Space-Fixed Position, Velocity, and Acceleration Vectors of a Landed Spacecraft Relative to Center of Mass of Planet, Planetary System, or the Moon

2005 ◽  
pp. 183-203
Keyword(s):  
Planetary System ◽  
Center Of Mass ◽  
The Moon ◽  
Fixed Position

scholarly journals Polyaxial Figures of the Moon

2011 ◽  
Vol 1 (4) ◽  
pp. 348-354 ◽  
Author(s):  
H. İz ◽  
X. Ding ◽  
C. Dai ◽  
C. Shum
Keyword(s):  
Center Of Mass ◽  
The Moon ◽  
Shape Parameters ◽  
Axially Symmetric ◽  
Laser Altimetry ◽  
Additional Information ◽  
All Solutions ◽  
Ellipsoidal Model ◽  
Lunar Topography ◽  
Topography Model

Polyaxial Figures of the MoonThis study investigates various models to represent the gross geometric shape of the Moon. Asymmetric polyaxial geometric models-namely three-, four- and six-axial lunar figure - are compared and contrasted with the axially symmetric three-axis ellipsoidal model derived from Chang'e 1 and SELENE laser altimetry data. All solutions confirm a hydrostatically stable lunar shape shifted with respect to the lunar center of mass by topography. Model solutions with increasing complexity offer additional information about the regional properties of the lunar topography. Solution statistics suggest that axially symmetric lunar figures and their center of figure parameters can be replaced by an equivalent asymmetric lunar shape centered at the center of mass of the Moon. Thus, using only three shape parameters, one can derive an "egg" shape that better accommodates the true geometry of the Moon.

Comment on the center‐of‐mass offset of the moon

1978 ◽  
Vol 46 (7) ◽  
pp. 762-762
Author(s):  
Allan Walstad
Keyword(s):  
Center Of Mass ◽  
The Moon

scholarly journals Libration of the Moon: shape of the Earth and motion of the ecliptic plane

1986 ◽  
Vol 114 ◽  
pp. 141-144
Author(s):  
M. Moons
Keyword(s):  
Gravity Field ◽  
Spherical Harmonics ◽  
Fourth Order ◽  
Center Of Mass ◽  
Ecliptic Plane ◽  
The Sun ◽  
Lunar Gravity ◽  
The Moon ◽  
Lunar Gravity Field ◽  
The Earth

Very accurate theories of the libration of the Moon have been recently built by Migus (1980), Eckhardt (1981, 1982) and Moons (1982, 1984). All of them take into account the perturbation due to the Earth and the Sun on the motion of a rigid Moon about its center of mass. Additional perturbations (influence of the planets, shape of the Earth, elasticity of the Moon, …) are also often included.We present here the perturbations due to the shape of the Earth and the motion of the ecliptic plane on our theory which already contains planetary perturbations. This theory is completely analytical with respect to the harmonic coefficients of the lunar gravity field which is expanded in spherical harmonics up to the fourth order. The ELP 2000 solution (Chapront and Chapront-Touzé, 1983) supplies us with the motion of the center of mass of the Moon.

scholarly journals A New Look at the Sun

1974 ◽  
Vol 3 ◽  
pp. 3-19 ◽  
Author(s):  
J. P. Wild
Keyword(s):  
Nuclear Energy ◽  
Planetary System ◽  
The Sun ◽  
The Moon ◽  
Atomic Spectra ◽  
Solar Astronomy ◽  
The Way ◽  
New Look

I have the feeling that to most astronomers the Sun is rather a nuisance. The reasons are quite complex. In the first place the Sun at once halves the astronomer’s observing time from 24 to 12 hours, and then during most of the rest of the time it continues its perversity by illuminating the Moon. Furthermore I have met numerous astronomers who regard solar astronomy to be now, as always before, in a permanent state of decline - rather like Viennese music or English cricket. Nevertheless those who study the Sun and its planetary system occasionally make significant contributions. There were, for instance, Galileo and Newton who gave us mechanics and gravitation; Fraunhofer who gave us atomic spectra; Eddington and Bethe who pointed the way to nuclear energy; and Alfvén who gave us magneto-hydrodynamics. Perhaps the point to be recognized is that the Sun has more immediately to offer to physics rather than to astronomy. That is why it is quite rare that a solar man finds himself with a large captive audience of mainline astronomers: and so the responsibility weighs heavily on my shoulders tonight.

scholarly journals On the Absolute Orientation of the Selenodetic Reference Frame

1981 ◽  
Vol 63 ◽  
pp. 281-286
Author(s):  
V. S. Kislyuk
Keyword(s):  
Coordinate System ◽  
Center Of Mass ◽  
The Moon ◽  
Coordinate Systems ◽  
Inertial Coordinate System ◽  
Reference Coordinate System ◽  
The Earth ◽  
Principal Axes ◽  
The Mean ◽  
Selection Of

The selection of selenodetic reference coordinate system is an important problem in astronomy and selenodesy. For the purposes of reduction of observations, planning and executing space missions to the Moon, it is necessary, in any case, to know the orientation of the adopted selenodetic reference system in respect to the inertial coordinate system.Let us introduce the following coordinate systems: C(ξc, ηc, ζc), the Cassini system which is defined by the Cassini laws of the Moon rotation;D(ξd, ηd, ζd), the dynamical coordinate system, whose axes coincide with the principal axes of inertia of the Moon;Q(ξq, ηq, ζq), the quasi-dynamical coordinate system connected with the mean direction to the Earth, which is shifted by 254" West and 75" North from the longest axis of the dynamical system (Williams et al., 1973);S(ξs, ηs, ζs), the selenodetic coordinate system, which is practically realized by the positions of the points on the Moon surface given in Catalogues;I(X,Y,Z), the space-fixed (inertial) coordinate system. All the systems are selenocentric with the exception of S(ξs, ηs, ζs On the whole, the origin of this system does not coincide with the center of mass of the Moon.

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