Did the Moonwatch need hesalite?

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Probably not, but remember … the Speedmasters used in the Apollo missions were off the shelf watches and those watches only came with hesalite. In fact, most sports watches (even those by Omega, Rolex, Heuer, etc) were only offered with acrylic crystals.

It would have been difficult to find a chronograph with a sapphire crystal in the 1960s.
True, but they never said that the original moonwatch with a sapphire crystal was hard to find so they went with the hesalite. They said only hesalite for the shatterproof ability.
 
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I can say from personal experience that fragments of sapphire glass are no joke. I still have some pieces lodged under my thumbnail when that damn Spiralwinder caseback shattered 6 weeks ago. Now imagine no gravity and that stuff flying around the cabin ....
Ok but why are they letting a sapphire crystal watch on board now?
 
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NASA did the best they could. Those were some tough requirements.

Is acrylic really shatterproof? Nope. Neither is mineral or sapphire. Some are harder to shatter or break into smaller or larger pieces, but they can be shattered.

Mineral was more common during the tests. Mineral is more glass than sapphire, so maybe the requirements could have meant no mineral crystals? Or maybe they were just happy any watch survived the grueling tests and overlooked the shatterproof requirement. My opinion is that we watch nerds care about it more than NASA.

As to why they allow sapphire on the ISS, that should say something about the myth of being nervous about sapphire shattering.

The Speedmaster is worn on EVAs because it passed the tests and it works. No need to pay for more tests.
 
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As to why they allow sapphire on the ISS, that should say something about the myth of being nervous about sapphire shattering.
Good point. I remember seeing photos of NASA astronaut Jonny Kim wearing a Seamaster Pro and a GMT Master on board the ISS. Both those watches had sapphire crystals.
 
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What I think is acrylic was widely used as the crystal of most watches back then so that is what came with the watch. Most watches back then came with something other Sapphire. I think then, because the classic watch kept the Hesalite, people came up with a story and it stuck. If they didn't want Sapphire on a watch back then because of shatter abilities, then you would think that would still hold true today. However, Sapphire is widely used on this mission and most missions ever since. Sure for EVA the moonwatch is the only approved watch, but that is outside the capsule where it matters less.
 
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Sure for EVA the moonwatch is the only approved watch, but that is outside the capsule where it matters  more.
FIFY
 
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. I think then, because the classic watch kept the Hesalite, people came up with a story and it stuck

Not exactly, but yes....Military and professional organizations had already had experience with mineral glass and rock crystal watch faces shattering in situations where that wasn't great.

As acrylics became more and more available, it was a natural replacement for something hard to cut, machine, and polish- and that scratched somewhat often.

The specification for a "shatterproof" crystal wasn't specifically adopted by NASA, the specification predates NASA. It really didn't take much consideration to stick with an existing decision in much less strenuous environments.

Since Sapphire has become so much more common, the policy has changed a bit.
 
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But they use the x33 now. It has sapphire
Yes.
That's why i mentioned that experience or time will tell.
NASA are only one bad event away from finding out if Saphire crystals are entirely suitable or preferable over Hesalite.
Having said that. The crystal on the X-33 is largely protected by the bezel as opposed to the crystals on watches back in the day protruding, which which placed them at greater risk of impact damage.
I imagine that NASA may have looked at the risk factors with using the X-33 and considered them to be miniscule in the modern age when balanced with any perceived practical advantage.
Besides.
It's not like they're going on any excursions on Artemis II.
 
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NASA did the best they could. Those were some tough requirements.

Is acrylic really shatterproof? Nope. Neither is mineral or sapphire. Some are harder to shatter or break into smaller or larger pieces, but they can be shattered.

Mineral was more common during the tests. Mineral is more glass than sapphire, so maybe the requirements could have meant no mineral crystals? Or maybe they were just happy any watch survived the grueling tests and overlooked the shatterproof requirement. My opinion is that we watch nerds care about it more than NASA.

As to why they allow sapphire on the ISS, that should say something about the myth of being nervous about sapphire shattering.

The Speedmaster is worn on EVAs because it passed the tests and it works. No need to pay for more tests.
Then again. The ISS is not on par with Mercury or Apollo programs all things considered.
 
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We're talking 1960s here !
Hesalite = synthetic transaprent thermoplastic
In other words a trade name like we know plexiglas for the same thing, acrylic "glass" !

While talking to Belgian artist Paul Van Hoeydonck ( 1925-2025 ), he explitcitly mentioned that his original artwork was representing a human figure floating up towards a blue sky... it sat in a block of acrylic (Hesalite) but NASA at the time did not allow such a large piece of hesalite due to fire hazard.
So PVH had to make a loose " Fallen Astronaut " figurine to be put beside a plaque on the Moon by Apollo 15 Commander David Scott.
In 2019, PVH decided to make a limited series of the orginal artwork as intended in the 1970s.
These were presented during VIP events, with Apollo 15 astronaut Alfred Worden prsent...
(Photo: Studio Paul Van Hoeydonck)
.
 
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Yes.
That's why i mentioned that experience or time will tell.
NASA are only one bad event away from finding out if Saphire crystals are entirely suitable or preferable over Hesalite.
Having said that. The crystal on the X-33 is largely protected by the bezel as opposed to the crystals on watches back in the day protruding, which which placed them at greater risk of impact damage.
I imagine that NASA may have looked at the risk factors with using the X-33 and considered them to be miniscule in the modern age when balanced with any perceived practical advantage.
Besides.
It's not like they're going on any excursions on Artemis II.
I don't think this was a factor. The reason because other sapphire crystal watches have gone into space like Rolex GMT, Seiko and Breitling Navitime. I have to believe they have no standards for watch crystal
 
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Rolex GMT

The first Rolex GMT worn into space was a 1675 with an acrylic crystal. Unless I am misremembering, it was worn on Apollo 14 in 1971.

To say that they didn't have a specification (written or otherwise) about the crystal, is, I think, silly- NASA had some pretty strict qualifications. The first automatic chronograph that went into space was"snuck" there (it was a Seiko 6139). NASA was apparently concerned that a chronograph with an automatic winding rotor would malfunction in microgravity. NASA was concerned about all sorts of issues in microgravity.


However, as it was proven that watches DO generally function normally in space, things relaxed. At some point during the Space Shuttle missions, the regulations regarding what watches could be worn into space were relaxed.
Edited:
 
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@ErichPryde
Indeed rules have been relaxed during the STS space shuttle program
.
First Rolex in space?
Depends on the definition of space, for military test pilots this was 50 miles...
So the very first Rolex in space was a Rolex GMT-master 1675 Pepsi bezel pilot watch worn by test pilot William "Pete" Knight during X-15 flight 190 (17 OCT 1967 reaching 85 kilometers).
Knight had also worn his Rolex GMT-master during X-15 flight 188 (03 OCT 1967 reaching a speed of Mach 6.7 or 7232 km/hour)!
.
The first automatic chronograph in space was a double win:
The very first automatic chronograph in space was a joint win, as during the 84 days long Skylab 4 mission (Nov 1973 - Feb 1974), both Commander Gerald Carr, 40mm Movado Datachron HS360, and pilot William Pogue, 41mm Seiko 6139-6005, wore an automatic chronograph !
The very first automatic chronograph directly exposed to the harsh vacuum environment of outer space, was the 38mm Fortis Official Cosmonauts chronograph, Lemania 5100 movement, worn by Mir-16 cosmonauts Yuri malenchenko and Talgat Musabayev (9 SEP 1994) !
See:
https://www.hodinkee.com/magazine/snuck-into-space
 
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The first Rolex GMT worn into space was a 1675 with an acrylic crystal. Unless I am misremembering, it was worn on Apollo 14 in 1971.

To say that they didn't have a specification (written or otherwise) about the crystal, is, I think, silly- NASA had some pretty strict qualifications. The first automatic chronograph that went into space was"snuck" there (it was a Seiko 6139). NASA was apparently concerned that a chronograph with an automatic winding rotor would malfunction in microgravity. NASA was concerned about all sorts of issues in microgravity.


However, as it was proven that watches DO generally function normally in space, things relaxed. At some point during the Space Shuttle missions, the regulations regarding what watches could be worn into space were relaxed.
INTERESTING
 
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Then again. The ISS is not on par with Mercury or Apollo programs all things considered.
Disagree. Crews are living in space for 6 to 8 months. The ISS is larger but still cramped and confining, more so than a submarine. The walls are thin and exposed to the risks of space, even though they are not exposed to radiation due to low Earth orbit. Flying to and from the ISS is less exciting than Mercury and Apollo only because they've done it more often without blowing up, but they are still on rockets and still experience reentry. The first two Mercury launches barely left Earth.

If you haven't been to a crewed launch, you might enjoy it. Knowing there are people sitting on top of the rocket will give you an appreciation for the ISS.
 
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To end this discusion. They have a jar of nutella floating freely in the casule. There multible Videos on this…
 
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To end this discusion. They have a jar of nutella floating freely in the casule. There multible Videos on this…
FWIW, I believe that jar is made of plastic, not glass.
 
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FWIW, I believe that jar is made of plastic, not glass.
That wouldn't last three seconds if one of my kids was an astronaught in that capsule.
 
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To end this discusion. They have a jar of nutella floating freely in the casule. There multible Videos on this…
Real Astronaut food!