Following the first failed attempt to connect to the nine-chevron Stargate address, Icarus base fell under attack from the Lucian Alliance. Dr. Rush and civilian recruit Eli Wallace worked out a quick solution which allowed the ninth chevron to connect, and over 80 personnel and visitors escaped through the Stargate to the Ancient ship Destiny before the attack destabilized the planet's core. The base was destroyed when the planet exploded.
Air, Part 1 - Icarus Base fulfills its purpose in the Ninth Chevron Project by connecting to the Destiny, just before the base and the planet are destroyed.