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Unmanned _ Chit Chat _ Problem I am having using SPICE to create .spk file

Posted by: ncc1701d Aug 21 2021, 04:58 AM

This question is for someone with experience making .spk files in SPICE and using MKSPK
I am over simplifying the data values to help explain or get to the point quicker.
I am working with real data from Pioneer 12 so the data I wouldnt think is the problem

True Anomaly values on approach to Periapsis go from -30 deg then -25 deg on down to then 0 deg at the point of periapsis and then goes back up to +30 deg as it leaves periapsis.

For the sake of discussion I use these numbers for True Anomaly.
-30 deg etc. on approach to periapsis
-0 deg True Anomaly at periapsis
30 deg leaving orbit after periapsis

Problem is when making the .spk and checking it in Cosmographia the approach trajectory looks normal but then stops right at 0 deg and then starts going backward practically overlapping the approach trajectory path.
I dont know why. Any SPICE .spk creators experience this phenom? I am using ELEMENTS for the input data type.


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