Python script using kRPC and Mechjeb2 to launch and land a reusable first stage. Upon landing the first stage, the code switches to the second stage and executes the final burn(s) to enter the desired orbit.

See demo video at https://youtu.be/avXz_AQ7HDI

• Mechjeb2
• kRPC
• kRPC.Mechjeb
• Kerbal Reusability Expansion (for grid fins, landing legs and large RCS thrusters)

• The first stage remote control pod must be the root node of the rocket (the first item placed in the VAB). Otherwise, upon staging KSP will switch control to the second stage.
• Make sure the first stage does not run out of electric charge before engine reignition for the landing burn.
• Make sure you have an antenna on both stages, otherwise they can't be controlled.
• Make sure you have lots of RCS control authority, especially for large rockets.
  • The KRE mod adds large RCS thrusters.

flight_program.py

• Target orbit height, inclination. First stage staging point. Autopilot PID parameters.

Ascent.py

• Various trajectory control parameters. Max pitch/throttle rates. Max craft dynamic pressure.

MechjebRTL.py

• Flip and landing autopilot PID parameters.

• Occasionally when reverting a flight to launch, the conn.mech_jeb.api_ready fails to ever become True, which will cause the first stage to fall to Earth. This is probably a bug in kRPC.Mechjeb.
  • Fix: Revert to VAB first, then proceed to launch from there.