76 research outputs found

    The control challenges for the Next Generation Gravity Mission

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    Several activities are on going in preparation of a "Next Generation Gravity Mission" (NGGM) aimed at measuring the temporal variations of the Earth gravity field over a long time span with high spatial resolution and high temporal resolution. The most appropriate measurement technique identified for such mission is the "Low-Low Satellite-Satellite Tracking" in which two satellites flying in loose formation in a low Earth orbit act as proof masses immersed in the Earth gravity field. The distance variation between the satellites and the non-gravitational accelerations of the satellites, measured respectively by a laser interferometer and by ultra-sensitive accelerometers, are the fundamental observables from which the Earth gravitational field is obtained. The control system for the NGGM must fulfil the challenging combination of requirements for the orbit and formation maintenance, attitude stabilisation, drag compensation and microradian laser beam pointing. This paper presents the assessment and the preliminary design of the NGGM control system, performed by Thales Alenia Space Italia and Politecnico di Torino for the European Space Agency

    Design of Ka-Band Low Noise Amplifier Using CMOS Technology

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    In this paper, design of a Low Noise Amplifier is undertaken for higher frequency bands, particularly Ka-band. The designed LNA can be used in satellite transponders for the mentioned frequency band. Generally LNAs are the first block in a transponder and are very sophisticated in trems of noise performance. A common-source topology along with source degeneration is used to achieve low noise figure and linearity with high gain. The use of CMOS technology provides new applications in designing this amplifier. It offers designs at lower cost, reduced power consumption and higher levels of integration. Proposed circuit achieves a maximum gain of 23dB with a relatively low noise figure of 2.9dB. This system can work in Deep-Space region as part of a satellite transponder

    On Small Satellites for Oceanography: A Survey

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    The recent explosive growth of small satellite operations driven primarily from an academic or pedagogical need, has demonstrated the viability of commercial-off-the-shelf technologies in space. They have also leveraged and shown the need for development of compatible sensors primarily aimed for Earth observation tasks including monitoring terrestrial domains, communications and engineering tests. However, one domain that these platforms have not yet made substantial inroads into, is in the ocean sciences. Remote sensing has long been within the repertoire of tools for oceanographers to study dynamic large scale physical phenomena, such as gyres and fronts, bio-geochemical process transport, primary productivity and process studies in the coastal ocean. We argue that the time has come for micro and nano satellites (with mass smaller than 100 kg and 2 to 3 year development times) designed, built, tested and flown by academic departments, for coordinated observations with robotic assets in situ. We do so primarily by surveying SmallSat missions oriented towards ocean observations in the recent past, and in doing so, we update the current knowledge about what is feasible in the rapidly evolving field of platforms and sensors for this domain. We conclude by proposing a set of candidate ocean observing missions with an emphasis on radar-based observations, with a focus on Synthetic Aperture Radar.Comment: 63 pages, 4 figures, 8 table

    Remote Sensing

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    This dual conception of remote sensing brought us to the idea of preparing two different books; in addition to the first book which displays recent advances in remote sensing applications, this book is devoted to new techniques for data processing, sensors and platforms. We do not intend this book to cover all aspects of remote sensing techniques and platforms, since it would be an impossible task for a single volume. Instead, we have collected a number of high-quality, original and representative contributions in those areas

    Radio Resource Management Techniques for Multibeam Satellite Systems

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    Next-generation of satellite communication (SatCom) networks are expected to support extremely high data rates for a seamless integration into future large satellite-terrestrial networks. In view of the coming spectral limitations, the main challenge is to reduce the cost per bit, which can only be achieved by enhancing the spectral efficiency. In addition, the capability to quickly and flexibly assign radio resources according to the traffic demand distribution has become a must for future multibeam broadband satellite systems. This article presents the radio resource management problems encountered in the design of future broadband SatComs and provides a comprehensive overview of the available techniques to address such challenges. Firstly, we focus on the demand-matching formulation of the power and bandwidth assignment. Secondly, we present the scheduling design in practical multibeam satellite systems. Finally, a number of future challenges and the respective open research topics are described.Comment: Submitted to IEEE Communications Letter

    Application of advanced technology to space automation

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    Automated operations in space provide the key to optimized mission design and data acquisition at minimum cost for the future. The results of this study strongly accentuate this statement and should provide further incentive for immediate development of specific automtion technology as defined herein. Essential automation technology requirements were identified for future programs. The study was undertaken to address the future role of automation in the space program, the potential benefits to be derived, and the technology efforts that should be directed toward obtaining these benefits

    Atmospheric science facility pallet-only mode space transportation system payload (feasibility study), Volume 1

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    The economic and technical feasibility is assessed of employing a pallet-only mode for conducting Atmospheric Magnetospheric Plasmas-in-Space experiments. A baseline design incorporating the experiment and instrument descriptions is developed. The prime instruments are packaged into four pallets in a physical and functional manner compatible with the Space Transportation System capabilities and/or constraints and an orbiter seven-day mission timeline. Operational compatibility is verified between the orbiter/payload and supporting facilities. The development status and the schedule requirements applicable to the Atmospheric Science Facility mission are identified. Conclusions and recommendations are presented and discussed

    Atmospheric, Magnetospheric, and Plasmas in Space (AMPS) spacelab payload definition study, technical summary document

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    Some 60 instrument candidates and 80 possible science investigations were evaluated. The early analysis emphasized the science aspect in terms of the functional requirements for each of the potential experiments identified by the AMPS science working group. These requirements were then used for the grouping of instruments into practical payloads which would fit the capabilities of the Shuttle/Spacelab. This analysis resulted in the definition of eleven different AMPS configurations. The data were then used to define a typical set of requirements for a flexible AMPS laboratory. The data gathered to this point showed that a planned sequential buildup of the laboratory would be necessary to meet both physical and funding limitations. This led to the definition of five strawman payloads by the science working group, which were used to establish a conceptual laboratory and to define preliminary design of a configuration which could satisfy AMPS needs during the early program period
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