diff --git a/ship.py b/ship.py
index ea7957f..92d2658 100644
--- a/ship.py
+++ b/ship.py
@@ -39,3 +39,5 @@ class Ship(Sprite):
 
         if self.moving_up and self.rect.top > 0:
             self.centery -= self.ai_settings.ship_speed_factor
+        if self.moving_down and self.rect.bottom < self.screen_rect.bottom:
+            self.centery += self.ai_settings.ship_speed_factor