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M. Grasso A. Renga G. Fasano M.D. Graziano M. Grassi A. Moccia 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2021,67(11):3909-3923
The paper focuses on space system design aspects related to an end-to-end demonstration mission, aiming at showing the feasibility of a Formation Flying Synthetic Aperture Radar (FF-SAR) with microsatellite class platforms (~100 kg). Trajectory design approaches that can fulfil payload requirements are addressed to enable selected FF-SAR applications. The exploitation of these applications relies on suitable combinations of FF-SAR techniques like Signal-to-Noise Ratio (SNR) enhancement, High-Resolution Wide Swath (HRWS) SAR imaging, and Coherence Resolution Enhancement (CRE). In this framework, a cluster of 3 micro-satellites, working in X-band, flying in a Low Earth Orbit (LEO) close-formation, has been designed as a candidate end-to-end system demonstration mission. One satellite embarks a Transmitting-Receiving (Tx/Rx) radar, i.e. it is a monostatic SAR. The other two satellites are Receiving-only platforms. Critical design aspects related to spacecraft subsystems and formation-flying analysis are addressed to confirm the technical feasibility of the spaceborne distributed system implementing the FF-SAR principle. 相似文献
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Peslier Anne H. Schönbächler Maria Busemann Henner Karato Shun-Ichiro 《Space Science Reviews》2017,212(1-2):811-811
Space Science Reviews - Correction to: Space Sci Rev DOI This article has been corrected. Figure 3 was initially published with erroneous axis titles in Fig. 3B and 3D where the $x$ axis should be... 相似文献
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Gordon Chin Scott Brylow Marc Foote James Garvin Justin Kasper John Keller Maxim Litvak Igor Mitrofanov David Paige Keith Raney Mark Robinson Anton Sanin David Smith Harlan Spence Paul Spudis S. Alan Stern Maria Zuber 《Space Science Reviews》2007,129(4):391-419
NASA’s Lunar Precursor Robotic Program (LPRP), formulated in response to the President’s Vision for Space Exploration, will
execute a series of robotic missions that will pave the way for eventual permanent human presence on the Moon. The Lunar Reconnaissance
Orbiter (LRO) is first in this series of LPRP missions, and plans to launch in October of 2008 for at least one year of operation.
LRO will employ six individual instruments to produce accurate maps and high-resolution images of future landing sites, to
assess potential lunar resources, and to characterize the radiation environment. LRO will also test the feasibility of one
advanced technology demonstration package. The LRO payload includes: Lunar Orbiter Laser Altimeter (LOLA) which will determine
the global topography of the lunar surface at high resolution, measure landing site slopes, surface roughness, and search
for possible polar surface ice in shadowed regions, Lunar Reconnaissance Orbiter Camera (LROC) which will acquire targeted
narrow angle images of the lunar surface capable of resolving meter-scale features to support landing site selection, as well
as wide-angle images to characterize polar illumination conditions and to identify potential resources, Lunar Exploration
Neutron Detector (LEND) which will map the flux of neutrons from the lunar surface to search for evidence of water ice, and
will provide space radiation environment measurements that may be useful for future human exploration, Diviner Lunar Radiometer
Experiment (DLRE) which will chart the temperature of the entire lunar surface at approximately 300 meter horizontal resolution
to identify cold-traps and potential ice deposits, Lyman-Alpha Mapping Project (LAMP) which will map the entire lunar surface
in the far ultraviolet. LAMP will search for surface ice and frost in the polar regions and provide images of permanently
shadowed regions illuminated only by starlight. Cosmic Ray Telescope for the Effects of Radiation (CRaTER), which will investigate
the effect of galactic cosmic rays on tissue-equivalent plastics as a constraint on models of biological response to background
space radiation. The technology demonstration is an advanced radar (mini-RF) that will demonstrate X- and S-band radar imaging
and interferometry using light weight synthetic aperture radar. This paper will give an introduction to each of these instruments
and an overview of their objectives. 相似文献
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Maria T. Zuber Oded Aharonson Jonathan M. Aurnou Andrew F. Cheng Steven A. Hauck II Moritz H. Heimpel Gregory A. Neumann Stanton J. Peale Roger J. Phillips David E. Smith Sean C. Solomon Sabine Stanley 《Space Science Reviews》2007,131(1-4):105-132
Current geophysical knowledge of the planet Mercury is based upon observations from ground-based astronomy and flybys of the
Mariner 10 spacecraft, along with theoretical and computational studies. Mercury has the highest uncompressed density of the
terrestrial planets and by implication has a metallic core with a radius approximately 75% of the planetary radius. Mercury’s
spin rate is stably locked at 1.5 times the orbital mean motion. Capture into this state is the natural result of tidal evolution
if this is the only dissipative process affecting the spin, but the capture probability is enhanced if Mercury’s core were
molten at the time of capture. The discovery of Mercury’s magnetic field by Mariner 10 suggests the possibility that the core
is partially molten to the present, a result that is surprising given the planet’s size and a surface crater density indicative
of early cessation of significant volcanic activity. A present-day liquid outer core within Mercury would require either a
core sulfur content of at least several weight percent or an unusual history of heat loss from the planet’s core and silicate
fraction. A crustal remanent contribution to Mercury’s observed magnetic field cannot be ruled out on the basis of current
knowledge. Measurements from the MESSENGER orbiter, in combination with continued ground-based observations, hold the promise
of setting on a firmer basis our understanding of the structure and evolution of Mercury’s interior and the relationship of
that evolution to the planet’s geological history. 相似文献
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The cyanobacterium Chroococcidiopsis, overlain by 3?mm of Antarctic sandstone, was exposed as dried multilayers to simulated space and martian conditions. Ground-based experiments were conducted in the context of Lichens and Fungi Experiments (EXPOSE-E mission, European Space Agency), which were performed to evaluate, after 1.5 years on the International Space Station, the survival of cyanobacteria (Chroococcidiopsis), lichens, and fungi colonized on Antarctic rock. The survival potential and the role played by protection and repair mechanisms in the response of dried Chroococcidiopsis cells to ground-based experiments were both investigated. Different methods were employed, including evaluation of the colony-forming ability, single-cell analysis of subcellular integrities based on membrane integrity molecular and redox probes, evaluation of the photosynthetic pigment autofluorescence, and assessment of the genomic DNA integrity with a PCR-based assay. Desiccation survivors of strain CCMEE 123 (coastal desert, Chile) were better suited than CCMEE 134 (Beacon Valley, Antarctica) to withstand cellular damage imposed by simulated space and martian conditions. Exposed dried cells of strain CCMEE 123 formed colonies, maintained subcellular integrities, and, depending on the exposure conditions, also escaped DNA damage or repaired the induced damage upon rewetting. 相似文献
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Gravity Recovery and Interior Laboratory (GRAIL): Mapping the Lunar Interior from Crust to Core 总被引:1,自引:0,他引:1
Maria T. Zuber David E. Smith David H. Lehman Tom L. Hoffman Sami W. Asmar Michael M. Watkins 《Space Science Reviews》2013,178(1):3-24
The Gravity Recovery and Interior Laboratory (GRAIL) is a spacecraft-to-spacecraft tracking mission that was developed to map the structure of the lunar interior by producing a detailed map of the gravity field. The resulting model of the interior will be used to address outstanding questions regarding the Moon’s thermal evolution, and will be applicable more generally to the evolution of all terrestrial planets. Each GRAIL orbiter contains a Lunar Gravity Ranging System instrument that conducts dual-one-way ranging measurements to measure precisely the relative motion between them, which in turn are used to develop the lunar gravity field map. Each orbiter also carries an Education/Public Outreach payload, Moon Knowledge Acquired by Middle-School Students (MoonKAM), in which middle school students target images of the Moon for subsequent classroom analysis. Subsequent to a successful launch on September 10, 2011, the twin GRAIL orbiters embarked on independent trajectories on a 3.5-month-long cruise to the Moon via the EL-1 Lagrange point. The spacecraft were inserted into polar orbits on December 31, 2011 and January 1, 2012. After a succession of 19 maneuvers the two orbiters settled into precision formation to begin science operations in March 1, 2012 with an average altitude of 55 km. The Primary Mission, which consisted of three 27.3-day mapping cycles, was successfully completed in June 2012. The extended mission will permit a second three-month mapping phase at an average altitude of 23 km. This paper provides an overview of the mission: science objectives and measurements, spacecraft and instruments, mission development and design, and data flow and data products. 相似文献
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Lutz Rastätter Maria M. Kuznetsova David G. Sibeck David H. Berrios 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2012
In this paper we present recent additions to the visualization toolset offered by the Community Coordinated Modeling Center (CCMC). Two suites of visualization tools are available that can address different needs during the analysis of model simulations of the magnetosphere that are provided by the CCMC. The online, server-side visualization allows the user to quickly browse through simulation runs and now can create maps of magnetic field line topology in the magnetosphere. The second tool, SWX, can be used on the client computer after data have been downloaded. With this second tool the user can interact directly with the three-dimensional objects that are being rendered. We present results from a simulation of a Flux Transfer Event that was performed at the CCMC using a magnetohydrodynamic model of the Earth’s magnetosphere with a high resolution grid focused on the dayside magnetosheath and dayside magnetopause. The simulation shows that the FTE that results from localized magnetic reconnection is a complicated three-dimensional structure that requires modern visualization techniques. Visualization techniques that are presented here allow the researcher to fully appreciate the complexity contained in magnetospheric simulation results. 相似文献