diff --git a/lib/navigation.ks b/lib/navigation.ks
index c64a91e..9045e1f 100644
--- a/lib/navigation.ks
+++ b/lib/navigation.ks
@@ -22,9 +22,10 @@ function CreateCircularizationNode {
   parameter nodeAtPeriapsis is false.
 
   local dt is choose SHIP:ORBIT:ETA:PERIAPSIS if nodeAtPeriapsis else SHIP:ORBIT:ETA:APOAPSIS.
+  local a is choose SHIP:ORBIT:PERIAPSIS if nodeAtPeriapsis else SHIP:ORBIT:APOAPSIS.
   local t is TIME + dt.
 
-  local Vc is sqrt(SHIP:BODY:MU/(SHIP:BODY:RADIUS + SHIP:ORBIT:APOAPSIS)).
+  local Vc is sqrt(SHIP:BODY:MU/(SHIP:BODY:RADIUS + a)).
   local dV is Vc - VelocityAt(SHIP, t):ORBIT:MAG.
   local n is Node(t, 0, 0, dV).