diff --git a/boot/rocket.ks b/boot/rocket.ks
index 43a0472..e354755 100644
--- a/boot/rocket.ks
+++ b/boot/rocket.ks
@@ -5,6 +5,7 @@ compile "0:/os/rocketos" to "1:/boot/rocketos".
 compile "0:/lib/navigation" to "1:/lib/navigation".
 compile "0:/lib/throttle" to "1:/lib/throttle".
 compile "0:/launch" to "1:/launch".
+compile "0:/nextnode" to "1:/nextnode".
 
 // Set OS to boot and restart.
 set core:bootfilename to "boot/rocketos".
diff --git a/launch.ks b/launch.ks
index 4e7f7d5..da057d8 100644
--- a/launch.ks
+++ b/launch.ks
@@ -35,14 +35,6 @@ lock THROTTLE to 1.0.
 lock STEERING to heading(90,90,270).
 stage.
 
-// // DEBUG
-// until false {
-//   lock STEERING to heading(90,90,-90).
-//   wait 3.
-//   lock STEERING to SHIP:SRFPROGRADE.
-//   wait 3.
-// }
-
 wait until SHIP:ALTITUDE > 200.
 lock STEERING to heading(90, GRAVITY_PITCH, 270).
 
@@ -76,9 +68,10 @@ until SHIP:ORBIT:APOAPSIS > 80000 {
   wait 0.001.
 }
 
+SHIP:ADD(CreateCircularizationNode(SHIP:ORBIT:ETA:APOAPSIS)).
+
 print "Releasing controls. Good luck, Kerman!".
-lock THROTTLE to 0.0.
-wait 0.001.
+set SHIP:CONTROL:PILOTMAINTHROTTLE to 0.
 unlock THROTTLE.
 unlock STEERING.
 SAS on.
diff --git a/lib/navigation.ks b/lib/navigation.ks
index 45b7519..8e50c06 100644
--- a/lib/navigation.ks
+++ b/lib/navigation.ks
@@ -1,6 +1,30 @@
+// functions for calculating steering values.
 @lazyglobal off.
 
 function GetPitch {
   parameter v is SHIP:FACING:FOREVECTOR.
   return 90 - vectorangle(SHIP:UP:FOREVECTOR, v).
 }
+
+function CreateCircularizationNode {
+  parameter usePeriapsis is false.
+  local target is SHIP:ORBIT:APOAPSIS.
+  local t is SHIP:ORBIT:ETA:APOAPSIS.
+  if usePeriapsis {
+    set target to SHIP:ORBIT:PERIAPSIS.
+    set t to SHIP:ORBIT:ETA:PERIAPSIS.
+  }
+  local n is Node(t, 0, 0, 0).
+
+  // move fast until we pass our target.
+  until (usePeriapsis and n:ORBIT:APOAPSIS < target) or n:ORBIT:PERIAPSIS > target {
+    set n:PROGRADE to n:PROGRADE + 1.
+  }
+
+  // now bring it back in real slow until we come back.
+  until (usePeriapsis and n:ORBIT:APOAPSIS > target) or n:ORBIT:PERIAPSIS < target {
+    set n:PROGRADE to n:PROGRADE - 0.01.
+  }
+
+  return n.
+}
diff --git a/lib/throttle.ks b/lib/throttle.ks
index d7fbb44..abe939a 100644
--- a/lib/throttle.ks
+++ b/lib/throttle.ks
@@ -1,4 +1,4 @@
-// Functions for calculating navigational and guidance values.
+// Functions for calculating thrust values.
 @lazyglobal off.
 
 // Returns the throttle value you should use to achieve the
@@ -42,15 +42,16 @@ function SensorCheck {
   set HAS_GRAV_SENSOR to false.
 }
 
-// adapted from https://github.com/sporadisk/KSP-KOS-scripts/blob/master/modules/GravityTurn.ks
-// todo: I don't think I actually like this code...
-function GravityTurn {
-  parameter TargetDirection is 90.
-  parameter TargetApoapsis is 80000.
-  parameter Factor is 1.
+function BurnTime {
+  parameter dV.
 
-  local remFactor is (2 / Factor).
-  local remHeight is (SHIP:APOAPSIS/TargetApoapsis).
-  local angle is (90 * (1 - (remHeight ^ remFactor))).
-  return heading(TargetDirection, angle, 90).
+  list ENGINES in en.
+
+  local f is en[0]:MAXTHRUST * 1000.  // Engine Thrust (kg * m/s²)
+  local m is SHIP:MASS * 1000.        // Starting mass (kg)
+  local e is CONSTANT():E.            // Base of natural log
+  local p is en[0]:ISP.               // Engine ISP (s)
+  local g is 9.80665.                 // Gravitational acceleration constant (m/s²)
+
+  return g * m * p * (1 - e^(-dV/(g*p))) / f.
 }
diff --git a/nextnode.ks b/nextnode.ks
new file mode 100644
index 0000000..e0e3d33
--- /dev/null
+++ b/nextnode.ks
@@ -0,0 +1,17 @@
+runpathonce("lib/navigation").
+runpathonce("lib/throttle").
+
+SAS off.
+local n is SHIP:NEXTNODE.
+local t is BurnTime(n:MAG)/2.
+
+lock STEERING to n:DELTAV.
+wait until VectorAngle(SHIP:VELOCITY, STEERINGMANAGER:TARGET) <= 0.1.
+  
+KUNIVERSE:WARP:WarpTo(n:TIME - t - 5).
+wait until n:ETA <= t.
+
+lock THROTTLE to 1.0.
+wait until n:DELTAV:MAG <= 0.1.
+unlock THROTTLE.
+unlock STEERING.
diff --git a/os/rocketos.ks b/os/rocketos.ks
index 71393ab..92ae973 100644
--- a/os/rocketos.ks
+++ b/os/rocketos.ks
@@ -1,14 +1,20 @@
 function launchButtonPressed {
-run "launch"(
-  targetApo:TEXT:ToNumber(),
-  gravTurnStart:TEXT:ToNumber(),
-  initialPitch:TEXT:ToNumber()
+  run "launch"(
+    targetApo:TEXT:ToNumber(),
+    gravTurnStart:TEXT:ToNumber(),
+    initialPitch:TEXT:ToNumber()
   ).
 }
 
+function nodeButtonPressed {
+  run "executenode".
+}
+
 // Button panel
+CreateGUI().
+
 local interface is gui(200).
-set interface:X to 150.
+set interface:X to 200.
 set interface:Y to 900.
 
 // Launch button
@@ -31,6 +37,9 @@ local targetApo is hBox:AddTextField("80000").
 local launchButton is interface:AddButton("Launch").
 set launchButton:onClick to launchButtonPressed@.
 
+local nodeButton is interface:AddButton("Execute Node").
+set launchButton:onClick to nodeButtonPressed@.
+
 interface:show().
 
 wait until false.