Orbiting weakref

code/modules/mob/mob_movement.dm

@@ -185,8 +185,9 @@
 			var/datum/orbit/O = thing
 			O.Check()
 
-	if(orbiting)
-		orbiting.Check()
+	var/datum/orbit/orbit = orbiting?.resolve()
+	if(istype(orbit))
+		orbit.Check()
 
 	SEND_SIGNAL(src, SIGNAL_MOVED, src, old_loc, loc)
 

code/modules/mob/observer/ghost/ghost.dm

@@ -459,7 +459,7 @@ This is the proc mobs get to turn into a ghost. Forked from ghostize due to comp
 		orbitsize = world.icon_size
 	orbitsize -= (orbitsize / world.icon_size) * (world.icon_size * 0.25)
 
-	if(orbiting && orbiting.orbiting != target)
+	if(weakref(orbiting) && weakref(orbiting).orbiting != target)
 		to_chat(src, "<span class='notice'>Now following \the [target].</span>")
 
 	forceMove(target)

code/modules/orbit/orbit.dm

@@ -68,18 +68,12 @@
 	lastloc = orbiter.loc
 	return TRUE
 
+/atom/movable
+	var/weakref/orbiting = null
+	var/cached_transform = null
 
-/atom/movable/var/datum/orbit/orbiting = null
-/atom/var/list/orbiters = null
-
-/atom/movable/var/cached_transform = null
-//A: atom to orbit
-//radius: range to orbit at, radius of the circle formed by orbiting (in pixels)
-//clockwise: whether you orbit clockwise or anti clockwise
-//rotation_speed: how fast to rotate (how many ds should it take for a rotation to complete)
-//rotation_segments: the resolution of the orbit circle, less = a more block circle, this can be used to produce hexagons (6 segments) triangles (3 segments), and so on, 36 is the best default.
-//pre_rotation: Chooses to rotate src 90 degress towards the orbit dir (clockwise/anticlockwise), useful for things to go "head first" like ghosts
-//lockinorbit: Forces src to always be on A's turf, otherwise the orbit cancels when src gets too far away (eg: ghosts)
+/atom
+	var/list/orbiters = null
 
 /atom/movable/proc/orbit(atom/A, radius = 10, clockwise = FALSE, rotation_speed = 20, rotation_segments = 36, pre_rotation = TRUE, lockinorbit = FALSE)
 	if(!istype(A))