diff --git a/s1process.py b/s1process.py
index 005227141cf6fd10eceb2a0a58fa325c8efd795b..ffc26d7ff7fac5fae5ef0fd95108a2919c00c62f 100644
--- a/s1process.py
+++ b/s1process.py
@@ -739,7 +739,7 @@ def s1process(indir, outdir, epsg=None,
             elif direction == 's1b':
                 safe_files = safe_files_s1b
             else:
-                sys.exit('Invalid direction parameter.')
+                sys.exit('Invalid satellite parameter.')
 
         if len(safe_files) == 0:
             raise IOError('No .SAFE file found in {}'.format(indir))