N-body Velocity Verlet integrator with three scenarios: inner Solar System orbits, Lagrange Points with Jupiter Trojan asteroids, and a gravity-assist flyby past a giant planet.
Velocity Verlet integration is symplectic — it conserves energy over long timescales, making it ideal for orbital simulations. Gravity-assist transfers orbital energy between bodies.
Switch between scenarios. Watch Trojan asteroids librate around Jupiter's L4/L5 Lagrange points. In flyby mode, observe how a spacecraft gains speed from planetary encounter.
Voyager 2 used four consecutive gravity assists (Jupiter, Saturn, Uranus, Neptune) — a rare planetary alignment that occurs only every 175 years. The next one is around 2152.