The Acasta was an Avenger-class DropShip owned and operated until at least 3067 by the mercenary unit known as The Medusans. The Acasta and her sister ships, the Active and the Agincourt, formed the over-size Second Division of Hydra Assault Squadron, serving under the commanding officer of the Second Division, Captain Robert Arbuthnott.
When the Medusans attempted to defend New Syrtis from a Capellan strike force in 3069, the Acasta was one of the ships involved in launching a deep space ambush against the Capellans. While the Medusans managed to destroy a Leopard and a Triumph and damaged a number of other Capellan DropShips, the mercenaries took damage in turn from the Capellan forces led by the Impavido class WarShip CCS Zhejiang, which was escorting the strike force. During the battle the Acasta and her sister ships took damage that would require months of repair time within a shipyard, and while the damage was repairable, the damage inflicted on shipyards throughout the Inner Sphere by the Word of Blake as the Jihad escalated meant that the Acasta was still waiting for those repairs at the end of 3071.
- Mercenaries Supplemental II, p. 51, "Basilisk Assault Squadron: Winning The Staring Match"
- Mercenaries Supplemental Update, p. 90, "Medusans"