Samantha Carter is an astrophysicist, engineer, and pilot as well as a Colonel in the United States Air Force who played a key role in establishing the Stargate Program before being assigned to Stargate Command's flagship team, SG-1 where she was the second-in-command for eight years before becoming the commanding officer of SG-1 for a year. Considered Earth's leading expert on the Stargate and a host of other alien technology, her former commanding officer, Colonel Jack O'Neill once emphatically proclaimed her brain to be a national resource.