yesterday i tried to launch that thing several times and it always worked for me....

The new patch notes says: "- fixed merge block are disconnected after owner change", tomorrow i will check if something has changed.

yes, the merge blocks are funny with ownership. The projector builds the first block then it detatches from ownership issues. the only way to fix it is to make a blueprint that belongs to the same person who owns the projector. This is a creative mode issue. in a survival mode situation, it doesnt do that. It has been a pain in aft since the beginning of my SE experience lol

@elKabong31000 Thank you for your suggestions, i will update the ownership tomorrow.
I really dont know why it works only once, this was an old missile station (created Months ago) that i readjusted for the only propouse of showing how to use my script, when you try to build it the second time i dont know why the merge block detach, but i know that if you retry some Times and maybe if you put a new merge block, it will work. This is probably a bug of the game.
And yes, in this last update the missile disappears on impact, another bug.

"Make sure to set yourself as owner of all blocks" The blueprint has to be owned by the owner of the projector or it won't "print" in creative. The blueprint is set to nobody, so change ownership of everything to "nobody" or the demo won't work. It also only does it once. The second try does nothing. Also there are too many warheads on the missile. The kinetic damage of the missile itself will do more damage. The warheads seem to destroy more of the missile than the target. Also, I loaded the demo world three times for three attempts. Twice the missile simply dissapeared on impact doing no damage to the target. That's something keen has to fix.