Turn off forcefield is a mission in Going Commando taking place in the flying lab, Aranos. After escaping from prison and meeting in the hangar bay, Ratchet and Clank sought to deactivate the force field compounding their ship, the Star Explorer. Once they did, they received a transmission from Angela Cross.
This mission is begun by entering the door at the back of the hangar bay, specifically the door that is reached by climbing a ladder first. Open the door with the Infiltrator to begin the mission, which involves using the Levitator. In the first corridor, wait until the lava descends, and then head inside the tunnel and hold to stay at the top. You should have enough fuel to reach the end, and then head right to the next corridor. Use the Levitator again, this time making sure to conserve fuel and also avoid the electricity and drills. For the final corridor after it, the same applies: go when the electricity is not active, avoid the obstacles and reach the end, getting inside a room. After the short cutscene, stand on the switch to open a hatch allowing you back to your ship, also deactivating the force field.
The next mission is "Defeat the Thug Fleet" on planet Gorn. This is a space combat mission, so ensure you take a trip to Slim Cognito's Ship Shack to purchase upgrades first. Before leaving Aranos, consider completing "Explore the rest of the flying base", leading to a small series of missions that will take you back to Todano to obtain the Armor Magnetizer.