Before NASA tested anything, an astronaut just went to a watch shop. Wally Schirra bought his CK2998 privately and wore it aboard Mercury Sigma 7 in October 1962, making the second-generation Speedmaster the first Omega in space three years before any official qualification existed. The reference itself refined the formula: alpha hands, the first black bezel, and the same caliber 321 underneath.
The CK2998 ran through a string of sub-references before the MAPICS numbering era began, and its blend of genuine space history with pre-Professional elegance has made it one of the most collected early Speedmasters, with the sub-reference details mattering enormously to originality and value.
The reference that earned the space connection on a private citizen's wrist. Sub-reference correctness is the collecting game here: bezels, hands and dials shifted across the run, and the right combination for the specific sub-reference is what separates a correct watch from a merely pretty one.
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.