Combat Store Ships play a critical role in resupplying U.S. Navy combatant ships that are out at sea for long periods of time.

Sirius and Mars
U.S. Military Sealift Command operates a total of six Combat Store Ships that carry a wide variety of supplies – including fuel and food. These vessels resupply combat ships with frozen and dry provisions, as well as propulsion and aviation fuel. The ships also provide clothing, mail and mechanical parts to combat ships. Combat Store Ships do not resupply ammunition.

There are two classes of Combat Store Ships operated by the U.S. Navy – Sirius and Mars. These ships first came into service in the early 1990s. Several of the Combat Store Ships have since been decommissioned and replaced with dry cargo ships that are operated by the U.S. Navy. Resupply ships are used exclusively to replenish needed supplies of combat ships that are out at sea on missions for several months at a time.