A system for pumping of high-pressure cryogenic fuel from a fuel source to provide a smooth, pulse-free output, comprising: a plurality of linear pumps each including in series: i. an upper power end and a lower fluid end, the power end having a linear-actuated drive system terminating in a drive shaft that linearly reciprocates along an axis; ii. the power end drive system of each pump being independently controllable via software contained within a multi-axis electronic controller, and each linear-actuated drive system being operable at a low turndown ratio to an output speed of about 1 cycle per minute; iii. the fluid end having a piston coupled to the drive shaft of the power end so as to linearly reciprocate within a fluid cylinder, the piston having a head with a plurality of piston rings distributed thereon that provide sealed sliding contact with an inner lumen of the fluid cylinder; iv. an absence of packing seals in the lower fluid end to reduce wear and extend operating life; v. an inlet tank for receiving and storing a high-pressure cryogenic fuel from the fuel source; vi. an inlet passageway leading from the inlet tank to a lower end of each fluid cylinder and into valved communication with a head space open to and below the head of the piston therein, wherein upward motion of the piston creates a negative pressure gradient in the head space sufficient to allow high-pressure cryogenic fuel into the head space, and downward motion of the piston expels high-pressure cryogenic fuel through a lower flow passage and into an outlet port common to all of the fluid cylinders; a sealed housing (24, 26) disposed around one or more of the linear pumps, the housing being sealed to contain any of the high-pressure cryogenic fuel that escapes from within the fluid cylinder; and wherein operation of the system includes coordinated actuation of the separate pumps to result in a pulse-free output pressure profile. a plurality of linear pumps each including in series: i. an upper power end and a lower fluid end, the power end having a linear-actuated drive system terminating in a drive shaft that linearly reciprocates along an axis; ii. the power end drive system of each pump being independently controllable via software contained within a multi-axis electronic controller, and each linear-actuated drive system being operable at a low turndown ratio to an output speed of about 1 cycle per minute; iii. the fluid end having a piston coupled to the drive shaft of the power end so as to linearly reciprocate within a fluid cylinder, the piston having a head with a plurality of piston rings distributed thereon that provide sealed sliding contact with an inner lumen of the fluid cylinder; iv. an absence of packing seals in the lower fluid end to reduce wear and extend operating life; v. an inlet tank for receiving and storing a high-pressure cryogenic fuel from the fuel source; vi. an inlet passageway leading from the inlet tank to a lower end of each fluid cylinder and into valved communication with a head space open to and below the head of the piston therein, wherein upward motion of the piston creates a negative pressure gradient in the head space sufficient to allow high-pressure cryogenic fuel into the head space, and downward motion of the piston expels high-pressure cryogenic fuel through a lower flow passage and into an outlet port common to all of the fluid cylinders; i. an upper power end and a lower fluid end, the power end having a linear-actuated drive system terminating in a drive shaft that linearly reciprocates along an axis; ii. the power end drive system of each pump being independently controllable via software contained within a multi-axis electronic controller, and each linear-actuated drive system being operable at a low turndown ratio to an output speed of about 1 cycle per minute; iii. the fluid end having a piston coupled to the drive shaft of the power end so as to linearly reciprocate within a fluid cylinder, the piston having a head with a plurality of piston rings distributed thereon that provide sealed sliding contact with an inner lumen of the fluid cylinder; iv. an absence of packing seals in the lower fluid end to reduce wear and extend operating life; v. an inlet tank for receiving and storing a high-pressure cryogenic fuel from the fuel source; vi. an inlet passageway leading from the inlet tank to a lower end of each fluid cylinder and into valved communication with a head space open to and below the head of the piston therein, wherein upward motion of the piston creates a negative pressure gradient in the head space sufficient to allow high-pressure cryogenic fuel into the head space, and downward motion of the piston expels high-pressure cryogenic fuel through a lower flow passage and into an outlet port common to all of the fluid cylinders; a sealed housing (24, 26) disposed around one or more of the linear pumps, the housing being sealed to contain any of the high-pressure cryogenic fuel that escapes from within the fluid cylinder; and wherein operation of the system includes coordinated actuation of the separate pumps to result in a pulse-free output pressure profile.