Project APEX

by 434 Aerospace

About Project APEX

Built by rocketeers,

for rocketeers.

Project APEX is a free, browser-based flight simulator for high power rocketry. It exists because we needed it ourselves — and decided to build it right.

Where it started


Project APEX grew out of a simple frustration: existing HPR simulation tools are either too expensive, too complex to set up, or locked behind a desktop install. When you’re at the range trying to decide whether to swap motors before a flight, you don’t want to open a laptop and wait for software to load.

So Conrad Mouton at 434 Aerospace built something different — a professional-grade physics simulation that runs entirely in the browser. No install. No account. Open the link, load your motor, get your answer.

The core idea: The physics shouldn’t be simplified just because the tool is convenient. APEX implements the same Barrowman equations, the same ISA atmosphere model, and the same seven-component drag breakdown used in more complex tools — it just removes all the friction around running them.

434 Aerospace


434 Aerospace is Conrad Mouton’s aerospace engineering practice, focused on high power rocketry design, analysis, and certification support. Project APEX is 434 Aerospace’s open contribution to the HPR community — free to use, free to inspect, and built to grow with input from the people who fly.

434aerospace.com

Modular Components for high-power rockets

What we believe


Microscope 2
Physics first
The simulation is only useful if it’s accurate. We don’t simplify the equations to make the tool faster — we make the tool fast enough to run the real equations.
Globe 33
Zero friction
Simulation tools should be available when you need them. Browser-based means no install, no license key, and no waiting. Open the link and start.
Eye Gray
Open for inspection
The physics engine is documented in the Physics Notes. The source code is on GitHub. Anyone who wants to verify the model can — and we encourage it.
Hands Shaking 2
Community driven
The roadmap is shaped by what the community actually needs. Feature requests are public. Upvoted ideas get built. We fly this stuff too.

Authenticity & trust


Every release of Project APEX is signed with an HMAC-SHA256 fingerprint that uniquely identifies the canonical 434 Aerospace build. Press Shift+Alt+V inside the simulator at any time to verify authenticity using the master passphrase. The passphrase is never stored in the app — only its fingerprint is embedded.

Build: Project APEX v2025.04.1
Author :Conrad Mouton · 434 Aerospace
Fingerprint: 195d220986b92d2e730e2561c20a5e8a75a2f8b5…
Verify: Shift+Alt+V inside the simulator

Get in touch


Bug reports, feature suggestions, or questions about the physics model — reach out directly. We read everything.

info@apexrocketsim.com

Questions, feedback, and feature requests

Source Code – issue tracker – physics engine documentation