First, mouse controlled steering with sensitivity options, the keyboard controls make too-wide swings for the precision required in the game combat.
Second, ease it on the collisions, why are there so many asteroids? (and why would there be a space station in an asteroid belt? irrelevant) why do they deal so much damage while being so hard to see from behind or the sides? why can I collide with the cargo?
Third, delimit the missions while making them harder, it's arbitrary that you can't finish missions by escape, and I'd argue making the enemies more oppressive (don't just increase the count, make them smarter and diverse) while allowing the choice for either confrontation or cowardice could make the game more fun and free.
There's the elephant in room, making the enemies smarter, mission level and design variety, making the controls more snappy, etc., but those are things that come later in development so I'd say they're quite moot coming from me.
If applicable, I'd recommend checking out the gameplay from Sky Rogue to get some pointers, though I don't know if it's exactly what you're aiming for.