Author Topic: Apollo 11 Lunar Lander Pre-Launch  (Read 122734 times)

Offline Jason Thompson

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Re: Apollo 11 Lunar Lander Pre-Launch
« Reply #225 on: December 18, 2018, 04:51:56 PM »
It's like Cooper writing up a service memo for how to take home one's newly-purchased armchair in a Mini.

Mr Bean has that one covered....

"There's this idea that everyone's opinion is equally valid. My arse! Bloke who was a professor of dentistry for forty years does NOT have a debate with some eejit who removes his teeth with string and a door!"  - Dara O'Briain

Offline Zakalwe

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Re: Apollo 11 Lunar Lander Pre-Launch
« Reply #226 on: December 18, 2018, 05:12:10 PM »
the author specifies this to apply only to the CSM-docked flight using the LM autopilot.

I was about to make that very point.

Where in the missions was the CSM/LM stack controlled by the LM RCS? Was it only in the case of an emergency (such as A13)? IIRC, the CSM guidance system had no control over the LM RCS and vice-versa or am I barking up completely the wrong tree here?
I'm pretty sure that the LM DAP could be operated in three modes- CSM+Ascent stage, Ascent+Descent stages stacked and Ascent stage only.
« Last Edit: December 18, 2018, 05:18:48 PM by Zakalwe »
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Offline JayUtah

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Re: Apollo 11 Lunar Lander Pre-Launch
« Reply #227 on: December 18, 2018, 05:31:47 PM »
Where in the missions was the CSM/LM stack controlled by the LM RCS?

Never, in the nominal flight plan.  It was a contingency flight mode for unaccelerated flight (i.e., cruise/drift).  You can use the LM RCS to control the whole stack, but the c.g. in that configuration is so far off the design assumptions for the LM DAP that the impingement moment on the plume deflector has a much more significant moment arm.  With either the DPS or SPS working, the moment is apparently second-order.  So you'd only consider flight in this mode when you need to use the DAP to reach a precise attitude with the whole docked stack, such as to align antennas or to set up a separation maneuver.  This would be like Appendix Q of any typical Apollo flight plan.

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I'm pretty sure that the LM DAP could be operated in three modes- CSM+Ascent stage, Ascent+Descent stages stacked and Ascent stage only.

If you trace the effects of the memo in question, you find that it was preliminary work for J-type missions using Luminary 3.  The version of the software in LM-5 contained no provision for controlling the whole stack with the LM PGNS or AGS.  This was something being considered only for Apollo 16 or 17, as an available backup flight mode.  And, as you can expect, it wasn't expected to be very useful.  Just survivable.  The points made in the memo were included as two out of 13 "release notes" items for operating the LM DAP in the CSM-docked configuration.  One note was that a certain thruster had to be disabled on the LM if the c.g. was very much in the CM or SM.  This would be a scenario where the SM fuel load was high and the LM DPS fuel load was low, the specific "mass loadings" referred to in the original memo.  The other note was that if one +X thruster was out, and the c.g. was in the CM, then the pilot had to manually disable the other +X thruster in order to keep the DAP out of a positive feedback loop.  Thus configured, the DAP in Luminary 3 was expected to be able to control the whole stack with the LM RCS.
"Facts are stubborn things." --John Adams

Offline Zakalwe

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Re: Apollo 11 Lunar Lander Pre-Launch
« Reply #228 on: December 18, 2018, 05:41:21 PM »
Great reply, thank you.

it's this that keeps me coming back to this place after all these years. No matter how ridiculous the hoaxie claim, the conversation usually branches off into something really interesting. There's always something new to learn.
"The strain of anti-intellectualism has been a constant thread winding its way through our political and cultural life, nurtured by the false notion that democracy means that 'my ignorance is just as good as your knowledge.' " - Isaac Asimov

Offline JayUtah

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Re: Apollo 11 Lunar Lander Pre-Launch
« Reply #229 on: December 18, 2018, 05:55:53 PM »
No matter how ridiculous the hoaxie claim, the conversation usually branches off into something really interesting. There's always something new to learn.

The sheer volume of the materials available in the Apollo record implies several things.  First, no person is likely to know it all.  That makes it a fun group effort.  Second, it's really hard to maintain a hoax where the cover story has been so correctly and meticulously documented.  And third, because so much was documented, it's easy for unscrupulous people to imply ludicrous things like mass starvation from a memo as innocuous as asking to have the vending machine refilled.  "I've seen a memo that says they were running out of food..."
"Facts are stubborn things." --John Adams

Offline Allan F

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Re: Apollo 11 Lunar Lander Pre-Launch
« Reply #230 on: December 18, 2018, 06:17:34 PM »
JK - can you tell us how you found that memo? Or did someone find it for you?
Well, it is like this: The truth doesn't need insults. Insults are the refuge of a darkened mind, a mind that refuses to open and see. Foul language can't outcompete knowledge. And knowledge is the result of education. Education is the result of the wish to know more, not less.

Offline jr Knowing

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Re: Apollo 11 Lunar Lander Pre-Launch
« Reply #231 on: December 18, 2018, 07:16:27 PM »
Hi Allan F,

I have done my research. I know you guys like to think others have no idea about things. The fact is I am the only person who has provided any documentation regarding the workings of the deflectors.

I find it comical on how everyone has twisted this MIT paper to mean nothing. And to suggest that these conclusions have no bearing to the LM flying solo (detached from the CSM). If anything, it is even more problematic for the LM operating solo. Atleast the CSM-LM had the ability of disabling the LM RCS’s if there is a failure or mismatch power issue ( ie one RCS operating at 50 percent of the opposite RCS) and rely on the CSM RCS’s. (That is what happen with Apollo 13, I have the report) But with the LM operating alone there is no backup if there is a failure or mismatch of power between two opposite thrusters and that will result in serious stability issues. And another MIT paper (which I will dig up) not only confirms this but it also asserts for the LM to remain stable the craft must be equally balanced to ensure the plumes don’t create an uncontrollable craft. It was concluded that the LM with deflectors could only maintain stability under optimum specific conditions. I would say the LM missions were very fortunate. Just the fact they had no RCS backups, let alone the deflector issue, it sure seems luck was on their side.

Offline JayUtah

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Re: Apollo 11 Lunar Lander Pre-Launch
« Reply #232 on: December 18, 2018, 08:08:57 PM »
The fact is I am the only person who has provided any documentation regarding the workings of the deflectors.

You dredged up a memo where it was mentioned in connection with an unlikely scenario and pretended it was something it clearly isn't.  I gave you a complete and correct analysis of the plume deflectors and their stability effects days ago, which you simply discarded.

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I find it comical on how everyone has twisted this MIT paper to mean nothing.

You blatantly misrepresented the memo.

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And to suggest that these conclusions have no bearing to the LM flying solo (detached from the CSM).

Because they don't.  If you had actually understood the memo, you would have seen that the entire scenario rests on the vehicle center of mass being highly eccentric.  This cannot be the case with the LM flying alone.

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If anything, it is even more problematic for the LM operating solo.

No, you don't know what you're talking about.  And you specifically edited away the qualifying statements from your quotes, where your source contradicts what you're now trying to make of it.  You specifically tried to make the statements seem more general than they plainly were.  Hence you are even more egregiously dishonest than I originally believed.

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But with the LM operating alone there is no backup if there is a failure or mismatch of power between two opposite thrusters and that will result in serious stability issues.

No.  I covered this at length earlier.  You entirely ignored it, and I suspect you still don't understand it.

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Just the fact they had no RCS backups, let alone the deflector issue, it sure seems luck was on their side.

No, I covered at length the issue of "backups," and you did not respond.  Now you're just repeating already-debunked nonsense and trying to insist that we accept your willful ignorance as if it's some kind of authority.
"Facts are stubborn things." --John Adams

Offline nomuse

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Re: Apollo 11 Lunar Lander Pre-Launch
« Reply #233 on: December 18, 2018, 08:10:34 PM »
Oh, that's explained in another "paper."

Why am I thinking of the scene in A Day at the Races when Groucho tries to buy a hot tip from Chico's racetrack tout and ends up with a cartload of books?

Offline JayUtah

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Re: Apollo 11 Lunar Lander Pre-Launch
« Reply #234 on: December 18, 2018, 08:31:30 PM »
Oh, that's explained in another "paper."

What did you expect from someone who's evidently incapable of admitting error.
"Facts are stubborn things." --John Adams

Offline Allan F

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Re: Apollo 11 Lunar Lander Pre-Launch
« Reply #235 on: December 18, 2018, 10:21:37 PM »
JK - please describe the PROCESS, which led you to find this memo. Can you do that?
Well, it is like this: The truth doesn't need insults. Insults are the refuge of a darkened mind, a mind that refuses to open and see. Foul language can't outcompete knowledge. And knowledge is the result of education. Education is the result of the wish to know more, not less.

Offline bknight

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Re: Apollo 11 Lunar Lander Pre-Launch
« Reply #236 on: December 18, 2018, 10:34:02 PM »
Hi Allan F,

I have done my research. I know you guys like to think others have no idea about things. The fact is I am the only person who has provided any documentation regarding the workings of the deflectors.

I find it comical on how everyone has twisted this MIT paper to mean nothing. And to suggest that these conclusions have no bearing to the LM flying solo (detached from the CSM). If anything, it is even more problematic for the LM operating solo. Atleast the CSM-LM had the ability of disabling the LM RCS’s if there is a failure or mismatch power issue ( ie one RCS operating at 50 percent of the opposite RCS) and rely on the CSM RCS’s. (That is what happen with Apollo 13, I have the report) But with the LM operating alone there is no backup if there is a failure or mismatch of power between two opposite thrusters and that will result in serious stability issues. And another MIT paper (which I will dig up) not only confirms this but it also asserts for the LM to remain stable the craft must be equally balanced to ensure the plumes don’t create an uncontrollable craft. It was concluded that the LM with deflectors could only maintain stability under optimum specific conditions. I would say the LM missions were very fortunate. Just the fact they had no RCS backups, let alone the deflector issue, it sure seems luck was on their side.

You still don't understand this paper and/or what it deals with.
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Eugene Cernan

Offline jr Knowing

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Re: Apollo 11 Lunar Lander Pre-Launch
« Reply #237 on: December 18, 2018, 11:26:35 PM »
Hi Alan F

Don't say I don't help you guys. Here is some bedtime reading for you. I have a lot more places to get docs. Happy Reading.

https://www.ibiblio.org/apollo/Documents/


Offline JayUtah

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Re: Apollo 11 Lunar Lander Pre-Launch
« Reply #238 on: December 18, 2018, 11:28:42 PM »
https://www.ibiblio.org/apollo/Documents/

Yeah, that's just the URL you already posted, without the file component.  Are you claiming you've read and understood all those documents?  My response to Zakalwe, which you wrote off as dismissive, was actually a summary of another document in that archive.  Tell me which one it was.
« Last Edit: December 18, 2018, 11:31:30 PM by JayUtah »
"Facts are stubborn things." --John Adams

Offline Von_Smith

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Re: Apollo 11 Lunar Lander Pre-Launch
« Reply #239 on: December 18, 2018, 11:31:43 PM »
Hi Allan F,

I have done my research. I know you guys like to think others have no idea about things. The fact is I am the only person who has provided any documentation regarding the workings of the deflectors.

I find it comical on how everyone has twisted this MIT paper to mean nothing. And to suggest that these conclusions have no bearing to the LM flying solo (detached from the CSM). If anything, it is even more problematic for the LM operating solo. Atleast the CSM-LM had the ability of disabling the LM RCS’s if there is a failure or mismatch power issue ( ie one RCS operating at 50 percent of the opposite RCS) and rely on the CSM RCS’s. (That is what happen with Apollo 13, I have the report) But with the LM operating alone there is no backup if there is a failure or mismatch of power between two opposite thrusters and that will result in serious stability issues. And another MIT paper (which I will dig up) not only confirms this but it also asserts for the LM to remain stable the craft must be equally balanced to ensure the plumes don’t create an uncontrollable craft. It was concluded that the LM with deflectors could only maintain stability under optimum specific conditions. I would say the LM missions were very fortunate. Just the fact they had no RCS backups, let alone the deflector issue, it sure seems luck was on their side.


Why would NASA put plume deflectors on Apollo 12, then?  This memo came out three weeks before Apollo 12's launch, meaning that from this point forward the deflectors would no longer serve the purpose of convincing engineers that the missions were legit, right?  Since those same engineers were supposedly now convinced that the deflectors were bad?