diff --git a/utils/space_ops.py b/utils/space_ops.py
index 821e86ac..b0c6efdd 100644
--- a/utils/space_ops.py
+++ b/utils/space_ops.py
@@ -43,7 +43,7 @@ def quaternion_conjugate(quaternion):
 def rotate_vector(vector, angle, axis=OUT):
     quat = quaternion_from_angle_axis(angle, axis)
     quat_inv = quaternion_conjugate(quat)
-    product = reduce(quaternion_mult, [quat, vector, quat_inv])
+    product = reduce(quaternion_mult, [quat, np.append(0, vector), quat_inv])
     return product[1:]