Function unpowered_flyby 

pub fn unpowered_flyby(
    mu_planet: Mu,
    v_inf_in: [f64; 3],
    r_periapsis: Km,
    flyby_plane_normal: [f64; 3],
) -> FlybyResult

Compute an unpowered (gravity-only) hyperbolic flyby.

The incoming v_infinity is rotated by the turn angle in the plane defined by the v_infinity vector and the periapsis direction.

Arguments

• mu_planet — Planet gravitational parameter (km³/s²)
• v_inf_in — Incoming v_infinity vector in planetocentric frame [km/s; 3]
• r_periapsis — Closest approach distance from planet center (km)
• flyby_plane_normal — Normal to the flyby plane (unit vector). The turn is applied in the plane perpendicular to this normal. For a 2D (ecliptic) flyby, use [0, 0, 1].