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Independent research [41] found small amounts of lift from Brown's gravitator based on an inefficient use of ionic propulsion. The devices were named Ion Lifters or Ionocraft and were reported to be able to lift the empty shell of a vehicle under ideal conditions, but not the additional machinery required to generate the electric field. Gravity ...
However, a spherical harmonics series expansion captures the actual field with increasing fidelity. If Earth's shape were perfectly known together with the exact mass density ρ = ρ(x, y, z), it could be integrated numerically (when combined with a reciprocal distance kernel) to find an accurate model for Earth's gravitational field. However ...
The technique exploits the Earth's gravitational field and tidal forces to keep the spacecraft aligned along the desired orientation. The gravity of the Earth decreases according to the inverse-square law , and by extending the long axis perpendicular to the orbit, the "lower" part of the orbiting structure will be more attracted to the Earth.
In classical mechanics, a gravitational field is a physical quantity. [5] A gravitational field can be defined using Newton's law of universal gravitation. Determined in this way, the gravitational field g around a single particle of mass M is a vector field consisting at every point of a vector pointing directly towards the particle. The ...
The simplest case of the gravity turn trajectory is that which describes a point mass vehicle, in a uniform gravitational field, neglecting air resistance. The thrust force is a vector whose magnitude is a function of time and whose direction can be varied at will. Under these assumptions the differential equation of motion is given by:
In the theory of general relativity, linearized gravity is the application of perturbation theory to the metric tensor that describes the geometry of spacetime.As a consequence, linearized gravity is an effective method for modeling the effects of gravity when the gravitational field is weak.
For example, in a system composed of one planet orbiting a star, the motion of the planet is determined by solving the field equations with the energy–momentum tensor the sum of that for the planet and the star. The gravitational field of the planet affects the total spacetime geometry and hence the motion of objects. It is therefore ...
These satellite missions aim at the recovery of a detailed gravity field model of the Earth, typically presented in the form of a spherical-harmonic expansion of the Earth's gravitational potential, but alternative presentations, such as maps of geoid undulations or gravity anomalies, are also produced.