One - [s1e12] The Defiant

: This episode is noted for Dr. McKay's growth; he chooses to join the fight alongside Sheppard rather than staying in safety.

While exploring a Lagrangian point satellite —an Ancient defense system located deep in space—Major John Sheppard and Dr. Rodney McKay intercept a distress signal from a nearby planet. Upon investigation, they discover a crashed that has been down for 10,000 years. [S1E12] The Defiant One

"Stargate: Atlantis" The Defiant One (TV Episode 2004) - IMDb : This episode is noted for Dr

: The episode is the first to explicitly identify the Ancients as the "Lanteans" . [S1E12] The Defiant One