@Mcwalrus unguided rockets can change their trajectory!!! Using a single unguided rocket, create burnTimer value with overload and set rocket operating time in seconds. Then set selfDestructTimer and change time when rocket explode after its launch
(Apologising for bad English)

I did alot of experimenting while building a katyusha here's what I observed
1.The missle(unguided) always travels in a straight line and never bends it's trajectory unless you do it physically like using engines with the custom missle. Explodes when out of fuel

1. Only the guided missle can bend it's trajectory .when the missle doesn't have a target it will start falling even if it still have thrust or fuel

There are funky trees to make ut missle stronger but I can't be botherd with that.
I hope this was helpful.