Luke Rattigan Luke Rattigan was a gifted and ambitious teenager who developed the ATMOS car technology in cooperation with the invading Sontaran race . He was the founder of the Rattigan Academy , a school for geniuses . However , he developed an irrational hatred for people he deemed less intelligent than him and willingly committed global treason in order to reconstruct humanity in his own perfect vision . Biography . At twelve years old , Luke invented the Fountain Six search engine , which made him a millionaire almost overnight . In his later teens , feeling misanthropic and unappreciated by society , he worked with the Sontaran s to develop the " Atmos " car device , which effectively eliminated all CO emissions of a car . Unbeknownst to its unwitting users , ATMOS would also poison the atmosphere , allowing the Sontarans to build a clone army to continue their war against the Rutan Host . The Tenth Doctor arrived when the then - eighteen - year - old Rattigan was running his own Rattigan Academy , teaching similarly gifted teenagers handpicked by Rattigan . Unbeknownst to any of them but Luke , the Sontarans had promised to give them the nonexistent planet " Castor 36 " ( renamed " Earth - Point - Two " by Rattigan ) to build a new world after the poisoning of Earth . The Sontarans activated " Atmos " which had been installed into 50 % of the world ' s vehicles . The Atmos systems emitted a gas which would kill all humans for their cloning process . Clouds soon wrapped the whole planet . Overcome by the thrill of war , Luke teleported from the Sontaran ship , where he ' d been watching the gas enveloping the planet , back to his academy . He tried to convince his pupils to come with him to " Castor 36 " to found their own civilisation ( for which they had been developing super - advanced technology in their labs ) . Horrified by the disaster and taking Rattigan to be mad , they abandoned him and fled . A dejected Luke returned to the Sontaran mothership and reported his failure . The Sontarans revealed they had had no plans to keep the students alive anyway ; they had merely needed Luke and his pupils for the creation and installation of the Atmos systems . After that , their only plans for the students were to use them as target practice . Devastated , Luke teleported back to Earth . He was met again by the Doctor , who told him to " do something clever with [ his ] life " . The Doctor teleported to the Sontaran ship with a reversed atmospheric converter . He intended to blow up the Sontarans — and himself — if they refused to leave Earth alone . Taking the Doctor ' s advice , Luke reprogrammed the teleporter , switched places with the Doctor , and blew up the Sontaran ship just in time , killing himself . When Martha and Donna ( who were present on Earth with the Doctor ) asked him what he was doing when he reprogrammed the teleporter , he said , " Something clever . " ( TV : " The Sontaran Stratagem " / " The Poison Sky " ) When Davros asked the Doctor , " How many have died in your name ? " , Rattigan appeared in a flashback of people who died , despite his treasonous actions . ( TV : " Journey ' s End " ) Personality . Even though Luke was brilliant ( having an IQ rating of 176 ) , he acted neurotically , in outbursts of unreasoning emotion . Luke lacked social skills . He believed all his students had been rejected from society for being intelligent and did not understand why they refused to join his vision to save the " ordinary " people they loved . He was very ambitious and callous towards people he felt did not meet his standard of intelligence , viewing the simultaneous deaths of 52 people via his own ATMOS system as amazing rather than horrible . He also viewed his home planet of Earth as a disappointment , stating that it was never big enough for him . He found the Doctor particularly annoying because of his cheeky attitude , his obviously superior intelligence and his use of tautology . Luke joined forces with the Sontarans because they seemed to appreciate his genius , leading him to commit global treason . When the Sontarans turned against him , Luke redeemed himself by sacrificing his life to destroy them . ( TV : " The Sontaran Stratagem " / " The Poison Sky " ) Behind the scenes . As revealed by writer Helen Raynor in PCOM : " The Sontaran Stratagem " , Luke was named after Luke Marlow , a young " Doctor Who " fan she knew , and in fact that was his original surname , as well . Russell T Davies , however , preferred the name Rattigan .