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sfsim is a realistic 3D space flight simulator under development. You can already download the sfsim playtest build on Steam and try it out. sfsim uses true celestial positions of Earth and Sun from NASA. Use an advanced single-stage-to-orbit space craft to take off, orbit the planet, perform reentry, and land back on Earth. sfsim features a true to scale Earth planet using NOAA elevation data and procedurally generated volumetric clouds.
Warning: Only download sfsim binary releases via Steam and not from other sources!
Take off
Blast off from the launch pad and slowly tilt your spacecraft to start building up horizontal speed and climb to orbital height. Make sure you don’t loose to much energy to air friction but also gather enough horizontal speed not to plunge back into the atmosphere.
Orbit the planet
Perform a controlled burn for orbital insertion. Your orbit should be nearly circular and above the atmosphere. If you get it wrong, you might enter the atmosphere unprepared and might even burn up!
Perform reentry
Perform a deorbit burn and reentry to come out at the desired location. Make sure you plan it right, otherwise you might end up over the ocean, or even burn up on reentry.
Land back on Earth
Approach the runway, deploy your landing gear, and touch down on the runway. Apply the brakes, come to a standstill, and celebrate mission success. Don’t touch down to fast, or you might break the landing gear or even destroy the spacecraft. Don’t touch down too late, or you will run out of runway.
The project
Since a long time I wanted to develop a 3D space flight simulator. As a kid I implemented several 2D space flight simulators on an Atari ST. Many years later I saw Orbiter 2016 and I was inspired to create a free and open source space flight simulator. After some half-hearted attempts, I decided to start the project for real in 2020. I worked on the tough issues first and I finally managed to get to a point where I felt confident to create a Steam page showcasing early results. Progress is slow as this is only a hobby project, but I hope to release a demo soon!
The beautiful ambient music used in the trailer was made by Andrewkn!
Wishlist it on Steam to get notified when it gets released:
News
- June 18, 2026 Steam Achievements
- June 14, 2026 Rate Needles
- June 11, 2026 Navball MFD
- June 04, 2026 Orbit MFD
- May 28, 2026 Reinforcement Learning of Rocket Launch
- March 17, 2026 Orbital Elements
- March 04, 2026 Sound effects
- January 04, 2026 RCS thrusters and renderer rework
- November 19, 2025 Rocket plume for aerospike engine
- August 24, 2025 Following camera and orbital physics
- July 28, 2025 Joystick configuration dialog released
- July 03, 2025 Playtest is live!
- May 30, 2025 Landing Gear Physics
- May 07, 2025 Landing Gear
- April 21, 2025 Welcome to the sfsim homepage!
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