How to detect that a rocket has flown off?

[Tobruk]

I need to detect the rocket flying off to switch the automation into "waiting for return" mode, where a satellites takes over all the rocket-related automation.

[LeftyRighty]

Since you didn't ask for a complete system I'll assume you're enjoying working it out yourself so I'll be a little vague of the specific details

 

I use a memory gate connected to the space scanner set for the ship's return to send an active "it's landed" signal, it is reset by the launch command sent through automation to the command capsule (no launching through the starmap anymore, just set the destination and trigger the launch through an atmo switch of something)

[Soylent]

I’ll go ahead and be the guy asking for the complete system, please 

[nvzboy]

For those not wanting a drop-in solution, I put it in a spoiler so you can figure it out on your own.

 

Spoiler

The leftmost wire goes to your satelite dishes detecting the particular rocket.

Middle wire goes to the terminals on the rocket.

Rightmost wire goes to your gantries and doors.

This scheme will upon ready: open the doors and retract gantries-> launch the rocket -> close the doors again and redeploy gantries-> open the doors and retract gantries when the rocket is detected by the satelites -> close the doors and deploy gantries when the rocket has landed.

Construct the wire out of tungsten to prevent them from melting due to hot rocket exhaust.