Looks like you tried my starfield window glass reflection idea:-)
The dark shadow in the top of the window opening is I think hurting the illusion. Shadows like that come from a source like the sun: are you implying the sun is “above” the ship? In the vacuum of space, the Sun, if present, is a point source, not a big, diffuse soft light. If the ship is not in sunlight, the hull in the shot will be in deep shadow, with perhaps only glancing, highly-angled lighting revealing any texture at all, and the light is mostly coming from the window, so it will look a little blown-out in contrast, and seem like back-lighting of the figure, so they too are mostly in shadow or silhouette.
What I’d do in a 3-d composition like this is turn off all the default lighting, then put in one harsh point source to represent the sun, and modify it to portray how far away it might be and from what angle. Next I would light the room or corridor of the ship, playing with where the lights hit the figure layer, and adjusting the relative brightness between inside and outside.
Also the gray back “wall” probably needs some kind of texture map on it. Pipes, panel lines, etc. Doesn’t need high detail, but some variation and pattern of “stuff” so it doesn’t just look like a gradient. You might construct the “ship from the inside-out, first making the room where the guy stands, furnishing it’s walls with texture maps, then lighting, then covering the room and window with the outer hull. With everything parented to the same null, this “diorama” you build will always have correct-looking angles, no matter where you fly the camera.
The lighting on the existing figure doesn’t look motivated by practicals: too bright and too flat. Try putting some small point source spotlights inside the cube above the corridor, leaving bands of bright and dark, with one of the light beams washing/fanning down past part of the human figure’s body.
You’re also experiencing something space movie FX people have faced for years: Empty space is hard to “light”: that’s why space scenes often throw in a gratuitous planet, or at least some kind of nebula in the background of a shot: it gives a practical source for reflections and bounced light, and a point of visual reference when the camera starts to swing.
I think you’re making good, visible progress, though. Keep going, can’t wait to see the next improved version.