diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2fdbf546..9946093e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -20,10 +20,10 @@ will consitute of a breaking change warranting a new major release:
 
 ## Added
 
-- SPG4 Propagator is now used for propagating the position of EIVE. It will only work once
+- SGP4 Propagator is now used for propagating the position of EIVE. It will only work once
   a TLE has been uploaded with the newly added action command for the ACS Controller. In
   return the actual GPS data will be ignored once SPG4 is running. However, by setting the
-  according parameter, the ACS Controller can be directed to ignore the SPG4 solution. 
+  according parameter, the ACS Controller can be directed to ignore the SGP4 solution.
 
 ## Fixed
 - The handling function of the GPS data is only called once per GPS read. This should remove
diff --git a/mission/acs/defs.h b/mission/acs/defs.h
index 827047dd..8cdd283b 100644
--- a/mission/acs/defs.h
+++ b/mission/acs/defs.h
@@ -71,7 +71,7 @@ static constexpr Event MEKF_INVALID_MODE_VIOLATION = MAKE_EVENT(6, severity::HIG
 //! failed.
 //! P1: Missing information about magnetic field, P2: Missing information about rotational rate
 static constexpr Event SAFE_MODE_CONTROLLER_FAILURE = MAKE_EVENT(7, severity::HIGH);
-//! [EXPORT] : [COMMENT] The TLE for the SPG4 Propagator has become too old.
+//! [EXPORT] : [COMMENT] The TLE for the SGP4 Propagator has become too old.
 static constexpr Event TLE_TOO_OLD = MAKE_EVENT(8, severity::INFO);
 
 extern const char* getModeStr(AcsMode mode);