Did some color keys (I believe that's the term?) to try out a couple of looks for it.
1, 2 & 6 resonates with me the most, as the cold blues give it that space-y feel and also enhances the sad undertones of the drawing.
While the warmer ones aree pretty neat too they looks like the ship just flew past a star or something. That isn't inherently a bad thing, but it does draw so much attention that you'd wonder if it's about her or the aforementioned star.
A comment I got on it mentioned that 1 & 6 had better values than 2. Around her face and hand in particular, that is indeed the case:
In 2, it's just so bright that she essentially has the same value as the wall behind her - resulting in her fading into it. This is an issue 1 & 6 doesn't have, and the light comes off as much softer, which just fits the image so much better.
Since I like 2 the most out of the three I mentioned earlier, I'll be looking to pay close attention to the values as I move forward. First by doing a lot of greyscale work, then going into colors.