diff --git a/rocketpy/Environment.py b/rocketpy/Environment.py
index 72dcf0902..ba5ce0ddd 100644
--- a/rocketpy/Environment.py
+++ b/rocketpy/Environment.py
@@ -3368,7 +3368,8 @@ def exportEnvironment(self, filename="environment"):
         f.write(json.dumps(
             self.exportEnvDictionary, 
             sort_keys=False,
-            indent=4)
+            indent=4,
+            default=str)
             )
                 
         # close file