You can do this in many different ways, and I would need to know a bit more in order to give you a proper solution. However, I’ll give you some alternatives.
If you only have two maps, one space map and one interior space level map you could simply put the interior space level map inside of the space map somewhere hidden. This would allow you to go into the interior spaceship without having to load a second map.
If you need multiple space maps, you can always use level streaming to load the interior map into memory; which results in faster loading times: Level Streaming | Unreal Engine 4.27 Documentation
If you keep the space level and interior level in the same game, you can do some pretty cool shader tricks to showcase the environment of the spaceship without actually being in it. Something like this: How to create 4 different mirrors (improved Audio) - YouTube.