From 17df9b2d79efa85c85fc424c14ab6f9892cb99c8 Mon Sep 17 00:00:00 2001
From: Batrachophreno <Batrochophreno@gmail.com>
Date: Wed, 27 May 2026 13:05:54 -0400
Subject: [PATCH] Remove rare gas isotopes from exoplanet atmospheres (#22509)

See title. Deuterium, Tritium, and Helium-3 no longer eligible to spawn
in the atmospheres of randomly-generated exoplanets.
---
 code/modules/overmap/exoplanets/exoplanet.dm | 5 ++++-
 html/changelogs/Bat-AtmosIsotopes.yml        | 4 ++++
 2 files changed, 8 insertions(+), 1 deletion(-)
 create mode 100644 html/changelogs/Bat-AtmosIsotopes.yml

diff --git a/code/modules/overmap/exoplanets/exoplanet.dm b/code/modules/overmap/exoplanets/exoplanet.dm
index 4c43b1a824d..549d807adc8 100644
--- a/code/modules/overmap/exoplanets/exoplanet.dm
+++ b/code/modules/overmap/exoplanets/exoplanet.dm
@@ -441,9 +441,12 @@
 	else //let the fuckery commence
 		var/list/newgases = gas_data.gases.Copy()
 		newgases -= GAS_PHORON
+		newgases -= GAS_DEUTERIUM
+		newgases -= GAS_TRITIUM
+		newgases -= GAS_HELIUMFUEL
+		newgases -= GAS_WATERVAPOR
 		if(prob(50)) //alium gas should be slightly less common than mundane shit
 			newgases -= GAS_ALIEN
-		newgases -= GAS_WATERVAPOR
 
 		var/total_moles = MOLES_CELLSTANDARD * rand(80,120)/100
 		var/badflag = 0
diff --git a/html/changelogs/Bat-AtmosIsotopes.yml b/html/changelogs/Bat-AtmosIsotopes.yml
new file mode 100644
index 00000000000..93e0e84d098
--- /dev/null
+++ b/html/changelogs/Bat-AtmosIsotopes.yml
@@ -0,0 +1,4 @@
+author: Batrachophrenoboocosmomachia
+delete-after: True
+changes:
+  - balance: "Rare gas isotopes are no longer present in the atmospheres of randomly-generated exoplanets."