• ⚠️ Mod Release Rules now apply to this board.

    All mods must include a license, source code (for executable mods), and proper attribution.

    Read the full rules here before posting.

Tools Artemis OEM Loader

arthomnix

Member
Nov 14, 2025
20
20
NASA are releasing orbital ephemerides for the Artemis II mission (https://www.nasa.gov/missions/artemis/artemis-2/track-nasas-artemis-ii-mission-in-real-time/), so I wrote a quick KSA mod to load this data and set your vehicle's orbit to Orion's in real time! Now someone just needs to make an Orion parts mod...

Download the mod from SpaceDock at https://spacedock.info/mod/4188/Artemis OEM Loader. This mod also requires ModMenu and KittenExtensions, so make sure to grab those too if you don't have them already.

After installing the mod (see https://modding.kittenspaceagency.wiki/en/Installing-Mods if you're not sure how), download the ephemeris ZIP file from the bottom of the NASA page linked above and extract it somewhere.
When launching the game, make sure to select the "Earth and Moon (April 2026 lunar ephemerides)" system (provided by this mod), as this will make the position of the moon much more accurate around the time of the Artemis II mission compared to the stock system.
In-game, go to Mods > OemLoader > Ephemeris Loader. Paste the full path to the extracted file in the text box (sorry, no file picker yet) and click the button to load the data.

Once the data is loaded, you can either press "Go to now" to set the orbit and position of your current vehicle to that of Artemis at the current real-world time, or use the slider and button below to select a different time.

1775247037286.png

Use the "Draw trajectory" option (added in version 0.1.0) to visualise the full trajectory like an orbit line. (This won't match up perfectly with KSA's orbit lines, because KSA doesn't use full n-body physics and doesn't know about Artemis II's planned burns.)

1775328509686.png

Download: https://spacedock.info/mod/4188/Artemis OEM Loader
License: MIT
Source code: https://tangled.org/arthomnix.dev/ksa_oemloader
Dependencies: StarMap Loader (https://forums.ahwoo.com/threads/starmap-mod-loader.384/), ModMenu (https://forums.ahwoo.com/threads/modmenu.562/), KittenExtensions (https://forums.ahwoo.com/threads/ki...patching-modulemanager-custom-xml-assets.695/)
 
Last edited:
download the ephemeris ZIP file from the bottom of the NASA page linked above and extract it somewhere. In-game, go to View > Ephemeris Loader. Paste the full path to the extracted file in the text box (sorry, no file picker yet) and click the button to load the data.
Unfortunately, this is not working for me. I get an error message and it appears the mod (or StarMaps?) is adding the game path in front of the path defined in the OEM loader window.
I need to put the .asc file in the game folder somewhere and apparently using double quotation marks is not working which excludes path names with spaces (I get the double quotes when I directly copy the path from Windows. I assume you haven't developed this with users not using an English language locale setup in mind).

1775191350364.png

When using the relative path, the mod finds the .asc file, but I cannot open the most recent OEM file NASA provided (attached in my post).

1775191671988.png

Any ideas on how to make this work?
 

Attachments

Unfortunately, this is not working for me. I get an error message and it appears the mod (or StarMaps?) is adding the game path in front of the path defined in the OEM loader window.
I need to put the .asc file in the game folder somewhere and apparently using double quotation marks is not working which excludes path names with spaces (I get the double quotes when I directly copy the path from Windows. I assume you haven't developed this with users not using an English language locale setup in mind).

View attachment 1405
It should find the file if you remove the quotes there. The quotes make it look for a file that's literally called "F:\Vid\whatever" inside the game folder, instead of using that as the full path.

When using the relative path, the mod finds the .asc file, but I cannot open the most recent OEM file NASA provided (attached in my post).

1775191671988.png
I think this is a stupid locale bug on my part (it's trying to use commas as the decimal separator when parsing the numbers because your locale is German). I'll push a quick update to fix this soon.
 
  • Like
Reactions: ShadowZone
I think this is a stupid locale bug on my part (it's trying to use commas as the decimal separator when parsing the numbers because your locale is German). I'll push a quick update to fix this soon.
Yeah, I switched the decimal symbol from , to . and now I was able to load the file.

Thanks for the quick reply!
 
Confirmed, version 0.0.2 resolves the . vs , decimal separator issue!


Another observation:
When pasting a file path into the OEM Loader window, that input field is now in focus. Closing or minimizing this window then results in KSA no longer accepting keyboard inputs (wasd, # for console or F2 for hiding the UI).

Solution: reopen Ephemeris Loader, click outside of the window and then close/minimize it.

Can be confusing at first. And I'm not sure if this is KSA related or related to the mod.


Also a very minor thing: Ephemeris Loader window does not react to F2, meaning it will remain visible while all other UI elements are hidden.


No hurry to look into this, for me the mod works fine as is now that I don't have to switch my locale settings before launching KSA :)
 
Released version 0.0.3:
* The menu entry now uses ModMenu instead of directly injecting into the View menu. (This adds a new dependency on ModMenu, so make sure to grab it from https://spacedock.info/mod/4054/ModMenu if you don't have it already.)
* The OemLoader window now respects F2 (hide UI).
* Fixed keyboard input breaking after closing the OemLoader window whilst the text input is focused.
 
Oooo this looks super cool. I'll have to try this out some time. Well done!
 
Released version 0.0.4. There are no code changes, but I have added explicit StarMap metadata to mod.toml which should give you better error messages if you are missing dependencies.
 
Currently working on adding a custom system that has a more up-to-date lunar orbit, since KSA uses data from November 2025 and the moon's orbit has changed quite significantly since then.
 
Released version 0.0.5.

This version adds a custom system derived from the stock "Earth and Moon" system, called "Earth and Moon (April 2026 lunar ephemerides)", which uses lunar orbital data that is up-to-date for the Artemis II mission. I suggest using this new system instead of the stock systems if you are using this mod to track Artemis II.

Before:
1775246815061.png
After:
1775246732165.png



The mod now depends on KittenExtensions (https://spacedock.info/mod/4144/KittenExtensions).
 
Released version 0.1.0:

* Added an option to visualise the full trajectory like an orbit line. (The darker blue line is the trajectory from the ephemeris, green and light blue lines are the standard KSA orbit lines)

1775328177362.png

* Further improved the accuracy of the moon's orbit in the custom system (note that KSA's orbit lines still won't perfectly match up with the real trajectory, because KSA doesn't use full n-body physics, and doesn't know about Orion's planned burns)