astroforge.force_models.F_third#

astroforge.force_models.F_third(r_s, r_p, GM)[source]#

Compute the perturbing gravitational acceleration due to a third body.

Note

There is not a required set of units for this function, but the input units must be consistent. That is, if r_s is in units of km, then r_p must also be in units of km and GM must be in units of km³ / s².

Parameters:

r_s (NDArray[np.float64]) – Satellite position vector, should have shape (3, )
r_p (NDArray[np.float64]) – Perturbing body position vector, should have shape (3, )
GM (float) – Gravitational parameter of perturbing body

Returns:

a_p – Perturbing gravitational acceleration due to the third body

Return type:

NDArray[np.float64]

Examples

Compute the perturbing gravitational acceleration due to the Sun for a satellite in a GEO orbit around Earth:

>>> import astroforge as af
>>> x = np.array([af.Rgeo, 0.0, 0.0])
array([42164.17236443,     0.        ,     0.        ])
>>> rs = af.R_sun(51720.0)
>>> rs
array([-9.94416191e+06,  1.39217228e+08,  6.03580553e+07])
>>> GMsun = af.ss_GM["sun"]
>>> af.force_models.F_third(x, rs, GMsun)
array([-1.57084634e-09, -2.86422805e-10, -1.24179484e-10])

astroforge.force_models.F_third#

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