0.5 Out Now

COMPLETE ENGINE CYCLES.

Turbopumps. Gas Generators. Injectors.

Every component to build a cryogenic GG-cycle engine is taught.

Design. Test. Fail. Learn.

About the Game

Design. Test. Fail. Learn.

A realistic rocket engine sim where every test that misses teaches you something real.

You're an underpaid engineer at Mecodyne, the kind of propulsion company that ships rockets aggressively and has opinions about your eyebrows. On your first day you accidentally fire up a Vulcain 1 on your coworker's workstation. The graphs come alive. The Vulcain runs. You probably shouldn't be doing this.

From there, you design real rocket engines using actual physics: cold-gas thrusters, gas generators, full pump-fed turbopump beasts. Combustion. Fluid dynamics. Heat transfer. Component-level engineering. Twist an injector orifice and the chamber pressure curve responds in real time. Tighten the cooling channels and watch the thermal margin shrink. Reshape the nozzle and see what it does to Isp.

It's a sim that won't lie to you. Nothing is a black box, and if your design wouldn't work in real life, it won't work here either.

Three ways to play

Missions (start here)

Thirteen guided challenges, from "what's a model?" to gas-generator turbopump engines inspired by Merlin 1D, F-1, and Vulcain 1. Senior engineer Miku Aoyama walks you through, deadpan, accurate, mostly patient. You don't need to arrive an expert. Mission 0 starts you with that accidental engine fire-up on her workstation, and the missions build from there.

Free build

Skip the missions. Empty canvas, node-based editor, live graphs. Drop in components, wire them up, hit run, see what happens. Good for "what if I just…" experiments.

Recreate real engines

Same components, same physics. Build a Merlin 1D from scratch. Or an F-1. Or something that's never existed and probably shouldn't. Push materials, propellants, and geometry until something gives.

Key features

• Mission Mode with real engineering challenges. Guided builds with senior engineer Miku Aoyama, from your first model to a complete gas-generator turbopump cycle.
  
• Live performance graphs and samplers. Chamber pressure, thrust, Isp, and thermal margins update in real time, with pump and turbine performance curves you can sample as you tune.
  
• 2D node-graph assembly. Drop in components, wire them together, and fire the engine on an open canvas.
  
• Real physics, no shortcuts. Combustion, fluid dynamics, and heat transfer through regenerative cooling channels, all solved in real time.
  
• Recreate real engines. Build a Merlin 1D, an F-1, or a Vulcain 1 from the same components and physics.
  
• Display Units. Read every output in the units you actually think in, from kN to bar, across charts, samplers, and mission text.

Pro Content (optional add-on)

Soundtrack, technical reference PDFs, 3D-printable component models (STL/3MF), and high-resolution wallpapers. For the people who want the lore in their toolbox.

What's new

• 0.5.0: Mission 0, your accidental first day on Miku's workstation. Three new gas-generator cycle missions (Turbopump Integration, Gas Generator Genesis, Injector Insights). Display Units, so you can finally read pressure in bar instead of pascals.
  
• 0.4.0: Real-time pump and turbine samplers with live performance curves. Auto-run on every edit. Pinned component editor with nudge buttons and mouse-wheel tweaking. Colorblind-safe chart colors (Okabe-Ito).
  
• 0.3.0: Multi-select and copy-paste in the schematic editor. Plus a pile of stability fixes for selection and menus.

Early Access roadmap

Meco is in Early Access and playable today. The full core loop is here: design an engine, fire it, read the graphs, and iterate. I ship updates regularly. Here's what's already in, and what I'm building next.

Playable now:

• Missions Chapters I to IV: Mission 0 through Mission 12, from "what's a model?" to complete gas-generator turbopump cycles
  
• Thrust and Isp measurement

Building next:

• 3D nozzle design and flow separation (in progress)
  
• Missions Chapter V, "Building On The Past": recreating historic engines
  
• 3D pump impeller, turbine rotor, and stator design
  
• Component mass, for thrust-to-weight numbers
  
• Thermal and load stress limits
  
• Historical campaigns

This roadmap can take a few years to finish. I build Meco solo, so every purchase directly funds the work, and if enough people who think like you buy it, I can do this full time. Your support genuinely makes the difference.

Dannie Sim

Solo Indie Dev, Meco Rocket Simulator (formerly at Activision/Blizzard on Candy Crush and Sony PlayStation on Spider-Man 2)

Heads up

This isn't a casual arcade game. It's a serious engineering sim with a real learning curve, and honestly, your first designs probably won't hit their targets. That's the point. When a build misses, the sim tells you exactly what is wrong and walks you to the fix one item at a time: run the test at least once, your mixture ratio is still stoichiometric so dial the gas-generator valve richer, that component name looks like a typo. You figure out which assumption was off, and try again.

If you've spent time curious about what actually goes on inside a running rocket engine, and why a 5% change in injector geometry can ruin your whole afternoon, Meco was built for you.

Come build something that works. Or something that doesn't, and find out exactly why. Both are fine outcomes.