In 2552, the ship was stationed at Earth with the Home Fleet during the Battle of Earth. The Redoubtable descended near New Mombasa to help in the fight taking place there, and was one of four ships fast enough to follow the UNSC In Amber Clad into Slipspace in pursuit of the Solemn Penance and the High Prophet of Regret. The ultimate fates of the Redoubtable, UNSC Paris and UNSC Coral Sea are unknown.
- The Redoubtable was faster than the Dusk and sped out of their sensor range in Slipspace, possibly heading right past Installation 05.
- Webster's Dictionary defines redoubtable as: Worthy of or inspiring fear, respect, and honor.
- The Redoubtable was possibly named after the older French Ship-of-the-Line (wooden battleship), which saw heavy action at the Battle of Trafalgar and fiercely engaged Lord Nelson's flagship, the HMS Victory.
- Halo: Ghosts of Onyx (First appearance)