Orbital Voyager

A spacecraft launches into a small solar system — one sun, four planets in circular orbits — and has to visit four fixed beacons scattered across deep space. The mission has a six-year window and a fuel budget, and one wrong turn flings it into the sun or off the edge of the map. The Genetic Algorithm (GA) decides what to do at every step of the way.

How it works

1. Each Reset reshuffles the seed. The same physics applies every time, but the launch pad shifts, so a plan from one run won't transfer to another.
2. Every roughly 0.1 simulated years the rocket pauses, and a fresh GA runs on our servers. It searches over candidate burns — a direction and a magnitude — starting from the spacecraft's actual current position, velocity, and remaining fuel.
3. The browser scores every candidate by simulating the next several months of flight through real Newtonian gravity. Sun crashes are heavily penalized, planet crashes less so, and progress toward the nearest unvisited beacon is rewarded.
4. The server picks the best burn and sends it back. The rocket applies the impulse and continues until the next decision point. This is closed-loop control: the GA always sees the live state, instead of trying to plan the whole mission in advance.
5. Each candidate has only two genes — burn direction and magnitude — so each inner GA converges in around ten generations and a fraction of a second.

What to watch

• While the rocket is paused at a decision point, faint trails appear from the craft. Each is a candidate burn the GA is considering; the brightest one is the current best.
• Once the rocket resumes, watch the beacons flip from green rings to gold checkmarks as the craft sweeps through them.
• Look for the trail kinking near a planet. The GA discovers gravitational slingshots — passing close at the right relative velocity to steal orbital energy — without being told they exist. Same trick NASA used to fly Voyager past the outer planets.
• Visiting all four beacons in one episode is the Grand Tour achievement.

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