Algodoo

nice. that's what i always had in my mind to steer the rocket so that it doesn't just point at it and misses it

Great job. Yet another script I cannot understand . And yeah, it turns in very weird way.

the script itself is easy to understand if you know what each part of it is for.
i understand, hovewer. that chain of brackets can really be annoying to check.

basically, instead of aiming in the missile's direction to the target's direction, it projects a point, on which the targetwould be if the missile hit. if it was straight on the missile's path if there was no airfriction and the engines were off, and continues from there. still, this makes precision to be problematic. a decent solution would be to change the distance to something more aceptable when missile is still within a decent aim, or just to change that part with a fraction of the time.

Updated the scene. it lost a small aumount of accuracy, but doesn't move weirdly for now.

I have interesting guidance idea, and i'm working on it:
I use k-probe to get velocity,position and accel of missile.
laser radar (like in my torpedo) finds target and reads it's position and velocity.
missile calculates when it's x pos will be equal to target x pos, saves result as TimeX.
then calculates the same for y, saves as TimeY.
then compares those 2 values, and appropriately goes more vertical or more horizontal.

@davidz
in principle it's the same like ra2lover's method but your idea is more of a numerical calculation
btw: timeX and timeY will be the same

no, they won't be the same. if missile moves horizontally, it'l soon reach target x position, but will need way more time to reach target's height. so it'll try to go more vertical etc.
The same timex and timey (missile and target in the same pos, in the same time) is what the missile is trying to reach..

then i didn't get what you explained first. i thought you mean to fly directly to the target. because then timeX and timeY would be the same.
but now that you additionally added some information it makes sense.

still, it will have shakiness problems, and also, the issue of negative time values.