diff --git a/assets/textures/callisto.jpg b/assets/textures/callisto.jpg
new file mode 100644
index 0000000..021e5ba
Binary files /dev/null and b/assets/textures/callisto.jpg differ
diff --git a/assets/textures/europa.jpg b/assets/textures/europa.jpg
new file mode 100644
index 0000000..51e8011
Binary files /dev/null and b/assets/textures/europa.jpg differ
diff --git a/assets/textures/ganymede.jpg b/assets/textures/ganymede.jpg
new file mode 100644
index 0000000..fba887c
Binary files /dev/null and b/assets/textures/ganymede.jpg differ
diff --git a/assets/textures/io.jpg b/assets/textures/io.jpg
new file mode 100644
index 0000000..8aa8aa5
Binary files /dev/null and b/assets/textures/io.jpg differ
diff --git a/src/defs.txt b/src/defs.txt
index 392ba72..13759e5 100644
--- a/src/defs.txt
+++ b/src/defs.txt
@@ -18,6 +18,30 @@ actor 300000 0 500000 jupiter
     rotationz -0.28
     angularmomentum 30 30 30
 
+actor -300000 0 -300000 io
+    scale 28000
+    rotationy -0.40
+    angularmomentum 0 0.0001 0
+    sphere yes
+
+actor -100000 0 400000 europa
+    scale 20000
+    rotationy 0.20
+    angularmomentum 0 0.0001 0
+    sphere yes
+
+actor 500000 0 -200000 ganymede
+    scale 18000
+    rotationy -0.40
+    angularmomentum 0 0.0001 0
+    sphere yes
+
+actor -800000 0 300000 callisto
+    scale 8000
+    rotationy -0.40
+    angularmomentum 0 0.0001 0
+    sphere yes
+
 actor 3000 0 0 moonlet
     scale 500
     mass 10000000