UNSC Magellan
From Halopedia, the Halo wiki
The UNSC Magellan was a UNSC Carrier. In 2517, Jacob Keyes was assigned to the Magellan as his first assignment prior to graduating Luna OCS Academy. Those orders were rescended when he was sent to help Dr. Catherine Halsey study the Spartan Children.
Sources
The UNSC Magellan is mentioned on page 19 after then Lt.Keyes asked Dr. Catherine Halsey why he is with her on the Han Shuttle on page 18 in Halo: The Fall of Reach
