Beautiful artwork! It greatly captures the solitude of this vast and “empty” place. The colors are perfect! The lighting and shadows are great as well 
I admit I would not have guessed it was a submarine at first, I thought it was some kind of facility, but then it made sense as I zoomed in.
My only suggestion: I would recommend incorporating additional elements of astronomy. Why? Because in the Arctic, there is minimal “luminosity pollution” (contrary to populated areas, where the abundance of street lamps, car lights, and similar sources creates a significant visual hindrance, obscuring our view of the stars). In these remote/desolate locations, it is very common to be able to see, for example, galactic arms and some distant planets. There is also phenomenons like “aurora borealis” which are more prevalent in the poles as well.
Additional note: If you are in need of space brushes, there are great space resources available on the community 