Dependent Variables

Dependent variables can be added to the propagation settings by first defining a list of desired dependent variables, which is supplied as input argument to the translational(), rotational(), mass(), custom_state() or multitype() propagators.

Each dependent variable is created via a dedicated factory function. See the example below for the definition of four separate dependent variables:

dependent_variables_to_save = [
    propagation_setup.dependent_variable.total_acceleration( "Delfi-C3" ),
    propagation_setup.dependent_variable.keplerian_state( "Delfi-C3", "Earth" ),
    propagation_setup.dependent_variable.latitude( "Delfi-C3", "Earth" ),
    propagation_setup.dependent_variable.longitude( "Delfi-C3", "Earth" )
]

this list is then added to one of the propagator setting functions listed above.

You can find a full list of dependent variables that can be saved in our API documentation. Note that all dependent variables are provided in SI units (meters, radians, kilograms, seconds since J2000).