Archimedes
From Halopedia, the Halo wiki
Located on the edge of the Sigma Octanus system, the Archimedes was an outpost designed to detect incoming threats to the Sigma Octanus System. It was crewed by three individuals. In 2552, The Archimedes detected a fleet of covenant vessels heading for Sigma Octanus IV. Ensign William Lovell worked aboard this station and, because of this incodent, he was transferred to the Pillar of Autumn by Captain Keyes
