diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5caaf84b..e872810d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -25,10 +25,11 @@ will consitute of a breaking change warranting a new major release:
 - Event Manager queue depth is configurable now.
 - Do not construct and schedule broken TMP1075 device anymore.
 - Do not track payload modes in system mode tables.
+- ACS modes derived from system modes.
 
 ## Added
 
-- Add the remaining system modes derived from the ACS modes.
+- Add the remaining system modes.
 
 ## Fixed
 
diff --git a/mission/acs/defs.h b/mission/acs/defs.h
index 7748562d..41d09976 100644
--- a/mission/acs/defs.h
+++ b/mission/acs/defs.h
@@ -3,6 +3,7 @@
 
 #include <eive/eventSubsystemIds.h>
 #include <fsfw/modes/HasModesIF.h>
+#include <mission/sysDefs.h>
 
 namespace acs {
 
@@ -11,12 +12,12 @@ enum class SimpleSensorMode { NORMAL = 0, OFF = 1 };
 // These modes are the modes of the ACS controller and of the ACS subsystem.
 enum AcsMode : Mode_t {
   OFF = HasModesIF::MODE_OFF,
-  SAFE = 10,
-  PTG_IDLE = 11,
-  PTG_NADIR = 12,
-  PTG_TARGET = 13,
-  PTG_TARGET_GS = 14,
-  PTG_INERTIAL = 15,
+  SAFE = satsystem::Mode::SAFE,
+  PTG_IDLE = satsystem::Mode::PTG_IDLE,
+  PTG_NADIR = satsystem::Mode::PTG_NADIR,
+  PTG_TARGET = satsystem::Mode::PTG_TARGET,
+  PTG_TARGET_GS = satsystem::Mode::PTG_TARGET_GS,
+  PTG_INERTIAL = satsystem::Mode::PTG_INERTIAL,
 };
 
 enum SafeSubmode : Submode_t { DEFAULT = 0, DETUMBLE = 1 };
diff --git a/mission/sysDefs.h b/mission/sysDefs.h
index a74cf369..c84c237f 100644
--- a/mission/sysDefs.h
+++ b/mission/sysDefs.h
@@ -1,9 +1,13 @@
 #ifndef MISSION_SYSDEFS_H_
 #define MISSION_SYSDEFS_H_
 
-#include <atomic>
+#include <fsfw/action/ActionMessage.h>
+#include <fsfw/action/HasActionsIF.h>
+#include <fsfw/modes/ModeMessage.h>
+#include <fsfw/serialize/SerializeIF.h>
 
-#include "acs/defs.h"
+#include <atomic>
+#include <cstring>
 
 extern std::atomic_uint16_t I2C_FATAL_ERRORS;
 
@@ -11,12 +15,13 @@ namespace satsystem {
 
 enum Mode : Mode_t {
   BOOT = 5,
-  SAFE = acs::AcsMode::SAFE,
-  PTG_IDLE = acs::AcsMode::PTG_IDLE,
-  PTG_NADIR = acs::AcsMode::PTG_NADIR,
-  PTG_TARGET = acs::AcsMode::PTG_TARGET,
-  PTG_TARGET_GS = acs::AcsMode::PTG_TARGET_GS,
-  PTG_INERTIAL = acs::AcsMode::PTG_INERTIAL,
+  // DO NOT CHANGE THE ORDER starting from here, breaks ACS mode checks.
+  SAFE = 10,
+  PTG_IDLE = 11,
+  PTG_NADIR = 12,
+  PTG_TARGET = 13,
+  PTG_TARGET_GS = 14,
+  PTG_INERTIAL = 15,
 };
 }