UNSC After-Action Report: Battle Group Sierra-3

United Nations Space Command After-Action Report: Battle Group Sierra-3 was an official UNSC after action report concerning the Battle of 18 Scorpii in 2543. It detailed the victory of UNSC Navy Battle Group Sierra-3 over a Covenant, as well as the involvement of unidentified friendly reinforcements which proved instrumental in deciding the engagement's outcome.

An excerpt of the after action report was included in the file Historical/Psychological Analysis of Cole, Preston J., sent by Codename: SURGEON to Codename: USUAL SUSPECTS in 2552. SURGEON believed that Vice Admiral Preston Cole, head of FLEETCOM Sector Three, had most likely read the report and concluded from it that his wife Lyrenne Castilla, the Insurrectionist captain of the Bellicose, had actually survived the Battle of Theta Ursae Majoris in 2504. Because of this, SURGEON held that the Sierra-3 After-Action Report provided context that was critical in understanding Cole's later actions at the Battle of Psi Serpentis.

{Excerpt} UNSC After-Action Report: Battle Group Sierra-3

 * AI-enhanced battle summation and casualty reports attached.
 * Battle Group Sierra-3 engages Covenant in 18 Scorpii.


 * PRELIMINARY: Battle Group Sierra-3, comprising two UNSC destroyers and one cruiser, engaged a Covenant CPV-class heavy destroyer in the 18 Scorpii system, March 6, 2543 (Military Calendar). The and Thermopylae sustained moderate damage, while the Io sustained heavy damage. Covenant vessel destroyed.
 * SUMMARY ADDENDUM: The Covenant ship inflicted heavy damage and Sierra-3 group was unable to peel its shields. Io ' s FTL drive was inoperative, so I faced a decision to fall back and save two destroyers, or fight and possibly lose all those ships. Reinforcements arrived when unknown friendly ships jumped in-system. Additional firepower penetrated enemy shields.
 * Lead reinforcement ship's silhouette matched a thirty-year-old UNSC frigate design with major modifications (see technical reports attached). Passive transponder pinged and yielded a ship reg. number, identifying the UNSC Bellerophon. Friendlies jumped out-system before comm contact established.
 * CAPTAIN'S NOTE: I don't believe in ghost ships. But I don't care if it is the Bellerophon, or if it was the Flying Dutchman sent by Lucifer himself- they saved our hides. Transmitted thanks to them before they jumped out and wished them well... whoever they were, and wherever they were headed.

List of appearances

 * Halo: Evolutions - Essential Tales of the Halo Universe
 * The Impossible Life and the Possible Death of Preston J. Cole