Ana (The Lost Generation)

Ana was the pilot of the ark ship Prosperity. It travelled for thousands of years without reaching a destination, and the ship would not let Ana die until the mission was complete, so she was kept alive in a decaying state. When the Fourth Doctor and Sarah Jane Smith arrived on Prosperity, the Doctor offered to boost the ships engines to take it to a planet. However, the engines would be destroyed and the ship would be unable to sustain Ana any longer. She accepted the offer, sacrificing her life to save the colonists. (PROSE: The Lost Generation)