This literally looks like something out of a dream I once had. I mean, it was forever ago. There weren't ponies in it, but, the ship or whatever just reminded me of a dream I haven't remembered in forever...weird.
Very nice piece. Foreground pony was obviously Trixie until the horn being more than usually obscure was pointed out and now it does look a little weird. Is the setting a shout out to anything? It looks very familiar, but that's not saying much with an anonymous sci-fi corridor.
at first i had a moment of "That's not Trixie" ... but then i saw the tip of her horn ... you may consider having the horn stick out of her hair a bit sooner ... other than that though it's a pretty well done and interesting piece ... raises a lot of questions about the story that took place to put them in such a setting