USA manned space flights started with the Mercury project. First suborbital flight was done by Alan Shepard on 5.5.1961 followed by Gus Grissom on 21.7.1961. First American in orbit flight was John Glenn on 20.2.1962. He didn't wear wrist watch on his flight, he used pocket Heuer stop watch. So for the watch collectors the next flight is more important. On 24.5.1962 Scott Carpenter made his orbital flight with Breitling chronograph "Cosmonaute" on his wrist. That was the first swiss made wrist watch in space and first chronograph in space. On 3.10.1962 Omega Speedmaster joint Breitling since Wally Schirra used that Omega in his flight.
On March 1965 NASA chose Omega Speedmaster as an official watch for all their space programs. On that tender Omega won against Rolex,Breitling and Longines-Wittnauer. Omega moonwatch legend was born....
Section about watches connected to NASA flights are split to four sections: Breitling Cosmonaute section, Omega moonwatch section, Stowaways - section about watches which were worn by the astronauts as their private watches, so those watches were in space (even in the Moon) but were not there officially. The last section is section about watches which are dedicated to Moon flights.