Shells lofted by surface navies crash back to earth when their acceleration is overwhelmed by gravity and air resistance. In space, a projectile has unlimited range, it will keep moving until it hits something.
Practical gunnery range is determined by the velocity of the attacker's ordinance [sic] and the maneuverability of the target. Beyond a certain range, a small ship's ability to dodge trumps a larger attacker's projectile speed. The largest-ranged combat occurs between dreadnoughts, whose projectiles have the highest velocity but are the least maneuverable. The shortest-range combat is between frigates, which have the slowest projectile velocities and highest maneuverability.
Opposing dreadnoughts open with main gun artillery duel at EXTREME ranges of tens of thousands of kilometers. The fleet close, maintaining evasive lateral motion while keeping their bow guns facing the enemy. Fighters are launched and attempt to close to disruptor torpedo range. Cautious admirals weaken the enemy with ranged fire and fighter strikes before committing to close action. Aggressive commanders advance so cruisers and frigates can engage.
At LONG range, the main guns of cruisers become useful. Friendly interceptors engage enemy fighters until the attackers enter the range of ship-based GARDIAN fire. Dreadnoughts fire from the rear, screened by smaller ships. Commanders must decide whether to commit to a general melee or retreat into FTL.
At MEDIUM range, ships can use broadside guns. Fleets intermingle, and it becomes difficult to retreat in order. Ships with damaged kinetic barriers are vulnerable to wolfpack1 frigate flotillas that speed through the battle space.
Only fighters and frigates enter CLOSE "knife fight" ranges of 10 or fewer kilometers. Fighters loose their disruptor torpedoes, bringing down a ship's kinetic barriers and allowing it to be swarmed by frigates. GARDIAN lasers become viable weapons, swatting down fighters and boiling away warship armor.
Neither dreadnoughts nor cruisers can use their main guns at close range; laying the bow on a moving target becomes impossible. Superheated thruster exhaust becomes a hazard.