pub fn dsf_window_start(mach_0_9_distance_m: Option<f64>) -> Option<f64>Expand description
The downrange distance (m) at which the DSF (drag-scale-factor) window starts: 90% of the
downward Mach 0.9 crossing distance. None when the trajectory never crosses Mach 0.9 —
mirrors TrajectoryResult::mach_0_9_distance_m’s own None case, MBA-1405. pub: consumed
by the native CLI’s dsf verb (MBA-1405 Task 2).