Launching today

SpaceSim

Launching today

Explore the universe

13 followers

Explore the universe

13 followers

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SpaceSim is a free browser-based universe simulator. Travel through a UTC-driven 3D Solar System, inspect source-linked scientific state, observe Earth from a pinned NASA ISS trajectory, build procedural stars, visit compact objects, and collect postcards. Scientific, reconstructed, representative, procedural, experimental, and promotional content are clearly labeled. No signup required.

Free

Launch tags:Education•Space•OpenAI Day

Launch Team

Framer AI AgentsDesign and publish professional sites with AI

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OpenAI

OpenAI Day

How did GPT-5.6 change the ambition or scope of what you shipped?

Melies

Maker

GPT-5.6 Sol turned SpaceSim from a visual Earth proof of concept into a source-aware browser universe. It helped me research primary NASA, JPL, NAIF and IERS sources; design typed scientific-state and provenance contracts; implement the Three.js WebGPU/TSL renderer and WebGL fallback; and build independent Rust, CSPICE C and SOFA cross-checks. Crucially, Sol kept scientific state, camera-relative render state, visual-truth labels and performance budgets coherent while the scope expanded to ten Solar System worlds, a pinned ISS observer, procedural stellar families and compact objects. Earlier models repeatedly lost correct 3D scale, positioning and camera relationships. With Sol, I could preserve those constraints across research, code, tests and browser visual QA, making the project substantially more ambitious and verifiable than I could have shipped in the same Build Week.

Report

10h ago

Melies

Maker

📌

Hey Hunters (and bots),

I created Spacesim, because I wanted a space simulator that beautiful and fun to explore, while being as scientifically accurate as possible.

What you can explore today:

🌍 Grand tour of the solar system (guided or your can explore from atlas)

🛰 Observe Earth from a NASA-data-backed ISS observer

⭐ Build stars and inspect compact objects in the browser-based stellar laboratory

📋 See my interactive recreation of Luminet's Black Hole rendering from 1979

🎴 Collect postcards for all places in the solar system your visit (while listening original soundtracks per destination
And more more things to come!

I began working on this during OpenAI Build Week and I was mainly built with Codex and GPT-5.6 Sol as a research and engineering partner. All illustrations including postcards are made with GPT Image Pro.

This is a public proof of concept, not a finished scientific platform.
I plan to add much more things (why not the whole universe ?) to have a SpaceEngine but running in the browser.

Please give me some useful feedback!
What should I build next?