internal static void RemoveFromSpaceObjects(SpaceObject selected)
 {
     if (SpaceObjects.Exists(x => x.Name == selected.Name))
     {
         SpaceObjects.Remove(selected);
         OnSpaceObjectsItemsChanged();
     }
 }
 public static void AddToSpaceObjects(SpaceObject so)
 {
     if (!SpaceObjects.Exists(x => x.Name == so.Name))
     {
         SpaceObjects.Add(so);
         OnSpaceObjectsItemsChanged();
     }
 }