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  The view through the Apollo LEVA visor

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Author Topic:   The view through the Apollo LEVA visor
LM-12
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posted 10-05-2011 02:18 PM     Click Here to See the Profile for LM-12     Edit/Delete Message   Reply w/Quote
How did the LEVA gold visor affect the way the moonwalkers saw the lunar surface? How different was the visor-down view compared to the visor-up view? Maybe these are questions only a moonwalker could answer.

Rick Mulheirn
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posted 10-05-2011 06:05 PM     Click Here to See the Profile for Rick Mulheirn   Click Here to Email Rick Mulheirn     Edit/Delete Message   Reply w/Quote
I cant speak for the Apollo moonwalkers, but I have donned a shuttle EMU...or at least the upper torso, "Snoopy cap" and helmet assembly.

With the gold visor down the view out was akin to wearing silvered sunglasses on a sunny day; no discernable change in colours or hues just darker.

One of the more memorable moments came when placing the helmet over my head. I was warned in advance that some find this very claustrophobic; "You can see it in the eyes".

I too experienced this same sensation but only for a second or two. Fresh air was pumped into the helmet from behind my neck over my head and down across my face and the inside surfaces of the helmet. I loved it!

LM-12
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posted 10-05-2011 06:48 PM     Click Here to See the Profile for LM-12     Edit/Delete Message   Reply w/Quote
I know the gold sun visor was worn for a reason. It seems to me that with the visor down, the moonwalkers would see the lunar surface differently than how we see the lunar surface in photographs.

Tom
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posted 10-05-2011 07:14 PM     Click Here to See the Profile for Tom   Click Here to Email Tom     Edit/Delete Message   Reply w/Quote
I seem to recall a few pictures taken in which their gold plated visors were raised, giving the astronauts a "true" view while on the surface.

LM-12
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posted 10-05-2011 07:33 PM     Click Here to See the Profile for LM-12     Edit/Delete Message   Reply w/Quote
On Apollo 15, Jim Irwin had his visor up when he came down the LM ladder. On Apollo 17, Gene Cernan raised his visor to look at the orange soil at Shorty Crater.

Jurg Bolli
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posted 10-05-2011 08:28 PM     Click Here to See the Profile for Jurg Bolli   Click Here to Email Jurg Bolli     Edit/Delete Message   Reply w/Quote
We can speculate all we want, a moonwalker's opinion is needed here!

MCroft04
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posted 10-05-2011 09:12 PM     Click Here to See the Profile for MCroft04   Click Here to Email MCroft04     Edit/Delete Message   Reply w/Quote
Jack Schmitt saw the orange soil first on A17.

Jim Irwin wrote in To Rule the Night that he often became claustrophobic when donning the suit. So don't feel too badly.

LM-12
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posted 10-06-2011 11:01 AM     Click Here to See the Profile for LM-12     Edit/Delete Message   Reply w/Quote
The Apollo Lunar Suface Journal has some very detailed information[ on the LEVA. I did not know that the gold coating is on the inner surface of the sun visor.

Scott
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posted 10-06-2011 11:35 AM     Click Here to See the Profile for Scott   Click Here to Email Scott     Edit/Delete Message   Reply w/Quote
At the 2006 AAPG field trip to JSC with Dr. Schmitt, I asked him if he lifted his gold visor to more accurately see colors. He told me yes that was the reason he did it.

SpaceAholic
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posted 10-06-2011 11:46 AM     Click Here to See the Profile for SpaceAholic   Click Here to Email SpaceAholic     Edit/Delete Message   Reply w/Quote
The transmittance of the total visor assembly was 10 percent in the visible range (.39 to .75 microns) and one percent in the UV range (.25 to .39 microns). The total transmittance' in the IR range was 5 percent (.75 to 2.5 microns).

LM-12
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posted 10-06-2011 12:27 PM     Click Here to See the Profile for LM-12     Edit/Delete Message   Reply w/Quote
With the LEVA on and the visors down, the moonwalkers were looking through three layers - the EMU pressure helmet, the protective visor and the gold sun visor.

DG27
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posted 10-06-2011 10:34 PM     Click Here to See the Profile for DG27     Edit/Delete Message   Reply w/Quote
The Apollo LEVA visors were coated with gold to block IR energy and attenuate visible light. The gold coating filters out the IR wavelengths, and also some of the adjoining red wavelengths from the visible light spectra as well. The rest of the visible light (green, blue etc) is less attenuated. Thus the result is a slight green tinge to what is seen through the gold visor. The amount of green tinge is dependent on the thickness of the gold coating. The thicker the gold coating, the more green the view through the visoe will be. (Note that the polycarbonate visor material filters out the UV light.)

However the story is different with the Shuttle EMU visors. The "gold" Shuttle EMU visors are not coated with gold, but instead are coated with a proprietary mix of thin films which result in a silvery-gold look, but no real gold is used. Thus the Shuttle EMU visors do not add a green cast to what is seen.

LM-12
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posted 11-19-2011 03:05 PM     Click Here to See the Profile for LM-12     Edit/Delete Message   Reply w/Quote
Wearing those bulky pressure suits, LEVA helmets and chest-mounted cameras, could the moonwalking astronauts even see what was underfoot?

It is very easy to trip over stuff when you can't see your feet.

p51
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posted 11-19-2011 06:38 PM     Click Here to See the Profile for p51   Click Here to Email p51     Edit/Delete Message   Reply w/Quote
I talked with one of the suit guys at NASA in the Apollo era many years ago (I can't recall his name now), and he said with a straight face that the gold color to the visors was there for many reasons, one of which was that some 'brainiac' at NASA HQ said on the improbable chance that the first men on the moon actually encountered something alive on the surface, they didn't want it to be able to see the person inside the suit and therefore realize said person was quite frail and in something that could be ripped open.

I assume that this was a bogus story they told the public for laughs, but I've read of some scenarios that Apollo 11 did train for just in case as NASA truly didn't know for certain what was gonna happen when the LM touched down...

FFrench
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posted 11-19-2011 07:10 PM     Click Here to See the Profile for FFrench     Edit/Delete Message   Reply w/Quote
The meeting-aliens-gold-visor story is one that appears in the "First on the Moon" book published not long after Apollo 11, where it was presented as a clearly tongue-in-cheek remark.

It sadly regained new attention around the 40th anniversary when another author "borrowed" the anecdote but apparently failed to understand the context, and thus presented the story straight. This may be partly what you are recalling.

p51
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posted 11-19-2011 09:15 PM     Click Here to See the Profile for p51   Click Here to Email p51     Edit/Delete Message   Reply w/Quote
No, this would have been in the mid 80s. I have no problem accepting it was a story to see how gullible the people you were talking with if you worked for NASA (God knows I've pulled some stories like this on civilians for lots of the stuff I worked with in the Army). But it sure wasn't from a book, I heard this in person over 30 years ago...

FFrench
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posted 11-19-2011 09:24 PM     Click Here to See the Profile for FFrench     Edit/Delete Message   Reply w/Quote
Interesting - thanks.

dbaker
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posted 11-30-2011 04:11 AM     Click Here to See the Profile for dbaker   Click Here to Email dbaker     Edit/Delete Message   Reply w/Quote
The idea to use gold coating to protect from certain UV frequencies came from the protective visors for aircrew on nuclear delivery ops. Without protection they would have been blinded from the flash and burned by UV rad.

The same company that did those helmets for the military produced the gold coatings for Apollo.

Useful to bear in mind that the moon mission requirements were unique, the space environment is very different the other side of the magnetosphere.

ilbasso
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posted 11-30-2011 11:23 AM     Click Here to See the Profile for ilbasso   Click Here to Email ilbasso     Edit/Delete Message   Reply w/Quote
There's a brief shot in "Magnificent Desolation: Walking on the Moon in 3D" which lets you see and hear what it was like inside the helmet during lunar EVA.

schnappsicle
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posted 01-19-2012 07:01 AM     Click Here to See the Profile for schnappsicle   Click Here to Email schnappsicle     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by LM-12:
Wearing those bulky pressure suits, LEVA helmets and chest-mounted cameras, could the moonwalking astronauts even see what was underfoot?
The answer is obviously no. On Apollo 11 Armstrong caught his foot on the TV cable which almost pulled the camera over. (Complete details can be found on the Apollo Lunar Surface Journal transcript at the 110:22:51 mark. A few seconds later, Armstrong adds the comment "You really can't see your feet.")

That became evident on Apollo 16 when John Young pulled out the cable from the Heat Flow experiment, rendering it useless.

There were also numerous times when astronauts were hopping around on the moon and their foot hit a rock and they would fall face down. Getting up from that position is hilarious to watch. They basically did a pushup which put them on their knees. After that it was a simple matter of hopping back up on their feet.

LM-12
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posted 02-12-2019 11:38 PM     Click Here to See the Profile for LM-12     Edit/Delete Message   Reply w/Quote
The Apollo 11 crew portrait photo S69-31740 includes the LEVA helmets. The outer visors are down, but you can see through them.

Rick Mulheirn
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posted 02-13-2019 04:22 AM     Click Here to See the Profile for Rick Mulheirn   Click Here to Email Rick Mulheirn     Edit/Delete Message   Reply w/Quote
That looks like the inner UV visor: whatever the arrangement that is not the outer visor which is mirror like.

LM-12
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posted 02-13-2019 05:39 AM     Click Here to See the Profile for LM-12     Edit/Delete Message   Reply w/Quote
Each LEVA in the photo shows two sets of tabs in the down position, indicating two visors down. Like in this Apollo 11 onboard clip.

Perhaps the photo shows what the outer visor looks like without a gold film.

Space Cadet Carl
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posted 02-13-2019 09:45 AM     Click Here to See the Profile for Space Cadet Carl   Click Here to Email Space Cadet Carl     Edit/Delete Message   Reply w/Quote
I remember Jack Schmitt in particular wanted to raise his gold visor many times to see rock and soil colors more accurately. He did it so often that Mission Control caught him a couple of times doing it in front of the television camera and they told him to put his visor back down. There's a great video clip of Jack smiling away as the rover TV camera zoomed in toward him in the distance, visor up.

NavyPilot
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posted 02-13-2019 03:32 PM     Click Here to See the Profile for NavyPilot     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by SpaceAholic:
The transmittance of the total visor assembly was 10 percent in the visible range (.39 to .75 microns) and one percent in the UV range (.25 to .39 microns). The total transmittance' in the IR range was 5 percent (.75 to 2.5 microns).
Curious if those values are spec or measured?

oly
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posted 02-13-2019 07:18 PM     Click Here to See the Profile for oly   Click Here to Email oly     Edit/Delete Message   Reply w/Quote
Most modern commercial and military large aircraft have a thin gold layer laminated between transparencies, used as a heating element to prevent windshield ice formation and fogging. The gold colour does not disrupt visibility or noticeably change the colours of the outside world.

The human eye and brain are an amazing creation that adapts well to a wide dynamic range. The colour shift that we can experience while wearing sunglasses with tinted lenses is something that the brain can acclimatise to easily, and we can use some specific lens tint/treatments to our advantage.

I believe that Jack Schmitt, being a trained and experienced geologist, was particularly inclined to want to view rock samples and scenes is direct sunlight, without the additional visors, in the same way people raise their sunglasses to examine fine detail. It can sometimes be habit.

Schmitt has also stated that the desire to use your breath to blow dust from rock samples was a habit hard to overcome.

quote:
Originally posted by LM-12:
Perhaps the photo shows what the outer visor looks like without a gold film.
There is also the possibility that these are training LEVAs and do not have the gold visor fitted.

David C
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posted 02-20-2019 08:19 AM     Click Here to See the Profile for David C     Edit/Delete Message   Reply w/Quote
There's also quite a bit of Apollo 11 EVA DAC footage where Armstrong clearly has his gold visor raised.

LM-12
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posted 02-20-2019 09:17 AM     Click Here to See the Profile for LM-12     Edit/Delete Message   Reply w/Quote
Gene Cernan raises his visor at 142:48:34 on EVA-2. He is at the rover, and you can see him speaking.

All times are CT (US)

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