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This set of models is often referred to collectively as SGP4 due to the frequency of use of that model particularly with two-line element sets produced by NORAD and NASA. These models predict the effect of perturbations caused by the Earth’s shape, drag, radiation, and gravitation effects from other bodies such as the sun and moon.
Pole figure and diffraction figure. Consider the diffraction pattern obtained with a single crystal, on a plane that is perpendicular to the beam, e.g. X-ray diffraction with the Laue method, or electron diffraction in a transmission electron microscope. The diffraction figure shows spots. The position of the spots is determined by the Bragg's ...
Orbital position vector, orbital velocity vector, other orbital elements. In astrodynamics and celestial dynamics, the orbital state vectors (sometimes state vectors) of an orbit are Cartesian vectors of position and velocity that together with their time () uniquely determine the trajectory of the orbiting body in space.
A two-line element set (TLE, or more rarely 2LE) or three-line element set (3LE) is a data format encoding a list of orbital elements of an Earth-orbiting object for a given point in time, the epoch. Using a suitable prediction formula, the state (position and velocity) at any point in the past or future can be estimated to some accuracy.
This article uses the standard notation ISO 80000-2, which supersedes ISO 31-11, for spherical coordinates (other sources may reverse the definitions of θ and φ): . The polar angle is denoted by [,]: it is the angle between the z-axis and the radial vector connecting the origin to the point in question.
In 4D space, the Hopf angles {ξ 1, η, ξ 2} parameterize the 3-sphere. For fixed η they describe a torus parameterized by ξ 1 and ξ 2, with η = π / 4 being the special case of the Clifford torus in the xy - and uz-planes. These tori are not the usual tori found in 3D-space. While they are still 2D surfaces, they are embedded in ...
The five equilibrium points of the circular problem are known as the Lagrangian points. See figure below: Restricted three-body problem. In the restricted three-body problem math model figure above (after Moulton), the Lagrangian points L 4 and L 5 are where the Trojan planetoids resided (see Lagrangian point); m 1 is the Sun and m 2 is Jupiter.
The state space or phase space is the geometric space in which the axes are the state variables. The system state can be represented as a vector , the state vector . If the dynamical system is linear, time-invariant, and finite-dimensional, then the differential and algebraic equations may be written in matrix form.