Moved all of the vessel parsing code into the new RelayDatabase, which
Moved all of the vessel parsing code into the new RelayDatabase, which
watches some events to dirty the cache when states change. Also modules
will no longer offer to transmit if their part is dead or deactivated.

--- a/AntennaRange.cfg
+++ b/AntennaRange.cfg
@@ -48,8 +48,3 @@
 	}
 }
 
-@PART[*]:HAS[MODULE[ModuleLimitedDataTransmitter]]:Final
-{
-	isAntenna = True
-}
-

file:b/AntennaRelay.cs (new)
--- /dev/null
+++ b/AntennaRelay.cs
@@ -1,1 +1,268 @@
-
+// AntennaRange © 2014 toadicus
+//
+// AntennaRange provides incentive and requirements for the use of the various antenna parts.
+// Nominally, the breakdown is as follows:
+//
+//     Communotron 16 - Suitable up to Kerbalsynchronous Orbit
+//     Comms DTS-M1 - Suitable throughout the Kerbin subsystem
+//     Communotron 88-88 - Suitable throughout the Kerbol system.
+//
+// This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. To view a
+// copy of this license, visit http://creativecommons.org/licenses/by-nc-sa/3.0/
+//
+// This software uses the ModuleManager library © 2013 ialdabaoth, used under a Creative Commons Attribution-ShareAlike
+// 3.0 Uported License.
+//
+// This software uses code from the MuMechLib library, © 2013 r4m0n, used under the GNU GPL version 3.
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace AntennaRange
+{
+	public class AntennaRelay : IAntennaRelay
+	{
+		// We don't have a Bard, so we'll hide Kerbin here.
+		protected CelestialBody Kerbin;
+
+		protected System.Diagnostics.Stopwatch searchTimer;
+		protected long millisecondsBetweenSearches;
+
+		/// <summary>
+		/// Gets the parent Vessel.
+		/// </summary>
+		/// <value>The parent Vessel.</value>
+		public Vessel vessel
+		{
+			get;
+			protected set;
+		}
+
+		/// <summary>
+		/// Gets or sets the nearest relay.
+		/// </summary>
+		/// <value>The nearest relay</value>
+		public IAntennaRelay nearestRelay
+		{
+			get;
+			protected set;
+		}
+
+		/// <summary>
+		/// Gets the transmit distance.
+		/// </summary>
+		/// <value>The transmit distance.</value>
+		public double transmitDistance
+		{
+			get
+			{
+				this.nearestRelay = this.FindNearestRelay();
+
+				// If there is no available relay nearby...
+				if (nearestRelay == null)
+				{
+					// .. return the distance to Kerbin
+					return this.DistanceTo(this.Kerbin);
+				}
+				else
+				{
+					/// ...otherwise, return the distance to the nearest available relay.
+					return this.DistanceTo(nearestRelay);
+				}
+			}
+		}
+
+		/// <summary>
+		/// The maximum distance at which this relay can operate.
+		/// </summary>
+		/// <value>The max transmit distance.</value>
+		public virtual float maxTransmitDistance
+		{
+			get;
+			set;
+		}
+
+		/// <summary>
+		/// Gets a value indicating whether this <see cref="AntennaRange.ProtoDataTransmitter"/> has been checked during
+		/// the current relay attempt.
+		/// </summary>
+		/// <value><c>true</c> if relay checked; otherwise, <c>false</c>.</value>
+		public virtual bool relayChecked
+		{
+			get;
+			protected set;
+		}
+
+		/// <summary>
+		/// Determines whether this instance can transmit.
+		/// </summary>
+		/// <returns><c>true</c> if this instance can transmit; otherwise, <c>false</c>.</returns>
+		public virtual bool CanTransmit()
+		{
+			if (this.transmitDistance > this.maxTransmitDistance)
+			{
+				return false;
+			}
+			else
+			{
+				return true;
+			}
+		}
+
+		/// <summary>
+		/// Finds the nearest relay.
+		/// </summary>
+		/// <returns>The nearest relay or null, if no relays in range.</returns>
+		public IAntennaRelay FindNearestRelay()
+		{
+			if (this.searchTimer.IsRunning && this.searchTimer.ElapsedMilliseconds < this.millisecondsBetweenSearches)
+			{
+				return this.nearestRelay;
+			}
+
+			if (this.searchTimer.IsRunning)
+			{
+				this.searchTimer.Stop();
+				this.searchTimer.Reset();
+			}
+
+			this.searchTimer.Start();
+
+			// Set this relay as checked, so that we don't check it again.
+			this.relayChecked = true;
+
+			// Get a list of vessels within transmission range.
+			List<Vessel> nearbyVessels = FlightGlobals.Vessels
+				.Where(v => (v.GetWorldPos3D() - vessel.GetWorldPos3D()).magnitude < this.maxTransmitDistance)
+					.ToList();
+
+			nearbyVessels.RemoveAll(v => v.vesselType == VesselType.Debris);
+
+			Tools.PostDebugMessage(string.Format(
+				"{0}: Non-debris vessels in range: {1}",
+				this.GetType().Name,
+				nearbyVessels.Count
+				));
+
+			// Remove this vessel.
+			nearbyVessels.RemoveAll(v => v.id == vessel.id);
+
+			Tools.PostDebugMessage(string.Format(
+				"{0}: Vessels in range excluding self: {1}",
+				this.GetType().Name,
+				nearbyVessels.Count
+				));
+
+			// Get a flattened list of all IAntennaRelay modules and protomodules in transmission range.
+			List<IAntennaRelay> nearbyRelays = nearbyVessels.SelectMany(v => v.GetAntennaRelays()).ToList();
+
+			Tools.PostDebugMessage(string.Format(
+				"{0}: Found {1} nearby relays.",
+				this.GetType().Name,
+				nearbyRelays.Count
+				));
+
+			// Remove all relays already checked this time.
+			nearbyRelays.RemoveAll(r => r.relayChecked);
+
+			Tools.PostDebugMessage(string.Format(
+				"{0}: Found {1} nearby relays not already checked.",
+				this.GetType().Name,
+				nearbyRelays.Count
+				));
+
+			// Remove all relays that cannot transmit.
+			// This call to r.CanTransmit() starts a depth-first recursive search for relays with a path back to Kerbin.
+			nearbyRelays.RemoveAll(r => !r.CanTransmit());
+
+			Tools.PostDebugMessage(string.Format(
+				"{0}: Found {1} nearby relays not already checked that can transmit.",
+				this.GetType().Name,
+				nearbyRelays.Count
+				));
+
+			// Sort the available relays by distance.
+			nearbyRelays.Sort(new RelayComparer(this.vessel));
+
+			// Get the nearest available relay, or null if there are no available relays nearby.
+			IAntennaRelay _nearestRelay = nearbyRelays.FirstOrDefault();
+
+			// If we have a nearby relay...
+			if (_nearestRelay != null)
+			{
+				// ...but that relay is farther than Kerbin...
+				if (this.DistanceTo(_nearestRelay) > this.DistanceTo(Kerbin))
+				{
+					// ...just use Kerbin.
+					_nearestRelay = null;
+				}
+			}
+
+			// Now that we're done with our recursive CanTransmit checks, flag this relay as not checked so it can be
+			// used next time.
+			this.relayChecked = false;
+
+			// Return the nearest available relay, or null if there are no available relays nearby.
+			return _nearestRelay;
+		}
+
+		/// <summary>
+		/// Initializes a new instance of the <see cref="AntennaRange.ProtoDataTransmitter"/> class.
+		/// </summary>
+		/// <param name="ms"><see cref="ProtoPartModuleSnapshot"/></param>
+		public AntennaRelay(Vessel v)
+		{
+			this.vessel = v;
+
+			this.searchTimer = new System.Diagnostics.Stopwatch();
+			this.millisecondsBetweenSearches = 5000;
+
+			// HACK: This might not be safe in all circumstances, but since AntennaRelays are not built until Start,
+			// we hope it is safe enough.
+			this.Kerbin = FlightGlobals.Bodies.FirstOrDefault(b => b.name == "Kerbin");
+		}
+
+		/*
+		 * Class implementing IComparer<IAntennaRelay> for use in sorting relays by distance.
+		 * */
+		internal class RelayComparer : IComparer<IAntennaRelay>
+		{
+			/// <summary>
+			/// The reference Vessel (usually the active vessel).
+			/// </summary>
+			protected Vessel referenceVessel;
+
+			// We don't want no stinking public parameterless constructors.
+			private RelayComparer() {}
+
+			/// <summary>
+			/// Initializes a new instance of the <see cref="AntennaRange.AntennaRelay+RelayComparer"/> class for use
+			/// in sorting relays by distance.
+			/// </summary>
+			/// <param name="reference">The reference Vessel</param>
+			public RelayComparer(Vessel reference)
+			{
+				this.referenceVessel = reference;
+			}
+
+			/// <summary>
+			/// Compare the <see cref="IAntennaRelay"/>s "one" and "two".
+			/// </summary>
+			/// <param name="one">The first IAntennaRelay in the comparison</param>
+			/// <param name="two">The second IAntennaRelay in the comparison</param>
+			public int Compare(IAntennaRelay one, IAntennaRelay two)
+			{
+				double distanceOne;
+				double distanceTwo;
+
+				distanceOne = one.vessel.DistanceTo(referenceVessel);
+				distanceTwo = two.vessel.DistanceTo(referenceVessel);
+
+				return distanceOne.CompareTo(distanceTwo);
+			}
+		}
+	}
+}
+
+

--- a/Extensions.cs
+++ b/Extensions.cs
@@ -15,11 +15,9 @@
 //
 // This software uses code from the MuMechLib library, © 2013 r4m0n, used under the GNU GPL version 3.
 
-using KSP;
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using UnityEngine;
 
 namespace AntennaRange
 {
@@ -53,7 +51,7 @@
 		/// </summary>
 		/// <param name="relay">This <see cref="IAntennaRelay"/></param>
 		/// <param name="Vessel">A <see cref="Vessel"/></param>
-		public static double DistanceTo(this IAntennaRelay relay, Vessel Vessel)
+		public static double DistanceTo(this AntennaRelay relay, Vessel Vessel)
 		{
 			return relay.vessel.DistanceTo(Vessel);
 		}
@@ -63,7 +61,7 @@
 		/// </summary>
 		/// <param name="relay">This <see cref="IAntennaRelay"/></param>
 		/// <param name="body">A <see cref="CelestialBody"/></param>
-		public static double DistanceTo(this IAntennaRelay relay, CelestialBody body)
+		public static double DistanceTo(this AntennaRelay relay, CelestialBody body)
 		{
 			return relay.vessel.DistanceTo(body);
 		}
@@ -73,7 +71,7 @@
 		/// </summary>
 		/// <param name="relayOne">This <see cref="IAntennaRelay"/></param>
 		/// <param name="relayTwo">Another <see cref="IAntennaRelay"/></param>
-		public static double DistanceTo(this IAntennaRelay relayOne, IAntennaRelay relayTwo)
+		public static double DistanceTo(this AntennaRelay relayOne, IAntennaRelay relayTwo)
 		{
 			return relayOne.DistanceTo(relayTwo.vessel);
 		}
@@ -84,63 +82,10 @@
 		/// <param name="vessel">This <see cref="Vessel"/></param>
 		public static IEnumerable<IAntennaRelay> GetAntennaRelays (this Vessel vessel)
 		{
-			Tools.PostDebugMessage(string.Format(
-				"{0}: Getting antenna relays from vessel {1}.",
-				"IAntennaRelay",
-				vessel.name
-			));
+			return RelayDatabase.Instance[vessel].Values.ToList();
+		}
 
-			List<IAntennaRelay> Transmitters;
 
-			// If the vessel is loaded, we can fetch modules implementing IAntennaRelay directly.
-			if (vessel.loaded) {
-				Tools.PostDebugMessage(string.Format(
-					"{0}: vessel {1} is loaded.",
-					"IAntennaRelay",
-					vessel.name
-					));
-
-				// Gets a list of PartModules implementing IAntennaRelay
-				Transmitters = vessel.Parts
-					.SelectMany (p => p.Modules.OfType<IAntennaRelay> ())
-					.ToList();
-			}
-			// If the vessel is not loaded, we need to find ProtoPartModuleSnapshots with a true IsAntenna field.
-			else
-			{
-				Tools.PostDebugMessage(string.Format(
-					"{0}: vessel {1} is not loaded.",
-					"IAntennaRelay",
-					vessel.name
-					));
-
-				Transmitters = new List<IAntennaRelay>();
-
-				// Loop through the ProtoPartModuleSnapshots in this Vessel
-				foreach (ProtoPartSnapshot pps in vessel.protoVessel.protoPartSnapshots)
-				{
-					foreach (PartModule prefabModule in PartLoader.getPartInfoByName(pps.partName).partPrefab.Modules)
-					{
-						if (prefabModule is ModuleLimitedDataTransmitter)
-						{
-							pps.Load(vessel, false);
-
-							Transmitters.Add(pps.partRef.Modules.OfType<ModuleLimitedDataTransmitter>().First());
-						}
-					}
-				}
-			}
-
-			Tools.PostDebugMessage(string.Format(
-				"{0}: vessel {1} has {2} transmitters.",
-				"IAntennaRelay",
-				vessel.name,
-				Transmitters.Count
-				));
-
-			// Return the list of IAntennaRelays
-			return Transmitters;
-		}
 	}
 }
 

--- a/IAntennaRelay.cs
+++ b/IAntennaRelay.cs
@@ -32,12 +32,6 @@
 		Vessel vessel { get; }
 
 		/// <summary>
-		/// Gets the nearest relay.
-		/// </summary>
-		/// <value>The nearest relay.</value>
-		IAntennaRelay nearestRelay { get; }
-
-		/// <summary>
 		/// Gets the distance to the nearest relay or Kerbin, whichever is closer.
 		/// </summary>
 		/// <value>The distance to the nearest relay or Kerbin, whichever is closer.</value>

--- a/ModuleLimitedDataTransmitter.cs
+++ b/ModuleLimitedDataTransmitter.cs
@@ -18,6 +18,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Text;
 using KSP;
 using UnityEngine;
 
@@ -41,29 +42,38 @@
 	 * */
 	public class ModuleLimitedDataTransmitter : ModuleDataTransmitter, IScienceDataTransmitter, IAntennaRelay
 	{
-		protected System.Diagnostics.Stopwatch searchTimer;
-		protected long millisecondsBetweenSearches;
-
 		// Stores the packetResourceCost as defined in the .cfg file.
 		protected float _basepacketResourceCost;
 
 		// Stores the packetSize as defined in the .cfg file.
 		protected float _basepacketSize;
 
+		// Every antenna is a relay.
+		protected AntennaRelay relay;
+
 		// Keep track of vessels with transmitters for relay purposes.
 		protected List<Vessel> _relayVessels;
 
 		// Sometimes we will need to communicate errors; this is how we do it.
 		protected ScreenMessage ErrorMsg;
-
-		// Let's make the error text pretty!
-		protected UnityEngine.GUIStyle ErrorStyle;
 
 		// The distance from Kerbin at which the antenna will perform exactly as prescribed by packetResourceCost
 		// and packetSize.
 		[KSPField(isPersistant = false)]
 		public float nominalRange;
 
+		[KSPField(isPersistant = false, guiActive = true, guiName = "Transmission Distance")]
+		public string UItransmitDistance;
+
+		[KSPField(isPersistant = false, guiActive = true, guiName = "Maximum Distance")]
+		public string UImaxTransmitDistance;
+
+		[KSPField(isPersistant = false, guiActive = true, guiName = "Packet Size")]
+		public string UIpacketSize;
+
+		[KSPField(isPersistant = false, guiActive = true, guiName = "Packet Cost")]
+		public string UIpacketCost;
+
 		// The multiplier on packetResourceCost that defines the maximum power output of the antenna.  When the power
 		// cost exceeds packetResourceCost * maxPowerFactor, transmission will fail.
 		[KSPField(isPersistant = false)]
@@ -73,60 +83,26 @@
 		[KSPField(isPersistant = false)]
 		public float maxDataFactor;
 
-		protected CelestialBody _Kerbin;
+		protected bool actionUIUpdate;
 
 		/*
 		 * Properties
 		 * */
-		// We don't have a Bard, so we'll hide Kerbin here.
-		protected CelestialBody Kerbin
-		{
-			get
-			{
-				if (this._Kerbin == null)
-				{
-					foreach (CelestialBody cb in FlightGlobals.Bodies)
-					{
-						if (cb.name == "Kerbin")
-						{
-							this._Kerbin = cb;
-							break;
-						}
-					}
-				}
-				return this._Kerbin;
-			}
-		}
-
-		/// <summary>
-		/// Gets or sets the nearest relay.
-		/// </summary>
-		/// <value>The nearest relay</value>
-		public IAntennaRelay nearestRelay
-		{
-			get;
-			protected set;
-		}
-
+		// Returns the parent vessel housing this antenna.
+		public new Vessel vessel
+		{
+			get
+			{
+				return base.vessel;
+			}
+		}
 
 		// Returns the distance to the nearest relay or Kerbin, whichever is closer.
 		public double transmitDistance
 		{
 			get
 			{
-				this.nearestRelay = this.FindNearestRelay();
-
-				// If there is no available relay nearby...
-				if (nearestRelay == null)
-				{
-					// .. return the distance to Kerbin
-					return this.DistanceTo(this.Kerbin);
-				}
-				else
-				{
-					/// ...otherwise, return the distance to the nearest available relay.
-					return this.DistanceTo(nearestRelay);
-				}
+				return this.relay.transmitDistance;
 			}
 		}
 
@@ -206,8 +182,10 @@
 		// Reports whether this antenna has been checked as a viable relay already in the current FindNearestRelay.
 		public bool relayChecked
 		{
-			get;
-			protected set;
+			get
+			{
+				return this.relay.relayChecked;
+			}
 		}
 
 		/*
@@ -216,21 +194,24 @@
 		// Build ALL the objects.
 		public ModuleLimitedDataTransmitter () : base()
 		{
-			// Make the error posting prettier.
-			this.ErrorStyle = new UnityEngine.GUIStyle();
-			this.ErrorStyle.normal.textColor = (UnityEngine.Color)XKCDColors.OrangeRed;
-			this.ErrorStyle.active.textColor = (UnityEngine.Color)XKCDColors.OrangeRed;
-			this.ErrorStyle.hover.textColor = (UnityEngine.Color)XKCDColors.OrangeRed;
-			this.ErrorStyle.fontStyle = UnityEngine.FontStyle.Normal;
-			this.ErrorStyle.padding.top = 32;
-
-			this.ErrorMsg = new ScreenMessage("", 4f, false, ScreenMessageStyle.UPPER_LEFT, this.ErrorStyle);
+			this.ErrorMsg = new ScreenMessage("", 4f, false, ScreenMessageStyle.UPPER_LEFT);
 		}
 
 		// At least once, when the module starts with a state on the launch pad or later, go find Kerbin.
 		public override void OnStart (StartState state)
 		{
 			base.OnStart (state);
+
+			if (state >= StartState.PreLaunch)
+			{
+				this.relay = new AntennaRelay(vessel);
+				this.relay.maxTransmitDistance = this.maxTransmitDistance;
+
+				this.UImaxTransmitDistance = Tools.MuMech_ToSI(this.maxTransmitDistance) + "m";
+
+				GameEvents.onPartActionUICreate.Add(this.onPartActionUICreate);
+				GameEvents.onPartActionUIDismiss.Add(this.onPartActionUIDismiss);
+			}
 		}
 
 		// When the module loads, fetch the Squad KSPFields from the base.  This is necessary in part because
@@ -245,9 +226,6 @@
 
 			this._basepacketSize = base.packetSize;
 			this._basepacketResourceCost = base.packetResourceCost;
-
-			this.searchTimer = new System.Diagnostics.Stopwatch();
-			this.millisecondsBetweenSearches = 5000;
 
 			Tools.PostDebugMessage(string.Format(
 				"{0} loaded:\n" +
@@ -275,9 +253,18 @@
 				Tools.MuMech_ToSI((double)this.transmitDistance, 2)
 				);
 
-			this.ErrorMsg.message = ErrorText;
-
-			ScreenMessages.PostScreenMessage(this.ErrorMsg, true);
+			this.ErrorMsg.message = string.Format(
+				"<color='#{0}{1}{2}{3}'><b>{4}</b></color>",
+				((int)(XKCDColors.OrangeRed.r * 255f)).ToString("x2"),
+				((int)(XKCDColors.OrangeRed.g * 255f)).ToString("x2"),
+				((int)(XKCDColors.OrangeRed.b * 255f)).ToString("x2"),
+				((int)(XKCDColors.OrangeRed.a * 255f)).ToString("x2"),
+				ErrorText
+			);
+
+			Tools.PostDebugMessage(this.GetType().Name + ": " + this.ErrorMsg.message);
+
+			ScreenMessages.PostScreenMessage(this.ErrorMsg, false);
 		}
 
 		// Before transmission, set packetResourceCost.  Per above, packet cost increases with the square of
@@ -324,21 +311,19 @@
 		// Override ModuleDataTransmitter.CanTransmit to return false when transmission is not possible.
 		public new bool CanTransmit()
 		{
-			Tools.PostDebugMessage(string.Format(
-				"{0}: Checking if {1} on {2} can transmit.",
-				this.GetType().Name,
-				base.part.name,
-				this.vessel
-			));
-
-			if (this.transmitDistance > this.maxTransmitDistance)
-			{
+			PartStates partState = this.part.State;
+			if (partState == PartStates.DEAD || partState == PartStates.DEACTIVATED)
+			{
+				Tools.PostDebugMessage(string.Format(
+					"{0}: {1} on {2} cannot transmit: {3}",
+					this.GetType().Name,
+					this.part.partInfo.title,
+					this.vessel.name,
+					Enum.GetName(typeof(PartStates), partState)
+				));
 				return false;
 			}
-			else
-			{
-				return true;
-			}
+			return this.relay.CanTransmit();
 		}
 
 		// Override ModuleDataTransmitter.TransmitData to check against CanTransmit and fail out when CanTransmit
@@ -361,103 +346,6 @@
 			);
 		}
 
-		/// <summary>
-		/// Finds the nearest relay.
-		/// </summary>
-		/// <returns>The nearest relay or null, if no relays in range.</returns>
-		public IAntennaRelay FindNearestRelay()
-		{
-			if (this.searchTimer.IsRunning && this.searchTimer.ElapsedMilliseconds < this.millisecondsBetweenSearches)
-			{
-				return this.nearestRelay;
-			}
-
-			if (this.searchTimer.IsRunning)
-			{
-				this.searchTimer.Stop();
-				this.searchTimer.Reset();
-			}
-
-			this.searchTimer.Start();
-
-			// Set this relay as checked, so that we don't check it again.
-			this.relayChecked = true;
-
-			// Get a list of vessels within transmission range.
-			List<Vessel> nearbyVessels = FlightGlobals.Vessels
-				.Where(v => (v.GetWorldPos3D() - vessel.GetWorldPos3D()).magnitude < this.maxTransmitDistance)
-				.ToList();
-
-			nearbyVessels.RemoveAll(v => v.vesselType == VesselType.Debris);
-
-			Tools.PostDebugMessage(string.Format(
-				"{0}: Non-debris vessels in range: {1}",
-				this.GetType().Name,
-				nearbyVessels.Count
-			));
-
-			// Remove this vessel.
-			nearbyVessels.RemoveAll(v => v.id == vessel.id);
-
-			Tools.PostDebugMessage(string.Format(
-				"{0}: Vessels in range excluding self: {1}",
-				this.GetType().Name,
-				nearbyVessels.Count
-			));
-
-			// Get a flattened list of all IAntennaRelay modules and protomodules in transmission range.
-			List<IAntennaRelay> nearbyRelays = nearbyVessels.SelectMany(v => v.GetAntennaRelays()).ToList();
-
-			Tools.PostDebugMessage(string.Format(
-				"{0}: Found {1} nearby relays.",
-				this.GetType().Name,
-				nearbyRelays.Count
-			));
-
-			// Remove all relays already checked this time.
-			nearbyRelays.RemoveAll(r => r.relayChecked);
-
-			Tools.PostDebugMessage(string.Format(
-				"{0}: Found {1} nearby relays not already checked.",
-				this.GetType().Name,
-				nearbyRelays.Count
-			));
-
-			// Remove all relays that cannot transmit.
-			// This call to r.CanTransmit() starts a depth-first recursive search for relays with a path back to Kerbin.
-			nearbyRelays.RemoveAll(r => !r.CanTransmit());
-
-			Tools.PostDebugMessage(string.Format(
-				"{0}: Found {1} nearby relays not already checked that can transmit.",
-				this.GetType().Name,
-				nearbyRelays.Count
-			));
-
-			// Sort the available relays by distance.
-			nearbyRelays.Sort(new RelayComparer(this.vessel));
-
-			// Get the nearest available relay, or null if there are no available relays nearby.
-			IAntennaRelay _nearestRelay = nearbyRelays.FirstOrDefault();
-
-			// If we have a nearby relay...
-			if (_nearestRelay != null)
-			{
-				// ...but that relay is farther than Kerbin...
-				if (this.DistanceTo(_nearestRelay) > this.DistanceTo(Kerbin))
-				{
-					// ...just use Kerbin.
-					_nearestRelay = null;
-				}
-			}
-
-			// Now that we're done with our recursive CanTransmit checks, flag this relay as not checked so it can be
-			// used next time.
-			this.relayChecked = false;
-
-			// Return the nearest available relay, or null if there are no available relays nearby.
-			return _nearestRelay;
-		}
-
 		// Override ModuleDataTransmitter.StartTransmission to check against CanTransmit and fail out when CanTransmit
 		// returns false.
 		public new void StartTransmission()
@@ -473,20 +361,25 @@
 
 			if (this.CanTransmit())
 			{
-				string message;
-
-				message = "Beginning transmission ";
-
-				if (this.nearestRelay == null)
-				{
-					message += "directly to Kerbin.";
+				StringBuilder message = new StringBuilder();
+
+				message.Append("[");
+				message.Append(base.part.partInfo.title);
+				message.Append("] ");
+
+				message.Append("Beginning transmission ");
+
+				if (this.relay.nearestRelay == null)
+				{
+					message.Append("directly to Kerbin.");
 				}
 				else
 				{
-					message += "via relay " + this.nearestRelay;
-				}
-
-				ScreenMessages.PostScreenMessage(message, 4f, ScreenMessageStyle.UPPER_LEFT);
+					message.Append("via ");
+					message.Append(this.relay.nearestRelay);
+				}
+
+				ScreenMessages.PostScreenMessage(message.ToString(), 4f, ScreenMessageStyle.UPPER_LEFT);
 
 				base.StartTransmission();
 			}
@@ -496,45 +389,39 @@
 			}
 		}
 
-
-		/*		
-		 * Class implementing IComparer<IAntennaRelay> for use in sorting relays by distance.
-		 * */
-		internal class RelayComparer : IComparer<IAntennaRelay>
-		{
-			/// <summary>
-			/// The reference Vessel (usually the active vessel).
-			/// </summary>
-			protected Vessel referenceVessel;
-
-			// We don't want no stinking public parameterless constructors.
-			private RelayComparer() {}
-
-			/// <summary>
-			/// Initializes a new instance of the <see cref="AntennaRange.AntennaRelay+RelayComparer"/> class for use
-			/// in sorting relays by distance.
-			/// </summary>
-			/// <param name="reference">The reference Vessel</param>
-			public RelayComparer(Vessel reference)
-			{
-				this.referenceVessel = reference;
-			}
-
-			/// <summary>
-			/// Compare the <see cref="IAntennaRelay"/>s "one" and "two".
-			/// </summary>
-			/// <param name="one">The first IAntennaRelay in the comparison</param>
-			/// <param name="two">The second IAntennaRelay in the comparison</param>
-			public int Compare(IAntennaRelay one, IAntennaRelay two)
-			{
-				double distanceOne;
-				double distanceTwo;
-
-				distanceOne = one.vessel.DistanceTo(referenceVessel);
-				distanceTwo = two.vessel.DistanceTo(referenceVessel);
-
-				return distanceOne.CompareTo(distanceTwo);
-			}
+		public void Update()
+		{
+			if (this.actionUIUpdate)
+			{
+				this.UItransmitDistance = Tools.MuMech_ToSI(this.transmitDistance) + "m";
+				this.UIpacketSize = this.CanTransmit() ? Tools.MuMech_ToSI(this.DataRate) + "MiT" : "N/A";
+				this.UIpacketCost = this.CanTransmit() ? Tools.MuMech_ToSI(this.DataResourceCost) + "E" : "N/A";
+			}
+		}
+
+		public void onPartActionUICreate(Part eventPart)
+		{
+			if (eventPart == base.part)
+			{
+				this.actionUIUpdate = true;
+			}
+		}
+
+		public void onPartActionUIDismiss(Part eventPart)
+		{
+			if (eventPart == base.part)
+			{
+				this.actionUIUpdate = false;
+			}
+		}
+
+		public override string ToString()
+		{
+			return string.Format(
+				"{0} on {1}.",
+				this.part.partInfo.title,
+				vessel.name
+			);
 		}
 
 		// When debugging, it's nice to have a button that just tells you everything.
@@ -571,7 +458,7 @@
 				this.DataRate,
 				this.DataResourceCost,
 				ScienceUtil.GetTransmitterScore(this),
-				this.FindNearestRelay()
+				this.relay.FindNearestRelay()
 				);
 			ScreenMessages.PostScreenMessage (new ScreenMessage (msg, 4f, ScreenMessageStyle.UPPER_RIGHT));
 		}

--- /dev/null
+++ b/ProtoAntennaRelay.cs
@@ -1,1 +1,106 @@
+// AntennaRange © 2014 toadicus
+//
+// AntennaRange provides incentive and requirements for the use of the various antenna parts.
+// Nominally, the breakdown is as follows:
+//
+//     Communotron 16 - Suitable up to Kerbalsynchronous Orbit
+//     Comms DTS-M1 - Suitable throughout the Kerbin subsystem
+//     Communotron 88-88 - Suitable throughout the Kerbol system.
+//
+// This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. To view a
+// copy of this license, visit http://creativecommons.org/licenses/by-nc-sa/3.0/
+//
+// This software uses the ModuleManager library © 2013 ialdabaoth, used under a Creative Commons Attribution-ShareAlike
+// 3.0 Uported License.
+//
+// This software uses code from the MuMechLib library, © 2013 r4m0n, used under the GNU GPL version 3.
 
+using System;
+using System.Linq;
+
+namespace AntennaRange
+{
+	/*
+	 * Wrapper class for ProtoPartModuleSnapshot extending AntennaRelay and implementing IAntennaRelay.
+	 * This is used for finding relays in unloaded Vessels.
+	 * */
+	public class ProtoAntennaRelay : AntennaRelay, IAntennaRelay
+	{
+		// Stores the relay prefab
+		protected IAntennaRelay relayPrefab;
+
+		// Stores the prototype part so we can make sure we haven't exploded or so.
+		protected ProtoPartSnapshot protoPart;
+
+		/// <summary>
+		/// The maximum distance at which this transmitter can operate.
+		/// </summary>
+		/// <value>The max transmit distance.</value>
+		public override float maxTransmitDistance
+		{
+			get
+			{
+				return relayPrefab.maxTransmitDistance;
+			}
+		}
+
+		/// <summary>
+		/// Gets a value indicating whether this <see cref="AntennaRange.ProtoDataTransmitter"/> has been checked during
+		/// the current relay attempt.
+		/// </summary>
+		/// <value><c>true</c> if relay checked; otherwise, <c>false</c>.</value>
+		public override bool relayChecked
+		{
+			get;
+			protected set;
+		}
+
+		public string Title
+		{
+			get
+			{
+				return this.protoPart.partInfo.title;
+			}
+		}
+
+		public override bool CanTransmit()
+		{
+			PartStates partState = (PartStates)this.protoPart.state;
+			if (partState == PartStates.DEAD || partState == PartStates.DEACTIVATED)
+			{
+				Tools.PostDebugMessage(string.Format(
+					"{0}: {1} on {2} cannot transmit: {3}",
+					this.GetType().Name,
+					this.Title,
+					this.vessel.name,
+					Enum.GetName(typeof(PartStates), partState)
+				));
+				return false;
+			}
+			return base.CanTransmit();
+		}
+
+		public override string ToString()
+		{
+			return string.Format(
+				"{0} on {1}.",
+				this.Title,
+				vessel.name
+			);
+		}
+
+		/// <summary>
+		/// Initializes a new instance of the <see cref="AntennaRange.ProtoAntennaRelay"/> class.
+		/// </summary>
+		/// <param name="ms">The ProtoPartModuleSnapshot to wrap</param>
+		/// <param name="vessel">The parent Vessel</param>
+		public ProtoAntennaRelay(IAntennaRelay prefabRelay, ProtoPartSnapshot pps) : base(pps.pVesselRef.vesselRef)
+		{
+			this.relayPrefab = prefabRelay;
+			this.protoPart = pps;
+			this.vessel = pps.pVesselRef.vesselRef;
+		}
+	}
+}
+
+

file:b/RelayDatabase.cs (new)
--- /dev/null
+++ b/RelayDatabase.cs
@@ -1,1 +1,236 @@
-
+// AntennaRange © 2014 toadicus
+//
+// This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. To view a
+// copy of this license, visit http://creativecommons.org/licenses/by-nc-sa/3.0/
+
+using KSP;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using UnityEngine;
+
+namespace AntennaRange
+{
+	public class RelayDatabase
+	{
+		/*
+		 * Static members
+		 * */
+		protected static RelayDatabase _instance;
+
+		public static RelayDatabase Instance
+		{
+			get
+			{	
+				if (_instance == null)
+				{
+					_instance = new RelayDatabase();
+				}
+
+				return _instance;
+			}
+		}
+
+		/*
+		 * Instance members
+		 * */
+
+		/*
+		 * Fields
+		 * */
+		protected Dictionary<Guid, Dictionary<int, IAntennaRelay>> relayDatabase;
+
+		protected Dictionary<Guid, int> vesselPartCountDB;
+
+		/*
+		 * Properties
+		 * */
+		public Dictionary<int, IAntennaRelay> this [Vessel vessel]
+		{
+			get
+			{
+				if (!this.ContainsKey(vessel.id))
+				{
+					this.AddVessel(vessel);
+				}
+				if (this.vesselPartCountDB[vessel.id] != vessel.Parts.Count)
+				{
+					this.UpdateVessel(vessel);
+				}
+
+				return relayDatabase[vessel.id];
+			}
+		}
+
+		/* 
+		 * Methods
+		 * */
+		public bool AddVessel(Vessel vessel)
+		{
+			if (relayDatabase.ContainsKey(vessel.id))
+			{
+				Debug.LogWarning(string.Format(
+					"{0}: Cannot add vessel '{1}' (id: {2}): Already in database.",
+					this.GetType().Name,
+					vessel.name,
+					vessel.id
+				));
+
+				return false;
+			}
+			else
+			{
+				this.UpdateVessel(vessel);
+
+				return true;
+			}
+		}
+
+		public void UpdateVessel(Vessel vessel)
+		{
+			if (!relayDatabase.ContainsKey(vessel.id))
+			{
+				Tools.PostDebugMessage(string.Format(
+					"{0}: Update called vessel '{1}' (id: {2}) not in database: vessel will be added.",
+					this.GetType().Name,
+					vessel.name,
+					vessel.id
+				));
+			}
+			else
+			{
+				// Remove stuff?
+			}
+
+			this.relayDatabase[vessel.id] = this.getVesselRelays(vessel);
+			this.vesselPartCountDB[vessel.id] = vessel.Parts.Count;
+		}
+
+		public bool ContainsKey(Guid key)
+		{
+			return (this.relayDatabase.ContainsKey(key) & this.vesselPartCountDB.ContainsKey(key));
+		}
+
+		public bool ContainsKey(Vessel vessel)
+		{
+			return this.ContainsKey(vessel.id);
+		}
+
+		public void onVesselWasModified(Vessel vessel)
+		{
+			if (this.ContainsKey(vessel))
+			{
+				if (this.vesselPartCountDB[vessel.id] != vessel.Parts.Count)
+				{
+					Tools.PostDebugMessage(string.Format(
+						"{0}: vessel '{1}' (id: {2}) was modified.",
+						this.GetType().Name,
+						vessel.name,
+						vessel.id
+					));
+
+					this.vesselPartCountDB[vessel.id] = -1;
+				}
+			}
+		}
+
+		protected Dictionary<int, IAntennaRelay> getVesselRelays(Vessel vessel)
+		{
+			Dictionary<int, IAntennaRelay> relays;
+
+			if (this.ContainsKey(vessel))
+			{
+				relays = this.relayDatabase[vessel.id];
+				relays.Clear();
+			}
+			else
+			{
+				relays = new Dictionary<int, IAntennaRelay>();
+			}
+
+			Tools.PostDebugMessage(string.Format(
+				"{0}: Getting antenna relays from vessel {1}.",
+				"IAntennaRelay",
+				vessel.name
+			));
+
+			// If the vessel is loaded, we can fetch modules implementing IAntennaRelay directly.
+			if (vessel.loaded) {
+				Tools.PostDebugMessage(string.Format(
+					"{0}: vessel {1} is loaded, searching for modules in loaded parts.",
+					"IAntennaRelay",
+					vessel.name
+				));
+
+				// Gets a list of PartModules implementing IAntennaRelay
+				foreach (Part part in vessel.Parts)
+				{
+					foreach (PartModule module in part.Modules)
+					{
+						if (module is IAntennaRelay)
+						{
+							relays.Add(part.GetHashCode(), module as IAntennaRelay);
+							break;
+						}
+					}
+				}
+			}
+			// If the vessel is not loaded, we need to build ProtoAntennaRelays when we find relay ProtoPartSnapshots.
+			else
+			{
+				Tools.PostDebugMessage(string.Format(
+					"{0}: vessel {1} is not loaded, searching for modules in prototype parts.",
+					"IAntennaRelay",
+					vessel.name
+				));
+
+				// Loop through the ProtoPartModuleSnapshots in this Vessel
+				foreach (ProtoPartSnapshot pps in vessel.protoVessel.protoPartSnapshots)
+				{
+					ProtoAntennaRelay protoRelay;
+					Part partPrefab = PartLoader.getPartInfoByName(pps.partName).partPrefab;
+
+					foreach (PartModule module in partPrefab.Modules)
+					{
+						if (module is IAntennaRelay)
+						{
+							protoRelay =
+								new ProtoAntennaRelay(module as IAntennaRelay, pps);
+							relays.Add(pps.GetHashCode(), protoRelay);
+							break;
+						}
+					}
+				}
+			}
+
+			Tools.PostDebugMessage(string.Format(
+				"{0}: vessel '{1}' has {2} transmitters.",
+				"IAntennaRelay",
+				vessel.name,
+				relays.Count
+			));
+
+			// Return the list of IAntennaRelays
+			return relays;
+		}
+
+		protected RelayDatabase()
+		{
+			relayDatabase =	new Dictionary<Guid, Dictionary<int, IAntennaRelay>>();
+			vesselPartCountDB = new Dictionary<Guid, int>();
+
+			GameEvents.onVesselWasModified.Add(this.onVesselWasModified);
+			GameEvents.onVesselChange.Add(this.onVesselWasModified);
+		}
+
+		~RelayDatabase()
+		{
+			GameEvents.onVesselWasModified.Remove(this.onVesselWasModified);
+			GameEvents.onVesselChange.Remove(this.onVesselWasModified);
+
+			Tools.PostDebugMessage(this.GetType().Name + " destroyed.");
+		}
+	}
+}
+
+