It was sent to the Harvest system in 2525 after the UNSC lost all contact with that world. It sent a signal back, informing its location after dropping out of Slipspace, (presumably to aid in further increasing Slipspace jump accuracy), but after that, nothing was heard from it. The UNSC lost contact with it on the 20th of April, 2525. It met the Covenant Cruiser Rapid Conversion in orbit, still in the process of glassing Harvest, and was destroyed. JOTUNs under the control of Mack, Harvest's agricultural AI, witnessed the Argo enter orbit, and tried to warn them off, but, with communications options limited, Mack was unable to warn them in time. Battlegroup 4, lead by Captain Maribeau Veredi on the UNSC Heracles, was dispatched to find out what happened to the Argo.
- The ship was presumably named after the Argo, Jason's ship in Greek mythology. It was said to have been planned or constructed with the help of the goddess Athena, and on which Jason and the Argonauts sailed to Colchis retrieve the Golden Fleece. It was named after the ship builder, Argus.