From Halopedia, the Halo wiki
In 2552, the Lark was docked above Reach. Cortana, testing her intrusion skills, broke into the ONI database and discovered the supposed yachts Lark, UNSC Applebee, and UNSC Circumference were ONI prowlers with innocuous names.
It is probable that this ship was destroyed during the Fall of Reach by the Covenant, or it made random slipspace-jumps back to Earth. This ship was likely part of Operation: HYPODERMIC along with the Circumference and the Applebee.
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