Custom satellite trajectory!

Turns out SPICE does not do everything I need it to after all, so I am going back to GMAT. Instead of compiling it to WebAssembly, I’m going to run calculations on my server (Maybe WASM in v2? We’ll see).

The image below is my custom 3d renderer made in my last devlog adapted to work with GMAT’s output. It’s showing the path of a simulated satellite in orbit around Earth as it starts a long burn pushing it off into space. The white circle is Earth.

Moon orbit… in a browser!

TL;DR: Spent a long time researching, also decided to use the SPICE library instead of GMAT for calculations, and run SPICE on a remote server instead of the browser. Images are the path of the moon’s orbit around Earth, drawn inside a web browser(!!!)

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So it’s been kind of a while since my last devlog. The main reason for this is that I’ve been working on things that can’t be tracked with Hackatime or measured very well, such as attempting to compile things (In the terminal, not an editor) or researching on various websites. (Speaking of which, here’s a really good NASA resource I found for explaining the basics of spaceflight)

I’ve decided to make some changes to how I’m going to simulate the game. Instead of using GMAT (Mentioned in previous devlogs), I’m going to use a different NASA program called SPICE. GMAT uses this internally, and SPICE is a library instead of a GUI application. Sadly, I have not yet managed to get SPICE running in a browser with WebAssembly, so I’ll be running all the calculations on a python web server. To summarize, I’m now using SPICE for calculations instead of GMAT, and running the calculations on a remote server instead of in the browser.

To demonstrate that this works, I made a webpage and simple python web server that calculates and displays the orbit of the moon around Earth for 90 days. It visualizes the orbit with a custom 3D engine I’m creating for this project. Screenshots of this are attached, where the rainbow line is the path of the orbit and the white dot is Earth. (Note: my 3D engine seems to stretch things out so it doesn’t look perfectly circular. I’ll probably fix this if I include it in the real game.)

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Edit: seems like Stardance isn’t showing all the images, if you can only see the first one, please look in the comments of this devlog for links to the other two!

Title screen!

In this update I added a title screen, as well as a small notice saying that the game is in development. This is so that when it’s deployed, people won’t get confused about why none of the buttons work on the title screen (they don’t yet). Speaking of deploying this, I put the current version on my site at https://burn.jmeow.net! Feel free to check it out, but be aware that the buttons don’t do anything just yet.

Next, I’ll probably be starting to experiment with WebAssembly and Emscripten, and try to compile NASA’s GMAT so it can run in the browser. (Don’t know what GMAT is? Read my first devlog for more about that!)

(Note: the screenshot attached is not of the entire page, the text isn’t this big in the real game. I cropped out the parts that aren’t interesting.)

I spent all day today configuring NeoVim (my code editor) and did not get much done so far. I did set up a web app with fun things like SCSS and hot reloading, and I made a cool splash screen (attached below)! Also made a simplified to-do list, which I’ll probably add more to at some point.

Fancy space visualization things!

I installed an open source piece of simulation software by NASA called GMAT (general mission analysis tool) which has a GUI and a scripting interface. (GMAT is really cool, though I sadly don’t understand much of it yet) It can output computer-readable files of where things go (among other things) and I made a demo program for reading these files (if GMAT is configured correctly) and visualizing the position of a satellite.

I’m planning to compile GMAT (written in C++) to WebAssembly so I can use its capabilities inside the game, for realistic physics. For now, I’m just pre-generating output files and showing them.

The image below is the path of a satellite being launched into orbit around the moon. Currently, neither the position of the earth nor the moon are shown, only the path of the satellite. The Z axis is also not shown yet, because I haven’t done much 3D graphics coding. The color represents time.

Disclaimer: This is my first time doing much with outer space and physics simulations, meaning I don’t know that much about it right now. I hope to learn more about these topics as this project continues in development!

TL;DR: GMAT = fancy NASA software for simulating/planning missions. I’m using GMAT for realistic simulations (currently manually, programmatically in the future). Image is of a satellite being launched into lunar orbit.