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Author
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Topic: The view through the Apollo LEVA visor
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LM-12
Member Posts: 3324
From: Ontario, Canada
Registered: Oct 2010
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posted 10-05-2011 02:18 PM
  
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
Member Posts: 4208
From: England
Registered: Feb 2001
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posted 10-05-2011 06:05 PM
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
Member Posts: 3324
From: Ontario, Canada
Registered: Oct 2010
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posted 10-05-2011 06:48 PM
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
Member Posts: 1610
From: New York
Registered: Nov 2000
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posted 10-05-2011 07:14 PM
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
Member Posts: 3324
From: Ontario, Canada
Registered: Oct 2010
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posted 10-05-2011 07:33 PM
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
Member Posts: 994
From: Albuquerque, NM
Registered: Nov 2000
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posted 10-05-2011 08:28 PM
We can speculate all we want, a moonwalker's opinion is needed here! |
MCroft04
Member Posts: 1647
From: Smithfield, Me, USA
Registered: Mar 2005
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posted 10-05-2011 09:12 PM
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
Member Posts: 3324
From: Ontario, Canada
Registered: Oct 2010
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posted 10-06-2011 11:01 AM
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
Member Posts: 3307
From: Houston, TX
Registered: May 2001
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posted 10-06-2011 11:35 AM
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
Member Posts: 4494
From: Sierra Vista, Arizona
Registered: Nov 1999
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posted 10-06-2011 11:46 AM
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
Member Posts: 3324
From: Ontario, Canada
Registered: Oct 2010
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posted 10-06-2011 12:27 PM
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
Member Posts: 178
From: USA
Registered: Nov 2010
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posted 10-06-2011 10:34 PM
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
Member Posts: 3324
From: Ontario, Canada
Registered: Oct 2010
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posted 11-19-2011 03:05 PM
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
Member Posts: 1658
From: Olympia, WA
Registered: Sep 2011
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posted 11-19-2011 06:38 PM
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
Member Posts: 3165
From: San Diego
Registered: Feb 2002
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posted 11-19-2011 07:10 PM
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
Member Posts: 1658
From: Olympia, WA
Registered: Sep 2011
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posted 11-19-2011 09:15 PM
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
Member Posts: 3165
From: San Diego
Registered: Feb 2002
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posted 11-19-2011 09:24 PM
Interesting - thanks. |
dbaker
Member Posts: 22
From: UK
Registered: Jun 2010
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posted 11-30-2011 04:11 AM
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
Member Posts: 1522
From: Greensboro, NC USA
Registered: Feb 2006
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posted 11-30-2011 11:23 AM
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
Member Posts: 396
From: Houston, TX, USA
Registered: Jan 2012
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posted 01-19-2012 07:01 AM
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
Member Posts: 3324
From: Ontario, Canada
Registered: Oct 2010
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posted 02-12-2019 11:38 PM
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
Member Posts: 4208
From: England
Registered: Feb 2001
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posted 02-13-2019 04:22 AM
That looks like the inner UV visor: whatever the arrangement that is not the outer visor which is mirror like. |
LM-12
Member Posts: 3324
From: Ontario, Canada
Registered: Oct 2010
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posted 02-13-2019 05:39 AM
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
Member Posts: 225
From: Lake Orion, Michigan
Registered: Feb 2006
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posted 02-13-2019 09:45 AM
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
Member Posts: 36
From:
Registered: Nov 2015
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posted 02-13-2019 03:32 PM
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
Member Posts: 971
From: Perth, Western Australia
Registered: Apr 2015
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posted 02-13-2019 07:18 PM
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
Member Posts: 1039
From: Lausanne
Registered: Apr 2012
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posted 02-20-2019 08:19 AM
There's also quite a bit of Apollo 11 EVA DAC footage where Armstrong clearly has his gold visor raised. |
LM-12
Member Posts: 3324
From: Ontario, Canada
Registered: Oct 2010
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posted 02-20-2019 09:17 AM
Gene Cernan raises his visor at 142:48:34 on EVA-2. He is at the rover, and you can see him speaking. |
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