Good work! What does it represent?
From left to right it shows their inhabited worlds in their solar system, the large one being their point of origin, the three pointed arrow is to represent the ships leaving towards the future (I may have to change how that looks so it points more forward). One little note, the big circle on the right (the future, a new planet, a big star) has the ID #wheel as I was going to put a ringworld around it. I like the idea of it being more representative of the unknown, as perhaps the civilisation is in a hurry and has to abandon their solar system, with no clear destination.
If you're in such a hurry, flag design won't be your first priority. There's nothing wrong with the civilization in question to work towards the future... ...or it's a special survey space program, somewhat akin to our planned missions to Mars; a new habitat frontier, if you wish. They would certainly need a good emblem.