Solar Sail Range Limit

A solar sail needs no propellant — it is pushed outward purely by the momentum of reflected sunlight. But that photon push is tied directly to sunlight intensity, which thins out with the inverse square of distance from the Sun, exactly like heat and light themselves. This simulator flies a solar-sail spacecraft outward through the solar system alongside a conventional propellant-driven spacecraft, tracking both crafts' thrust in real time: the sail's thrust collapses the farther it travels, while the propellant engine's thrust never changes, no matter how far from the Sun it flies.