Fix calculation of vessel target transfers

src/KerbalTools.cs

@@ -105,9 +105,7 @@ public static CelestialBody StartBody(CelestialBody b = null, Vessel v = null)
 		/// <param name="target">Body or vessel to use</param>
 		public static ITargetable StartBody(ITargetable target = null)
 		{
-			return target?.GetVessel()?.mainBody
-				?? target
-				?? FlightGlobals.GetHomeBody();
+			return target ?? FlightGlobals.GetHomeBody();
 		}
 
 		/// <summary>

src/TransferModel.cs

@@ -60,7 +60,13 @@ public TransferModel(CelestialBody org, ITargetable dest, Vessel v, int order)
 
 		private BurnModel GenerateEjectionBurn(Orbit currentOrbit)
 		{
-			if (currentOrbit == null || destination == null) {
+			if (currentOrbit == null) {
+				DbgFmt("Skipping transfer from null starting orbit.");
+				// Sanity check just in case something unexpected happens.
+				return null;
+
+			} else if (destination == null) {
+				DbgFmt("Skipping transfer to null destination.");
 				// Sanity check just in case something unexpected happens.
 				return null;
 
@@ -96,6 +102,7 @@ private BurnModel GenerateEjectionBurn(Orbit currentOrbit)
 
 				if (origin == immediateDestination as CelestialBody) {
 					// Trying to get to the start SOI or one of its sub-SOIs
+					DbgFmt("Skipping origin destination");
 					return null;
 				}