Tripoli
From Halopedia, the Halo wiki
The Tripoli was a remote station held by the UNSC probably located in deep space. As of 2552, it was fully operational. That year, it was the meeting place for the UNSC Stalingrad and a small task force that had been assigned to go to Onyx to rescue the Spartan-IIs and Dr. Catherine Halsey, along with the prowler Dusk.
