Comet Gravity Assist: Hyperbolic Flyby Deflection (2D)

This 2D companion drives the same Newtonian gravity-assist physics as the 3D scene through a plain top-down canvas built for reading the orbit rather than orbiting a rendered planet: the comet is placed directly on the exact hyperbolic solution for the chosen approach speed and impact parameter, three sliders (approach speed, impact parameter, planet mass) let you reshape the encounter, and a live panel sets the closed-form predicted deflection angle side by side with the angle actually measured from the RK4-integrated flight path — along with energy and angular-momentum drift as a running accuracy check — so the slingshot effect that reshapes real spacecraft and comet trajectories is directly verifiable instead of just animated.