排序方式: 共有30条查询结果,搜索用时 46 毫秒
11.
Three 2.104 s observations were carried out with EXOSAT on three fields following the shock from the north to the east of the Cygnus Loop supernova remnant. Due to the softness of the source, most of the photons were collected with the LE package (CMA). For each exposure we used at least three filters (4000 Å lexan, Al-Par, boron) in order to extract the maximum spectral information from the data. The few photons gathered with the boron filter are particularly important in that respect. The total count number collected with the other filters allows a statistically significant overall mapping of the fields with 1*1 pixels, but a better resolution can be achieved on the brightest areas of the Loop. Interesting details are revealed, such as bright small spots. Irregularities are also evident both in the shock front and inside the remnant, specially in the northern and eastern fields. 相似文献
12.
Émilie Hardy Agnès Levy Manuel Rodrigues Pierre Touboul Gilles Métris 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2013
The MICROSCOPE space mission aims to test the Equivalence Principle with an accuracy of 10-15. The drag-free micro-satellite will orbit around the Earth and embark a differential electrostatic accelerometer including two cylindrical test masses submitted to the same gravitational field and made of different materials. The experience consists in testing the equality of the electrostatic acceleration applied to the masses to maintain them relatively motionless. The accuracy of the measurements exploited for the test of the Equivalence Principle is limited by our a priori knowledge of several physical parameters of the instrument. These parameters are partially estimated on-ground, but with an insufficient accuracy, and an in-orbit calibration is therefore required to correct the measurements. The calibration procedures have been defined and their analytical performances have been evaluated. In addition, a simulator software including the dynamics model of the instrument, the satellite drag-free system and the perturbing environment has been developed to numerically validate the analytical results. After an overall presentation of the MICROSCOPE mission, this paper will describe the calibration procedures and focus on the simulator. Such an in-flight calibration is mandatory for similar space missions taking advantage of a drag-free system. 相似文献
13.
Philippe Beaumier Gilles Arnaud Christophe Castellin 《Aerospace Science and Technology》1999,3(8):473-484
The performance prediction of helicopter in hover is of key importance for manufacturers because hover is a design configuration for the definition of a rotorcraft. A lot of effort has been made for more than 10 years all over the world in order to develop and validate numerical methods based on CFD. An Euler method (WAVES) developed by ONERA and coupled with a boundary layer code (MI3DI) is presented, validated and applied to compute the total performance of rotors with different tip shapes. A new boundary condition for the Euler code has been tested and enables better calculation by eliminating ‘numerical' recirculation. The code has demonstrated its ability to rank two rotors with different planforms in good agreement with experiment. Under industrial requirements new grid strategies have been studied and should allow to reduce CPU time consumption. It is shown that WAVES/MI3DI can be efficiently used in the aerodynamic design process of a new rotor. 相似文献
14.
15.
Gillmann Cedric Way M. J. Avice Guillaume Breuer Doris Golabek Gregor J. Höning Dennis Krissansen-Totton Joshua Lammer Helmut O’Rourke Joseph G. Persson Moa Plesa Ana-Catalina Salvador Arnaud Scherf Manuel Zolotov Mikhail Y. 《Space Science Reviews》2022,218(7):1-21
Space Science Reviews - The BepiColombo Environment Radiation Monitor (BERM) on board the European Space Agency’s Mercury Planetary Orbiter (MPO), is designed to measure the radiation... 相似文献
16.
Significant advances have been made during the last decade in several fields of solid propulsion: the advances have enabled new savings in the motor development phase and recurring costs, because they help limit the number of prototypes and tests.The purpose of the paper is to describe the improvements achieved by SNPE in solid grain technologies, making these technologies available for new developments in more efficient and reliable future SRMs: new energetic molecules, new solid propellants, new processes for grain manufacturing, quick response grain design tools associated with advanced models for grain performance predictions.Using its expertise in chemical synthesis, SNPE develops new molecules to fit new energetic material requirements.Tests based on new propellant formulations have produced good results in the propellant performance/safety behavior ratio. New processes have been developed simultaneously to reduce the manufacturing costs of the new propellants.In addition, the grain design has been optimized by using the latest generation of predictive theoretical tools supported by a large data bank of experimental parameters resulting from over 30 years' experience in solid propulsion:
- • Computer-aided method for the preliminary grain design
- • Advanced models for SRM operating and performance predictions
References
A Davenas, D Boury, M Calabro, B D'Andrea and A Mc Donald, Solid Propulsion for Space Applications: A Roadmap, 51st IAF Congress, Rio de Janeiro, Brazil (2000).
H Austruy, M Biagioni and Y Pelipenko, Improvement in Propellant and Process for Ariane 5 Boosters (1998) AIAA 98-35588.
Y Longevialle, M Golfier, H Graindorge and G Jacob, The use of new molecules in high performances energetic materials, NDIA Insensible munitions and energetic materials technology symposium, Tampa, Florida (1999).
A.T. Nielsen, J. Org. Chem. 55 (1990), pp. 1459–1466 US Patent 5 693 794, 30/09/1998. Full Text via CrossRef | View Record in Scopus | Cited By in Scopus (58)
Bescond P, Graindorge H, Mace H, EP 913374, 6/05/1999.
G Jacob, G Lacroix and V Destombes, Identification and analysis of impurities of HNIW, 31st Annual Conference of ICT (2000).
B D'Andrea, F Lillo, A Faure and C Perut, A New Generation of Solid Propellants for Space Launchers, 50th IAF Congress, Amsterdam, The Netherlands (1999).
D.W. Doll and G.K. Lund, Magnesium neutralized clean propellant (1991) AIAA 91-2560.
C. Beckman, Clean propellants for space launch boosters, Propulsion and Energetic Panel, 84th Symposium held in Aalesund, Norway (2921994).
B. D'Andrea, B. Lillo, A. Volpi, C. Zanotti and P. Giuliani, Advanced solid propellant composition for low environmental impact and negligible erosive effect, ISTS (1998) 98-a-1-12.
J.C Chastenet and A Mobuchon, Prediction of Air Bag Performance, 5 ISCP, Stresa, Italy (2000).
J. Thépénier, D. Ribereau and E. Giraud, Grain Design for thrust trace shaping in segmented solids for the SRBs IAF-99-S.2.09, 50th IAF Congress, Amsterdam, The Netherlands (1999).
J. Thépénier, D. Ribereau and E. Giraud, Application of advanced computational softwares in propellant grain analysis : a major contribution to future SRM development for space application IAF-97-S.4.06, 48th IAF Congress, Torino, Italy (97).
A. Davenas and J. Thépénier, Recent Progress in the prediction and analysis of the operation of Solid Rocket Motors IAF-98-S2.06, 49th IAF Congress, Melbourne, Australia (1998).
D. Ribéreau, P. Le Breton and E. Giraud, SRM 3D surface burnback computation using mixes stratification deduced from 3D grain filling simulation, AIAA 99-2802, 35th AIAA JPC Conference, Los Angeles, USA (1999).
Mary. Y; “Simulation de coulée gravitaire, validation du code MONTREAL.”, DEA mechanics report, 1995.
P. Le Breton, D. Ribéreau, F. Godfroy, R. Abgrall and S. Augoula, SRM Performance Analysis by coupling bidimensional surface burnback and Pressure field computations AIAA 98-3968, 34th AIAA JPC Conference, Cleveland, USA (1998).
P. Durand, B. Vieille, H. Lambare, P. Vuillermoz, G. Bourit and P. Steinfeld, A three dimensional CFD numerical Code dedicated to space propulsive flows AIAA 00-3864, 36th AIAA JPC Conference, Huntsville, USA (2000).
17.
Émilie Hardy Agnès Levy Gilles Métris Manuel Rodrigues Pierre Touboul 《Space Science Reviews》2013,180(1-4):177-191
The MICROSCOPE space mission aims at testing the Equivalence Principle (EP) with an accuracy of 10?15. The test is based on the precise measurement delivered by a differential electrostatic accelerometer on-board a drag-free microsatellite which includes two cylindrical test masses submitted to the same gravitational field and made of different materials. The experiment consists in testing the equality of the electrostatic acceleration applied to the masses to maintain them relatively motionless at a well-known frequency. This high precision experiment is compatible with only very little perturbations. However, aliasing arises from the finite time span of the measurement, and is amplified by measurement losses. These effects perturb the measurement analysis. Numerical simulations have been run to estimate the contribution of a perturbation at any frequency on the EP violation frequency and to test its compatibility with the mission specifications. Moreover, different data analysis procedures have been considered to select the one minimizing these effects taking into account the uncertainty about the frequencies of the implicated signals. 相似文献
18.
Florent Deleflie Alessandro Rossi Christophe Portmann Gilles Métris François Barlier 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
This paper aims at investigating the stability over 150 years of a very large number of trajectories in the Medium Earth Orbit (MEO) region, near the orbits devoted to radionavigation such as the Global Navigation Satellite Systems (GNSS like GPS, Glonass, Galileo, COMPASS). 相似文献
19.
Arnaud Masson Ondrej Santolík Donald L. Carpenter Fabien Darrouzet Pierrette M. E. Décréau Farida El-Lemdani Mazouz James L. Green Sandrine Grimald Mark B. Moldwin František Němec Vikas S. Sonwalkar 《Space Science Reviews》2009,145(1-2):137-191
This paper highlights significant advances in plasmaspheric wave research with Cluster and Image observations. This leap forward was made possible thanks to the new observational capabilities of these space missions. On one hand, the multipoint view of the four Cluster satellites, a unique capability, has enabled the estimation of wave characteristics impossible to derive from single spacecraft measurements. On the other hand, the Image experiments have enabled to relate large-scale plasmaspheric density structures with wave observations and provide radio soundings of the plasmasphere with unprecedented details. After a brief introduction on Cluster and Image wave instrumentation, a series of sections, each dedicated to a specific type of plasmaspheric wave, put into context the recent advances obtained by these two revolutionary missions. 相似文献
20.