Possibility to augment spacecraft state

Orekit usage
1

Hi all!

I open this topic to ask if it possible in Orekit to create an augmented spacecraft state. For example, for some applications it is useful to include in the spacecraft state the mass and the thruster acceleration components.

X_augmented = [x, y, z, vx, vy, vz, m, Tx, Ty, Tz]

Augmenting the spacecraft state implies to include additional differential equations (one for every additional state). In this case I would need to add the time differential equations for the spacecraft mass, and for the thrust acceleration components.

Assuming that I have the time laws for the thrust acceleration components (and so I can derive the differential equations for all the additional states), my question is if Orekit provides some built-in classes to handle this problem or there is no possibility to augment the spacecraft state.

Regards,

Marco

2

Hi,

The mass is already included in SpacecraftState.
As for the thrust, you could simply retrieve it afterwards from a Maneuver that you’ve added to your NumericalPropagator, no need to add it to your state as the thrust components are not state variables anyway in the sense of dynamical systems.

Cheers,
Romain.

3

Hi Romain,

thank you for the answer. Is it possible to retrieve also information about the derivatives of the thrust acceleration components with respect to the spacecraft state?

For example, if I have a control thrust that is function of some orbital elements and I have some uncertainty information (variance) regarding the thrust magnitude and pointing direction, what should be the best approach to include these uncertainties in the numerical propagation?