Here is release version 0.28-1 of sfsim.

This release has a minor fix for time lapse limits. Also I have increased the coverage of the schemas used for checking correctness of the software.

The bigger change which hopefully is not noticeable is that I am trialing Github CI builds. Github kindly provides free CI for public repositories. I was already using Github CI for running unit tests.

Using an automated build process on a controlled environment has many advantages:

• less error prone than performing multiple manual build steps
• configuration changes on developer machines do not affect software releases
• builds for both Linux and Windows can be triggered from any computer
• the complete build process including dependencies is captured
• build logs are online
• it is easier for others to create modified builds

Let me know in the sfsim playtest discussion forum if there are any problems.

Also this week brendengmock shared an sfsim artwork!

Don’t forget to wishlist sfsim!

Enjoy!

Here is release version 0.23-1 of sfsim.

I started adding achievements to sfsim.

To begin with I added the following achievements:

• breaking the sound barrier: spacecraft exceeds speed of sound
• crossing the Kármán line: spacecraft reaches altitude of more than 100 kilometers
• achieving stable Earth orbit: lowest point of orbit is above 160 kilometers

I think achievements are a useful feature of Steam, because they give feedback to players about their progress in the game.

Let me know in the sfsim playtest discussion forum if you have any thoughts. Don’t forget to wishlist sfsim!

Enjoy!

Here is release version 0.22-1 of sfsim.

I added rate pointers for roll, pitch, and yaw angles to the MFD. The pointers are arranged around the navball in the center.

• Top: roll rate indicator
• Right: pitch rate indicator
• Bottom: yaw rate indicator

See here for a detailed overview of the space shuttle primary flight display.

The rate indicators make it easier to control the attitude of the craft. Especially in orbit it is important to control the orientation, because there are no aerodynamic forces stabilising the angles of the spacecraft.

Let me know in the sfsim playtest discussion forum if you have any thoughts. Don’t forget to wishlist sfsim!

Enjoy!

I have released version 0.21-1 of sfsim.

The new version of sfsim shows a navball in the bottom right corner of the window. At the moment I configured it to show pitch and roll angle relative to the Earth’s horizon and yaw angle relative to the orbital plane. This should make it useful for orbital flight. I might change it to let the user select the yaw angle instead of aligning it to the orbital plane which changes during launch. I am also thinking of introducing a separate navball mode showing cardinal directions. Furthermore I would like to introduce attitude error needles once I get some guidance code working.

Creating the navball was quite a bit of work. I used one of the textures from the NavBall Texture Changer for KSP as a reference. I recreated the texture because sfsim uses the B612 aeronautic font for increased readability.

The proper name of the navball is Flight Director Attitude Indicator (FDAI). It was actuated using Inertial Measurement Unit (IMU) gyroscopes. Furthermore it was possible to use the Orbit Rate Display Earth and Lunar (ORDEAL) system to keep the horizon aligned with the Earth’s or Moon’s horizon. Here is a picture showing the navball in the Apollo 11 Lunar Module cockpit (source: NASA).

Let me know in the sfsim playtest discussion forum if you have any thoughts. Don’t forget to wishlist sfsim!

Enjoy!

I have released version 0.20-1 of sfsim.

sfsim now has an orbit display to make launching into an orbit easier. The orbit display shows a visualisation of the planet Earth and the orbit as well as several orbital parameters:

• periapsis altitude
• apoapsis altitude
• current altitude
• eccentricity
• orbital period
• time to periapsis
• time to apoapsis
• velocity
• inclination
• longitude of ascending node

Let me know any feedback and comments in the sfsim playtest discussion forum.

Enjoy!

I have released version 0.19-1 of sfsim.

This version introduces scaling of the graphical user interface. All the user interface elements are scaled up when switching to fullscreen or back taking into account the monitor resolution. This should make it easier to start implementing multi function displays (MFDs).

Furthermore I am working on launch trajectory optimization. It is not optimal yet as the rocket should first go up to leave the atmosphere more quickly. I am using proximal policy optimization (PPO) which is a reinforcement learning method which has become popular. Hopefully PPO will be able to also solve the more difficult problem of reentry. If you want to know more about this reinforcement learning method, I posted an article about PPO at ClojureCivitas.

Let me know any feedback and comments in the sfsim playtest discussion forum.

Enjoy!

Hello spacers,

I released version 0.15-1 of sfsim. sfsim is a realistic 3D space flight simulator with an advanced single-stage-to-orbit space craft.

This version displays some orbital information:

• height of periapsis above surface
• height of apoapsis above surface
• time to periapsis
• time to apoapsis

This should make it much easier to achieve a stable orbit. For example if the periapsis is moving closer (or even was passed) in the later stages of a launch, you need to pitch up to prevent the spacecraft from dropping.

Also Andrewkn’s Surrealism (Ambient Mix) is played when achieving low Earth orbit (both periapsis and apoapsis above 160 kilometer).

Let me know any feedback and comments in the sfsim playtest discussion forum.

Enjoy!

Hello everyone,

I released version 0.11-2 of sfsim. sfsim is a realistic 3D space flight simulator with an advanced single-stage-to-orbit space craft.

I have now added several sound effects and a music track:

• Added Andrewkn’s At the Edge of Space for the event when crossing 100 kilometer height
• Air flow noise depending on dynamic pressure
• Drag noise caused by air brakes and gear
• Sound effects when retracting or deploying gear
• Main rocket engine sound
• Sonic boom
• RCS thruster sounds
• Tyre skiding sound

Let me know any feedback and comments in the sfsim playtest discussion forum.

Enjoy!

Hello everyone,

I released version 0.6-1 of sfsim. sfsim is a realistic 3D space flight simulator with an advanced single-stage-to-orbit space craft.

The graphics implementation is now using deferred rendering to improve performance and facilitate rendering of small thrusters and lights. Using the “\” key one can now toggle between aerofoil surfaces and RCS thrusters (please always see the keyboard shortcut page for up-to-date keyboard bindings). This is the first release of sfsim with RCS thruster physics. This means that you now can control the orientation of the spacecraft when outside the atmosphere! It should be now possible to get into orbit. Make sure you climb at a sufficient angle so that the atmospheric moments are weaker than the RCS thrusters when you start entering orbit. Note that information about orbital parameters is not implemented yet.

I hope you will have as much fun with the RCS thrusters as I did.

Let me know any feedback and comments in the sfsim playtest discussion forum.

Enjoy!

Hi,

I finally managed to release version 0.5-1 of sfsim. sfsim is a realistic 3D space flight simulator with an advanced single-stage-to-orbit space craft.

The new version comes with rocket plume graphics. The plume was implemented using OpenGL shaders and uses volumetric rendering. I used the Shadertoy website to get ideas from other users and to develop the shader.

The rocket plume shows Mach diamonds when the atmospheric pressure is high enough. It then expands with decreasing atmospheric pressure. If you want to, you can try out the Mach diamonds shader in your browser.

The difficult part was figuring out the plume behaviour for different atmospheric pressure values and also the integration with the volumetric cloud shader. There is still some work left to be done for sfsim, but most difficult problems are solved now I think.

Let me know any feedback and comments in the sfsim playtest discussion forum.

Enjoy!