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Are there photos of the Apollo LM showing disturbed lunar soil resulting from descent engine exhaust?

Why didn't the Apollo 11 lander blow the dust away? (or why does it look like it didn't)Where is the first Lunar soil sample currently located?Why didn't Apollo land on the Lunar poles?What is the procedure to stop the descent engine on the Apollo 11 LEM?Nozzle material of Apollo Lunar Module ascent engine?Did the Apollo lunar module descent stage have a role as a sort of service module?How different was the Apollo LM descent trajectory from the most fuel-efficient?How much did we know about lunar soil conditions prior to Apollo 11?Was there fuel consumption budgeting for Apollo 11 Lunar module?Why could the Lunar Ascent Engine be used only once?

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Are there any photos of the Apollo LM descent engine bell and the lunar soil beneath it disturbed by the engine exhaust?

apollo-program lunar-landing lunar-module

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asked 10 hours ago

UweUwe

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$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  hq.nasa.gov/alsj/a11/AS11-40-5921.jpg
  $endgroup$
  – JCRM
  9 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  see also space.stackexchange.com/questions/1691/…
  $endgroup$
  – JCRM
  8 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  Would you accept video of the dust being disturbed? ->Apollo 11 landing showed this.
  $endgroup$
  – Hobbes
  7 hours ago
  

  
  
  
  

add a comment | 

2

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Are there any photos of the Apollo LM descent engine bell and the lunar soil beneath it disturbed by the engine exhaust?

apollo-program lunar-landing lunar-module

share|improve this question

asked 10 hours ago

UweUwe

15.3k33 gold badges4141 silver badges6969 bronze badges

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  hq.nasa.gov/alsj/a11/AS11-40-5921.jpg
  $endgroup$
  – JCRM
  9 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  see also space.stackexchange.com/questions/1691/…
  $endgroup$
  – JCRM
  8 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  Would you accept video of the dust being disturbed? ->Apollo 11 landing showed this.
  $endgroup$
  – Hobbes
  7 hours ago
  

  
  
  
  

add a comment | 

$begingroup$

Are there any photos of the Apollo LM descent engine bell and the lunar soil beneath it disturbed by the engine exhaust?

apollo-program lunar-landing lunar-module

share|improve this question

asked 10 hours ago

UweUwe

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$endgroup$

share|improve this question

asked 10 hours ago

UweUwe

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share|improve this question

asked 10 hours ago

UweUwe

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asked 10 hours ago

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asked 10 hours ago

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2 Answers
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Most of the Apollo photo libraries have a few shots of the surface under the descent engine bell; I think A14 has some interesting ones:

The disturbance of the soil is very subtle; compared with the surface further out, I see more 1-2cm-sized pebbles, suggesting that smaller particles have been blown away from under the engine.

The lack of a massive blast crater under the LM engine is often pointed to as evidence of a hoax, but there are several factors involved, which are not obvious or not intuitive, which minimize the effect of the engine exhaust:

1. At touchdown, the engine is running at only about 25% throttle (~2500 lb-f or 11kN), as the descent fuel tanks are nearly empty, making the LM fairly light;


2. The area at the end of the engine bell is about half that of the four LM footpads, so pressure at that point while hovering should be about twice as much as the ground pressure of the footpads with the LM on the surface, which of course displace only a few cm of soil;


3. The LM engine is normally shut off while the footpads are still a meter or so above the surface (the contact probes extend about 1.6m below the footpads, but it takes a moment for the crew to react to the contact light) so the exhaust has quite a distance to disperse before reaching the surface soil. (On Apollo 14, however, per the annotated transcript at 108:15:12, Al Shepard left the engine firing all the way to the surface and for a couple of seconds after touchdown, so this doesn't apply to the above picture.)

share|improve this answer

edited 8 hours ago

answered 9 hours ago

Russell BorogoveRussell Borogove

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There is a very nice Apollo 14 image:

Erik van Meijgaarden has combined 9254 and 9255 as a 4 o'clock
portrait of the LM.

From the Apollo 14 lunar surface journal, see.

share|improve this answer

answered 8 hours ago

UweUwe

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4

$begingroup$

Most of the Apollo photo libraries have a few shots of the surface under the descent engine bell; I think A14 has some interesting ones:

The disturbance of the soil is very subtle; compared with the surface further out, I see more 1-2cm-sized pebbles, suggesting that smaller particles have been blown away from under the engine.

The lack of a massive blast crater under the LM engine is often pointed to as evidence of a hoax, but there are several factors involved, which are not obvious or not intuitive, which minimize the effect of the engine exhaust:

1. At touchdown, the engine is running at only about 25% throttle (~2500 lb-f or 11kN), as the descent fuel tanks are nearly empty, making the LM fairly light;


2. The area at the end of the engine bell is about half that of the four LM footpads, so pressure at that point while hovering should be about twice as much as the ground pressure of the footpads with the LM on the surface, which of course displace only a few cm of soil;


3. The LM engine is normally shut off while the footpads are still a meter or so above the surface (the contact probes extend about 1.6m below the footpads, but it takes a moment for the crew to react to the contact light) so the exhaust has quite a distance to disperse before reaching the surface soil. (On Apollo 14, however, per the annotated transcript at 108:15:12, Al Shepard left the engine firing all the way to the surface and for a couple of seconds after touchdown, so this doesn't apply to the above picture.)

share|improve this answer

edited 8 hours ago

answered 9 hours ago

Russell BorogoveRussell Borogove

103k44 gold badges365365 silver badges447447 bronze badges

$endgroup$

add a comment | 

4

$begingroup$

Most of the Apollo photo libraries have a few shots of the surface under the descent engine bell; I think A14 has some interesting ones:

The disturbance of the soil is very subtle; compared with the surface further out, I see more 1-2cm-sized pebbles, suggesting that smaller particles have been blown away from under the engine.

The lack of a massive blast crater under the LM engine is often pointed to as evidence of a hoax, but there are several factors involved, which are not obvious or not intuitive, which minimize the effect of the engine exhaust:

1. At touchdown, the engine is running at only about 25% throttle (~2500 lb-f or 11kN), as the descent fuel tanks are nearly empty, making the LM fairly light;


2. The area at the end of the engine bell is about half that of the four LM footpads, so pressure at that point while hovering should be about twice as much as the ground pressure of the footpads with the LM on the surface, which of course displace only a few cm of soil;


3. The LM engine is normally shut off while the footpads are still a meter or so above the surface (the contact probes extend about 1.6m below the footpads, but it takes a moment for the crew to react to the contact light) so the exhaust has quite a distance to disperse before reaching the surface soil. (On Apollo 14, however, per the annotated transcript at 108:15:12, Al Shepard left the engine firing all the way to the surface and for a couple of seconds after touchdown, so this doesn't apply to the above picture.)

share|improve this answer

edited 8 hours ago

answered 9 hours ago

Russell BorogoveRussell Borogove

103k44 gold badges365365 silver badges447447 bronze badges

$endgroup$

add a comment | 

$begingroup$

Most of the Apollo photo libraries have a few shots of the surface under the descent engine bell; I think A14 has some interesting ones:

The disturbance of the soil is very subtle; compared with the surface further out, I see more 1-2cm-sized pebbles, suggesting that smaller particles have been blown away from under the engine.

The lack of a massive blast crater under the LM engine is often pointed to as evidence of a hoax, but there are several factors involved, which are not obvious or not intuitive, which minimize the effect of the engine exhaust:

1. At touchdown, the engine is running at only about 25% throttle (~2500 lb-f or 11kN), as the descent fuel tanks are nearly empty, making the LM fairly light;


2. The area at the end of the engine bell is about half that of the four LM footpads, so pressure at that point while hovering should be about twice as much as the ground pressure of the footpads with the LM on the surface, which of course displace only a few cm of soil;


3. The LM engine is normally shut off while the footpads are still a meter or so above the surface (the contact probes extend about 1.6m below the footpads, but it takes a moment for the crew to react to the contact light) so the exhaust has quite a distance to disperse before reaching the surface soil. (On Apollo 14, however, per the annotated transcript at 108:15:12, Al Shepard left the engine firing all the way to the surface and for a couple of seconds after touchdown, so this doesn't apply to the above picture.)

share|improve this answer

edited 8 hours ago

answered 9 hours ago

Russell BorogoveRussell Borogove

103k44 gold badges365365 silver badges447447 bronze badges

$endgroup$

share|improve this answer

edited 8 hours ago

answered 9 hours ago

Russell BorogoveRussell Borogove

103k44 gold badges365365 silver badges447447 bronze badges

answered 9 hours ago

Russell BorogoveRussell Borogove

103k44 gold badges365365 silver badges447447 bronze badges

answered 9 hours ago

Russell BorogoveRussell Borogove

103k44 gold badges365365 silver badges447447 bronze badges

4

$begingroup$

There is a very nice Apollo 14 image:

Erik van Meijgaarden has combined 9254 and 9255 as a 4 o'clock
portrait of the LM.

From the Apollo 14 lunar surface journal, see.

share|improve this answer

answered 8 hours ago

UweUwe

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$endgroup$

add a comment | 

4

$begingroup$

There is a very nice Apollo 14 image:

Erik van Meijgaarden has combined 9254 and 9255 as a 4 o'clock
portrait of the LM.

From the Apollo 14 lunar surface journal, see.

share|improve this answer

answered 8 hours ago

UweUwe

15.3k33 gold badges4141 silver badges6969 bronze badges

$endgroup$

add a comment | 

$begingroup$

There is a very nice Apollo 14 image:

Erik van Meijgaarden has combined 9254 and 9255 as a 4 o'clock
portrait of the LM.

From the Apollo 14 lunar surface journal, see.

share|improve this answer

answered 8 hours ago

UweUwe

15.3k33 gold badges4141 silver badges6969 bronze badges

$endgroup$

share|improve this answer

answered 8 hours ago

UweUwe

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answered 8 hours ago

UweUwe

15.3k33 gold badges4141 silver badges6969 bronze badges

answered 8 hours ago

UweUwe

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