Snow reveals his first name to Grace at the end of the movie, "Marion...my dad was a John Wayne fan." John Wayne's real name was Marion Robert Morrison (his middle name was soon changed from Robert to Mitchell when his parents decided to name their next son Robert) which was changed to John Wayne when he became an actor.
The trivia items below may give away important plot points.
The film bears a strong resemblance to the cult classic Escape from New York (1981) and its sequel, Escape from L.A. (1996). The former was about the protagonist, a convict, being sent into the title city, a prison in the future, to rescue the President after Air Force One crashes. The latter was about the same protagonist being sent into the title city (also a prison in the future) to save the President's daughter and recover a doomsday device. This film follows a convict as he's sent onto a prison ship in space to rescue the President's daughter and prevent the prisoners from crashing into Earth. Even the lead protagonists' name are similar, Escape's Snake (Kurt Russell) and Lockout's Snow (Guy Pearce).