It requires : Physical damage 10 (11 to be super safe), explosive 10 and Laser 7 (might be able to run with 6 but haven't tried. )
This ship was built for my Express Delivery game. It can run as many trips to aquillo as you want (though, a couple of turrets on the back need manual reloading if it stations in non-nauvis orbit for too long.) It's very cheap in term of material needed, requiring only blue belts, stack inserters, Uncommon grabbers and a handful of module 3s, as well as a nuclear reactor.
Run it between nauvis-vulcanus a couple of times to get some ammo stored
You can just plop down that blueprint pre-aquillo and it will work until you can get railguns. As soon as you unlock them, you can send it to the system edge and it should be able to make the trip there.
For precaution : empty a few turrets every now and then while the ship is safe, to store up rockets and yellow ammo, then manually drop them in the turrets if things look tight.