- #1
Rasalhague
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What does "not perturbative accelerations" mean in the following quote?
Bate, Mueller & White: Fundamentals of Astrodynamics, p. 11: "To simplify this equation [for the acceleration of a satellite due to gravity, with respect to the earth] it is necessary to determine the magnitude of the perturbing effects compared to the force between Earth and satellite. Table 1.2-1 lists the relative accelerations (not perturbative accelerations) for a satellite in a 200 n[autical] mi[le] orbit about the earth."
The table gives acceleration in G's due to the sun, the moon and each of the planets in the solar system, together with a value for acceleration due to the Earth's oblateness. E.g. sun 6x10-4, moon 3.3x10-6. From the context, and the expression "it is necessary to determine the magnitude of the perturbing effects", I'd expect the values in the table to be just that, perturbative effects. What distinction is it making? I thought perturbation, in this context, meant gravitational effects in addition to those described by a given simplified model such as, in this case, supposing that the only gravitational influence on the satellite was that of the Earth and that the Earth was perfectly spherical.
Bate, Mueller & White: Fundamentals of Astrodynamics, p. 11: "To simplify this equation [for the acceleration of a satellite due to gravity, with respect to the earth] it is necessary to determine the magnitude of the perturbing effects compared to the force between Earth and satellite. Table 1.2-1 lists the relative accelerations (not perturbative accelerations) for a satellite in a 200 n[autical] mi[le] orbit about the earth."
The table gives acceleration in G's due to the sun, the moon and each of the planets in the solar system, together with a value for acceleration due to the Earth's oblateness. E.g. sun 6x10-4, moon 3.3x10-6. From the context, and the expression "it is necessary to determine the magnitude of the perturbing effects", I'd expect the values in the table to be just that, perturbative effects. What distinction is it making? I thought perturbation, in this context, meant gravitational effects in addition to those described by a given simplified model such as, in this case, supposing that the only gravitational influence on the satellite was that of the Earth and that the Earth was perfectly spherical.