diff --git a/python/swiftest/swiftest/simulation_class.py b/python/swiftest/swiftest/simulation_class.py
index e0ec698a2..af9b36475 100644
--- a/python/swiftest/swiftest/simulation_class.py
+++ b/python/swiftest/swiftest/simulation_class.py
@@ -53,7 +53,6 @@ def __init__(self, codename="Swiftest", param_file=""):
         self.codename = codename
         if param_file != "" :
             self.read_param(param_file, codename)
-            self.param['GU'] = constants.GC  / (param['DU2M'])**3 / (param['MU2KG'] * param['TU2S']**2)
         return