Topic: Launching a Rocket to Orbit

  • Rocket works by shooting hot gas backwards to push rocket forwards.
  • Go up to get above atmosphere and avoid drag.
  • Go sideways fast enough to miss planet when falling down (~2200 m/s @ Kerbin)

Stuff a launch script needs to do:

  • Intially launch rocket.
  • Staging: When a rocket stage gets empty, we need to drop it and start the next one.
  • Point rocket in correct direction at each point in the flight.
  • Stop burning when apoapsis reaches target altitude.
  • Calculate and perform circularization burn at apoapsis.


  • Minimize time spent with rocket thrusting up against gravity.
  • Avoid going too fast through atmosphere, drag costs energy.
  • The traditional plan is a "gravity turn".
  • This can be handled with a function from altitude to angle.
  • I like using "sin" to generate smooth curves, but that may not be optimal.