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1.
《Acta Astronautica》1986,13(4):185-196
As a result of studies undertaken during 1981 and 1982, in support of NASA's Solar System Exploration Committee activities, several new approaches have been identified for development of flight hardware as well as ground systems for the execution of U.S. planetary missions through the close of the century. This paper will summarize these new approaches for achieving lower cost in planetary exploration in three different ways:
  • •• Use of modified “production line” spacecraft developed by aerospace companies for scientific and commercial use in earth orbit—study results will be discussed which demonstrate that with only modest modifications to existing earth orbiting spacecraft, excellent results can be expected at planetary targets in the inner solar system ranging from Venus to the inner portions of the asteroid belt. Use of both communications satellites typical of those used in geosynchronous applications, as well as low earth orbiting scientific and meteorological satellites will be discussed. The range of changes and the rationale for these changes required to perform planetary missions will be displayed in detail.
  • •• The development of a multi-mission modular type spacecraft for planetary missions—a new approach and new flexible spacecraft design proposed for development for planetary missions to comets, main-belt asteroids, and the outer planets will be identified. This Mariner Mark II spacecraft will enable reconfiguration at low cost for adaptation to a wide range of missions. Design concepts which draw heavily on early planetary missions as well as technology developments that are expected to be available in the late 80's and early 90's will be described in detail.
  • •• Development of low-cost multi-mission end-to-end information system—a system design including spacecraft command and data handling system requirements, as well as an architecture for a cost effective multi-mission operations system will be described. This system is intended to be applied to both classes of spacecraft/missions described above.
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《Acta Astronautica》2001,48(5-12):681-691
The considerable surge in satellite constellations has brought to the fore the imperative need for an efficient constellation design and management plan. To address this emerging need, GMV has studied and tested algorithms for the analysis of the key phases in constellation development. These algorithms provide complete analysis capabilities and outline optimal strategies to deal with the following issues of the constellation life cycle:
  • •Constellation orbital design
  • •Constellation performance evaluation
  • •Launch strategy and constellation set-up
  • •Constellation replacement and spare strategy
  • •Constellation long-term evolution and end-of-life policy.
This paper presents a comprehensive overview of the algorithms developed to plan and handle a generic constellation. The main effort has been devoted to define a general approach to the problem, so as to allow the characterization of a wide range of possible mission requirements and constraints. A representative Earth observation constellation for fire detection and monitoring (FUEGO) has been considered to assess the effectiveness and the commercial viability of the algorithms and the strategies implemented.  相似文献   

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《Acta Astronautica》1987,15(9):719-723
The paper describes initiation and nature of the PS contingency situation and analyzes the capabilities for its elimination. The following activities for restoration procedures to provide propulsion system functioning are considered in full scope:
  • 1.a) Methods and program development to provide repair-restoration operations (RRO)
  • 2.b) Equipment development and manufacture (instruments, rigging, devices etc.)
  • 3.c) Repair-restorations operations definition in ground conditions on mock-ups and cosmonauts training.
Furthermore the prepared restoration procedures performed during the flight are described as well.  相似文献   

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《Acta Astronautica》1999,44(2-4):187-192
The Advanced Deep Space System Development Program is managed by the Jet Propulsion Laboratory for NASA and is also called X2000. X2000 is organized to create advanced flight and ground systems for the exploration of the outer planets and beyond; it has been created to develop the engineering elements of flight and ground systems. Payloads will be developed by another team. Each X2000 delivery gets its requirements from a set of planned missions, or “mission customers”.The X2000 First Delivery Project supports missions to the Sun (to 4 solar radii), Europa (looking for a liquid ocean), Mars (in support of several Mars missions including a sample return), a comet (including a sample return), and Pluto followed by a trip into the Kuiper belt. This set of missions leads to some outstanding requirements:
  • 1.1. Long-life (10–12 years)
  • 2.2. Total Ionizing Dose of 4 Mrad (for a Europa Orbiter)
  • 3.3. Average power consumption less than or equal to 150 Watts
  • 4.4. Autonomous operations that result in an extreme reduction in operations costs
This paper describes the X2000 first delivery and its technologies following a brief overview of the program.  相似文献   

8.
《Acta Astronautica》2010,66(11-12):1689-1697
In late 2006, NASA's Constellation Program sponsored a study to examine the feasibility of sending a piloted Orion spacecraft to a near-Earth object. NEOs are asteroids or comets that have perihelion distances less than or equal to 1.3 astronomical units, and can have orbits that cross that of the Earth. Therefore, the most suitable targets for the Orion Crew Exploration Vehicle (CEV) are those NEOs in heliocentric orbits similar to Earth's (i.e. low inclination and low eccentricity). One of the significant advantages of this type of mission is that it strengthens and validates the foundational infrastructure of the United States Space Exploration Policy and is highly complementary to NASA's planned lunar sortie and outpost missions circa 2020. A human expedition to a NEO would not only underline the broad utility of the Orion CEV and Ares launch systems, but would also be the first human expedition to an interplanetary body beyond the Earth–Moon system. These deep space operations will present unique challenges not present in lunar missions for the onboard crew, spacecraft systems, and mission control team. Executing several piloted NEO missions will enable NASA to gain crucial deep space operational experience, which will be necessary prerequisites for the eventual human missions to Mars.Our NEO team will present and discuss the following:
  • •new mission trajectories and concepts;
  • •operational command and control considerations;
  • •expected science, operational, resource utilization, and impact mitigation returns; and
  • •continued exploration momentum and future Mars exploration benefits.
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In a recent paper (Maccone, 2011 [15]) and in a recent book (Maccone, 2012 [17]), this author proposed a new mathematical model capable of merging SETI and Darwinian Evolution into a single mathematical scheme. This model is based on exponentials and lognormal probability distributions, called “b-lognormals” if they start at any positive time b (“birth”) larger than zero. Indeed:
  • 1.Darwinian evolution theory may be regarded as a part of SETI theory in that the factor fl in the Drake equation represents the fraction of planets suitable for life on which life actually arose, as it happened on Earth.
  • 2.In 2008 (Maccone, 2008 [9]) this author firstly provided a statistical generalization of the Drake equation where the number N of communicating ET civilizations in the Galaxy was shown to follow the lognormal probability distribution. This fact is a consequence of the Central Limit Theorem (CLT) of Statistics, stating that the product of a number of independent random variables whose probability densities are unknown and independent of each other approached the lognormal distribution if the number of factors is increased at will, i.e. it approaches infinity.
  • 3.Also, in Maccone (2011 [15]), it was shown that the exponential growth of the number of species typical of Darwinian Evolution may be regarded as the geometric locus of the peaks of a one-parameter family of b-lognormal distributions constrained between the time axis and the exponential growth curve. This was a brand-new result. And one more new and far-reaching idea was to define Darwinian Evolution as a particular realization of a stochastic process called Geometric Brownian Motion (GBM) having the above exponential as its own mean value curve.
  • 4.The b-lognormals may be also be interpreted as the lifespan of any living being, let it be a cell, or an animal, a plant, a human, or even the historic lifetime of any civilization. In Maccone, (2012 [17, Chapters 6, 7, 8 and 11]), as well as in the present paper, we give important exact equations yielding the b-lognormal when its birth time, senility-time (descending inflexion point) and death time (where the tangent at senility intercepts the time axis) are known. These also are brand-new results. In particular, the σ=1 b-lognormals are shown to be related to the golden ratio, so famous in the arts and in architecture, and these special b-lognormals we call “golden b-lognormals”.
  • 5.Applying this new mathematical apparatus to Human History leads to the discovery of the exponential trend of progress between Ancient Greece and the current USA Empire as the envelope of the b-lognormals of all Western Civilizations over a period of 2500 years.
  • 6.We then invoke Shannon's Information Theory. The entropy of the obtained b-lognormals turns out to be the index of “development level” reached by each historic civilization. As a consequence, we get a numerical estimate of the entropy difference (i.e. the difference in the evolution levels) between any two civilizations. In particular, this was the case when Spaniards first met with Aztecs in 1519, and we find the relevant entropy difference between Spaniards an Aztecs to be 3.84 bits/individual over a period of about 50 centuries of technological difference. In a similar calculation, the entropy difference between the first living organism on Earth (RNA?) and Humans turns out to equal 25.57 bits/individual over a period of 3.5 billion years of Darwinian Evolution.
  • 7.Finally, we extrapolate our exponentials into the future, which is of course arbitrary, but is the best Humans can do before they get in touch with any alien civilization. The results are appalling: the entropy difference between aliens 1 million years more advanced than Humans is of the order of 1000 bits/individual, while 10,000 bits/individual would be requested to any Civilization wishing to colonize the whole Galaxy (Fermi Paradox).
  • 8.In conclusion, we have derived a mathematical model capable of estimating how much more advanced than humans an alien civilization will be when SETI succeeds.
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10.
《Acta Astronautica》2001,48(5-12):299-309
Microbolometers are infrared detectors of an emerging technology mainly developed in US and few other countries for few years. The main targets of these developments are low performing military and civilian applications like survey cameras.Applications in space are now arising thanks to the design simplification and the associated cost reduction allowed by this new technology.The paper describes two applications in development in SODERN:
  • 1. an infrared camera for the Infrared Atmospheric Sounding Interferometer (IASI): this camera integrated in IASI is used to take pictures of the main instrument field of view and to correlate them with other instrument measurements;
  • 2. an infrared radiometer for PICASSO-CENA based on the same camera design.
In both cases, the use of microbolometer detectors leads to very competitive designs in terms of volume, mass, power consumption and cost.  相似文献   

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Building upon the important experience acquired with the development of the International Space Station, the major spacefaring countries are working within the International Space Exploration Coordination Group (ISECG) at the definition of a coordinated framework for expanding the human presence beyond the Low Earth Orbit, the Global Exploration Roadmap (GER). The GER defines a long-range strategy for global exploration and include three major elements.
  • •Common goals of ISECG participating agencies for space exploration.
  • •Notional mission scenarios which are technically feasible and programmatically implementable. Two mission scenarios were defined in the 1st iteration of the GER: the “Asteroid Next” and the “Moon Next” mission scenarios.
  • •Identification of near-term opportunities for coordination and cooperation related to e.g. the development of technologies, the implementation of robotic missions to destination of interest for closing strategic knowledge gaps which need to be addressed prior to human missions as well as the utilization of ISS for demonstration of exploration enabling capabilities.
In 2009 two studies have been awarded by ESA to Industrial Teams led by Thales Alenia Space—Italy and by Astrium—Germany to define, analyze and assess optional European scenarios for future human spaceflight and exploration activities, and to derive the required capabilities for the investigated timeframe until the year 2033. Work on the European scenarios has been aligned with and informed by the international work on the GER.A conceptual design of different Building Block Elements, representing critical contributions to international Design Reference Missions (DRM's) included in the ISECG GER, has been performed and analyzed with respect to programmatic risks, budgets and required technologies. Key driving requirements for the analyzed Building Block elements have been derived from the international DRM's included in the GER.The interim outcomes of the human exploration scenario study will be presented, identifying opportunities for European Contributions to an international exploration undertaking.  相似文献   

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The results of measurements of fluxes and spectra carried out using the RELEC (relativistic electrons) equipment onboard the VERNOV satellite in the second half of 2014 are presented. The VERNOV satellite was launched on July 8, 2014 in a sun-synchronous orbit with an altitude from 640 to 830 km and an inclination of 98.4°. Scientific information from the satellite was first received on July 20, 2014. The comparative analysis of electron fluxes using data from RELEC and using experimental data on the electron detection by satellites Elektro-L (positioned at a geostationary orbit) and Meteor-M no. 2 (positioned at a circular polar orbit at an altitude of about 800 km as the VERNOV satellite) will make it possible to study the spatial distribution pattern of energetic electrons in near-Earth space in more detail.  相似文献   

19.
ABSTRACT

In three experiments, after exploring a virtual environment (VE), adult participants made spatial judgments about the location of target objects that were higher and lower than their perceived test location within the VE. In Experiment 1, the locations of the target objects were inferred from verbal instructions. The main results were a tendency to judge objects as closer to the horizontal plane than their true locations, and more efficient downward than upward judgments. Both effects generally accord with findings reported by Wilson et al. (2004a Wilson, P. N., Foreman, N., Stanton, D. and Duffy, H. 2004a. Memory for targets in a multilevel simulated environment: Evidence for vertical asymmetry in spatial memory. Memory & Cognition, 32: 283297. [Crossref] [Google Scholar], 2004b Wilson, P. N., Foreman, N., Stanton, D. and Duffy, H. 2004b. Memory for targets in a multi-level simulated-environment: A comparison between able-bodied and physically disabled children. British Journal of Psychology, 95: 325338.  [Google Scholar]). In Experiments 2 and 3, which were closely modeled on the design of the Wilson et al. studies, regression to the horizontal plane was noted but no downward bias was observed. A misperception in the viewing height between the floors and ceilings of the virtual rooms was apparent in both experiments. The results from the present study together with earlier investigations suggest different hierarchical encoding of between-axis and within-axis information.  相似文献   

20.
The use of the Internet has been grown tremendously within the last decade to more than one billion subscribers. The other five billion people on Earth cannot enjoy the possibilities offered by the Internet.The digital divide is everywhere: in the developing as well as in the developed part of the world.In the developing countries basic communication needs (voice, IP access) need to be provided to a large population not living in cities.In the developed part of the world people residing outside the large cities, on the nice country side, have still difficulties to get broadband access. The reason being, that the investment to install the network infrastructure to this minority part of the population is a major part of the total investment for the network. The benefit for the telecom operators is marginal to get these customers on board.In this paper an analysis of the Internet and satellite development is being presented and based on these historical data a prediction of a possible evolution of satellite communications and broadband access is performed.One result is that the capacity of the GEO ring at the Ka-band alone would allow to provide to each individual on Earth in 2050 (assumed to be 10 billion people) a monthly capacity of about 1 Gbyte for a charge of 1$ per month.  相似文献   

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