Show HN: A self-running space economy SIM in Rust and Bevy The Space Project, an agent-driven space economy simulation built in Rust and Bevy, is now open-source under MIT. The simulation runs hundreds of autonomous ships, facilities, populations, and factions in a single native binary with no runtime dependencies, featuring a GOAP planner for ship AI and a coverage-model market system. Creator 'kettlecorn' released the code after rewriting it from Elixir/Phoenix to Rust, aiming for others to build upon the simulation engine. A self-running space-economy simulator, in Rust + Bevy. Hundreds of autonomous ships trade, mine, haul cargo, take out contracts, run out of fuel, and occasionally go bankrupt across a living solar economy — markets find their own prices, factions tax and subsidize, populations migrate when they're unhappy, and abandoned stations rot. It all runs in one native binary with no runtime dependencies. The Space Project is an agent-driven economic simulation wrapped in a native 3D client. There's no scripted storyline and no player objective — you're an observer and god-mode admin watching an economy run itself. Every ship is an autonomous agent with its own credits, crew, fuel, cargo hold, and a GOAP planner that decides what to do next: chase the highest-margin trade route, accept a delivery contract, seek out a shipyard to retrofit, or dock and let its crew rest before morale collapses. Facilities run production recipes, degrade and self-repair, level up, and get abandoned when they go broke. Factions collect taxes and post subsidies. Populations consume food, produce labor, and pack up and leave when sentiment craters. Markets price everything off a coverage model with shortage urgency multipliers — no fixed prices anywhere. It started as an Elixir/Phoenix prototype and was rewritten in Rust because the BEAM scheduler struggled on Windows gaming PCs. The engine sim core is pure, synchronous, IO-free Rust; the Bevy client embeds it directly as a library, so the simulation and the renderer share the same ECS world with zero marshalling between them. Scale today: ~485 live agents 282 ships · 93 facilities · 27 populations · 8 factions · 60 celestial bodies , ticking at p50 ≈ 10–20 ms inside a 125 ms budget. The architecture is built to push toward 100k+. Nowhere, on its own — and that's kind of the point.This started as a fun idea: a from-scratch space economy that actually simulates itself instead of faking it. It grew waypast what I expected, mostly in late-night sessions pairing with Claude. But I'm not pretending it's a game with a roadmap, and I'm not actively pushing it toward "shippable."I'm putting it out under MIT because the bones are genuinely good and I'd rather someone do something with it than let it sit in a private repo. So: fork it, gut it, rename it, bolt a game on top of it, rip the economy engine out and use it somewhere else entirely.Build the thing I didn't.PRs and issues are welcome and I'll look at them, but I can't promise a cadence. If you want to take it somewhere real, see CONTRIBUTING.md — there's a "directions you could take this" section written exactly for you. | System | What happens | |---|---| Ship AI GOAP | A forward planner scores every goal — trade, deliver, refuel, retrofit, rest, explore — over an abstract world state, then builds a behavior tree to execute the cheapest plan. Ships replan mid-flight when a better option appears. | Economy | An order-book market per station prices 13 commodities off a coverage model with shortage-urgency multipliers. Ships move real supply between markets as they trade. | Contracts | Six kinds — Delivery, Courier, Passenger, Subsidy, Supply, CrewMission — with a full posted → accepted → paid lifecycle, reputation gating, auto-renewal, and age-escalating payments. | Facilities | Run production recipes smelting, refining, manufacturing, farming, mining , degrade over time, self-repair with tools, level up 1–10, restock from local markets, and get abandoned when chronically broke. | Factions | Collect taxes on member facilities, post subsidy contracts for chronic shortages, fund construction of new facilities where demand is unmet, and hold pairwise relations. | Populations | Consume food and fuel, produce labor, post food and passenger contracts under stress, and physically migrate to happier systems when sentiment collapses. | Crew | Aggregate hunger / fatigue / morale with derived tasks piloting, engineering, trading, eating, resting , skill progression, wages, and a morale death-spiral guard. | Construction | Chronic shortages spawn construction sites that accrete delivered cargo 0 → 1.0, then materialize into a real, persistent facility. | Persistence | Everything flushes to SQLite; a sim resumes from the exact tick it left off. A per-universe world seed keeps the nebula backdrop and landmarks stable across restarts. | Spatial LOD | Distant ships tick less often with rate-scaled state changes so the frame budget goes where you're looking. | For the deep dive — tick phase ordering, the AI stack, the economic feedback loop, runtime ownership — see docs/ARCHITECTURE.md /Kalcode/spaceprojectsim/blob/main/docs/ARCHITECTURE.md , which has mermaid diagrams for all of it. You need a Rust toolchain https://rustup.rs/ stable . Then: make run equivalent to: cargo run -p client bevy That boots the Bevy app into the main menu. Start opens a fresh universe name it, or take the default ; Load Game lists every save in the binary's directory. Saves live next to the binary as