Adelaide Brooke

Captain Adelaide Brooke was briefly a companion of the Tenth Doctor. She was commander of Bowie Base One on Mars in the late 2050s. In November 2059, the base came under attack by a water-based entity called the Flood.

Early life
Adelaide was born in Finchley, North London on 12 May 1999. She was a child during the Daleks' abduction and invasion of Earth in 2009. Her father told her to stay in the house while he searched for her mother, but neither of her parents were ever seen again. The young Adelaide was spotted by a Dalek, but for an unknown reason it deliberately spared her. The event inspired Adelaide to go into space travel. She was later raised by her grandmother. (DW: The Waters of Mars)
 * The Doctor believed the Dalek recognised her as she was a "fixed" point in history.

Colony on Mars
She studied at Cambridge University, and achieved a first honours degree in combined Physics and Mathematics. She transferred to Rice University in 2017, where she earned her doctoral degree in Physics. Following Rice, she began working at NASA's Johnson Space Center in Houston, Texas. Brooke became the first NASA candidate selected who was not a citizen of the United States. After an intensive two year training programme, she served on numerous shuttle missions.

Despite her youth and inexperience within NASA, she was selected to head up Project Pit Stop, which used the moon as a re-fuelling base for planetary exploration. This was highly successful; exploratory, unmanned shuttles began to be dispatched to Neptune and Jupiter via the moon. The data they obtained increased greatly humanity's knowledge of these planets.

At the age of 42 (presumably in the year 2041), she was a member of a three-person mission to Mars. She was the first woman to land there. Afterwards, she campaigned to have Mars chosen as a location for colonisation.

In 2058, when Adelaide was now a mother, and a grandmother, she led an international team to Mars, the first human colony on the planet. She found fame on Earth as a result. (DW: The Waters of Mars)

Meeting the Doctor
In 2059, after seventeen months of success, two of her crew were taken over by the Flood. She tried to contain the infection, and after realising this was impossible, ordered the evacuation of the base. Adelaide was suspicious of the newly arrived Doctor's actions and comments. She forced him to tell her the truth: Bowie Base One was going to be destroyed, and the crew killed. As this was a "fixed" point in time, he could not save her.

Though she struggled to save the colonists, when the Doctor returned to help she resigned herself to her fate and set the base's self-destruct timer. When the Doctor saved her, Mia Bennett, and Yuri Kerenski, returning them all to Earth in front of her house, she realised her survival would alter her granddaughter's life and thus human history. She grew angry with the Doctor when he dismissed the problem and referred to her fellow survivors as "little people." She killed herself to preserve the timeline. (DW: The Waters of Mars)

Legacy
Her granddaughter, Susie Fontana Brooke, was inspired by her memory and went into space, later piloting the first lightspeed ship to Proxima Centauri. The rest of her family followed as well; one descendant fell in love with a Trandorian prince and created a new species. (DW: The Waters of Mars)

Though the Doctor managed to save three people from Bowie Base One, Adelaide's suicide ensured that the timeline was not altered significantly. Her death was the fixed point in time. The only evident change was that history now recorded that she died on Earth, rather than on Mars and that she had committed suicide under "unexplained circumstances." Mia and Yuri told the world the story of Bowie Base One and hailed her as a hero. This, and not the mystery of her death on Mars, was what inspired her granddaughter.

Personality
Adelaide Brooke was a strict and serious woman who often showed other people a cold demeanour, reserving her warmth for her family. Though she cared about her crew, she treated them in a professional manner and demanded decorum and discipline. One of her crew noted that she only gave compliments if the situation was serious.

Adelaide was a selfless woman who sacrificed herself to preserve history. Though she knew the Doctor for less than a day, she quickly grew to accept that he was a time traveller even before she travelled in the TARDIS. She was angry with the Doctor when he rescued her, insisting that "The 'Time Lord victorious' is wrong!" and aghast that he could have changed the history of the entire human race.

Behind the scenes

 * Adelaide is one of only a few companions in the revived series to die and the second to die without being "reborn" somehow in the new series (such as Captain Jack or Astrid Peth).
 * The details of her career can be briefly seen in her obituary.
 * Adelaide was the oldest human companions, until Wilfred Mott.
 * Adelaide was the first companion to commit suicide while not in the process of directly protecting others or defending herself (as was the case with Katarina and Sara Kingdom (DW: The Daleks' Master Plan), Adric (DW: Earthshock) and Astrid Peth (DW: Voyage of the Damned)).
 * Adelaide went to the same university as Liz Shaw.
 * When initially sketching out the story, Davies considered Helen Mirren as a potential actress to play the character that eventually became Adelaide. In an early draft, the character that became Adelaide was Russian, but this was changed when, still thinking of Mirren as a potential guest star, Davies felt it would have been too close to the character played by Mirren in the film 2010: The Year We Make Contact. (REF: Doctor Who: The Writer's Tale - The Final Chapter)