SpacecraftState question

Orekit development
1

Hi again,

Another question, and this has likely be discussed at length somewhere, but when working with recent TLE generations we found that SpacecraftState has the two options of either be based on an orbit or on absolutePV coordinate. In the TLE conversion, it seems like only the orbit version of internal representation is allowed. Is there a basis of this, my initial expectation would be that SpacecraftState is a internally stateless representation of an object? Not sure this is a bug or more something that has been discussed. Somehow it feels like if they are really different representations they should almost be different types.

Regards!

2

Hi Petrus,

We are very sorry for this late answer.

The capability of initializing a spacecraft’s state based on AbsolutePVCoordinates was initially motivated to perform orbit propagations in non inertial frames (e.g., orbit propagation around Lagrangian points). Indeed, the implementation using Orbit objects first verify if the given orbit is expressed in inertial frame. Because the TEME frame used to define the TLE is an inertial frame, the TLE conversion methods use the spacecraft’s state definition based on Orbit.

Best regards,
Bryan

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