David Rankinson was the former Commander of the Sol United Military Alliance and was the father to Commander Christopher Rankinson. David Rankinson were born in October 2016 in New York City. He married with lunar science officer Ariana Fey in 2054, a couple of months before he took his family with him to the Aeolis City on planet Mars. In 2064, he took his son Christopher Rankinson on a trip to Saturn's largest moon Titan. Before his spaceship entered the atmosphere, the main-engine of the ship failed. They crashlanded, only his son survived. David never got the chance to tell his son the purpose of travelling to Titan, which Christopher Rankinson later found out why.