By Piya Sinha-Roy LOS ANGELES (Reuters) – For his first journey into a galaxy far, far away, director Christopher Nolan wanted to tether himself to something close to home. In his daughter, he found inspiration for a lead character in “Interstellar,” Nolan’s big-budget epic space adventure rooted in intimate family drama. “I took the decision to change Murphy into a girl, and I think I may well have done that because my oldest child is a daughter,” Nolan said of the teen who suffers when her father, played by Matthew McConaughey, leaves for a long, potentially fatal space journey. “I wanted to have as close a relationship as possible to the emotional journey of the character.” “Interstellar,” out in U.S.