Author Topic: Photo Anomalies  (Read 41906 times)

Offline JayUtah

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Re: Photo Anomalies
« Reply #15 on: August 03, 2015, 12:34:09 PM »
On the upper right is the Ascent Stage, where the crew rides.  Notice that the pressurized compartment is supported by closely-space aluminum ribs.

Actually those are what aircraft makers call stringers.  "Skin-and-stringer" construction is a common technique, similar to what corrugated cardboard tries to achieve.  What made the LM special is Grumman's technique for chemically milling those panels out of a solid aluminum billet in such a way that the skin and stringers were the same piece of metal.  In normal aircraft construction the stringers are glued, welded, or riveted to the skins.  Grumman used mechanical milling processes to create the three-dimensional skin-and-stringer panels down to the thicknesses were metal bits would no longer be safe to apply.  Then they were placed in chemical baths that ate away more of the metal, according to a precise rate, until the appropriate thicknesses of skins and stringers had been achieved.  Then those panels were welded together at the edges to form the pressure hull.

Similar methods were used to create the isogrids for the two major bulkheads inside the LM structure.
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Offline bknight

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Re: Photo Anomalies
« Reply #16 on: August 03, 2015, 12:43:53 PM »
On the upper right is the Ascent Stage, where the crew rides.  Notice that the pressurized compartment is supported by closely-space aluminum ribs.

Actually those are what aircraft makers call stringers.  "Skin-and-stringer" construction is a common technique, similar to what corrugated cardboard tries to achieve.  What made the LM special is Grumman's technique for chemically milling those panels out of a solid aluminum billet in such a way that the skin and stringers were the same piece of metal.  In normal aircraft construction the stringers are glued, welded, or riveted to the skins.  Grumman used mechanical milling processes to create the three-dimensional skin-and-stringer panels down to the thicknesses were metal bits would no longer be safe to apply.  Then they were placed in chemical baths that ate away more of the metal, according to a precise rate, until the appropriate thicknesses of skins and stringers had been achieved.  Then those panels were welded together at the edges to form the pressure hull.

Similar methods were used to create the isogrids for the two major bulkheads inside the LM structure.
It seems like the manufacturing process reduced the number of welds use to construct, thereby reducing possible leak points that would have possibly been disastrous.  Very clever of those group of engineers.
Truth needs no defense.  Nobody can take those footsteps I made on the surface of the moon away from me.
Eugene Cernan

Offline Zakalwe

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Re: Photo Anomalies
« Reply #17 on: August 03, 2015, 12:59:12 PM »
It seems like the manufacturing process reduced the number of welds use to construct, thereby reducing possible leak points that would have possibly been disastrous.  Very clever of those group of engineers.

It was more to do with reducing the mass of the LM.  The initial LMs were overweight and NASA introduced a bonus system that would pay $25,000 for every pound of weight shaved off. Operation Scrape was put in place which literally lead to individual bolts being pared down. Chemically etching the parts allowed for very precise control of the thickness of each part. They even went so far as to eliminate a varnish coat that protected the panels from Earths atmosphere.

The Mylar blankets replaced the original rigid thermal shields. They also made an effective Whipple shield
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Offline Abaddon

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Re: Photo Anomalies
« Reply #18 on: August 03, 2015, 01:14:08 PM »
It seems like the manufacturing process reduced the number of welds use to construct, thereby reducing possible leak points that would have possibly been disastrous.  Very clever of those group of engineers.

It was more to do with reducing the mass of the LM.  The initial LMs were overweight and NASA introduced a bonus system that would pay $25,000 for every pound of weight shaved off. Operation Scrape was put in place which literally lead to individual bolts being pared down. Chemically etching the parts allowed for very precise control of the thickness of each part. They even went so far as to eliminate a varnish coat that protected the panels from Earths atmosphere.

The Mylar blankets replaced the original rigid thermal shields. They also made an effective Whipple shield
The SWIP team cut over 1,000 kilos from the overall LM weight. The substitution of Mylar was one of their ideas.

Offline bknight

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Re: Photo Anomalies
« Reply #19 on: August 03, 2015, 01:15:33 PM »
It seems like the manufacturing process reduced the number of welds use to construct, thereby reducing possible leak points that would have possibly been disastrous.  Very clever of those group of engineers.

It was more to do with reducing the mass of the LM.  The initial LMs were overweight and NASA introduced a bonus system that would pay $25,000 for every pound of weight shaved off. Operation Scrape was put in place which literally lead to individual bolts being pared down. Chemically etching the parts allowed for very precise control of the thickness of each part. They even went so far as to eliminate a varnish coat that protected the panels from Earths atmosphere.

The Mylar blankets replaced the original rigid thermal shields. They also made an effective Whipple shield
Ok that was one of the unspecified weight problems that caused the delay of deleivery.
Truth needs no defense.  Nobody can take those footsteps I made on the surface of the moon away from me.
Eugene Cernan

Offline ka9q

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Re: Photo Anomalies
« Reply #20 on: August 03, 2015, 01:33:15 PM »
Because it is foil, specifically aluminised mylar.
It's actually aluminized Kapton, not Mylar. Kapton is yellow or orange, depending on thickness, while Mylar is grey. Kapton tolerates wider temperatures, so it is generally preferred for external thermal coverings. Mylar is used inside (e.g., below the micrometeoroid shields covering the ascent stage) where the temperatures aren't as extreme.

Offline Abaddon

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Re: Photo Anomalies
« Reply #21 on: August 03, 2015, 01:39:53 PM »
Because it is foil, specifically aluminised mylar.
It's actually aluminized Kapton, not Mylar. Kapton is yellow or orange, depending on thickness, while Mylar is grey. Kapton tolerates wider temperatures, so it is generally preferred for external thermal coverings. Mylar is used inside (e.g., below the micrometeoroid shields covering the ascent stage) where the temperatures aren't as extreme.

Well, pobodies nerfect.

Offline JayUtah

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Re: Photo Anomalies
« Reply #22 on: August 03, 2015, 02:18:58 PM »
Kapton is also a non-Kerchoff material.  It radiates heat more favorably than its absorption properties suggest.
"Facts are stubborn things." --John Adams

Offline Abaddon

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Re: Photo Anomalies
« Reply #23 on: August 03, 2015, 02:59:03 PM »
Out of sheer curiousity I checked out Kapton. Stable range is −269 to +400 °C. Holy cow, that approaching absolute zero.

Offline bknight

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Re: Photo Anomalies
« Reply #24 on: August 03, 2015, 03:12:24 PM »
Out of sheer curiousity I checked out Kapton. Stable range is −269 to +400 °C. Holy cow, that approaching absolute zero.

And you probably won't find it on the local grocery store aisle either, for the construction project of course.
Truth needs no defense.  Nobody can take those footsteps I made on the surface of the moon away from me.
Eugene Cernan

Offline Glom

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Re: Photo Anomalies
« Reply #25 on: August 03, 2015, 03:40:31 PM »
On the upper right is the Ascent Stage, where the crew rides.  Notice that the pressurized compartment is supported by closely-space aluminum ribs.

Actually those are what aircraft makers call stringers.  "Skin-and-stringer" construction is a common technique, similar to what corrugated cardboard tries to achieve.  What made the LM special is Grumman's technique for chemically milling those panels out of a solid aluminum billet in such a way that the skin and stringers were the same piece of metal.  In normal aircraft construction the stringers are glued, welded, or riveted to the skins.  Grumman used mechanical milling processes to create the three-dimensional skin-and-stringer panels down to the thicknesses were metal bits would no longer be safe to apply.  Then they were placed in chemical baths that ate away more of the metal, according to a precise rate, until the appropriate thicknesses of skins and stringers had been achieved.  Then those panels were welded together at the edges to form the pressure hull.

Similar methods were used to create the isogrids for the two major bulkheads inside the LM structure.
Noting all this down as part of pre-read for my course.

Offline ineluki

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Re: Photo Anomalies
« Reply #26 on: August 04, 2015, 08:12:46 AM »
They built it that way, because it didn't have to look "aerodynamic" since it was operated in a nearly void atmosphere with low gravity.

I understand that... but I believe you misunderstood my question.

Even if NASA had intended to fake the landings (which no reasonable person should believe anymore) , they would still have to construct and build a convincing LM - unless the Hoax was directed by Ed Wood instead of Kubrick :-)






Offline bknight

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Re: Photo Anomalies
« Reply #27 on: August 04, 2015, 08:28:54 AM »
They built it that way, because it didn't have to look "aerodynamic" since it was operated in a nearly void atmosphere with low gravity.

I understand that... but I believe you misunderstood my question.

Even if NASA had intended to fake the landings (which no reasonable person should believe anymore) , they would still have to construct and build a convincing LM - unless the Hoax was directed by Ed Wood instead of Kubrick :-)
I understand your question, look at the comments that followed the quoted part.
Quote
Looks can be deceptive all it "had to do" was land, take off and rendezvous/dock.  Why would NASA have any thoughts at what a group of people perceived to their very successful vehicle.
Perhaps I didn't state my thoughts correctly.  Why would NASA build any vehicle so that someone in the future would perceive it as being "correctly built".  The LM as many of the posts indicate, the construction had the major criterion of weight.  Any process that could accomplish this end was acceptable, with the provision that is would work of course.  It seems informative to view what the Russian lander (LK) looked like.  I can't find an actual picture this morning, but WIKI has a reasonable image.
https://en.wikipedia.org/wiki/LK_(spacecraft)
Looks very similar to the LM, doesn't it?  The Russians had the same problems with weight and therefore built a "non-aerodynamic" just like we did.
Truth needs no defense.  Nobody can take those footsteps I made on the surface of the moon away from me.
Eugene Cernan

Offline ineluki

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Re: Photo Anomalies
« Reply #28 on: August 04, 2015, 12:03:05 PM »
Perhaps I didn't state my thoughts correctly. 

It seems we are still talking about different issues...  Reality on your side and the missing "real" common sense and logic in a hypothetical (and obviously BS) Hoaxscenario on my side.





Offline bknight

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Re: Photo Anomalies
« Reply #29 on: August 04, 2015, 12:17:43 PM »
There have been many misguided allegations concerning the LM, all debunked as you have indicated.  Again all I may say is that NASA didn't/doesn't care what a HB might believe about the construction/appearance of the LM.  All they wished is it was within weight limits and it performed the required task.
Truth needs no defense.  Nobody can take those footsteps I made on the surface of the moon away from me.
Eugene Cernan