Somantics. There is nothing "realistic" about star travel. Its a concept. If true reality is what you seek, and not a futuristic escapist game, go play WWII online or something like that if realism is what bothers you about this game. I am sure there are plenty of holes to pick in that storyline also regarding accuracy.
When we define realistic we get:
Having or showing a sensible and practical idea of what can be achieved or expected:
So if you first accept the possibility of space travel and space combat with futuristic weaponry and equipment then the game does sort of live up to its quote of "realistic" of what it achieves. The time line is sped up naturally to be playable as i mentioned earlier. We dont all want to wait 5 billion years for a supernova to happen (though at times it feels that long that i have been waiting for it to occur). The fact that everyone in the game has to follow the same timings to achieve their "moves" in game supports the concept of "what can be achieved or expected". Do a Google of the adj. "Realistic" and you will get so many varied definitions. i still recall a Jules Verne book labelled, "From the earth to the moon" Although the delivery of personnel is way different from the way it is really done, we can now say that it is "realistic" that we can put someone onto the moon and return them to earth. Back then it was only a concept.
OK realism requires physical laws to work correctly but if you accept the concept of worm hole travel and other such mathematically unproven or currently impossible methods of transportation, then the game does live up to the title of what can be achieved or expected. ie "realistic"
If you notice all my other postings regarding reality in game, you will understand that i am also picking small holes in the reality concept (i often refer it to "doctor who'ism" lol) particularly with this hangar bay tech just released, where i could feasibly stuff a titan class vessel into a scout ship sized hull with the right amount of tech. That sort of math i do debate on realism, but when it comes to the basic concept of the game, if you accept the possibility of space/stellar flight to begin with, the game does offer a practical idea on how to achieve this.
At the end of the day, Its a game. Not always a correct physical model of the way the universe works in reality, but an attempt by the author to rationalize how things could be done, if it was possible to actually propel oneself to even the nearest star "proxima centauri" which sadly doesnt get even a mention in the game ( its a little M class red dwarf in a tri-star system along with alpha and beta centauri. Trust me, its there but not on any ingame star maps)