Assigned to Service Squadron 1, Mars left San Diego on 16 March 1964 for Acapulco, Mexico, for shakedown, returning to San Diego on Easter Sunday. On 1 September she departed for the western Pacific, arriving at Yokosuka, Japan, on the 23rd. With Yokosuka as home port, the combat storeship operated from the Philippines to the South China Sea through the rest of the year. Mars continued through the next three years to provide logistic support to the far-ranging 7th Fleetat sea, especially off Vietnam, while revisiting the South Pacific ports of Hong Kong; Sasebo, Japan; and Subic Bay, Philippines. Typical of the combat storeship's supply activities was a night vertical replenishment of while the heavy cruiser was fighting off Vietnam, her guns on the engaged side fired in support of troops ashore. Mars had taken an especially active part in similar operations in South Vietnam. She set several replenishment records in 1967 and 1968, and into 1969 continued to play an important role in the fleet operations in the Southeast Asia area. In January 1968, Mars sailed to the waters off North Korea as part of the support fleet for Operation Formation Star when the USS Pueblo was seized by North Korea.
1971–1979
She underwent extensive overhaul from late August 1971-April 1972 in Richmond, California, receiving naval distillate fuel burning boilers, upgraded electronics, etc. She was then immediately deployed to the South China Sea to support the 7th Fleet and Marine Amphibious forces after the North Vietnamese Easter Offensive. She returned to her homeport of Alameda, California, that December; her homeport was then moved to Sasebo, Japan during April 1973. From April 1973 to the end of 1974, Mars continued replenishing the ships of the western Pacific and made two trips to the Indian Ocean to support the U.S. Navy patrolling the Persian Gulf area. She was transferred back to CONUS in August, 1976, arriving at Oakland Army Depot. On 14 May 1979, and Mars collided off Point Loma near San Diego, California, injuring seven.
1980–1988
Mars departed its homeport of Alameda, California in February, 1980, transited the Pacific, and arrived in the Indian Ocean in May. One of her first assignments was to send a working party ashore on the island of Masirah off the coast of Oman to clear the area of the debris left at the staging point for the attempted rescue of the embassy hostages in Tehran, Iran. Once this task was complete, Mars stayed in the Indian Ocean, conducting underway replenishments with the battle groups assigned, steaming to Diego Garcia to be re-supplied, and conducting re-supply evolutions on Masirah. The State Department had negotiated a specific window of 0900-1300 for the U.S. Air Force to land a C-141 cargo plane so Mars personnel could unload it and transfer it to the Mars via its CH-46 helicopters. Mars arrived back in Alameda in November to begin preparations for her next deployment in January 1982. Mars continued to make WestPac and Indian Ocean deployments from Naval Supply Center, Oakland then from its forward-deployed home of Sasebo Japan until its transfer to the Military Sealift Command in 1993.
