Build the coordinate machinery every flight dynamics system depends on — your way.
No step-by-step this time. You are given a specification and the acceptance criteria; the architecture is yours. Build a module that converts between a Cartesian state vector (r, v) and the six classical orbital elements — both directions — and plots the ground track of an orbit.
Write rv_to_coe(r, v, mu) and coe_to_rv(a, e, i, raan, argp, nu, mu). A round-trip through both must return the original state to numerical precision. Then plot the ground track for the ISS orbit.