SpaceX CEO Elon Musk on Tuesday said he has renamed the space startup's largest 'BFR' rocket as 'Starship'. Musk clarified that while the upper stage will be called 'Starship', the rocket's booster will be called 'Super Heavy'. The BFR, which is designed to be a sustainable interplanetary spaceship, will eventually replace SpaceX's Falcon 9 and Falcon Heavy rockets.