What Jorgen said. Frankly as the game is now, there's simply no way you can justify the presence of pirates.
And as Steve said before, you'd basically have to make them a mini faction, with shipyards, facilities, habitats/colonies and such.
Pirates in a sci-fi setting only work if the setting is huge, with hundreds of worls/systems at the very least. Thousands is better to be even remotely plausible. Anything smaller, and you cannot justify piracy because there's simply not enough trade to justify piracy, not enough explored systems to justify the military not finding such pirates, and just no reason for pirates to exist. Let's say Pirate Group A harasses a trade ship and steals trade commodities. So what? What are they going to do with that? Keep it all to themselves? Come to your worlds to sell it? How are they even going to hide, considering there's literally a few hundred ships at MOST in the entire space? What are they goign to eat, were are they going to buy necessities and spare parts?
You just cannot say: Oh look, somehow military ships from our race appeared. And yes, we have a grand total of three shipyards, so who knows who built them. They just magically came into existance somehow. And they're pirates! YARRRR.
Piracy can work in something like Star Wars, because you have literally hundreds of millions of inhabited systems and millions of billions of starships flying around between them. Also, all of this has been around for millennias. So it is plausible that there's hidden bases around, or hijacked ships, or places where you can sell stolen goods. And that pirates can hide and pretend to be traders in order to smuggle goods, because once again, they can simply "hide" most of the time amongst normal traders and such. And in fact a setting like Star Wars, huge as it is, also has semi independet enclaves, mercenaries and the like. And that can be justified, because once again the sheer size and age of the settings makes it plausible.
In Aurora you have a civilization that has been around at most for a few decades, and that maybe produced 2-300 ships total. The scale of the game does not allow for realistic pirates.
What you could possibily justify is a colony/system that went rogue and seceded from the home planet, and wages low-intensity war on its homeworlds by harassing from time to time. All the while, being careful they don't ever become a problem big enough to justify the homeworlds coming in guns blazing and reconquering the secessionists.
But such a scenario cannot and should not be just a random "chance". At the moment and with the structure of Aurora it's truly best modeled via SM.
