A contact header assembly configured to be installed as part of a cryogenic electrical power feed-through assembly, the contact header assembly comprising: a) a feed-through body having a feed-through body cavity disposed therethrough extending between a first opening end to a second opening end, wherein the feed-through body includes an integrally formed first flange disposed at the first opening end, and the feed-through body further includes an integrally formed second flange disposed at the second opening end; b) a first contactor plate assembly comprising: i) a first contactor plate; ii) a first plurality of insulative bushings hermetically sealed to and extending through the first contactor plate; iii) a first plurality of contact pins hermetically sealed to and extending through the first plurality of insulative bushings, wherein the first plurality of contact pins are electrically conductive and in non-conductive relation to the first contactor plate and feed-through body; c) a second contactor plate assembly comprising: i) a second contactor plate; ii) a second plurality of insulative bushings hermetically sealed to and extending through the second contactor plate; iii) a second plurality of contact pins hermetically sealed to and extending through the second plurality of insulative bushings, wherein the second plurality of contact pins are electrically conductive and in non-conductive relation to the second contactor plate; d) wherein the first contactor plate assembly is disposed at and hermetically seals the first opening end of the feed-through body with a first electron beam weld formed between the first contactor plate and the first opening end; and e) wherein the second contactor plate assembly is disposed at and hermetically seals the second opening end of the feed-through body with a second electron beam weld formed between the second contactor plate and the second opening end; characterized in that the first contactor plate assembly is completely disposed within the integrally formed first flange and wherein the second contactor plate assembly is completely disposed within the integrally formed second flange. a) a feed-through body having a feed-through body cavity disposed therethrough extending between a first opening end to a second opening end, wherein the feed-through body includes an integrally formed first flange disposed at the first opening end, and the feed-through body further includes an integrally formed second flange disposed at the second opening end; b) a first contactor plate assembly comprising: i) a first contactor plate; ii) a first plurality of insulative bushings hermetically sealed to and extending through the first contactor plate; iii) a first plurality of contact pins hermetically sealed to and extending through the first plurality of insulative bushings, wherein the first plurality of contact pins are electrically conductive and in non-conductive relation to the first contactor plate and feed-through body; i) a first contactor plate; ii) a first plurality of insulative bushings hermetically sealed to and extending through the first contactor plate; iii) a first plurality of contact pins hermetically sealed to and extending through the first plurality of insulative bushings, wherein the first plurality of contact pins are electrically conductive and in non-conductive relation to the first contactor plate and feed-through body; c) a second contactor plate assembly comprising: i) a second contactor plate; ii) a second plurality of insulative bushings hermetically sealed to and extending through the second contactor plate; iii) a second plurality of contact pins hermetically sealed to and extending through the second plurality of insulative bushings, wherein the second plurality of contact pins are electrically conductive and in non-conductive relation to the second contactor plate; i) a second contactor plate; ii) a second plurality of insulative bushings hermetically sealed to and extending through the second contactor plate; iii) a second plurality of contact pins hermetically sealed to and extending through the second plurality of insulative bushings, wherein the second plurality of contact pins are electrically conductive and in non-conductive relation to the second contactor plate; d) wherein the first contactor plate assembly is disposed at and hermetically seals the first opening end of the feed-through body with a first electron beam weld formed between the first contactor plate and the first opening end; and e) wherein the second contactor plate assembly is disposed at and hermetically seals the second opening end of the feed-through body with a second electron beam weld formed between the second contactor plate and the second opening end;