two_body_dynamics#

Functions for (semi-)analytical calculations in a simple two-body point-mass system.

Functions#

propagate_kepler_orbit(...[, root_finder])

Function to propagate Keplerian elements to a later epoch, assuming an unperturbed system.

propagate_kepler_orbit(initial_kepler_elements: numpy.ndarray[numpy.float64[6, 1]], propagation_time: float, gravitational_parameter: float, root_finder: tudatpy.kernel.math.root_finders.RootFinderCore = None) numpy.ndarray[numpy.float64[6, 1]]#

Function to propagate Keplerian elements to a later epoch, assuming an unperturbed system.

Function to propagate Keplerian elements to a later epoch, assuming an unperturbed system. This function will take the initial Keplerian elements, and propagate the true anomaly in time as per the requested input. This is done by converting true anomaly to mean anomaly, apply the constant rate in mean motion for the requested time, and converting the result back to true anomaly. Currently both elliptic and hyperbolic orbits are supported. Parabolic orbits are not supported and will result in an error message.

Parameters:
  • initial_kepler_elements (numpy.ndarray) – Keplerian elements that are to be propagated (see element_conversion for order)

  • propagation_time (float) – Time for which the elements are to be propagated w.r.t. the initial elements

  • gravitational_parameter (float) – Gravitational parameter of central body used for propagation

  • root_finder (RootFinder, default = None) – Root finder used to solve Kepler’s equation when converting mean to eccentric anomaly. When no root finder is specified, the default option of the mean to eccentric anomaly function is used (see :func:`~mean_to_eccentric_anomaly’).

Returns:

Keplerian elements, propagated in time from initial elements assuming unperturbed dynamics. Note that the true anomaly is returned within the -PI to PI spectrum. If the user desires a different spectrum (possibly including the number of revolutions), these should be added by the user a posteriori.

Return type:

numpy.ndarray