Security rings are giant, round gates of Luminoth design. Two of them act as safeguards near the entrance to the Sanctuary Fortress, in the Temple Transport Access room. The rings block archways in Samus' path. To lower the the first one, Samus simply has to scan an Interface Module; to lower the second one, she must use a Spinner device and charge it until the ring is fully retracted. They will remain this way for the rest of Metroid Prime 2: Echoes.
Scans[]
"Object scan complete.
Security ring is locked down and active.
You may be able to access its control system and move it to open position."