In late 1964 NASA bought chronographs from several brands and tortured them: heat, cold, vacuum, humidity, vibration, acceleration. The Speedmaster 105.003 was the only watch to pass everything, and in 1965 it was qualified for all manned space missions - the certification that created the Moonwatch legend. Ed White wore the reference on America's first spacewalk that June, which is why collectors simply call it the Ed White.
The reference bookends the whole story: it was also the last watch worn on the moon, on Eugene Cernan's wrist during Apollo 17 in 1972. The last of the straight-lug, no-crown-guard cases, it sits at the hinge between the elegant early Speedmasters and the Professional era, and its production records are loose enough that the file marks the window circa 1963 to 1969 across its sub-references.
The qualification winner and the quiet grail of the pre-Professional era. The Ed White premium has pulled every parts drawer in Bienne toward this reference, so the movement serial, dial era and bezel must agree - and a correct, honest example is a watch that carries both the beginning and the end of the moon story on one wrist.
Production windows and specifications compiled from documented collector references and period catalogs, cross-checked across independent sources; manufacturer records for this era are approximate by Seiko's own account.