diff --git a/sc2/ChangeLog b/sc2/ChangeLog
index b95df910b..f6d9b4f1a 100644
--- a/sc2/ChangeLog
+++ b/sc2/ChangeLog
@@ -1,4 +1,5 @@
 Changes towards version 0.7:
+- Fixed AI ship not moving on warp in (bug #648) - Alex
 - Revert gfx settings entirely when a mode switch fails (bug #1056) - Alex
 - Fixed the Syreen lights-out scene timing (bug #1011) - Alex
 - Added a native error box for MacOSX (like we have for Windows) - Alex
diff --git a/sc2/src/uqm/cyborg.c b/sc2/src/uqm/cyborg.c
index f2e6c329d..f8fc5ba23 100644
--- a/sc2/src/uqm/cyborg.c
+++ b/sc2/src/uqm/cyborg.c
@@ -1124,13 +1124,14 @@ if (!(ShipPtr->state_flags & FINITE_LIFE)
 						ed.facing = ARCTAN (-dx, -dy);
 						if (UltraManeuverable)
 							ed.MoveState = AVOID;
-						else
+						else // Try a gravity whip
 							ed.MoveState = ENTICE;
 
 						ObjectsOfConcern[GRAVITY_MASS_INDEX] = ed;
 					}
-					else if (!UltraManeuverable)
-					{
+					else if (!UltraManeuverable &&
+							!IsVelocityZero (&Ship.velocity))
+					{	// Try an orbital insertion, don't thrust
 						++Ship.thrust_wait;
 						if (Ship.turn_wait)
 							ShipMoved = TRUE;
diff --git a/sc2/src/uqm/velocity.h b/sc2/src/uqm/velocity.h
index 29d19cf6e..eb2585b17 100644
--- a/sc2/src/uqm/velocity.h
+++ b/sc2/src/uqm/velocity.h
@@ -45,6 +45,14 @@ extern void SetVelocityComponents (VELOCITY_DESC *velocityptr, SIZE dx,
 extern void DeltaVelocityComponents (VELOCITY_DESC *velocityptr, SIZE dx,
 		SIZE dy);
 
+static inline BOOLEAN
+IsVelocityZero (VELOCITY_DESC *vptr)
+{
+	return vptr->vector.width == 0 && vptr->vector.height == 0 &&
+			vptr->incr.width == 0 && vptr->incr.height == 0 &&
+			vptr->fract.width == 0 && vptr->fract.height == 0;
+}
+
 static inline DWORD
 VelocitySquared (SIZE dx, SIZE dy)
 {