Exactly 52 years ago today, the Apollo 11 crew turned the Omega Speedmaster Professional chronograph into the Moonwatch. It may have actually been one of the first nicknames ever given to a wristwatch. As a watch enthusiast, you probably have heard the story about the Moonwatch a thousand times already. However, in case you’re new to watches, or simply don’t mind hearing about it for the 1001st time, read on for more on one of the greatest chronographs of all time.

Speedmaster Professional 105.012

The Omega Speedmaster Professional did not become the Moonwatch purely by coincidence. Quite the opposite, in fact. One of the toughest rumors — for a long time — in the watch industry was that the Speedmaster was simply purchased by NASA at a jewelry store in Houston and thus became their watch of choice. It is NASA that we are talking about, so there had to be some guidelines (e.g. a tender process) and rules when it comes to purchasing equipment for astronauts. So, let’s quickly step back even further in time, to explain how it came to be that the Speedmaster was the watch strapped to Astronaut’s wrists. The fact that Schirra, Slayton, and Cooper already owned a Speedmaster CK2998 wasn’t an influence.

Schirra wearing his Speedmaster CK2998 right after Sigma 7

How The Speedmaster Became the Moonwatch

On Monday September 21st, in the year 1964, Flight Crew Operations Director Deke Slayton issued an internal memo that there was the need for a highly durable and accurate chronograph to be used by Gemini and Apollo flight crews. This request came from astronauts who approached Slayton, as they wanted to have a watch they could use during training and flight. This memo landed on the desk of NASA engineer James Ragan, who in turn put together a request for quotation and sent it to about 10 different watch manufacturers, including Omega, Rolex, Longines, and Lucien Piccard.

Rolex 6238 - photo courtesy of Phillips

Rolex 6238 – photo courtesy of Phillips

Of the 10, only four responded: Rolex, Longines-Wittnauer, Hamilton, and Omega. Hamilton was immediately disqualified, as they thought it was a good idea to send a pocket watch instead of a chronograph wristwatch. In hindsight, this might have made the shortlist of most awful mistakes ever made by a watch company. With the other brands’ outright lack of response topping that list.

Longines, Rolex, and Omega put to the test

Longines-Wittnauer sent a reference 235T chronograph, Rolex US sent its reference 6238 chronograph, and Omega US sent the Speedmaster 105.003. An interesting sidenote is that both the Rolex chronograph ref. 6238 (“pre-Daytona) and the Longines-Wittnauer 235T were powered by a Valjoux 72 movement and the Speedmaster by the Lémania based caliber 321 movement.

NASA engineer James Ragan testing the Speedmaster 105.003

In order for the watch to be (flight) qualified for use by the astronauts, NASA came up with a set of tests that were basically designed to give these watches hell.

  1. High temperature test: 70° C for 48 hours, then 93° C for 30 minutes in a partial vacuum.
  2. Low temperature test: -18° C for 4 hours.
  3. Vacuum test: heated in a vacuum chamber and then cooled to -18° C for several cycles.
  4. Humidity test: ten 24-hour cycles in >95% humidity with temperatures ranging from 25° C to
    70° C.
  5. Corrosion test: in an atmosphere of oxygen at
    70° C for 48 hours.
  6. Shock-resistance test: six 40 G shocks in six different directions.
  7. Acceleration test: progressive acceleration to 7.25 G for about five minutes and then to 16 G for 30 seconds in three axes.
  8. Low pressure test: pressure of 10’6 atmospheres at 70° C for 90 minutes, then at 93° C for 30 minutes.
  9. High pressure test: in an air pressure of 1.6 atmospheres for 60 minutes.
  10. Vibration test: random vibrations in three axes between 5 and 2,000 Hz With an acceleration of
    8.8 G.
  11. Sound test: 130 decibels at frequencies from 40
    to 10,000 Hz for 30 minutes.

Image (c) Omega

NASA’s qualification of the Speedmaster

NASA’s testing standards allowed each watch to show a maximum deviation of 6 seconds per day on average during normal use (again). According to official documentation we’ve seen from Omega’s Archives, it seems that the Rolex reference 6238 failed the humidity test, with the movement simply coming to a stop, and again it failing during the high-temperature test. The Longines-Wittnauer 235T failed the high-temperature test as well, as the crystal warped and disengaged. All tests were completed on March 1st, 1965. Interestingly enough, on March 23rd 1965, the Speedmaster 105.003 was brought into space on the wrists of astronauts Virgil Grissom and John Young. It was only a few days later, on June 1st, 1965, the Omega Speedmaster 105.003 received its qualification (but not certification! NASA doesn’t certify anything!) to be used as the chronograph for all manned space missions.

Ed White wearing two Speedmaster 105.003 watches

Just two days later, on June 3rd, NASA astronaut Ed White wore not one, but two Speedmaster 105.003 watches over his space suit during the first spacewalk performed by an American.

Now that we know a bit of the history of how the Speedmaster became NASA’s chronograph of choice (a more in-depth story on this can be found here), let’s move on to the next big thing that happened: Apollo 11.

The Apollo XI crew: Armstrong, Collins, and Aldrin

Apollo 11 – Who Wore What?

Meanwhile, Omega continued bringing innovation to their watches, including the 4th generation of Speedmasters, this one with “Professional” in the name. The addition of “Professional” had little to do with NASA’s qualification, as it was already in use in 1964. It was added because of the new case featured in this model. A 42mm diameter a-symmetrical case with lyre lugs and crown guards. These guards were put in place to prevent the pushers from being damaged or even knocked off. The former Speedmaster generations featured straight-lug cases and a smaller diameter (39.7mm for the 105.003 and CK2998 and 38.6 for the CK2915 with steel bezels).

Edwin “Buzz” Aldrin and his Speedmaster 105.012

Omega then started shipping these watches to NASA as well. This is how it came to be that the famous Apollo 11 crew, Neil Armstrong, Edwin “Buzz” Aldrin, and Michael Collins, all wore the 4th generation Speedmasters. Armstrong and Aldrin were equipped with the Speedmaster Professional reference 105.012(-65 for Armstrong’s) and Collins wore a Speedmaster Professional 145.012-68.

Neil Armstrong examining a rock sample, wearing his Speedmaster on a JB Champion bracelet.

These watches all used the same internal reference number by NASA, SEB1210039-002 (the 105.003 used the -001 designator) which was engraved on the case back and a unique number engraved on the side of the case, near the lugs.


Michael Collins on the left, Deke Slayton in the background.

Armstrong’s watch had serial number 46, Aldrin’s 105.012 had serial number 43, and Collins 145.012-68 had serial number 73 (we wrote about his watch here). The story goes that Armstrong left his Speedmaster behind in the capsule, as a backup for the malfunctioning board clock. The Omega Speedmaster Professional watches of Neil Armstrong and Michael Collins are now located in the Smithsonian National Air and Space Museum. Aldrin’s Speedmaster is a different story, apparently, it was supposedly lost during transportation to the Smithsonian in Washington DC.

Picture of Collin’s Speedmaster 145.012-68. (c) National Air and Space Museum

Earlier this year, Michael Collins passed away, leaving Buzz Aldrin as the only living Apollo 11 astronaut. Though his original Speedmaster may have been lost, rest assured that he is not without an Omega Speedmaster watch on his wrist.

Ron Evan’s Speedmaster Professional 145.022 with caliber 861

No Speedmaster with caliber 861 on the Moon

The Speedmaster 105.003 and Speedmaster Professional 105.012 and 145.012 were worn to (and on) the Moon until the very last Apollo mission in 1972. The Speedmaster Professional 145.022 with caliber 861 was never worn on the Moon (only near the Moon, also during Apollo 17, as a board instrument by astronaut Ron Evans), even though the caliber 861 had already been introduced in 1968. Omega stuck to shipping the Speedmasters with the NASA-qualified caliber 321.


Today’s Speedmaster Professional Moonwatch

In all these years, Omega kept the Speedmaster Professional in its collection. Even when it didn’t really fit the new innovative product developments anymore. Not only that, but the way the Speedmaster was manufactured, was not all that different from how it was done decades ago. This was changed recently, with the introduction of the new Speedmaster Professional Moonwatch, featuring caliber 3861.

Omega Speedmaster Pro Moonwatch caseback

A Master Chronometer certified movement, that has an average accuracy of +5/0 seconds per day, anti-Magnetic up to > 15,000 gauss and has been equipped with the Co-Axial escapement and a silicon balance spring. This might not be the same movement which was used on the Moon all those years ago, but it is very similar to the caliber 861, that qualified in 1978 for the Space Shuttle program. And the caliber 1861 movement, one that was never qualified, but still used by astronauts and cosmonauts leaving Earth via Russian soil.

Moonwatch Master Chronometer

The current Omega Speedmaster Professional Moonwatch Master Chronometer

Design cues of the new Moonwatch

Omega decided to go with the same case shape and dimensions as the 4th generation Speedmaster, the 105.012/145.012 references. Meaning it has a 42mm case diameter and the instantly recogniseable lyre lugs. The dial and hands on the new model also look very similar to the ones used in those references. A step-dial and the same shape chronograph second’s hand as the 105.012 and 145.012 are also featured. Where as the original Moonwatch had an applied logo, you will only find this on the modern version with a sapphire crystal, with the Hesalite version featuring a printed logo on the dial. This helps to make a distinction between the two available variations. The sapphire version has a display back, to showcase the beautiful caliber 3861 movement. The Hesalite version has reference 310. and the sapphire version has reference 310. We published our hands-on reviews on the modern Moonwatch here.


An additional modern Moonwatch

In 2019, Omega announced the return of caliber 321. In July that year, Omega introduced it in the platinum Speedmaster Professional with an onyx dial and meteorite subdials. Last year, Omega introduced the steel Speedmaster Calibre 321, based on the 105.003.

Actually, the watch Omega used as a reference for the recreation was Gene Cernan’s Moonwatch. It respects the dimensions and design of the original 105.003 Moonwatch but features a sapphire crystal and ceramic bezel. The reference number for this 39.7mm Speedmaster Calibre 321 is 311.


Celebration pieces: The Apollo XI Moonshine, the platinum Calibre 321 and the steel Apollo XI. All from 2019.

We’ve been covering the Speedmaster extensively here at Fratello over the past 17 years. We’ve published over 500 articles on the Omega Speedmaster and its many variations, of which the majority can be found in our Speedy Tuesday section.