The name dates back more than a hundred years, when a naval medical tent was first erected in the middle of San Diego's Balboa Park (on the site of the present day NMCSD), for the Panama–California Exposition in 1915.

[3] The Flight II variant is designed to bring enhanced medical capabilities at the request of Combatant Commanders, and allows patients to recover onboard rather than in a higher-level facility.

They can respond faster, and to more places than the Navy's larger, slower and unarmed hospital ships.

[5] In January 2023, the Navy announced that three Expeditionary Medical Ships (EMS) had been approved in the 2023 military budget.

[6] Two 11-meter rigid-hulled inflatable boats allow for the transfer of patients from other ships or water rescue; the flight deck has room for a single V-22, or an H-53 or H-60 helicopter.