Advanced Grabbing Unit cannot re-grapple an asteroid

[FuzzyLlama]

As far as I have seen, there is a bug in which an asteroid which has been grappled cannot be re-grappled. For instance, if I grab the asteroid, release it and reposition the craft, the grabbing unit is unable to re-attach to the asteroid. I've tried fiddling with the savegame, hoping it was something fixable like the docking port bug (in which you simply have to change the port's state back to 'Ready'). I see the PotatoRoid part has a few hundred (!) lines of "attN = grapple, -1" after attempting to re-grab. I have also left a small adapter (grabbing unit and docking port) in a 'roid, but could not re-dock with the docking port. I've tried editing the save file to make the docking port 'Ready', and although the magnets pull the docking ports together and seem to hold, the ships do not become joined.

Using KAS pipes to connect the ships also does not result in connecting the ships.

[DeMatt]

I have to say that I have the same problem. Un-grabbed the asteroid to move the probe around (rather than rotate the whole asteroid), can't re-grab.

Probe's entry in persistent.sfs (minus all the parts save the Klaw):

VESSEL
{
	pid = 8d5cd12b5b384612852edff4edee668f
	name = Pusher XRZ-886
	type = Probe
	sit = ORBITING
	landed = False
	landedAt = 
	splashed = False
	met = 843904.674821795
	lct = 1699779.07786351
	root = 0
	lat = 1.57429384552836
	lon = -40.8880465270186
	alt = 13771045928.2353
	hgt = -1
	nrm = -0.0001853776,-0.0121984,0.9999256
	rot = -0.5935039,0.6924151,-0.2545876,0.3217137
	CoM = 0.002100301,0.01565827,1.607194E-06
	stg = 1
	prst = False
	ref = 1442432966
	ctrl = True
	cPch = 
	cHdg = 
	cMod = 0
	ORBIT
	{
		SMA = 14459790881.5075
		ECC = 0.0583260541655585
		INC = 1.63928652489948
		LPE = 168.683585234419
		LAN = 172.656423360769
		MNA = 5.2937630057258
		EPH = 2543683.7526853
		REF = 0
	} // edited out PART entries...
	PART
	{
		name = GrapplingDevice
		uid = 2266354856
		mid = 1644142589
		launchID = 113
		parent = 2
		position = 0,1.48380088806152,0
		rotation = 0,0,0,1
		mirror = 1,1,1
		istg = 0
		dstg = 0
		sqor = -1
		sidx = -1
		attm = 0
		srfN = None, -1
		attN = top, 2
		mass = 0.075
		temp = 7.660917
		expt = 0.5
		state = 1
		connected = True
		attached = True
		flag = Squad/Flags/kerbinmunflag
		rTrf = GrapplingDevice
		modCost = 0
		EVENTS
		{
		}
		ACTIONS
		{
		}
		MODULE
		{
			name = ModuleGrappleNode
			isEnabled = True
			state = Disabled
			dockUId = 2144052774
			grapplePos = 13.94105,4.337672,2.137333
			grappleOrt = -0.9447441,-0.2940901,-0.1448096
			grappleOrt2 = 0.3023647,-0.611139,-0.7314948
			EVENTS
			{
				Release
				{
					active = False
					guiActive = True
					guiIcon = Release
					guiName = Release
					category = Release
					guiActiveUnfocused = True
					unfocusedRange = 2
					externalToEVAOnly = True
				}
				ReleaseSameVessel
				{
					active = False
					guiActive = True
					guiIcon = Release
					guiName = Release
					category = Release
					guiActiveUnfocused = True
					unfocusedRange = 2
					externalToEVAOnly = True
				}
				Decouple
				{
					active = False
					guiActive = True
					guiIcon = Decouple Node
					guiName = Decouple Node
					category = Decouple Node
					guiActiveUnfocused = True
					unfocusedRange = 2
					externalToEVAOnly = True
				}
				MakeReferenceTransform
				{
					active = True
					guiActive = True
					guiIcon = Control from Here
					guiName = Control from Here
					category = Control from Here
					guiActiveUnfocused = False
					unfocusedRange = 2
					externalToEVAOnly = True
				}
				SetLoose
				{
					active = False
					guiActive = True
					guiIcon = Free Pivot
					guiName = Free Pivot
					category = Free Pivot
					guiActiveUnfocused = False
					unfocusedRange = 2
					externalToEVAOnly = True
				}
				LockPivot
				{
					active = False
					guiActive = True
					guiIcon = Lock Pivot
					guiName = Lock Pivot
					category = Lock Pivot
					guiActiveUnfocused = False
					unfocusedRange = 2
					externalToEVAOnly = True
				}
			}
			ACTIONS
			{
				ReleaseAction
				{
					actionGroup = None
				}
				DecoupleAction
				{
					actionGroup = None
				}
			}
			DOCKEDVESSEL
			{
				vesselName = Pusher XRZ-886
				vesselType = 3
				rootUId = 1442432966
			}
			DOCKEDVESSEL_Other
			{
				vesselName = Ast. XRZ-886
				vesselType = 1
				rootUId = 2144052774
			}
		}
		MODULE
		{
			name = ModuleAnimateGeneric
			isEnabled = True
			status = Locked
			animSwitch = True
			animTime = 0
			animSpeed = -1
			EVENTS
			{
				Toggle
				{
					active = True
					guiActive = True
					guiActiveEditor = True
					guiIcon = Toggle
					guiName = Arm
					category = Toggle
					guiActiveUnfocused = True
					unfocusedRange = 5
					externalToEVAOnly = True
				}
			}
			ACTIONS
			{
				ToggleAction
				{
					actionGroup = Custom01
				}
			}
		}
		MODULE
		{
			name = FXModuleLookAtConstraint
			isEnabled = True
			EVENTS
			{
			}
			ACTIONS
			{
			}
		}
		MODULE
		{
			name = FlagDecal
			isEnabled = True
			flagDisplayed = True
			EVENTS
			{
				ToggleFlag
				{
					active = True
					guiActive = False
					guiActiveEditor = True
					guiIcon = ToggleFlag
					guiName = ToggleFlag
					category = ToggleFlag
					guiActiveUnfocused = False
					unfocusedRange = 2
					externalToEVAOnly = True
				}
			}
			ACTIONS
			{
			}
		}
		MODULE
		{
			name = FARBasicDragModel
			isEnabled = True
			EVENTS
			{
			}
			ACTIONS
			{
			}
		}
	}
	ACTIONGROUPS
	{
		Stage = True, 2525484.90892683
		Gear = False, 1699848.43786358
		Light = False, 0
		RCS = False, 0
		SAS = False, 2543440.53268508
		Brakes = False, 0
		Abort = False, 0
		Custom01 = False, 0
		Custom02 = False, 0
		Custom03 = False, 0
		Custom04 = False, 0
		Custom05 = False, 0
		Custom06 = False, 0
		Custom07 = False, 0
		Custom08 = False, 0
		Custom09 = False, 0
		Custom10 = False, 2539606.87028406
	}
	DISCOVERY
	{
		state = -1
		lastObservedTime = 0
		lifetime = Infinity
		refTime = Infinity
		size = 2
	}
	FLIGHTPLAN
	{
	}
	TARGET
	{
		type = Vessel
		vesselID = d9cc518b-64bb-4ace-80a5-b2a5e56a5baa
	}
	CTRLSTATE
	{
		pitch = 0
		yaw = 0
		roll = 0
		trimPitch = 0
		trimYaw = 0
		trimRoll = 0
		mainThrottle = 0
	}
}

Asteroid's entry:

	VESSEL
	{
		pid = d9cc518b64bb4ace80a5b2a5e56a5baa
		name = Ast. XRZ-886
		type = SpaceObject
		sit = ORBITING
		landed = False
		landedAt = 
		splashed = False
		met = 4886.04240200482
		lct = 2538797.7102833
		root = 0
		lat = 1.57429386226097
		lon = -40.8880466262876
		alt = 13771045927.9369
		hgt = -1
		nrm = -0.3925391,0.579319,0.7143548
		rot = 0.7495806,0.129304,0.5767156,-0.298008
		CoM = 0,0,0
		stg = 1
		prst = False
		ref = 0
		ctrl = False
		cPch = 0
		cHdg = 0
		cMod = 0
		ORBIT
		{
			SMA = 14459779522.9039
			ECC = 0.0583257600765503
			INC = 1.63928703997213
			LPE = 168.684348965906
			LAN = 172.656363327985
			MNA = 5.29375091647882
			EPH = 2543683.7526853
			REF = 0
		}
		PART
		{
			name = PotatoRoid
			uid = 2144052774
			mid = 2144052774
			launchID = 0
			parent = 0
			position = 0,0,0
			rotation = 0,0,0,1
			mirror = 1,1,1
			istg = 0
			dstg = 0
			sqor = 0
			sidx = 0
			attm = 0
			srfN = None, -1
			attN = grapple, -1
			// a bunch more "attN = grapple, -1" lines edited out here
			attN = grapple, -1
			mass = 173.8646
			temp = 14.85547
			expt = 0.1
			state = 1
			connected = True
			attached = True
			flag = 
			rTrf = PotatoRoid (Ast. XRZ-886)
			modCost = 0
			EVENTS
			{
			}
			ACTIONS
			{
			}
			MODULE
			{
				name = ModuleAsteroid
				isEnabled = True
				seed = 16489110
				AsteroidName = Ast. XRZ-886
				prefabBaseURL = Procedural/PA_C
				EVENTS
				{
					MakeTarget
					{
						active = True
						guiActive = True
						guiIcon = Target Center of Mass
						guiName = Target Center of Mass
						category = Target Center of Mass
						guiActiveUnfocused = True
						unfocusedRange = 500
						externalToEVAOnly = False
					}
					TakeSampleEVAEvent
					{
						active = True
						guiActive = False
						guiIcon = Take Sample
						guiName = Take Sample
						category = Take Sample
						guiActiveUnfocused = True
						unfocusedRange = 18.07728
						externalToEVAOnly = True
					}
					RenameAsteroidEvent
					{
						active = True
						guiActive = True
						guiIcon = Rename Asteroid
						guiName = Rename Asteroid
						category = Rename Asteroid
						guiActiveUnfocused = True
						unfocusedRange = 18.07728
						externalToEVAOnly = True
					}
				}
				ACTIONS
				{
				}
			}
			MODULE
			{
				name = FARBasicDragModel
				isEnabled = True
				EVENTS
				{
				}
				ACTIONS
				{
				}
			}
		}
		ACTIONGROUPS
		{
			Stage = False, 0
			Gear = True, 0
			Light = False, 0
			RCS = False, 0
			SAS = False, 0
			Brakes = False, 0
			Abort = False, 0
			Custom01 = False, 0
			Custom02 = False, 0
			Custom03 = False, 0
			Custom04 = False, 0
			Custom05 = False, 0
			Custom06 = False, 0
			Custom07 = False, 0
			Custom08 = False, 0
			Custom09 = False, 0
			Custom10 = False, 0
		}
		DISCOVERY
		{
			state = -1
			lastObservedTime = 0
			lifetime = Infinity
			refTime = Infinity
			size = 2
		}
		FLIGHTPLAN
		{
		}
		CTRLSTATE
		{
			pitch = 0
			yaw = 0
			roll = 0
			trimPitch = 0
			trimYaw = 0
			trimRoll = 0
			mainThrottle = 0
		}
	}
}

[BudgetHedgehog]

It's nothing to do with the parts, I'm guessing you have Fine Print installed.

If so, it's a known issue with it and will be fixed for 0.90.0. Check your output_log.txt for this to confirm it:

NullReferenceException: Object reference not set to an instance of an object
  at FinePrint.Contracts.Parameters.AsteroidParameter.OnDock (FromToAction`2 action) [0x00000] in <filename unknown>:0 
  at EventData`1[GameEvents+FromToAction`2[Part,Part]].Fire (FromToAction`2 data) [0x00000] in <filename unknown>:0 
  at Part.Couple (.Part tgtPart) [0x00000] in <filename unknown>:0 
  at ModuleGrappleNode.Grapple (.Part other, .Part dockerSide) [0x00000] in <filename unknown>:0 
  at ModuleGrappleNode.<SetupFSM>m__10 () [0x00000] in <filename unknown>:0 
  at KerbalFSM.RunEvent (.KFSMEvent evt) [0x00000] in <filename unknown>:0 
  at KerbalFSM.updateFSM (KFSMUpdateMode mode) [0x00000] in <filename unknown>:0 
  at KerbalFSM.FixedUpdateFSM () [0x00000] in <filename unknown>:0 
  at ModuleGrappleNode.FixedUpdate () [0x00000] in <filename unknown>:0

I don't know if it can be fixed without cancelling the ARM mission though. Arsonide will have to weigh in with that.

Edited December 1, 2014 by ObsessedWithKSP

[DeMatt]

It's nothing to do with the parts, I'm guessing you have Fine Print installed.

If so, it's a known issue with it and will be fixed for 0.90.0. Check your output_log.txt for this to confirm it:

NullReferenceException: Object reference not set to an instance of an object
  at FinePrint.Contracts.Parameters.AsteroidParameter.OnDock (FromToAction`2 action) [0x00000] in <filename unknown>:0 
  at EventData`1[GameEvents+FromToAction`2[Part,Part]].Fire (FromToAction`2 data) [0x00000] in <filename unknown>:0 
  at Part.Couple (.Part tgtPart) [0x00000] in <filename unknown>:0 
  at ModuleGrappleNode.Grapple (.Part other, .Part dockerSide) [0x00000] in <filename unknown>:0 
  at ModuleGrappleNode.<SetupFSM>m__10 () [0x00000] in <filename unknown>:0 
  at KerbalFSM.RunEvent (.KFSMEvent evt) [0x00000] in <filename unknown>:0 
  at KerbalFSM.updateFSM (KFSMUpdateMode mode) [0x00000] in <filename unknown>:0 
  at KerbalFSM.FixedUpdateFSM () [0x00000] in <filename unknown>:0 
  at ModuleGrappleNode.FixedUpdate () [0x00000] in <filename unknown>:0

I don't know if it can be fixed without cancelling the ARM mission though. Arsonide will have to weigh in with that.

...bugger. Yes, I have Fine Print, and yes, those NullRef's show up in the log. Well, at least I know the problem, if not the solution. Thanks.

[Arsonide]

...bugger. Yes, I have Fine Print, and yes, those NullRef's show up in the log. Well, at least I know the problem, if not the solution. Thanks.

There is a workaround in the mean time. Make sure that the first asteroid you grab is the correct size and status (newly tracked). As far as I am aware, this bug occurs when you grab multiple asteroids in succession, starting with one that does not qualify for the contract.