Investigate return case of de440s_transform_verif_venus2emb

[Chris]

Bug report

Bug reports will lead to a stakeholder need report, and will need to be linked to this issue

Describe the bug

The lower half of de440s_transform_verif_venus2emb in tests/ephemerides/transform.rs is disabled. The SPICE data shows that both queries should be strictly opposite. ANISE shows that it isn't the case, and it only matches SPICE when transforming from IAU VENUS to EARTH ITRF93, but not the other way around.

I wonder if somehow the rotations need to be applied in a given order? I'm really confused about this one.

Note that this only applies if there are rotations involved. If the frame is J2000, there is no issue.

Expected behavior

ANISE return computation should be the exact opposite of the original computation.

Code to reproduce the issue

Uncomment the lower part of the code of that test in release 0.1 of ANISE.

Platform

Rust, Linux

[Chris]

This bug also happens when rotating a spacecraft expressed in an inertial frame into a body fixed frame. My hunch is that if the frames differ, the intermediate states need to be rotated into an inertial frame immediately instead of performing one large rotation. I'll need to dive into the spkezr function to see where the rotations are performed.

The validation should include rotations of the Hermite BSP into the Earth body fixed frame and confirm that it matches SPICE.