Do you want the returne of the Solar System?

[Ingenious]

Gravity certainly exists.

Your ship isn't pulled down to planet because the ship automatically stops all movement when you tell it to stop.
Not much point bringing your ship to halt if it's only going to start sliding one way or another.

Trade lanes would not be possible under orbital mechanics.
The only acknowledgement of gravity in the entire game is in the Docking Ring and Heavy Lifter infocards.

Incredibly advanced spaceships would easily be able to keep themselves in space.

Yes, if you have some way to generate momentum or counteract gravity, not by "magic."

• superconductors
  
• gyroscopes
  
• adaptive thrusting
  

No FL fluff discusses antigravity.

In terms of vacuum, it's there too. Only real flaw is the sounds from other ship weapons.

In a true vacuum, space dust would not cause any deceleration in space. Angular and translational acceleration by thrusters would asymptotically bring a ship to the speed of light, not to some "maximum speed" defined by "angular_drag". Drag is air/fluid friction, yet there is negligible fluid in space. EDIT: you'd actually decelerate significantly in a gas cloud.

The sounds from ship weapons can actually be explained as a helpfully indicative electromagnetic interruption or detection on your shortwave radio, thus actually keeping with true vacuum...