- "Carter, you're one of this country's natural resources, if not national treasures."
- — Jack O'Neill
Dr. Samantha Carter, Ph.D is a female Human astrophysicist, engineer, and soldier who served as second-in-command, and later leader, of SG-1. Prior to joining the team, she was instrumental in assisting Daniel Jackson in bringing the Stargate Program into existence, and quickly accepted a post at the International Stargate Command to explore alien worlds across the galaxy. Considered Earth's leading expert on the Stargate and a host of other technologies, Jack O'Neill once emphatically proclaimed her brain to be a natural resource. After the Fall of Earth, she left her duties as an SG team member, and has served as captain of the MBP-305 Jupiter and commander of the human starfleet ever since.
By 2381, she had joined the Continuity Division of Alliance Intelligence, working on a top-secret project to send the SG-1 of 2362 back to their proper time.
After much reflection, she had also married Typhuss James Halliwell, a Colonel in the Starfleet Marine Corps.