I'm running a sci-fi campaign using D&D 5e, Ultramodern 5e (an add-on that allows you to run modern and sci-fi settings using D&D 5e), with Esper Genesis space combat rules. I have a player who's planning to acquire a spacesuit and, when space combat begins, jump out the airlock and start using spells to shoot at spaceships.
My main problem is that the ships are really really big and they've been balanced around ship weapons, not player spells. I worry that if I let his spells affect a ship it'll just instantly vaporize any enemy. I know Starfinder doesn't let player weapons and spells affect ships and I'm wondering if I should implement this. What should I do?