SMART-1 mission description and development status     

G. D. Racca  A. Marini  L. Stagnaro  J. van Dooren  L. di Napoli  B. H. Foing  R. Lumb  J. Volp  J. Brinkmann  R. Grünagel  D. Estublier  E. Tremolizzo  M. McKay  O. Camino  J. Schoemaekers  M. Hechler  M. Khan  P. Rathsman  G. Andersson  K. Anflo  S. Berge  P. Bodin  A. Edfors  A. Hussain  J. Kugelberg  N. Larsson  B. Ljung  L. Meijer  A. Mrtsell  T. Nordebck  S. Persson  F. Sjberg 《Planetary and Space Science》2002,50(14-15)

SMART-1 is the first of the Small Missions for Advanced Research in Technology of the ESA Horizons 2000 scientific programme. The SMART-1 mission is dedicated to testing of new technologies for future cornerstone missions, using Solar-Electric Primary Propulsion (SEPP) in Deep Space. The chosen mission planetary target is the Moon. The target orbit will be polar with the pericentre close to the South-Pole. The pericentre altitude lies between 300 and 2000 km, while the apocentre will extend to about 10,000 km. During the cruise phase, before reaching the Moon, the spacecraft thrusting profile allows extended periods for cruise science. The SMART-1 spacecraft will be launched in the spring of 2003 as an auxiliary passenger on an Ariane 5 and placed into a Geostationary Transfer Orbit (GTO). The expected launch mass is about 370 kg, including 19 kg of payload. The selected type of SEPP is a Hall-effect thruster called PPS-1350. The thruster is used to spiral out of the GTO and for all orbit maneuvers including lunar capture and descent. The trajectory has been optimised by inserting coast arcs and the presence of the Moon's gravitational field is exploited in multiple weak gravity assists.The Development Phase started in October 1999 and is expected to be concluded by a Flight Acceptance Review in January 2003. The short development time for this high technology spacecraft requires a concerted effort by industry, science institutes and ESA centres. This paper describes the mission and the project development status both from a technical and programmatic standpoint.  相似文献   

The Remanent Magnetization of the Basic Tertiary Igneous Rocks of Skye, Inverness-shire     

Mohammed Aftab Khan 《Geophysical Journal International》1960,3(1):45-62

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Identical Frequency Correlations of two Irrotational Force Fields of a Nearly Spherical Planet     

Mohammad Asadullah Khan 《Geophysical Journal International》1971,23(4):411-415

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A three-dimensional finite element program for brittle bimodular rock-like materials     

Akhtar S. Khan  Si Yuan 《国际地质力学数值与分析法杂志》1988,12(6):599-609

The present paper models the behaviour of bimodular materials (materials with different tensile and compressive moduli) by using a three-dimensional finite element method. Since there is no explicit and definite expression for the shear modulus G of bimodular materials, the analysis starts with a 3 × 3 elasticity matrix in the principal stress coordinate system, and then uses a transformation from principal to Cartesian coordinates to obtain the 6 × 6 elasticity matrix. A corresponding iterative technique is proposed, and multiloading sequences in non-proportionate loading—which need more iterations because of the non-linear elastic property—are also discussed. Numerical examples are presented which show good agreement with analytical results.  相似文献   

General Solution of the Problem of Hydrostatic Equilibrium of the Earth     

Mohammad Asadullah Khan 《Geophysical Journal International》1969,18(2):177-188

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Growth and decay of sonic discontinuities in non-equilibrium magnetogasdynamics     

B. G. Verma  R. C. Srivastava  A. H. Khan 《Astrophysics and Space Science》1983,94(2):361-369

The phenomenon associated with sonic discontinuities in non-equilibrium magnetogasdynamics has been studied by the use of singular surface theory. The fundamental differential equations for growth and decay of sonic discontinuities have been formulated for general class of relaxing gas applying compatibility conditions for surface of discontinuity in continuum mechanics. This class of equations have been solved completely and for particular case of plane. We have also obtained the critical time at which sonic wave terminates in shock wave.  相似文献   

Statistical significance of some optical evidence for the bending of the galactic plane     

D. Sher 《Astrophysics and Space Science》1972,18(2):468-471

It is argued on the basis of an analysis of variance test that the distribution of Wolf-Rayet stars in the Galaxy departs systematically from the plane in the same sense as the neutral hydrogen.  相似文献   

A Detailed Opaque Petrological and Magnetic Investigation of a Single Tertiary Lava Flow from Skye, Scotland—III     

J. M. Ade-Hall  M. A. Khan  P. Dagley  R. L. Wilson 《Geophysical Journal International》1968,16(4):401-415

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CHEMICAL CHARACTERISTICS OF WETLAND＇S INFLOW DRY DIFFUSE DUST AND DIRT FROM IMPERVIOUS SURFACE     

Azam Khan　Saadat Ashraf 《湿地科学》2005,3(4):249-257

This paper presented chemical characteristics of wetland inflow diffuse dust and dirt. Single land use impervious areas (parking and roads) were observed and analyzed in commercial and residential areas for organic matters, phosphorus and heavy metals. The buildup data were collected for approximately six months from December to June. The frequency of monitoring was observed daily for the first two months, twice a week for the next two months and once a week for the last two months. The results indicated significant variations in the organic matters and heavy metals strength and total accumulation among the observed areas. High pollutants strength was associated with smaller dust and dirt (DD) particles. Concentrations of phosphorus varied between 5.1 μg/g and 8.3 μg/g in DD particle less than 75 μm and account for 35%-60% of the total phosphorus. The organic matter accumulation rate associated with particles less than 600 μm and greater than 600 μm was 0.1-1 g·(curb-m)-1·d-1 and 0.1-1.5 g·(curb-m)-1·d-1 , respectively. DD particles greater than 600 μm consist of 70%-90% of leaves and other plant residues. The strength of heavy metals was more at road compared to parking areas both in commercial and residential areas. Percentage of Zn, Cu and Pb attached with particles less than 200 μm were in the range of 50%-70% in parking, 45%-90% on smooth roads and 30%-80% on rough roads. All the dust and dirt exhibited rising trend with time. Dust and dirt buildup data follow a non-linear accumulation function and can be presented better either by an exponential or power function.  相似文献   

Groundwater hydrochemistry of a sugarcane cultivation belt in parts of Muzaffarnagar district, Uttar Pradesh, India     

R. Umar  M. Muqtada A. Khan  A. Absar 《Environmental Geology》2006,49(7):999-1008

The Kali-Hindon is a watershed in the most productive central Ganga plain of India. The whole area is a fertile track with sugarcane being the principal crop. Systematic sampling was carried out to assess the source of dissolved ions, impact of sugar factories and the quality of groundwater. Thirty-six samples were collected covering an area of 395 km². The quality of groundwater is suitable for irrigational purposes but is rich in SO₄ which is not best for human consumption. Graphical treatment of major ion chemistry helps identify six chemical types of groundwater. All possible species such as Na–Cl, K–Cl, Na–HCO₃, Na–SO₄, Ca–HCO₃, Mg–HCO₃, Ca–SO₄ and Mg–SO₄ are likely to occur in the groundwater system. The most conspicuous change in chemistry of groundwater is relative enrichment of SO₄. The interpretation of data reveals that SO₄ has not been acquired through water–rock interaction. The source of SO₄ is anthropogenic. Sugar factories alone are responsible for this potential environmental hazard.  相似文献