diff --git a/CMakeLists.txt b/CMakeLists.txt
index ecb59506..4f48047c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -13,6 +13,7 @@ option(FSFW_WARNING_SHADOW_LOCAL_GCC "Enable -Wshadow=local warning in GCC" ON)
 option(FSFW_ADD_INTERNAL_TESTS "Add internal unit tests" ON)
 option(FSFW_USE_RMAP "Compile with RMAP" ON)
 option(FSFW_USE_DATALINKLAYER "Compile with Data Link Layer" ON)
+option(FSFW_ADD_SPG4_PROPAGATOR "Add SPG4 propagator code" ON)
 
 set(LIB_FSFW_NAME fsfw)
 add_library(${LIB_FSFW_NAME})
@@ -85,6 +86,7 @@ message(STATUS "Compiling FSFW for the ${OS_FSFW_NAME} operating system.")
 
 add_subdirectory(src)
 add_subdirectory(tests)
+add_subdirectory(contrib)
 
 # The project CMakeLists file has to set the FSFW_CONFIG_PATH and add it.
 # If this is not given, we include the default configuration and emit a warning.
diff --git a/contrib/CMakeLists.txt b/contrib/CMakeLists.txt
new file mode 100644
index 00000000..48cb21d2
--- /dev/null
+++ b/contrib/CMakeLists.txt
@@ -0,0 +1,11 @@
+if(FSFW_ADD_SPG4_PROPAGATOR)
+    target_sources(${LIB_FSFW_NAME} PRIVATE
+        spg4unit.cpp
+    )
+    target_include_directories(${LIB_FSFW_NAME} PRIVATE
+        ${CMAKE_CURRENT_SOURCE_DIR}/spg4
+    )
+    target_include_directories(${LIB_FSFW_NAME} INTERFACE
+        ${CMAKE_CURRENT_SOURCE_DIR}/spg4
+    )
+endif()