1st Probability Before Take Off as the Bay doors open.
2nd Probability as the whole Rocket is seen then roll the dice again.
3rd Stage as the rocket is in the Center of the Top Screen then Explodes. and add another roll when it crashes back to the site how much damage it takes out on the silo.
4th when Rocket is out of screen it fails but Silo is intact.
probably good if the silo is surrounded with water mass. and act as another coolant Facility. is there added installations to be built around the Silo to increase it's success rate? or it's just Tech research tree? 4th Stage explosion would be nice as the parts of the rockets rain down all over the Chunk area and you can salvage the parts. having the expensive parts further than the silo map chunk. https://mods.factorio.com/mod/SupplyDrop might help with that scenario. and add a 4th stage 1% chance that the Rocket crashes to map chunk like multiple artillery strikes in a row and the Space ship sprite from the initial crash landing is strewn across. luck of the draw if it crashes a neighboring Base. and can't mine the wreckage out of their Base either redesign the whole base trying to salvage the crash site area or just move. "Fire in the Hole" -says you. after the dog crashes "You Motherbleeper get your rocket off my Lawn!" says the ally near by. Talk about the OTHER players getting invested in Your Launch. Better yet the 1st launch of the map has 5% chance of mowing the neighbors lawn. and decreases AFTER every Rocket crash till 1%.
If so then, please add mod options to disable destruction of the silo. I have another mod Silo Construction-Site here and would not like to do the same thing again. Maybe damage so 1 HP is left.