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Susan Jason Alex da Silva Curiel Doug Liddle Francis Chizea Ugur Murat Leloglu Mustafa Helvaci Mohammed Bekhti Djouad Benachir Lee Boland Luis Gomes Martin Sweeting 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2010
This paper focuses on ways in which space is being used to build capacity in science and technology in order to: 相似文献
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Every few years, the eternally resurgent question of whether humans or robots should be adopted for space exploration is dusted off, with arguments on both sides leading nowhere. I argue that this debate is misplaced—there is a well-defined distribution of tasks across humans and the machine, and this distribution is of an evolutionary nature. This article uses a variety of examples to illustrate where robotic capabilities are most appropriate and where human attributes cannot be dispensed with. It further suggests that, even as robotics and artificial intelligence are becoming more sophisticated, they will not be able to deal with ‘thinking-on-one's-feet’ tasks that require generalisations from past experience. Given the current and perceived status of robotics research, I submit that there will be a critical role for humans in space for the foreseeable future. 相似文献
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Abstract The Life Marker Chip (LMC) instrument is part of the proposed payload on the ESA ExoMars rover that is scheduled for launch in 2018. The LMC will use antibody-based assays to detect molecular signatures of life in samples obtained from the shallow subsurface of Mars. For the LMC antibodies, the ability to resist inactivation due to space particle radiation (both in transit and on the surface of Mars) will therefore be a prerequisite. The proton and neutron components of the mission radiation environment are those that are expected to have the dominant effect on the operation of the LMC. Modeling of the radiation environment for a mission to Mars led to the calculation of nominal mission fluences for proton and neutron radiation. Various combinations and multiples of these values were used to demonstrate the effects of radiation on antibody activity, primarily at the radiation levels envisaged for the ExoMars mission as well as at much higher levels. Five antibodies were freeze-dried in a variety of protective molecular matrices and were exposed to various radiation conditions generated at a cyclotron facility. After exposure, the antibodies' ability to bind to their respective antigens was assessed and found to be unaffected by ExoMars mission level radiation doses. These experiments indicated that the expected radiation environment of a Mars mission does not pose a significant risk to antibodies packaged in the form anticipated for the LMC instrument. Key Words: Life-detection instruments-Planetary habitability and biosignatures-Radiation-Mars-Life in extreme environments. Astrobiology 12, 718-729. 相似文献
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Alex Derber 《航空维修与工程》2020,(4):25-26
虽然,区块链需要达到一定规模才能充分实现其优势,但是航空售后市场仍然可以从其早期开发中获得价值。在航空售后市场,数字化优势已广为人知并得到了广泛接受,但人们对于区块链实用性(数字化鲜为人知的要素之一)的认知还远远不足。例如,空客公司和汉莎航空技术公司认可分布式账本技术的潜力,但仍然担心该技术还不足以解决当前的行业问题,因此对其持保留意见。 相似文献
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Bruno Mialon Alex Khrabrov Saloua Ben Khelil Andreas Huebner Andrea Da Ronch Ken Badcock Luca Cavagna Peter Eliasson Mengmeng Zhang Sergio Ricci Jean-Christophe Jouhaud Gilbert Rogé Stephan Hitzel Martin Lahuta 《Progress in Aerospace Sciences》2011,47(8):674-694
The dynamic derivatives are widely used in linear aerodynamic models in order to determine the flying qualities of an aircraft: the ability to predict them reliably, quickly and sufficiently early in the design process is vital in order to avoid late and costly component redesigns. This paper describes experimental and computational research dealing with the determination of dynamic derivatives carried out within the FP6 European project SimSAC. Numerical and experimental results are compared for two aircraft configurations: a generic civil transport aircraft, wing-fuselage-tail configuration called the DLR-F12 and a generic Transonic CRuiser, which is a canard configuration. Static and dynamic wind tunnel tests have been carried out for both configurations and are briefly described within this paper. The data generated for both the DLR-F12 and TCR configurations include force and pressure coefficients obtained during small amplitude pitch, roll and yaw oscillations while the data for the TCR configuration also include large amplitude oscillations, in order to investigate the dynamic effects on nonlinear aerodynamic characteristics. In addition, dynamic derivatives have been determined for both configurations with a large panel of tools, from linear aerodynamic (Vortex Lattice Methods) to CFD. This work confirms that an increase in fidelity level enables the dynamic derivatives to be calculated more accurately. Linear aerodynamics tools are shown to give satisfactory results but are very sensitive to the geometry/mesh input data. Although all the quasi-steady CFD approaches give comparable results (robustness) for steady dynamic derivatives, they do not allow the prediction of unsteady components for the dynamic derivatives (angular derivatives with respect to time): this can be done with either a fully unsteady approach i.e. with a time-marching scheme or with frequency domain solvers, both of which provide comparable results for the DLR-F12 test case. As far as the canard configuration is concerned, strong limitations for the linear aerodynamic tools are observed. A key aspect of this work are the acceleration techniques developed for CFD methods, which allow the computational time to be dramatically reduced while providing comparable results. 相似文献
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Alex T.K. Shrivastava S.K. 《IEEE transactions on aerospace and electronic systems》1989,25(3):373-379
Infrared Earth sensors are used in spacecraft for attitude sensing. Their accuracy is limited by systematic and random errors. Dominant sources of systematic errors are analyzed for a typical scanning infrared Earth sensor used in a remote-sensing satellite in a 900-km Sun-synchronous orbit. The errors considered arise from seasonable variation of infrared radiation; oblate shape of the Earth; ambient temperature of sensors; changes in spin/scan period; and misalignment of the axis of the sensors. Simple relations are derived using least-squares curve fitting for onboard correction of these errors. With these, it is possible to improve the accuracy of attitude determination by eight fold and achieve performance comparable to ground-based post-facto attitude computation 相似文献
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Alex N. Halliday 《Space Science Reviews》2000,92(1-2):355-370
Models for the mechanisms of accretion of the terrestrial planets are re-examined using the experimental technique of high-precision
isotope ratio mass spectrometry of tungsten (W). The decay of 182Hf to 182W (via 182Ta) provides a new kind of radiometric chronometer of planet formation processes. Hafnium and W, the parent and daughter trace
elements, are highly refractory; however, Hf is lithophile and strongly partitioned into the silicate portion of a planet,
whereas W is moderately siderophile and preferentially partitioned into a coexisting metallic phase. More than 90% of terrestrial
W has gone into the Earth's core during its formation. The residual silicate portion, the Earth's primitive mantle, has a
Hf/W ratio in the range 10−40, an order of magnitude higher than chondritic (∼1.3). Tungsten isotopic data for the Earth and
the Moon suggest that we can date a major event of planet formation: The Moon formed about 50 Myrs after the start of the
solar system, providing strong support for the Giant Impact Theory of lunar origin. Recent simulations of this event imply
that the Earth was probably only half formed at the time. From this we can deduce the planetary accretion rate. Tungsten isotope
data for Mars provide evidence of a much shorter accretion interval, perhaps as little as 10 Myrs, but the rates for the Earth
over the same time interval could have been comparable. The large W isotopic heterogeneities on Mars could only have been
produced within the first 30 Myrs of the solar system. Large-scale mixing, e.g. from convective overturn, as is thought to drive the Earth's plates, must be absent from Mars.
Limitations of the method such as 1) cosmogenic 182Ta effects on lunar samples, 2) incomplete mixing of debris to cause W isotope heterogeneity on the Moon, and 3) initial 182Hf/180Hf heterogeneities of the early solar system are critically discussed.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
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