In your quest to kill the Visionary Charlie Montague, you may come across an AI by the name of 2-BIT. 2-BIT is a part of Charlie's brain and will make you a proposition. That offer is to ignite the rocket in Condition Detachment.
However, you cannot immediately ignite the rocket as it requires more power. To properly power the rocket engine, you will need to find five batteries and insert them into the computers. You can find batteries throughout Condition Detachment.
2-BIT is located on the central floor. There are two batteries in the rocket already so you will only need to find three more. On the bottom floor, you can find two sitting on the ground in front of the wall panels that look like moving tentacles. You can find two on the same floor you overheard the enemies on the ground at the moving tentacle wall panels. There is one on the same floor as 2-BIT in a side room. Finally, there is one battery on the top floor in the room with the Minicom Computer that has readable emails.
Some of these batteries are not charged. You can find a battery charger on the bottom floor. Locate the green water and if it is on your right, the battery charger will be to the left. If the water is on your left, the battery charger will be on your right. Charge the batteries and head back to the rocket engine. Be careful to drop the batteries because if you throw them they can explode. After you have inserted five charged batteries into the rocket engine, it will be ready to fire.
For more information on Deathloop, check out How to play Multiplayer in Deathloop – How to play as Julianna the Assassin and How to unlock and change outfits in Deathloop on Pro Game Guides.