As part of a contract between General Dynamics NASSCO and the U.S. Navy to build two Expeditionary Transfer Docks (formerly known as Mobile Landing Platforms), the U.S. Navy added a third ship to be constructed and configured as an Expeditionary Mobile Base (ESB), or formerly known as an Afloat Forward Staging Base. On June 12, 2015, NASSCO delivered the first ESB, USNS Lewis B. Puller (ESB 1), to the U.S. Navy, and in October 2014, NASSCO began construction on a second ESB.
The ESBs are configured with a 52,000 square-foot flight deck, fuel and equipment storage, repair spaces, magazines, mission planning spaces and accommodations for up to 250 personnel. The ships are capable of supporting multiple missions including Air Mine Counter Measures (AMCM), counter-piracy operations, maritime security operations, humanitarian aid and disaster relief missions and U.S. Marine Corps crisis response. It will also support MH-53 and MH-60 helicopters, and will be upgraded to support MV-22 tilt rotor aircraft.