Hassayampa maintained her posture and seaworthiness while repeatedly responding to the needs of Pacific- and 7th-Fleet vessels and crewmembers into the late 60s with further missions including Operation Sealords (an acronym for Southeast Asia Lake, Ocean, River, and Delta Strategy). Conceived by Admiral Elmo R. Zumwalt, Jr., it was a joint operation between U.S. and South Vietnamese forces. Operation Sealords, launched on October 8, 1968, was intended to disrupt North Vietnamese supply lines in and around the Mekong Delta. As a two-year operation, by 1971, all aspects of Sealords had been turned over to the South Vietnam Navy.

Continuing her service in the Western Pacific, Hassayampa served as replenishment vessel during the Apollo 11 recovery mission where she was on hand for replenishment duties for USS Hornet (CVS-12) and  support vessels USS Arlington (AGMR-2), USS Goldsborough (DDG-20), USS New (DD-818), USS Ozark (MCS-2) and USS Salinan (ATF-161). On 22 July 1969, Hassayampa refueled USS Hornet (CVS-12) just prior to Hornet's recovery of the Apollo 11 space capsule. Hornet's deck log shows this occurring on July 22, 1969, about 36 hours before Hornet picked up the Apollo 11 astronauts and crew fresh from their lunar excursion. The command module "Columbia" splashed down about 200 nautical miles south of Johnston Island at 12:50 GMT July 24, 1969. Apollo 11 was the first manned mission to land on the Moon. It was the fifth human spaceflight of the Apollo program and the third human voyage to the moon. Launched on July 16, 1969, it carried Commander Neil Armstrong, Command Module Pilot Michael Collins and Lunar Module Pilot Edwin 'Buzz' Aldrin. On July 20, 1969, Armstrong and Aldrin became the first humans to land on the Moon while Collins orbited above. The mission fulfilled President John F. Kennedy's goal of "landing a man on the moon and returning him safely to the Earth" by the end of the 1960s. Many consider the landing one of the defining moments of the 20th century.

Four months later, USS Hornet (CVS-12) repeated this flawless performance as PRS for the recovery of Apollo 12, America's second lunar landing mission. On November 24, 1969, the spacecraft Yankee Clipper, with its all-Navy astronaut crew of Pete Conrad, Alan Bean and Dick Gordon, splashed down a little over 2 miles from the aircraft carrier. Again , Hassayampa was there facilitating with Underway Replenishment Operations as needed. Photos of replenishment operations can be seen here.

As a fleet oiler, Hassayampa continued to operate out of Pearl Harbor well into the 1970s to maintain peak readiness and efficiency while preparing to further support the 7th Fleet off Southeast Asia.

July, August, September and October 1972 found Hassayampa facilitating heavy cruiser Newport News (CA-148) and other naval ships in combat action throughout southeast Asia -- and continued that stance well into the 1980's.

During a bleak period in U.S. Naval history in 1972, racial tensions erupted aboard several naval vessels, including Hassayampa. These incidents indicated the depth of racial problems in the Navy. All of the services had experienced similar problems earlier, but the Navy had lagged behind the others in addressing the issues that contributed to the racial tensions that had erupted. At this point, Admiral Elmo R. Zumwalt, Jr., Chief of Naval Operations, instituted new race relations programs and made significant changes to Naval Regulations to address many of the very real issues raised by black sailors regarding racial injustice in the Navy.

In early August 1973 Hassayampa had just started shipyard availability when orders came down to proceed and assist with refueling operations of two specially configured Military Sealift Command ships (USNS Corpus Christi Bay and USNS Wheeling) that were observing French nuclear tests on Mururoa Atoll, 750 miles Southeast of Tahiti. A six-day “all ahead full” run to Pago Pago ensued and refueling operations took place in port with NSFO on 6 August and 11 August 1973. Hassayampa returned to Pearl Harbor on 17 August to continue shipyard availability. Three weeks later, Hassayampa received orders to return to Pago Pago to again refuel the MSC ships due to repeated delays of the French testing and the MSC vessels running low on fuel as a result. On 6 September 1973, Hassayampa proceeded at 19 knots to accomplish this, meeting up with Corpus Christi Bay, underway, and began what turned out to be a 42-hour UNREP. Corpus Christi Bay had no alongside UNREP capability so Hassayampa streamed a 2-1/2 inch hose to Corpus Christi Bay as she maintained her station astern, rather than alongside. Seven Hassayampa crewmen were heloed over to help secure and operate the refueling station. Both vessels steamed at bare steerage way (3-5 knots) and in the crystal clear water, each blade of the screws could be seen as it came by. Hassayampa returned to Pearl Harbor 24 September 1973 and was nominated for a National Defense Transportation Unit Award.

On 17 November 1978, USS Hassayampa (AO-145), Captain Captain Roger Box, USN, along with his Executive Officer, LCDR R. T. Sloane, USN, transferred Hassayampa to the Military Sealift Command, where she began her second life as USNS Hassayampa (T-AO 145) under the command of Captain Gottfried C. Krull.

In (c.) 1981, working in conjunction with USS Barbel (SS-580), Hassayampa was instrumental in securing the rescue of 87 Vietnamese refugees drifting at sea in an open boat off the coast of South Vietnam. While en-route to Singapore to safely offload the 87 refugees picked up by Barbel, Hassayampa came upon an additional boat with 104 refugees. Several years later, on May 8, 1984, Hassayampa spotted a 25 foot teak fishing boat that was adrift and located 65 miles from the nearest island and 130 miles south of Saigon. On board was a group of 20 Vietnamese refugees, which included many women with infants. In all, Hassayampa had now facilitated in the rescue of 211 Vietnamese Boat People.

September and October 1983 found Hassayampa entwined in Russian politics and foreign intrigue when she accompanied Coast Guard Cutter Munro, the rescue salvage ship USS Conserver and the Fleet Tug USNS Narrangansett in search and salvage efforts surrounding the wreckage of Korean Air Lines Flight 007 that was brought down by Russian firepower. In addition, there were also three Japanese tugs chartered through the U.S. Navy’s Far East Salvage Contractor (Selco)—the Ocean Bull, the Kaiko-Maru 7, and the Kaiko-Maru 3. These vessels, which housed navigation systems equipment, had the assignment of towing sideways scanning sonar designed to detect objects at the bottom of the sea such as the wreckage of Korean Air Lines Flight 007. Additionally, there were U.S. naval combatants and logistical support ships—the USS Elliot, USS Badger, USS Sterrett, USS Callaghan, USS Brooke, USS Meyerkord, USS Tower, USS Stark and USS Wichita. In addition to the above ships, there were numerous Japanese Maritime Safety Agency (JMSA) patrol boats and South Korean vessels. Additionally, there were scores of Russian vessels navigating the area. On October 17, 1983, Rear Admiral Walter T. Piotti, Jr., was placed in command of U.S. Seventh Fleet Task Force 71 which was overseeing search and salvage efforts. Commander Piotti’s assessment of the enormity of this naval undertaking was: “Not since the search for the hydrogen bomb lost off Palamares, Spain has the U.S. Navy undertaken a search effort of the magnitude or import of the search for the wreckage of KAL Flight 007.

During November 1984, USNS Hassayampa was a participant in FLEETEX 85, a major exercise involving five aircraft carrier battlegroups and sixty-five ships from various countries. At one point during a consolidation operation with MV Falcon Champion, a giant wave struck both vessels and forced Hassayampa seven degrees to port causing a near-collision between her and Falcon Champion. A significant amount of material damage was suffered by Hassayampa, in addition to three crewmembers having to be air-lifted at maximum helo range, to USS Carl Vison (CVW-15), two of which were further air-lifted to Japan for emergency medical treatment.

By 1987, Hassayampa was well-versed in war effort management and was operating with Battle Group Echo. The 1987 COMCARGRU 1 / Battle Group Echo deployment to the Arabian Sea included Ranger (CV-61), Missouri (BB-63); Hassayampa (T-AO 145), Leftwich (DD-984), Hoel (DDG-13); Kansas City (AOR-3), Bunker Hill (CG-52), Robert E. Peary (FF-1073); Long Beach (CGN-9), Wichita (AOR-1) , Gridley (CG-21), Curts (FFG-38); Shasta (AE-33), John Young (DD-973), Curts (FFG 38) and Buchanan (DDG-14).

Throughout the late 1980's, Hassayampa played an integral role in Western Pacific, Indian Ocean and Persian Gulf peace keeping efforts and worked in harmony with naval and military operations including Operation Earnest Will {July 24, 1987-September 26, 1988), protection of Kuwaiti owned oil tankers from attacks from Iranian forces, Operation Nimble Archer, an October 19, 1987 attack on two Iranian oil platforms in the Persian Gulf by United States Navy forces ---platforms that were being used by Iranian forces to attack U.S. ships and aircraft transiting the Persian Gulf and was in response to Iran's October 16, 1987 attack on MV Sea Isle City, a re-flagged Kuwaiti oil tanker at anchor off Kuwait} and Operation Praying Mantis an April 18, 1988 attack by U.S. naval forces in retaliation for the Iranian mining of the Persian Gulf and the subsequent damage to an American warship---the largest battle by American naval forces since World War II which sank two Iranian warships and three armed speedboats. It also marked the first anti-ship surface-to-surface missile engagement in U.S. Navy history.

In the years that followed, up to October 1991, Hassayampa  continued to support United States protection policy. Hassayampa provided underway replenishments to Naval forces on an ongoing basis, as did many other U.S. Naval Ships and auxiliaries that participated in Desert Shield and Desert Storm in 1990 and 1991. During this period she operated as a vital unit with the Military Sealift Command in the North Arabian Sea. In the summer of 1991, USNS Hassayampa further distinguished herself in participating in Operation Fiery Vigil following the June 12, 1991 eruption of Mount Pinatubo, the Philippines. Hassayampa, along with 22 other ships, helped move over 45,000 people from the Subic Bay Naval Station to the Port of Cebu in the Visayas. Operation Fiery Vigil was the largest peacetime evacuation of active military personnel and their families in history.

In 1991, she was removed from active naval service and placed in reserve in the Susin Bay Reserve Fleet in California. In 1994, she was struck from the Naval Register and awaited disposal. On 1 May 1999, she was transferred to MARAD and in April 2014, she was sold for scrap and was removed from the National Defense Reserve Fleet for cleaning on 29 May 2014, at Mare Island and was removed from Mare Island on 11 June 2014. On 26 June 2014, she arrived at All Star Metals in Brownsville, Texas.

Throughout her distinguished life, Hassayampa earned numerous service awards , some of which include the Combat Action Ribbon, Joint Meritorious Unit Award, Navy Unit Commendation, Navy Meritorious Unit Commendation, Navy "E" Ribbon, Navy Expeditionary Medal, National Defense Service Medal, Armed Forces Expeditionary Medal, Vietnam Service Medal, Southwest Asia Service Medal, Humanitarian Service Medal, Republic of Vietnam Gallantry Cross Unit Citation, Republic of Vietnam Campaign Medal and several others....

In characteristics depicting military proficiency, Hassayampa, on several occasions, displayed her abilities to act offensively, as well as defensively. In the late 50's, '60's and 70's, Hassayampa earned battle efficiencies and was so honored by being able to display the coveted "E" for Battle Efficiency. Throughout her active duty lifetime, Hassayampa continued to display that proficiency in military readiness. Time and time again she continued to prove herself. Even as she served with the Military Sealift Command, in 1989 USNS Hassayampa earned an MSCPAC Smart Ship Award, which is the MSC’s version of the coveted Navy "E."

Hassayampa was one hell of a ship.