Astron

I built Astron because gravity is usually taught as a diagram after the motion is gone. Astron puts the motion back.

Astron is a Rust and WebAssembly universe sandbox where students, teachers, and curious people can operate the system instead of only reading about it: select a world, inspect its physical state, change one condition, accelerate time, and watch the consequences.

What it does

• Simulates a source-backed, 35-body Solar System state with deterministic double-precision N-body physics.
• Keeps real geometry honest: PHYSICAL 1× uses actual radii and distances, while VISUAL 10×–1000× changes display size only—never gravity, collisions, or trajectories.
• Makes difficult phenomena visible through interactive scenarios: orbital resonance, Roche disruption, impacts, atmospheric entry and ablation, eclipses, climate, biospheres, stellar evolution, relativistic precession, gravitational-wave inspiral, and photon drag.
• Runs as a complete browser product, backed by 1,021 automated tests and reproducible release evidence.

The education loop is simple: observe → predict → change one variable → compare the result. A teacher can demonstrate why the Moon seems to disappear at honest scale, then switch on a clearly labeled visual exaggeration without corrupting the simulation. A student can move from that scale lesson directly into an impact or Roche-limit experiment and see conservation, energy, atmosphere, and topology respond.

What changed during OpenAI Build Week

Astron existed before the July 13–21 event. Commit fa52481 (v0.27.0) is the verified baseline. The submitted work is the meaningful extension from that baseline through the production-verified v0.52.0 release: atmospheric entry and flight, climate and biospheres, advanced orbital operators, true physical display scale, calibrated optics, a source-backed JPL Solar System and Atlas, registered planetary surface pipelines, deterministic browser fixtures, and reproducible production deployment.

How I used Codex and GPT-5.6

I used Codex and GPT-5.6 as an engineering collaborator for primary-source research, Rust implementation and review, deterministic test authoring, asset-pipeline construction, browser diagnosis, visual QA, and release verification. I kept ownership of product direction, scientific boundaries, tradeoffs, and every final release decision.

The repository preserves the collaboration trail through dated commits, tagged releases, exact production hashes, test evidence, and the submitted Codex /feedback session ID.

Try it

Open the live sandbox, choose Atlas or a scenario, and use the BODY RADII control to compare honest physical scale with an explicit visual aid. Then accelerate time and let physics answer.

Built With

• bevy
• codex
• gpt-5.6
• rust
• webassembly
• webgl2