P4F-221

P4F-221 is a planet where SGC is maintaining Mining Operations for Naquadah. When SGC sent the virus Avenger to P5S-117 which was modified by Baal's scientists and sent it to every other stargate in the galaxy, the team on this planet was one of three teams that successfully made it back to Earth in the first run before the whole Stargate network was taken down. (SG1: "Avenger 2.0")