This page of Marvel's Guardians of the Galaxy game guide has a detailed walkthrough of the fight against the boss called Captain Glory in Chapter 9 (Desperate Times). Our description informs how to fight in space, defeat the boss guard, and successfully destroy Captain Glory's spacecraft.
Phase 1 - Destroying smaller spaceships
Captain Glory is the leader of the Lethal Legion, and the fight with him and his squadron happens in the initial part of Chapter 9. Fighting in space will start soon after reaching the control deck. You will use Milano ship to fight.
Additional information - If in Chapter 2 you decided to hide Rocket's equipment when you learned about the inspection by the Nova Corps, it won't be taken from the Guardians of the Galaxy and can be used to strengthen Milano. It will increase your power a little, but even without it, winning all the battles in space shouldn't be very difficult.
In the first part of the fight in space, you have to deal with a group of regular ships controlled by the boss's subordinates. You can attack them in any order - pay attention to the arrows located around the crosshair, which indicate their location.
When fighting, use the dodge to the sideways to avoid being hit. You can also do a 180-degree turn-around, but it's only useful if you've got an enemy ship right behind you. Enemy machines are very weak and each of them will explode after a short fire.
Phase 2 - Destroying the ship of Captain Glory
The main part of the boss fights starts after you destroy all the smaller ships. Captain Glory is piloting a much larger spacecraft, and your objective is to destroy all points marked on the boss' ship.
Flying towards Captain Glory, you have to watch out for the red laser attacks. To avoid being hit, dodge to the sides, but wait with that until the last moment - try to do it at the right time and not allow the boss to correct the trajectory of the laser.
Captain Glory can also shoot purple lasers. They inflict minor damage, but you can be hit by them several times in a row. In this case, the solution is also to dodge to the left or right.
You can destroy the targets marked by the game in any order, while you have to be aware that the boss, after each of your successful actions, teleports to another location and leaves behind a minefield. You don't have to destroy the mines and you can just quickly turn the other way to avoid colliding with them. Take a look at the arrow in the crosshairs to quickly locate Captain Glory's ship and fly towards it.
Destroying all targets will lead to Captain Glory's defeat, and you will advance to the next part of the chapter.