I can build it just fine, up until the very last checklist. Everytime I launch my mortars to test its capabilities, it wouldn't shoot down the shells. I've allowed it to target friendly shells, the animation of the purple laser fired, but the shell just isn't destroyed.

Am I doing something wrong? I just can't seem to fix this problem. I've tried re-setting my modlist, different save files, heck I've even re-download Rimworld multiple times now.