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31.
Remote sounding of atmospheric gravity waves with satellite limb and nadir techniques 总被引:4,自引:0,他引:4
Dong L. Wu Peter Preusse Stephen D. Eckermann Jonathan H. Jiang Manuel de la Torre Juarez Lawrence Coy Ding Y. Wang 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2006,37(12):2269-II
Recent advances in satellite techniques hold great potential for mapping global gravity wave (GW) processes at various altitudes. Poor understanding of small-scale GWs has been a major limitation to numerical climate and weather models for making reliable forecasts. Observations of short-scale features have important implication for validating and improving future high-resolution numerical models. This paper summarizes recent GW observations and sensitivities from several satellite instruments, including MLS, AMSU-A, AIRS, GPS, and CLAES. It is shown in an example that mountain waves with horizontal wavelengths as short as 30 km now can be observed by AIRS, reflecting the superior horizontal resolution in these modern satellite instruments. Our studies show that MLS, AMSU-A and AIRS observations reveal similar GW characteristics, with the observed variances correlated well with background winds. As a complementary technique, limb sounding instruments like CRISTA, CLAES, and GPS can detect GWs with better vertical but poorer horizontal resolutions. To resolve different parts of the broad GW spectrum, both satellite limb and nadir observing techniques are needed, and a better understanding of GW complexities requires joint analyses of these data and dedicated high-resolution model simulations. 相似文献
32.
33.
L. Barbareschi C. La Padula M. Mastropietro F. Perotti G. Villa A. Bazzano L. Boccaccini R. Patriarca V.F. Polcaro P. Ubertini R.C. Butler G. Di Cocco G. Spada J.N. Carter P. Charalambous A.J. Dean J.B. Stephen 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1983,3(4):91-93
In order to improve the low energy capability (15 ÷ 150 KeV) of the balloon borne “ZEBRA” low energy gamma imaging telescope (150 KeV-20 MeV), a large area, high spectral resolution (5% at 60 KeV), low background detector has been designed and is now under development.It consists of two MultiWire Spectroscopic Proportional Counter (SPC), escape gated, that have a sensitive area of 6000 cm2, and are placed above the large area array of sodiumiodide position sensitive elements. 相似文献
34.
35.
Over the past several years Satellites International has developed an integrated suite of satellite sub-systems and small satellite buses. The sub-systems include S-band communications, attitude sensing and control, power conversion and distribution, and on-board data handling. They are inherently modular and readily adaptable to different satellite configurations, a concept known as semi-standardisation. This concept has been adopted by two generic low-cost buses: MicroSIL for satellites in the mass range 40–80kg; and MiniSIL for satellites in the range 100–500kg. Their architecture is based on the semi-standard sub-systems, but easily modified to utilise sub-systems from other manufacturers. They can support all stabilisation methods including spinning, 3-axis control and gravity gradient and are adaptable to a wide variety of missions including Earth resources, scientific, communications and technology demonstration. The Company also manufactures a range of low cost ground support equipment and complete ground stations to complement the space-borne systems. 相似文献
36.
Stephen M. Pompea 《Space Science Reviews》1995,74(1-2):181-193
The performance of infrared and submillimeter systems can be severely degraded by stray light. Stray light includes off-axis radiation, system diffraction and scattering effects, and thermal self-emission. The purpose of this paper is to identify several keys to preventing system degradation due to stray radiation. The first key is to apply stray light design rules and analysis techniques early in the program before the design is finalized. A systems level analysis using stray light analysis software is often necessary in order to identify more subtle problems and to assess the magnitude of their effect on system performance. Another key is to address contamination control and the choice of surface coatings early in the program. The management of stray radiation issues is extremely cost-effective, if begun early in the program, and can reduce later schedule hardships. 相似文献
37.
James C. Leary Richard F. Conde George Dakermanji Carl S. Engelbrecht Carl J. Ercol Karl B. Fielhauer David G. Grant Theodore J. Hartka Tracy A. Hill Stephen E. Jaskulek Mary A. Mirantes Larry E. Mosher Michael V. Paul David F. Persons Elliot H. Rodberg Dipak K. Srinivasan Robin M. Vaughan Samuel R. Wiley 《Space Science Reviews》2007,131(1-4):187-217
The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft was designed and constructed to withstand the harsh environments associated with achieving and operating in Mercury
orbit. The system can be divided into eight subsystems: structures and mechanisms (e.g., the composite core structure, aluminum
launch vehicle adapter, and deployables), propulsion (e.g., the state-of-the-art titanium fuel tanks, thruster modules, and
associated plumbing), thermal (e.g., the ceramic-cloth sunshade, heaters, and radiators), power (e.g., solar arrays, battery,
and controlling electronics), avionics (e.g., the processors, solid-state recorder, and data handling electronics), software
(e.g., processor-supported code that performs commanding, data handling, and spacecraft control), guidance and control (e.g.,
attitude sensors including star cameras and Sun sensors integrated with controllers including reaction wheels), radio frequency
telecommunications (e.g., the spacecraft antenna suites and supporting electronics), and payload (e.g., the science instruments
and supporting processors). This system architecture went through an extensive (nearly four-year) development and testing
effort that provided the team with confidence that all mission goals will be achieved.
Larry E. Mosher passed away during the preparation of this paper. 相似文献
38.
The low-energy neutral atom imager for IMAGE 总被引:1,自引:0,他引:1
Moore T.E. Chornay D.J. Collier M.R. Herrero F.A. Johnson J. Johnson M.A. Keller J.W. Laudadio J.F. Lobell J.F. Ogilvie K.W. Rozmarynowski P. Fuselier S.A. Ghielmetti A.G. Hertzberg E. Hamilton D.C. Lundgren R. Wilson P. Walpole P. Stephen T.M. Peko B.L. Van Zyl B. Wurz P. Quinn J.M. Wilson G.R. 《Space Science Reviews》2000,91(1-2):155-195
The `Imager for Magnetosphere-to-Aurora Global Exploration (IMAGE) will be launched early in the year 2000. It will be the first mission dedicated to imaging, with the capability to determine how the magnetosphere changes globally in response to solar storm effects in the solar wind, on time scales as short as a few minutes. The low energy neutral atom (LENA) imager uses a new atom-to-negative ion surface conversion technology to image the neutral atom flux and measure its composition (H and O) and energy distribution (10 to 750 eV). LENA uses electrostatic optics techniques for energy (per charge) discrimination and carbon foil time-of-flight techniques for mass discrimination. It has a 90°×° field-of-view in 12 pixels, each nominally 8°×°. Spacecraft spin provides a total field-of-view of 90°×360°, comprised of 12×45 pixels. LENA is designed to image fast neutral atom fluxes in its energy range, emitted by auroral ionospheres or the sun, or penetrating from the interstellar medium. It will thereby determine how superthermal plasma heating is distributed in space, how and why it varies on short time scales, and how this heating is driven by solar activity as reflected in solar wind conditions. 相似文献
39.
Nikos Mastrodemos Daniel G. Kubitschek Stephen P. Synnott 《Space Science Reviews》2005,117(1-2):95-121
The engineering goal of the Deep Impact mission is to impact comet Tempel 1 on July 4, 2005, with a 370 kg active Impactor
spacecraft (s/c). The impact velocity will be just over 10 km/s and is expected to excavate a crater approximately 20 m deep
and 100 m wide. The Impactor s/c will be delivered to the vicinity of Tempel 1 by the Flyby s/c, which is also the key observing
platform for the event. Following Impactor release, the Flyby will change course to pass the nucleus at an altitude of 500
km and at the same time slow down in order to allow approximately 800 s of observation of the impact event, ejecta plume expansion,
and crater formation. Deep Impact will use the autonomous optical navigation (AutoNav) software system to guide the Impactor
s/c to intercept the nucleus of Tempel 1 at a location that is illuminated and viewable from the Flyby. The Flyby s/c uses
identical software to determine its comet-relative trajectory and provide the attitude determination and control system (ADCS)
with the relative position information necessary to point the High Resolution Imager (HRI) and Medium Resolution Imager (MRI)
instruments at the impact site during the encounter. This paper describes the Impactor s/c autonomous targeting design and
the Flyby s/c autonomous tracking design, including image processing and navigation (trajectory estimation and maneuver computation).
We also discuss the analysis that led to the current design, the expected system performance as compared to the key mission
requirements and the sensitivity to various s/c subsystems and Tempel 1 environmental factors. 相似文献
40.
Farzad Kamalabadi Jianqi Qin Brian J. Harding Dimitrios Iliou Jonathan J. Makela R. R. Meier Scott L. England Harald U. Frey Stephen B. Mende Thomas J. Immel 《Space Science Reviews》2018,214(4):70
The Ionospheric Connection Explorer (ICON) Far Ultraviolet (FUV) imager, ICON FUV, will measure altitude profiles of OI 135.6 nm emissions to infer nighttime ionospheric parameters. Accurate estimation of the ionospheric state requires the development of a comprehensive radiative transfer model from first principles to quantify the effects of physical processes on the production and transport of the 135.6 nm photons in the ionosphere including the mutual neutralization contribution as well as the effect of resonant scattering by atomic oxygen and pure absorption by oxygen molecules. This forward model is then used in conjunction with a constrained optimization algorithm to invert the anticipated ICON FUV line-of-sight integrated measurements. In this paper, we describe the connection between ICON FUV measurements and the nighttime ionosphere, along with the approach to inverting the measured emission profiles to derive the associated O+ profiles from 150–450 km in the nighttime ionosphere that directly reflect the electron density in the F-region of the ionosphere. 相似文献