Christina Sierra (クリスティナ・シエラ Kurisutina Shiera?) is a fictional character in Mobile Suit Gundam 00. Christina is member of Celestial Being and crew-member of CBS-70 Ptolemaios in Season 1 of the series. She helps maintenance with the ships daily operations and primarily specializes in programming. When on combat missions, she provides tactical communications between Ptolemaios and the Gundam Meisters.