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enigma

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## Main Question or Discussion Point

Hi all,

hopefully someone can help me out here:

I'm looking at the Gibbs' method for orbit determination, and I'm losing the conceptual picture in the vector calculations.

I have no problems seeing how

Anyone have any insights?

I'm reading Vallado

hopefully someone can help me out here:

I'm looking at the Gibbs' method for orbit determination, and I'm losing the conceptual picture in the vector calculations.

I have no problems seeing how

**D**and**N**point in the**W**direction (**PQW**coordinate system), but I'll be damned if I can get a grip outside of simply swimming through the math why**S**: [(r2-r3)**r1**+ (r3-r1)**r2**+ (r1-r2)**r3**] points in the**Q**direction.Anyone have any insights?

I'm reading Vallado

*Fundamentals of Astrodynamics and Applications*section 7.5.1 if it helps.