Hi, after upgrading to Ground Platform upgrade 5, I now have big asteriods during transitions. At that time I only have turrets with piercing ammo, but they do only negligible damage. I have double-walls everywhere, but some asteroids damage the platform, the walls don't stop it. I saw a YouTuber who solved asteroids only with walls. How to deal with big asteroids at this stage of the game?

Yeah, I ran into the same issue. Gun Turrets and Lasers are not enough for big asteroids. The only way I was able to reliably survive the big asteroids was to roll back my save to before the upgrade and then spend a looooong time getting Agricultural Science + Electro Science + Metal Science -> Space Science -> Carbon Fiber -> Rocket Turrets on my level 4 platform. And even with dozens of Rocket Turrets, I am still getting chip damage on my platform every once in a while. I believe any medium+ size asteroid contacting the platform will break it, ignoring walls. I recommend rushing explosive damage soon after getting rocket turrets.

Not great, there is not enough space with Ground Platform 4 to do Electro+metal+space science. Imo platform upgrade should bring only medium, not big asteroids. Big biters are not a problem, I can escape them but I can't escape warp transitions.

I tried mod Enhanced Walls and both Sturdy Wall and Plated Wall is not enough to destroy big asteroids.