Follow Cortana's directions to escape the capsule. Next, head to the observation deck to investigate. Head to the elevator and pry it open. Climb up and move from side to side to avoid falling debris. Continue up until you reach the top of the elevator entrance. An enemy awaits so eliminate him using melee kill. Move forth to find another group of enemies. You are weapons free at this point so grab the grenades nearby and clear the room.
Refill your ammo and grenades then grab a secondary weapon from the downed covenant. After a while, two landing ships will drop off reinforcements. Kill them then head to elevator to the left. Follow the path and take out the enemies along the way. Once you've reached a large circular room, carefully engage and take out the enemies since there are several to be found in this area.
Head outside and prepare for zero-gravity battle. Pick up the nearby Battle Rifle and snipe out some targets to lessen the annoyance. Jump down to the deck and make your way to the launch station. Once there, activate the missile controls.
The missile will fail to launch so you have to manually unblock the door. More enemies will arrive via dropship. Engage them then push the magnetic accelerator to release the missile bay door.
After the scene, run inside the ship then make your way to the escape pod. Follow the path until you encounter a group of lesser enemies. The floor will crumble underneath them so go down there and continue moving forth. Ignore the enemies and continue following the path until you reach the marked door. A scene will trigger afterward, ending the current chapter.