排序方式: 共有21条查询结果,搜索用时 15 毫秒
11.
Barry Y. Welsh 《Space Science Reviews》2009,143(1-4):241-252
I present a short review of the physical properties and relationships between warm partially ionized and hot and highly ionized gas in the local interstellar-medium (ISM). The majority of the measurements reviewed have been obtained through ultraviolet absorption spectroscopy recorded towards stellar targets located within ~150 pc of the Sun. Many questions still remain to be answered concerning the location, temperature, density and source of ionization of both of these phases of the diffuse interstellar gas. In particular, we focus on absorption observations of the ions of C IV λ 1550 Å and Si IV λ 1394 Å and discuss if highly ionized gas (as traced by the O VI λ 1032 Å ion) has in fact actually been detected within the Local Cavity. 相似文献
12.
An approach is described to supplying an environment for the integration and test of the Space Station distributed avionics systems. Background is included on the development of this concept including the lessons learned from Space Shuttle experience. The environment's relationship to the process flow of the Space-Station verification, from systems development to on-orbit verification, is presented. The uses of the environment's hardware implementation, called Data Management System (DMS) kits, are covered. It is explained how these DMS kits provide a development version of the Space-Station operational environment and how this environment allows system developers to verify their systems performance, fault detection, and recovery capability. Conclusions on how the use of the DMS kits, in support of this concept, will ensure adequate on-orbit test capability are included 相似文献
13.
Barry D. Fishburn 《Acta Astronautica》1976,3(11-12)
Numerical solutions of the blast wave flow from a spherical explosive charge were obtained using the artificial viscosity technique as employed by Oppenheim. The flow is treated as adiabatic and inviscid and ideal equations of state are used for reactants, products and the surrounding air environment. Differences are noted in the peak pressure, static impulse and dynamic impulse resulting from three representative types of idealized initiation: (1) centrally initiated, self-similar Chapman-Jouguet detonation, (2) edge initiated spherical implosion and (3) constant volume energy release followed by sudden venting to the environment. These are compared to the ideal point blast with counterpressure of the same total energy release. In addition, numerical solutions are presented for centrally initiated, stoichiometric hydrogen-oxygen mixtures surrounded by air for detonation and for deflagration according to an empirically determined, non-steady flame velocity. The greater energy transfer to the environment in the case of detonation is demonstrated. 相似文献
14.
The operation of a large class of physical systems ems can be described through application of singular integral equations written in the time domain. This correspondence shows that Wolf's theorem and a general form of Parseval's theorem can be used to transform the integral equation to the S-plane, the result being an integral equation which readily yields the complex frequency response of the system. 相似文献
15.
Mars Science Laboratory Mission and Science Investigation 总被引:5,自引:0,他引:5
John P. Grotzinger Joy Crisp Ashwin R. Vasavada Robert C. Anderson Charles J. Baker Robert Barry David F. Blake Pamela Conrad Kenneth S. Edgett Bobak Ferdowski Ralf Gellert John B. Gilbert Matt Golombek Javier Gómez-Elvira Donald M. Hassler Louise Jandura Maxim Litvak Paul Mahaffy Justin Maki Michael Meyer Michael C. Malin Igor Mitrofanov John J. Simmonds David Vaniman Richard V. Welch Roger C. Wiens 《Space Science Reviews》2012,170(1-4):5-56
Scheduled to land in August of 2012, the Mars Science Laboratory (MSL) Mission was initiated to explore the habitability of Mars. This includes both modern environments as well as ancient environments recorded by the stratigraphic rock record preserved at the Gale crater landing site. The Curiosity rover has a designed lifetime of at least one Mars year (~23?months), and drive capability of at least 20?km. Curiosity’s science payload was specifically assembled to assess habitability and includes a gas chromatograph-mass spectrometer and gas analyzer that will search for organic carbon in rocks, regolith fines, and the atmosphere (SAM instrument); an x-ray diffractometer that will determine mineralogical diversity (CheMin instrument); focusable cameras that can image landscapes and rock/regolith textures in natural color (MAHLI, MARDI, and Mastcam instruments); an alpha-particle x-ray spectrometer for in situ determination of rock and soil chemistry (APXS instrument); a?laser-induced breakdown spectrometer to remotely sense the chemical composition of rocks and minerals (ChemCam instrument); an active neutron spectrometer designed to search for water in rocks/regolith (DAN instrument); a weather station to measure modern-day environmental variables (REMS instrument); and a sensor designed for continuous monitoring of background solar and cosmic radiation (RAD instrument). The various payload elements will work together to detect and study potential sampling targets with remote and in situ measurements; to acquire samples of rock, soil, and atmosphere and analyze them in onboard analytical instruments; and to observe the environment around the rover. The 155-km diameter Gale crater was chosen as Curiosity’s field site based on several attributes: an interior mountain of ancient flat-lying strata extending almost 5?km above the elevation of the landing site; the lower few hundred meters of the mountain show a progression with relative age from clay-bearing to sulfate-bearing strata, separated by an unconformity from overlying likely anhydrous strata; the landing ellipse is characterized by a mixture of alluvial fan and high thermal inertia/high albedo stratified deposits; and a number of stratigraphically/geomorphically distinct fluvial features. Samples of the crater wall and rim rock, and more recent to currently active surface materials also may be studied. Gale has a well-defined regional context and strong evidence for a progression through multiple potentially habitable environments. These environments are represented by a stratigraphic record of extraordinary extent, and insure preservation of a rich record of the environmental history of early Mars. The interior mountain of Gale Crater has been informally designated at Mount Sharp, in honor of the pioneering planetary scientist Robert Sharp. The major subsystems of the MSL Project consist of a single rover (with science payload), a Multi-Mission Radioisotope Thermoelectric Generator, an Earth-Mars cruise stage, an entry, descent, and landing system, a launch vehicle, and the mission operations and ground data systems. The primary communication path for downlink is relay through the Mars Reconnaissance Orbiter. The primary path for uplink to the rover is Direct-from-Earth. The secondary paths for downlink are Direct-to-Earth and relay through the Mars Odyssey orbiter. Curiosity is a scaled version of the 6-wheel drive, 4-wheel steering, rocker bogie system from the Mars Exploration Rovers (MER) Spirit and Opportunity and the Mars Pathfinder Sojourner. Like Spirit and Opportunity, Curiosity offers three primary modes of navigation: blind-drive, visual odometry, and visual odometry with hazard avoidance. Creation of terrain maps based on HiRISE (High Resolution Imaging Science Experiment) and other remote sensing data were used to conduct simulated driving with Curiosity in these various modes, and allowed selection of the Gale crater landing site which requires climbing the base of a mountain to achieve its primary science goals. The Sample Acquisition, Processing, and Handling (SA/SPaH) subsystem is responsible for the acquisition of rock and soil samples from the Martian surface and the processing of these samples into fine particles that are then distributed to the analytical science instruments. The SA/SPaH subsystem is also responsible for the placement of the two contact instruments (APXS, MAHLI) on rock and soil targets. SA/SPaH consists of a robotic arm and turret-mounted devices on the end of the arm, which include a drill, brush, soil scoop, sample processing device, and the mechanical and electrical interfaces to the two contact science instruments. SA/SPaH also includes drill bit boxes, the organic check material, and an observation tray, which are all mounted on the front of the rover, and inlet cover mechanisms that are placed over the SAM and CheMin solid sample inlet tubes on the rover top deck. 相似文献
16.
The Pluto Energetic Particle Spectrometer Science Investigation (PEPSSI) on the New Horizons Mission
Ralph L. McNutt Jr. Stefano A. Livi Reid S. Gurnee Matthew E. Hill Kim A. Cooper G. Bruce Andrews Edwin P. Keath Stamatios M. Krimigis Donald G. Mitchell Barry Tossman Fran Bagenal John D. Boldt Walter Bradley William S. Devereux George C. Ho Stephen E. Jaskulek Thomas W. LeFevere Horace Malcom Geoffrey A. Marcus John R. Hayes G. Ty Moore Nikolaos P. Paschalidis Mark E. Perry Bruce D. Williams Paul Wilson IV Lawrence E. Brown Martha B. Kusterer Jon D. Vandegriff 《Space Science Reviews》2009,145(3-4):381-381
17.
John E. Moores Raymond Francis Marianne Mader G.R. Osinski T. Barfoot N. Barry G. Basic M. Battler M. Beauchamp S. Blain M. Bondy R-D. Capitan A. Chanou J. Clayton E. Cloutis M. Daly C. Dickinson H. Dong R. Flemming P. Furgale J. Gammel N. Gharfoor M. Hussein R. Grieve H. Henrys P. Jaziobedski A. Lambert K. Leung C. Marion E. McCullough C. McManus C.D. Neish H.K. Ng A. Ozaruk A. Pickersgill L.J. Preston D. Redman H. Sapers B. Shankar A. Singleton K. Souders B. Stenning P. Stooke P. Sylvester L. Tornabene 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2012
18.
"Mount Everest" is a vague name. That is (on the account here defended) there are many portions of reality all of which have equal claims to serve as its referent. We propose a new account of such vagueness in terms of a theory of what we shall call granular partitions. We distinguish different kinds of crisp and non-crisp granular partitions and we describe the relations between them, concentrating especially on spatial examples. In addition, we describe the practice whereby subjects use systems of reference grids as a means for tempering the vagueness of their judgments for example when they say that Libya straddles the Equator or that the meeting will take place between 2 and 3pm. We then demonstrate how the theory of reference partitions can yield a natural account of this practice, which is referred to in the literature as 'approximation'. 相似文献
19.
The Energetic Particle and Plasma Spectrometer Instrument on the MESSENGER Spacecraft 总被引:1,自引:0,他引:1
G. Bruce Andrews Thomas H. Zurbuchen Barry H. Mauk Horace Malcom Lennard A. Fisk George Gloeckler George C. Ho Jeffrey S. Kelley Patrick L. Koehn Thomas W. LeFevere Stefano S. Livi Robert A. Lundgren Jim M. Raines 《Space Science Reviews》2007,131(1-4):523-556
The Energetic Particle and Plasma Spectrometer (EPPS) package on the MErcury Surface, Space ENvironment, GEochemistry, and
Ranging (MESSENGER) mission to Mercury is composed of two sensors, the Energetic Particle Spectrometer (EPS) and the Fast
Imaging Plasma Spectrometer (FIPS). EPS measures the energy, angular, and compositional distributions of the high-energy components
of the in situ electrons (>20 keV) and ions (>5 keV/nucleon), while FIPS measures the energy, angular, and compositional distributions
of the low-energy components of the ion distributions (<50 eV/charge to 20 keV/charge). Both EPS and FIPS have very small
footprints, and their combined mass (∼3 kg) is significantly lower than that of comparable instruments. 相似文献
20.