Introducing 3 types of missile shooting turrets, integrating them to 'Space Age' DLC
base version: https://mods.factorio.com/mod/missile_defense_systems
Thanks for the report! I could reproduce the issue, and the error reads as follows:
'Failed to load mods: Error while running setup for technology prototype "spidertron" (technology): Technology prerequisite "rocketry" is registered more than once.'
