251-2014.
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Abstract. After a historical survey of space related EUV measurements in Germany and the role of Karl Rawer in pursuing this work, we describe present developments in EUV spectroscopy and provide a brief outlook on future activities. The group of Karl Rawer has performed the first scientific space project in Western Europe on 19th October 1954. Then it was decided to include the field of solar EUV spectroscopy in ionospheric investigations. Starting in 1957 an intensified development of instrumentation was going on to explore solar EUV radiation, atmospheric airglow and auroral emissions until the institute had to stop space activities in the early nineteen-eighties. EUV spectroscopy was continued outside of the institute during eight years. This area of work was supported again by the institute developing the Auto-Calibrating Spectrometers (SolACES) for a mission on the International Space Station (ISS). After more than six years in space the instrument is still in operation. Meanwhile the work on the primary task also to validate EUV data available from other space missions has made good progress. The first results of validating those data and combine them into one set of EUV solar spectral irradiance are very promising. It will be recommended for using it by the science and application community. Moreover, a new low-cost type of an EUV spectrometer is presented for monitoring the solar EUV radiation. It shall be further developed for providing EUV-TEC data to be applied in ionospheric models replacing the Covington index F10.7. Applying these data for example in the GNSS signal evaluation a more accurate determination of GNSS receiver positions is expected for correcting the propagation delays of navigation signals traveling through the ionosphere from space to earth. – Latest results in the field of solar EUV spectroscopy are discussed, too.
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Yano, Hajime. "Future Small Body Exploration after the Investigation of Asteroid Itokawa by Remote Sensing and Returned Sample Analyses." Proceedings of the International Astronomical Union 10, H16 (August 2012): 152. http://dx.doi.org/10.1017/s1743921314005080.
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AbstractThis paper outlines current achievements of the Hayabusa mission and future small body missions with an emphasis on scientific prospects by both remote sensing in the vicinity of target objects and retuned sample analyses of them. First, the Hayabusa spacecraft aimed as technology demonstration for the worldfs first deep space round trip and sample return from an asteroid and it was launched via the M-V rocket in May of 2003. Soon after the touchdown on Asteroid Itokawa, a sub-km, S-type NEO in November 2005, the spacecraft lost its attitude control due to the leak of RCS propellant; the communication link was lost for 46 days. While the ion engine thrusters reached their lifetime by November of 2009 owing to either of an ion source or neutralizers at each engine, a challenging combination of the neutralizer-A with the ion source-B was devised to resume the spacecraftfs propulsion. This enabled the spacecraft to have returned to the Australian desert on the Earth in June 2010. The sample return capsule (SRC) was successfully recovered and returned to Japan for initial inspection of the Itokawa samples. After the announcement of initial sample analysis results, international announcement of sample distributions has started in the spring of 2012. Following up the original Hayabusa mission, JAXA has approved the Hayabusa-2 project in 2011, an asteroid sample return mission to 1999 JU3, a sub-km, C-type NEO aiming for 2014-5 launch, 2018-9 remote sensing including artificial impactor excavation and 2020 Earth return of both surface and sub-surface samples of the asteroid. C-type asteroid is thought to be abundant in organic matters and hydrated compound, so it has important clues to solve the origin and evolution of the life. NASAfs OSIRIS-Rex and ESAfs Marco Polo-R missions are also carbonaceous asteroid sample return missions in 2010fs-2020fs. Cometary nucleus or/and D-type asteroid sample returns like Hayabusa-Mk-II concept are natural progression of this type of the endeavor. JAXAfs solar power sail mission aims for eventual rendezvous with Jovian Trojan asteroids, reservoir of D/P-type asteroids as either leftovers of Jupiter system formation or the second generation intruders from the Kuiper belt regions.
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Anthony Thomas, Digina Derose, Sahaya Cyril, and Smita Dange. "Intelligent Lunar Landing Site Recommender." International Journal of Engineering and Management Research 11, no. 2 (April 30, 2021): 184–88. http://dx.doi.org/10.31033/ijemr.11.2.26.
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Space exploration is brewing to be one of the most sought after fields in today’s world with each country pooling in resources and skilled minds to be one step ahead of the other. The core aspect of space exploration is exoplanet exploration, i.e., by sending unmanned rovers or manned spaceships to planets and celestial bodies within and beyond our solar system to determine habitable planets. Landscape inspection and traversal is the core feature of any planetary exploration mission. It is often a strenuous task to carry out a machine learning experiment on an extraterrestrial surface like the Moon. Consequent lunar explorations undertaken by various space agencies in the last four decades have helped to analyze the nature of the Lunar Terrain through satellite images. The motion of the rovers has traditionally been governed by the use of sensors that achieve obstacle avoidance. In this project we aim to detect craters on the lunar landscape which in turn will be used to determine soft landing sites on the lunar landscape for exploring the terrain, based on the classified lunar landscape images.
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Courtin, Régis, Melissa A. McGrath, Guy J. Consolmagno, Carlo Blanco, Leonid V. Ksanfomality, Luisa M. Lara, David Morrison, John R. Spencer, and Victor G. Tejfel. "COMMISSION 16: PHYSICAL STUDY OF PLANETS AND SATELLITES." Proceedings of the International Astronomical Union 4, T27A (December 2008): 163–68. http://dx.doi.org/10.1017/s1743921308025416.
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This report is divided in four parts: the first part summarizes the activities of the Commission between September 2006 and June 2008; the second part reports on recent advances in the physical study of planets and satellites. However, instead of attempting to cover the large body of new knowledge gathered over the last three years, we have chosen to highlight just a few exciting results – on Mercury, the exploration of unchartered terrains with ground-based imaging and a new measurement of its libration parameters, some spectacular findings from the Cassini mission inside the Saturnian system, and the results of methane-band spectrophotometric monitoring of Saturn over the last 13 years; the third part summarizes future plans now being drawn by the various space agencies for the exploration of planets and satellites in the solar system; the last part tries to project the activities of the Commission over the period June 2008–August 2009, and to express a few thoughts concerning the future developments in the field, and the role of the Commission therein.
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Hill, Frank. "Networks for Helioseismic Observations." International Astronomical Union Colloquium 121 (1990): 265–78. http://dx.doi.org/10.1017/s0252921100067993.
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AbstractHelioseismology from a single ground-based observatory is severely compromised by the diurnal rising and setting of the Sun. This causes sidelobes to appear in the helioseismic power spectrum at multiples of ± 11.57 μHz from each solar line, contaminating the spectrum and rendering mode identification and frequency measurement extremely difficult. The difficulty can be overcome in three ways — observing from a fully sunlit orbit in space, observing from the Polar regions, or observing with a network of stations placed around the Earth. This paper discusses the networks that are either currently in operation or being planned. These include the Global Oscillation Network Group (GONG) project, the Birmingham network, the IRIS network of the University of Nice, and the SCLERA network of the University of Arizona. The scientific objectives and instrumentation of these networks are briefly described. Theoretical predictions for network performance are compared with actual results. The problem of merging simultaneous data from multiple instruments is discussed, as well as the relationship of the networks with the helioseismology experiments on the SOHO space mission.
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Hodgkin, S. T., D. L. Harrison, E. Breedt, T. Wevers, G. Rixon, A. Delgado, A. Yoldas, et al. "Gaia Early Data Release 3." Astronomy & Astrophysics 652 (August 2021): A76. http://dx.doi.org/10.1051/0004-6361/202140735.
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Context. Since July 2014, the Gaia mission has been engaged in a high-spatial-resolution, time-resolved, precise, accurate astrometric, and photometric survey of the entire sky. Aims. We present the Gaia Science Alerts project, which has been in operation since 1 June 2016. We describe the system which has been developed to enable the discovery and publication of transient photometric events as seen by Gaia. Methods. We outline the data handling, timings, and performances, and we describe the transient detection algorithms and filtering procedures needed to manage the high false alarm rate. We identify two classes of events: (1) sources which are new to Gaia and (2) Gaia sources which have undergone a significant brightening or fading. Validation of the Gaia transit astrometry and photometry was performed, followed by testing of the source environment to minimise contamination from Solar System objects, bright stars, and fainter near-neighbours. Results. We show that the Gaia Science Alerts project suffers from very low contamination, that is there are very few false-positives. We find that the external completeness for supernovae, CE = 0.46, is dominated by the Gaia scanning law and the requirement of detections from both fields-of-view. Where we have two or more scans the internal completeness is CI = 0.79 at 3 arcsec or larger from the centres of galaxies, but it drops closer in, especially within 1 arcsec. Conclusions. The per-transit photometry for Gaia transients is precise to 1% at G = 13, and 3% at G = 19. The per-transit astrometry is accurate to 55 mas when compared to Gaia DR2. The Gaia Science Alerts project is one of the most homogeneous and productive transient surveys in operation, and it is the only survey which covers the whole sky at high spatial resolution (subarcsecond), including the Galactic plane and bulge.
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Holt, Timothy R., Jonathan Horner, David Nesvorný, Rachel King, Marcel Popescu, Brad D. Carter, and Christopher C. E. Tylor. "Astrocladistics of the Jovian Trojan Swarms." Monthly Notices of the Royal Astronomical Society 504, no. 2 (April 1, 2021): 1571–608. http://dx.doi.org/10.1093/mnras/stab894.
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ABSTRACT The Jovian Trojans are two swarms of small objects that share Jupiter’s orbit, clustered around the leading and trailing Lagrange points, L4 and L5. In this work, we investigate the Jovian Trojan population using the technique of astrocladistics, an adaptation of the ‘tree of life’ approach used in biology. We combine colour data from WISE, SDSS, Gaia DR2, and MOVIS surveys with knowledge of the physical and orbital characteristics of the Trojans, to generate a classification tree composed of clans with distinctive characteristics. We identify 48 clans, indicating groups of objects that possibly share a common origin. Amongst these are several that contain members of the known collisional families, though our work identifies subtleties in that classification that bear future investigation. Our clans are often broken into subclans, and most can be grouped into 10 superclans, reflecting the hierarchical nature of the population. Outcomes from this project include the identification of several high priority objects for additional observations and as well as providing context for the objects to be visited by the forthcoming Lucy mission. Our results demonstrate the ability of astrocladistics to classify multiple large and heterogeneous composite survey data sets into groupings useful for studies of the origins and evolution of our Solar system.
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Yu, Bingkun, Christopher J. Scott, Xianghui Xue, Xinan Yue, and Xiankang Dou. "Derivation of global ionospheric Sporadic E critical frequency ( f o Es) data from the amplitude variations in GPS/GNSS radio occultations." Royal Society Open Science 7, no. 7 (July 2020): 200320. http://dx.doi.org/10.1098/rsos.200320.
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The ionospheric sporadic E (Es) layer has a significant impact on the global positioning system (GPS)/global navigation satellite system (GNSS) signals. These influences on the GPS/GNSS signals can also be used to study the occurrence and characteristics of the Es layer on a global scale. In this paper, 5.8 million radio occultation (RO) profiles from the FORMOSAT-3/COSMIC satellite mission and ground-based observations of Es layers recorded by 25 ionospheric monitoring stations and held at the UK Solar System Data Centre at the Rutherford Appleton Laboratory and the Chinese Meridian Project were used to derive the hourly Es critical frequency ( f o Es) data. The global distribution of f o Es with a high spatial resolution shows a strong seasonal variation in f o Es with a summer maximum exceeding 4.0 MHz and a winter minimum between 2.0 and 2.5 MHz. The GPS/GNSS RO technique is an important tool that can provide global estimates of Es layers, augmenting the limited coverage and low-frequency detection threshold of ground-based instruments. Attention should be paid to small f o Es values from ionosondes near the instrumental detection limits corresponding to minimum frequencies in the range 1.28–1.60 MHz.
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Lima, Maria Andrea, and James W. Wilson. "Convective Storm Initiation in a Moist Tropical Environment." Monthly Weather Review 136, no. 6 (June 1, 2008): 1847–64. http://dx.doi.org/10.1175/2007mwr2279.1.
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Abstract Radar and satellite data from the Tropical Rainfall Measuring Mission–Large-Scale Biosphere–Atmosphere (TRMM–LBA) project have been examined to determine causes for convective storm initiation in the southwest Amazon region. The locations and times of storm initiation were based on the National Center for Atmospheric Research (NCAR) S-band dual-polarization Doppler radar (S-Pol). Both the radar and the Geostationary Operational Environmental Satellite-8 (GOES-8) visible data were used to identify cold pools produced by convective precipitation. These data along with high-resolution topographic data were used to determine possible convective storm triggering mechanisms. The terrain elevation varied from 100 to 600 m. Tropical forests cover the area with numerous clear-cut areas used for cattle grazing and farming. This paper presents the results from 5 February 1999. A total of 315 storms were initiated within 130 km of the S-Pol radar. This day was classified as a weak monsoon regime where convection developed in response to the diurnal cycle of solar heating. Scattered shallow cumulus during the morning developed into deep convection by early afternoon. Storm initiation began about 1100 LST and peaked around 1500–1600 LST. The causes of storm initiation were classified into four categories. The most common initiation mechanism was caused by forced lifting by a gust front (GF; 36%). Forcing by terrain (>300 m) without any other triggering mechanism accounted for 21% of the initiations and colliding GFs accounted for 16%. For the remaining 27% a triggering mechanism was not identified. Examination of all days during TRMM–LBA showed that this one detailed study day was representative of many days. A conceptual model of storm initiation and evolution is presented. The results of this study should have implications for other locations when synoptic-scale forcing mechanisms are at a minimum. These results should also have implications for very short-period forecasting techniques in any location where terrain, GFs, and colliding boundaries influence storm evolution.
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Fang, Cheng. "Past, Present and Future of Chinese Astronomy." Proceedings of the International Astronomical Union 10, H16 (August 2012): 19–29. http://dx.doi.org/10.1017/s1743921314004621.
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AbstractThrough out the ancient history, Chinese astronomers had made tremendous achievements. Since the main purpose of the ancient Chinese astronomy was to study the correlation between man and the universe, all the Emperors made ancient Chinese astronomy the highly regarded science throughout the history. After a brief introduction of the achievement of ancient Chinese astronomy, I describe the beginnings of modern astronomy research in China in the 20th century. Benefiting from the fast development of Chinese economy, the research in astronomy in China has made remarkable progress in recent years. The number of astronomers has doubled in the past ten years, and the number of graduate students has grown over 1300. The current budget for astronomy research is ten times larger than that ten years ago. The research covers all fields in astronomy, from galaxies to the Sun. The recent progress in both the instruments, such as the Guo Shoujing's telescope, a Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST), and the theoretical research will be briefly presented. The ongoing and future projects on the space- and ground-based facilities will be described, including the Five Hundred Meter Aperture Spherical Radio Telescope (FAST), “Chang E” (Lunar mission) project, Hard X-ray Modulate Telescope (HXMT), DArk Matter Particle Explorer (DAMPE), Deep Space Solar Observatory (DSO), Chinese Antarctic Observatory (CAO), 65m steerable radio telescope, Chinese Spectral Radioheliogaph (CSRH) etc.
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Alsadik, Bashar, and Fabio Remondino. "Flight Planning for LiDAR-Based UAS Mapping Applications." ISPRS International Journal of Geo-Information 9, no. 6 (June 8, 2020): 378. http://dx.doi.org/10.3390/ijgi9060378.
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In the last two decades, unmanned aircraft systems (UAS) were successfully used in different environments for diverse applications like territorial mapping, heritage 3D documentation, as built surveys, construction monitoring, solar panel placement and assessment, road inspections, etc. These applications were correlated to the onboard sensors like RGB cameras, multi-spectral cameras, thermal sensors, panoramic cameras, or LiDARs. According to the different onboard sensors, a different mission plan is required to satisfy the characteristics of the sensor and the project aims. For UAS LiDAR-based mapping missions, requirements for the flight planning are different with respect to conventional UAS image-based flight plans because of different reasons related to the LiDAR scanning mechanism, scanning range, output scanning rate, field of view (FOV), rotation speed, etc. Although flight planning for image-based UAS missions is a well-known and solved problem, flight planning for a LiDAR-based UAS mapping is still an open research topic that needs further investigations. The article presents the developments of a LiDAR-based UAS flight planning tool, tested with simulations in real scenarios. The flight planning simulations considered an UAS platform equipped, alternatively, with three low-cost multi-beam LiDARs, namely Quanergy M8, Velodyne VLP-16, and the Ouster OS-1-16. The specific characteristics of the three sensors were used to plan flights and acquired dense point clouds. Comparisons and analyses of the results showed clear relationships between point density, flying speeds, and flying heights.
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Shou, Ho Nien. "Discoid and Asymmetrical Micro-Satellite Propulsion Mode Attitude Control with Great Mass Change and without Angular Rate Sensor." Applied Mechanics and Materials 479-480 (December 2013): 753–57. http://dx.doi.org/10.4028/www.scientific.net/amm.479-480.753.
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The center of mass of the micro-satellite can offset due to fuel consumption in the course of propulsion, with the interference of external orbital environment such as gravity gradient torque and solar radiation torque. If the structural shape is discoid and asymmetrical, the attitude control may be difficult. The only solution is to design a robust controller, so that the attitude pointing of the satellite can meet the mission requirements with the interference of internal parameter perturbation and external disturbance. This study applied the robust control theory control law in the design of Formosat-3 propulsion mode attitude control, and carried out cross validation of the feasibility of the controller by time domain and frequency domain stability analyses. This study used controller as the experimental result. The time domain performance indexes (e.g., rise time, maximum overshoot and stabilization time) of the designed controller were consistent with the robust stability margin of stable performance index of frequency domain. Meanwhile, in order to reduce the weight and manufacturing cost of satellite, in the design of satellite attitude angular rate determination, the project used unscented kalman filter (UKF) algorithm, coarse sun sensor (CSS) and earth horizon sensor (EHS) as measurement components to obtain the satellite attitude without rate gyro. The research method and procedures in this study are applicable to any shaped and asymmetrical satellites with large mass variation and without angular rate sensor. The attitude sensors include three-axis magnetometer, horizon sensor, CSS as the analytic platform for stability of attitude control.
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Lee, Yu-Chi, and Yi-Chi Wang. "Evaluating Diurnal Rainfall Signal Performance from CMIP5 to CMIP6." Journal of Climate 34, no. 18 (September 2021): 7607–23. http://dx.doi.org/10.1175/jcli-d-20-0812.1.
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AbstractThis study provides a comprehensive overview of diurnal rainfall signal performance within the current collection of models in phase 6 of the Coupled Model Intercomparison Project (CMIP6). The results serve as a reference for understanding model physics performance to represent precipitating processes and atmosphere–land–ocean interactions in response to the diurnal solar radiation cycle. Performance metrics are based on the phase, amplitude, and two empirical orthogonal function (EOF) modes of the climatological diurnal rainfall cycle derived from a Tropical Rainfall Measuring Mission observational dataset. We found that the ensemble model biases of diurnal phase and amplitude over lands improved from CMIP5 to CMIP6; however, those over oceans are still highly uncertain among CMIP6 models. Evaluation with observed EOF modes shows that the CMIP6 models are bifurcated based on the second EOF (EOF2), which represents diurnal rainfall contrast of coastal regimes where large biases of phase and amplitude reside. While the model ensemble suggests that models benefit from higher resolution in simulating phase and amplitude biases, the most distinct difference between the bifurcations is that one group successfully captures prevailing nighttime rainfall over tropical islands and coasts, especially over the Maritime Continent. Convective rainfall diagnosed by cumulus parameterization is found to be responsible for such biases. Our results suggest that CMIP6 models have generally been improved in their representation of diurnal rainfall cycles; however, for coastal diurnal regimes, more study is needed to improve the model parameterization of precipitation processes interacting with islands and coastal regions as current model resolution is still too coarse to resolve them.
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Yaodong, Li, Wang Yun, Song Yang, Hu Liang, Gao Shouting, and Rong Fu. "Characteristics of Summer Convective Systems Initiated over the Tibetan Plateau. Part I: Origin, Track, Development, and Precipitation." Journal of Applied Meteorology and Climatology 47, no. 10 (October 1, 2008): 2679–95. http://dx.doi.org/10.1175/2008jamc1695.1.
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Abstract Summer convective systems (CSs) initiated over the Tibetan Plateau identified by the International Satellite Cloud Climatology Project (ISCCP) deep convection database and associated Tropical Rainfall Measuring Mission (TRMM) precipitation for 1998–2001 have been analyzed for their basic characteristics in terms of initiation, distribution, trajectory, development, life cycle, convective intensity, and precipitation. Summer convective systems have a dominant center over the Hengduan Mountain and a secondary center over the Yaluzangbu River Valley. Precipitation associated with these CSs contributes more than 60% of total precipitation over the central-eastern area of the Tibetan Plateau and 30%–40% over the adjacent region to its southeast. The average CS life cycle is about 36 h; 85% of CSs disappear within 60 h of their initiation. About 50% of CSs do not move out of the Tibetan region, with the remainder split into eastward- and southward-moving components. These CSs moving out the Tibetan Plateau are generally larger, have longer life spans, and produce more rainfall than those staying inside the region. Convective system occurrences and associated rainfall present robust diurnal variations. The midafternoon maximum of CS initiation and associated rainfall over the plateau is mainly induced by solar heating linked to the unique Tibetan geography. The delayed afternoon–late night peak of rainfall from CSs propagating out of this region is a combined outcome of multiple mechanisms working together. Results suggest that interactions of summer Tibetan CSs with the orientation of the unique Tibetan geography and the surrounding atmospheric circulations are important for the development, intensification, propagation, and life span of these CSs.
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Graham-Smith, Francis, Andrew G. Lyne, and Clive Dickinson. "Rodney Deane Davies CBE. 8 January 1930—8 November 2015." Biographical Memoirs of Fellows of the Royal Society 64 (March 28, 2018): 149–62. http://dx.doi.org/10.1098/rsbm.2017.0037.
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Following early life on a farm in South Australia and a degree in Physics at the University of Adelaide, Rod Davies began his research career at the Radiophysics Laboratory in Sydney in 1951, working on the development of radio interferometers for solar observations. In 1953, he moved to the University of Manchester, Jodrell Bank, working with Bernard Lovell, later becoming the Director of Jodrell Bank from 1988 to 1997 and the President of the Royal Astronomical Society from 1987 to 1989. He is best known for leading observations of the structure of the cosmic microwave background, first carried out at Jodrell Bank and then transferred to Tenerife during the 1980s and 90s. Later, he was instrumental in establishing the European Space Agency's Planck spacecraft mission and continued after retirement to be closely involved in the interpretation of the data from Planck . He was elected a Fellow of the Royal Society in 1992 and awarded a CBE in 1995. During Rod's tenure as Director of Jodrell Bank, he was responsible for the start of a major project to upgrade the Lovell Telescope, recognizing that with increased capability it could play a leading role into the 21st century. He was also Director during a major upgrade to the MERLIN telescope array, completed around 1991, and making MERLIN a modern, useable, open-access instrument. It was transformed into a true national facility, funded by government, and widely used by the national and international radio astronomy community. Rod Davies was always a kind and generous colleague, and a great inspiration to several generations of radio astronomers.
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Jacobowitz, Herbert, Larry L. Stowe, George Ohring, Andrew Heidinger, Kenneth Knapp, and Nicholas R. Nalli. "The Advanced Very High Resolution Radiometer Pathfinder Atmosphere (PATMOS) Climate Dataset: A Resource for Climate Research." Bulletin of the American Meteorological Society 84, no. 6 (June 1, 2003): 785–94. http://dx.doi.org/10.1175/bams-84-6-785.
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As part of the joint National Oceanic and Atmospheric Administration (NOAA) and National Aeronautics and Space Administration (NASA) Pathfinder program, the NOAA National Environmental Satellite, Data, and Information Service (NESDIS) has created a research-quality global atmospheric dataset through the reprocessing of Advanced Very High Resolution Radiometer (AVHRR) observations since 1981. The AVHRR is an imaging radiometer that flies on NOAA polar-orbiting operational environmental satellites (POES) measuring radiation reflected and emitted by the earth in five spectral channels. Raw AVHRR observations were recalibrated using a vicarious calibration technique for the reflectance channels and an appropriate treatment of the nonlinearity of the infrared channels. The observations are analyzed in the Pathfinder Atmosphere (PATMOS) project to obtain statistics of channel radiances, cloud amount, top of the atmosphere radiation budget, and aerosol optical thickness over ocean. The radiances and radiation budget components are determined for clear-sky and all-sky conditions. The output products are generated on a quasi-equalarea grid with an approximate 110 km × 110 km spatial resolution and twice-a-day temporal resolution, and averaged over 5-day (pentad) and monthly time periods. PATMOS data span the period from September 1981 through June 2001. Analyses show that the PATMOS data in their current archived form are sufficiently accurate for studies of the interaction of clouds and aerosol with solar and terrestrial radiation, and of climatic phenomena with large signals (e.g., the annual cycle, monsoons, ENSOs, or major volcanic eruptions). Global maps of the annual average of selected products are displayed to illustrate the capability of the dataset to depict the climatological fields and the spatial detail and relationships between the fields, further demonstrating how PATMOS is a unique resource for climate studies. Smaller climate signals, such as those associated with global warming, may be more difficult to detect due to the presence of artifacts in the time series of the products. Principally, these are caused by the drift of each satellite's observation time over its mission. A statistical method, which removes most of these artifacts, is briefly discussed. Quality of the products is assessed by comparing the adjusted monthly mean time series for each product with those derived from independent satellite observations. The PATMOS dataset for the monthly means is accessible at www.saa.noaa.gov/.
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Martini, M., S. Dell’Agnello, D. Currie, G. O. Delle Monache, R. Vittori, S. Berardi, A. Boni, et al. "MOONLIGHT: A NEW LUNAR LASER RANGING RETROREFLECTOR AND THE LUNAR GEODETIC PRECESSION." Acta Polytechnica 53, A (December 17, 2013): 746–49. http://dx.doi.org/10.14311/ap.2013.53.0746.
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Since the 1970s Lunar Laser Ranging (LLR) to the Apollo Cube Corner Retroreflector (CCR) arrays (developed by the University of Maryland, UMD) supplied almost all significant tests of General Relativity (Alley et al., 1970; Chang et al., 1971; Bender et al.,1973): possible changes in the gravitational constant, gravitational self-energy, weak equivalence principle, geodetic precession, inverse-square force-law. The LNF group, in fact, has just completed a new measurement of the lunar geodetic precession with Apollo array, with accuracy of 9 × 10−3, comparable to the best measurement to date. LLR has also provided significant information on the composition and origin of the moon. This is the only Apollo experiment still in operation. In the 1970s Apollo LLR arrays contributed a negligible fraction of the ranging error budget. Since the ranging capabilities of ground stations improved by more than two orders of magnitude, now, because of the lunar librations, Apollo CCR arrays dominate the error budget. With the project MoonLIGHT (Moon Laser Instrumentation for General relativity High-accuracy Tests), in 2006 INFN-LNF joined UMD in the development and test of a new-generation LLR payload made by a single, large CCR (100mm diameter) unaffected by the effect of librations. With MoonLIGHT CCRs the accuracy of the measurement of the lunar geodetic precession can be improved up to a factor 100 compared to Apollo arrays. From a technological point of view, INFN-LNF built and is operating a new experimental apparatus (Satellite/lunar laser ranging Characterization Facility, SCF) and created a new industry-standard test procedure (SCF-Test) to characterize and model the detailed thermal behavior and the optical performance of CCRs in accurately laboratory-simulated space conditions, for industrial and scientific applications. Our key experimental innovation is the concurrent measurement and modeling of the optical Far Field Diffraction Pattern (FFDP) and the temperature distribution of retroreflector payloads under thermal conditions produced with a close-match solar simulator. The apparatus includes infrared cameras for non-invasive thermometry, thermal control and real-time payload movement to simulate satellite orientation on orbit with respect to solar illumination and laser interrogation beams. These capabilities provide: unique pre-launch performance validation of the space segment of LLR/SLR (Satellite Laser Ranging); retroreflector design optimization to maximize ranging efficiency and signal-to-noise conditions in daylight. Results of the SCF-Test of our CCR payload will be presented. Negotiations are underway to propose our payload and SCF-Test services for precision gravity and lunar science measurements with next robotic lunar landing missions. In particular, a scientific collaboration agreement was signed on Jan. 30, 2012, by D. Currie, S. Dell’Agnello and the Japanese PI team of the LLR instrument of the proposed SELENE-2 mission by JAXA (Registered with INFN Protocol n. 0000242-03/Feb/2012). The agreement foresees that, under no exchange of funds, the Japanese single, large, hollow LLR reflector will be SCF-Tested and that MoonLIGHT will be considered as backup instrument.
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Cornilleau-Wehrlin, N., H. St Alleyne, K. H. Yearby, B. de la Porte de Vaux, A. Meyer, O. Santolík, M. Parrot, et al. "The STAFF-DWP wave instrument on the DSP equatorial spacecraft: description and first results." Annales Geophysicae 23, no. 8 (November 8, 2005): 2785–801. http://dx.doi.org/10.5194/angeo-23-2785-2005.
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Abstract. The STAFF-DWP wave instrument on board the equatorial spacecraft (TC1) of the Double Star Project consists of a combination of 2 instruments which are a heritage of the Cluster mission: the Spatio-Temporal Analysis of Field Fluctuations (STAFF) experiment and the Digital Wave-Processing experiment (DWP). On DSP-TC1 STAFF consists of a three-axis search coil magnetometer, used to measure magnetic fluctuations at frequencies up to 4 kHz and a waveform unit, up to 10 Hz, plus snapshots up to 180 Hz. DWP provides several onboard analysis tools: a complex FFT to fully characterise electromagnetic waves in the frequency range 10 Hz-4 kHz, a particle correlator linked to the PEACE electron experiment, and compression of the STAFF waveform data. The complementary Cluster and TC1 orbits, together with the similarity of the instruments, permits new multi-point studies. The first results show the capabilities of the experiment, with examples in the different regions of the magnetosphere-solar wind system that have been encountered by DSP-TC1 at the beginning of its operational phase. An overview of the different kinds of electromagnetic waves observed on the dayside from perigee to apogee is given, including the different whistler mode waves (hiss, chorus, lion roars) and broad-band ULF emissions. The polarisation and propagation characteristics of intense waves in the vicinity of a bow shock crossing are analysed using the dedicated PRASSADCO tool, giving results compatible with previous studies: the broad-band ULF waves consist of a superimposition of different wave modes, whereas the magnetosheath lion roars are right-handed and propagate close to the magnetic field. An example of a combined Cluster DSP-TC1 magnetopause crossing is given. This first case study shows that the ULF wave power intensity is higher at low latitude (DSP) than at high latitude (Cluster). On the nightside in the tail, a first wave event comparison - in a rather quiet time interval - is shown. It opens the doors to future studies, such as event timing during substorms, to possibly determine their onset location.