Author Topic: Lunar Module panels  (Read 19796 times)

Offline I14R10

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Lunar Module panels
« on: 09/17/2014 12:28 am »
I have started building LM simulator. Idea is that it will be as close to real one as possible. I already have two part LM handbook but I still have some questions, if someone knows.
Panel numbers are here http://www.apolloproject.com/diagrams/ad013.gif

1. FDAI switch on panel 11 does it turn off both FDAIs? If turned off FDAI stays in same orientation?
2. Lighting control on Panel 5 and 3 - Does Panel 5 control left side loverhead light and Panel 3 right side overhead light?
3. Is there some checklist that shows how all switches need to be at some time, let's say at beginning of P63?
4. What are ANUN/NUM Lighting and INTEGRAL Lighting?
« Last Edit: 09/17/2014 12:32 am by I14R10 »

Offline dks13827

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Re: Lunar Module panels
« Reply #1 on: 09/17/2014 01:14 am »
NASA has lengthy and detailed and complete LM checklists on PDF that you can download.  You have these, right ?   I bet there are 1,000 pages of LM information in detail.   They are very good.

Offline I14R10

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Re: Lunar Module panels
« Reply #2 on: 09/17/2014 11:20 am »
NASA has lengthy and detailed and complete LM checklists on PDF that you can download.  You have these, right ?   I bet there are 1,000 pages of LM information in detail.   They are very good.

Yes, I have these, LM handbooks, two part. Sorry, I didn't know what was all in there. It's 2000 pages of stuff.

Offline HDTVGuy

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Re: Lunar Module panels
« Reply #3 on: 09/17/2014 11:16 pm »
Can you supply a link for the LM checklists mentioned above?

Offline I14R10

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Re: Lunar Module panels
« Reply #4 on: 09/18/2014 07:05 pm »
Can you supply a link for the LM checklists mentioned above?

Sorry for late response. Here https://www.hq.nasa.gov/alsj/alsj-LMdocs.html . There are those two parts of LM handbook along with some other documents.

Offline HDTVGuy

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Re: Lunar Module panels
« Reply #5 on: 09/19/2014 02:52 am »
Thank you.

Offline I14R10

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Re: Lunar Module panels
« Reply #6 on: 09/21/2014 06:55 pm »
One more question, it can go here. I read in flight plan that LM FDAI was R0 P0 Y0 at landing site. Does that mean that Roll, Pitch and Yaw were calculated in relation to Lunar horizon? So wherever they were, if R, P and Y were all zero it means they were looking perpendicular to Lunar gravity vector?

Offline munrowood

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Re: Lunar Module panels
« Reply #7 on: 09/25/2014 04:28 pm »
NASA has lengthy and detailed and complete LM checklists on PDF that you can download.  You have these, right ?   I bet there are 1,000 pages of LM information in detail.   They are very good.

Yes, I have these, LM handbooks, two part. Sorry, I didn't know what was all in there. It's 2000 pages of stuff.

The question is, how thoroughly did the LEM pilots actually study those 2,000 pages before flying?

Offline Jim

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Re: Lunar Module panels
« Reply #8 on: 09/25/2014 04:43 pm »
One more question, it can go here. I read in flight plan that LM FDAI was R0 P0 Y0 at landing site. Does that mean that Roll, Pitch and Yaw were calculated in relation to Lunar horizon? So wherever they were, if R, P and Y were all zero it means they were looking perpendicular to Lunar gravity vector?

The mode is LVLH (Local Vertical Local Horizontal)

Offline I14R10

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Re: Lunar Module panels
« Reply #9 on: 09/26/2014 07:27 pm »

The question is, how thoroughly did the LEM pilots actually study those 2,000 pages before flying?

well, of course, would you not study it and find yourself not knowing about something while in lunar orbit.


The mode is LVLH (Local Vertical Local Horizontal)

So than, the answer is yes, it was calculated in relation to lunar horizon.

And if you could answer that question about circuit breakers on side panels - how were they activated - by pulling them or pushing them?


Offline Jim

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Re: Lunar Module panels
« Reply #10 on: 09/26/2014 08:07 pm »

And if you could answer that question about circuit breakers on side panels - how were they activated - by pulling them or pushing them?


Out - open, in - closed.

Offline I14R10

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Re: Lunar Module panels
« Reply #11 on: 09/26/2014 08:17 pm »


Out - open, in - closed.

Thank you very much Jim.

Offline I14R10

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Re: Lunar Module panels
« Reply #12 on: 10/05/2014 08:06 pm »
How does thruster "flame" look like in vacuum? I know there can't be smoke, but I wonder can you see some fuel exiting thrust chamber or something?

Offline apollolanding

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Re: Lunar Module panels
« Reply #13 on: 10/05/2014 08:25 pm »
How does thruster "flame" look like in vacuum? I know there can't be smoke, but I wonder can you see some fuel exiting thrust chamber or something?

You can see (in extremely slow motion video of Aerozine 50/Nitrogen Tetroxide engines fired in vacuum) a slight spray of Nitrogen Tetroxide, a brief flash of combustion when the fuel ignites (some from material on the surface of engine bell) and then colorless operation.
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Offline Jim

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Re: Lunar Module panels
« Reply #14 on: 10/05/2014 08:26 pm »
How does thruster "flame" look like in vacuum? I know there can't be smoke, but I wonder can you see some fuel exiting thrust chamber or something?

Depends on the propellent.  Mostly looks like a spray of a fluid.
« Last Edit: 10/05/2014 08:26 pm by Jim »

Offline DaveS

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Re: Lunar Module panels
« Reply #15 on: 10/05/2014 08:53 pm »
This the MMH/N2O4 RCS exhaust during the standard L-1 RCS Hotfile test:
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Offline I14R10

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Re: Lunar Module panels
« Reply #16 on: 10/05/2014 09:18 pm »
If I recall correctly, shuttle used compressed gas for RCS, not real combustion in thrust chamber?

Offline DaveS

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Re: Lunar Module panels
« Reply #17 on: 10/05/2014 09:29 pm »
If I recall correctly, shuttle used compressed gas for RCS, not real combustion in thrust chamber?
Yes, real combustion due to the hypergolic propellants which was stored as liquids. The system just like the OMS was pressure-fed but once both propellants mixed in the MCC you got thrust as the propellants ignited and was forced through the nozzle(s).

If you take a close look, you can see a small propellant leak from one of the lateral RCS jets, just to the right of the RMS.
"For Sardines, space is no problem!"
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"We're rolling in the wrong direction but for the right reasons"
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Offline I14R10

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Re: Lunar Module panels
« Reply #18 on: 10/05/2014 09:32 pm »
I suppose LM RCS firing also looked like this. I couldn't find any picture of it.

Offline the_other_Doug

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Re: Lunar Module panels
« Reply #19 on: 10/15/2014 04:00 am »
The LM RCS thrusters produced no visible exhaust while the vehicle was in sunlight.  Neither did the ascent engine, and I'm pretty certain the DPS and SPS didn't, either (although only four LM crews were ever in a position to watch the SPS engine burn, during the Circ burn, and I've never found any descriptions of the event by the crews of Apollos 14-17).

Various CMPs have described witnessing the LM DPS firing, simply describing it as a bright dot.  This was reported on the first few flights where the LM performed the DOI burn, as well as a few times when the CMPs were able to track the LMs as they began PDI.  In the latter case, the CSMs were quite far away from the LMs and none of them were ever able to visually track the LMs much more than two or three minutes into PDI.

If you looked directly into a thruster or larger engine firing while the vehicle was sunlit, you could see a bright flash about the size of the end of the engine bell.  Look at the film footage of Eagle coming up to meet Columbia sometime -- you can only see the LM thrusters firing when looking directly down into them.  Otherwise, there is no visible plume whatsoever.

Similarly, the APS produced no visible plume, as per the ascent videos from Apollos 15 through 17.  However, on the Apollo 17 ascent video (the only one where the LM's pitchover maneuver was captured), when the ascent stage pitches over such that the camera is looking right into the APS engine bell, the bell suddenly becomes a very bright dot, again roughly the size of the end of the engine bell.  You can actually watch as the center of the base of the ascent stage brightens into a very bright dot -- the end of the engine bell had been quite visible (though a bit lost in detail on the video, since at pitchover the ascent stage was at about a kilometer's distance from the Rover camera), but only when it pitched over far enough such that the camera was looking directly into the bell did you see the sudden brightening.

I imagine that the Apollo engine plumes would have been visible had they been viewed in darkness (as behind the Moon or on the Earth's nightside in LEO), or if they had been significantly backlit.  The Shuttle RCS test fire image above looks to be taken at night and strongly backlit.  But the Apollo crews did report seeing flashes out the window when they fired the SM RCS in darkness (and the engines themselves were well out of the direct field of view of any of the CM's windows), so obviously in darkness the plumes were visible.

Oh, and to the OP's other questions -- the LGC's REFSMMAT was set to the landing site's "perfect" orientation for landing and ascent operations.  This meant that, if yaw was perfectly trimmed and the LM landed on a completely flat surface, the needles on the eight ball would all read zeroes.  After landing, since none of the landings were on perfectly flat ground, the ball never actually read all zeroes after landing.  The landing site REFSSMMAT wasn't actually referenced to the horizon -- it was referenced to a direct line from the surface to the center of the Moon for the thrust axis and the plane of the orbit/descent trajectory for the forward direction (thus defining zero yaw).  The REFSMMAT was updated after landing not only with star sightings but also with a gravity alignment that further defined the exact line between the surface where the LM sat and the center of the Moon.

Finally, for your simulator, I'm assuming you've seen the collection of LM cabin close-out photos on the NASA history website?  I've found the complete set of close-out photos for LMs 6, 10, 11 and 12 (Apollos 12, 15, 16 and 17).  They're out at the Apollo Lunar Surface Journal website -- here's the link for the LM 6 photos:

http://www.hq.nasa.gov/alsj/a12/a12LMCloseOutPhotos.html

These sure give you an excellent idea of what the crews saw the first time they entered the LM in flight.  (Except for the occasional stocking feet of one of the members of the close-out crew -- they weren't allowed to wear shoes inside the cabin!)

-Doug

With my shield, not yet upon it
« Last Edit: 10/15/2014 04:13 am by the_other_Doug »
-Doug  (With my shield, not yet upon it)

Offline I14R10

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Re: Lunar Module panels
« Reply #20 on: 10/17/2014 08:14 pm »
@ the other doug

Thank you for your explanation. And yes I have studied those pictures for few months. Actually I completed LM interior 6 months ago and now I'm making a simulation out of it. It's going slowly but well. I'm sure some of you here on this forum would like to give me some opinion when I finish some early alpha version (maybe by the end of the year).

Offline I14R10

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Re: Lunar Module panels
« Reply #21 on: 10/28/2014 08:38 pm »
I was trying to calculate orbital period after DOI burn. I got around 42 minutes. But when I look at LM burn Schedule there is 57 minute period from DOI burn to PDI burn. Did I miscalculated or did they actually orbited one whole orbit after DOI burn before PDI burn?
It's more than likely that I miscalculated, but I just want to rule out this possibility.

Offline Proponent

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Re: Lunar Module panels
« Reply #22 on: 10/28/2014 10:32 pm »
There must be a miscalculation: the period of a low lunar orbit can't be much shorter than 2 hours (assuming the altitude is positive throughout the orbit).
« Last Edit: 10/28/2014 10:34 pm by Proponent »

Offline I14R10

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Re: Lunar Module panels
« Reply #23 on: 12/21/2014 02:17 pm »
One more question. Does anybody know what was propellant consumption for DPS? I am digging through all those manuals and reports and I only found "Engine life - 910 seconds or 17 510 pounds of propellant". Does that mean for full throttle all time?
« Last Edit: 12/21/2014 02:24 pm by I14R10 »

Offline Proponent

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Re: Lunar Module panels
« Reply #24 on: 12/22/2014 05:26 pm »
One more question. Does anybody know what was propellant consumption for DPS? I am digging through all those manuals and reports and I only found "Engine life - 910 seconds or 17 510 pounds of propellant". Does that mean for full throttle all time?


Well, according to Wikipedia, the maximum thrust was 10,125 lb and the specific impulse was 311 s.  That implies a consumption rate at full throttle of 35.6 lb/s.  At that rate, the engine would burn 17,510 lb of propellant in just 538 s.  But I'd have more confidence in the calculation if all of the numbers came from the same source.

Offline dks13827

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Re: Lunar Module panels
« Reply #25 on: 12/24/2014 12:50 am »
The DOI burn was on the backside of course, not a very long burn, then they came around and initiated PDI once they were at the correct distance from the landing site.  Listen to the complete audio of powered descent and you will notice the throttle down after about 8 minutes then pitch over and the CDR began visualizing the landing area and redesignating if necessary.

In your LM simulator have you got the Rate of Descent switch ?  Descent engine command override switch ?   Those are 2 of the items of interest, you may find.
« Last Edit: 12/24/2014 02:21 am by dks13827 »

Offline saturnapollo

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Re: Lunar Module panels
« Reply #26 on: 12/24/2014 12:59 am »
Quote
However, on the Apollo 17 ascent video (the only one where the LM's pitchover maneuver was captured),

You saw it on Apollo 16 too. In fact on 16, the camera followed the bright dot of the Ascent Stage for some considerable time after the camera reacquired the AS, something they didn't manage on 17. You actually begin to see the engine light as it starts to pitch over so you are probably seeing it illuminating the inside of the engine bell, before you see the actual engine firing.

Keith
« Last Edit: 12/24/2014 01:04 am by saturnapollo »

Offline I14R10

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Re: Lunar Module panels
« Reply #27 on: 12/24/2014 09:38 pm »

In your LM simulator have you got the Rate of Descent switch ?  Descent engine command override switch ?   Those are 2 of the items of interest, you may find.

Of course, I have all switches  :). But the rate of descent is a bit tricky for mouse click because it's under that engine stop switch. So that one I will have to incorporate on graphic overlay. Here is what I got so far.

Also, If anyone of the moderators reads this - Can you change the title of this threat to be Lunar Module simulator. Or something like that?
« Last Edit: 12/24/2014 09:47 pm by I14R10 »

Offline I14R10

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Re: Lunar Module panels
« Reply #28 on: 12/27/2014 08:45 pm »


Well, according to Wikipedia, the maximum thrust was 10,125 lb and the specific impulse was 311 s.  That implies a consumption rate at full throttle of 35.6 lb/s. 

I run this through my simulation and it is correct. Or 14.763kg/s on full throttle. I assumed that there is linear relationship between thrust and fuel consumption for given engine.

Offline Proponent

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Re: Lunar Module panels
« Reply #29 on: 12/28/2014 04:38 pm »


Well, according to Wikipedia, the maximum thrust was 10,125 lb and the specific impulse was 311 s.  That implies a consumption rate at full throttle of 35.6 lb/s. 

I run this through my simulation and it is correct. Or 14.763kg/s on full throttle. I assumed that there is linear relationship between thrust and fuel consumption for given engine.

In a vacuum, it's not unreasonable to assume that thrust is proportional to flow rate.  You can play with a tool like RPA to get more precise results.

Offline the_other_Doug

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Re: Lunar Module panels
« Reply #30 on: 12/28/2014 04:58 pm »
As an FYI, the LM DPS used a pintle system to adjust fuel and oxidizer flow into the combustion chamber to vary thrust, so throttling the engine up and down did directly impact the rate of depletion of the propellants.  The original proposal for throttling the DPS used injection of helium into the propellant streams to dilute them and thereby reduce thrust, which would have had much less of an impact on depletion rates.
-Doug  (With my shield, not yet upon it)

Offline I14R10

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Re: Lunar Module panels
« Reply #31 on: 12/28/2014 05:17 pm »
Thanks. So far the linear relation is working fine. I am almost ready to land it :)

Offline Proponent

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Re: Lunar Module panels
« Reply #32 on: 12/29/2014 04:16 pm »
As an FYI, the LM DPS used a pintle system to adjust fuel and oxidizer flow into the combustion chamber to vary thrust, so throttling the engine up and down did directly impact the rate of depletion of the propellants.  The original proposal for throttling the DPS used injection of helium into the propellant streams to dilute them and thereby reduce thrust, which would have had much less of an impact on depletion rates.

I'm glad to see this confirmed.  I remember having read about it a very long time ago in a popular book published in 1963.  It seemed really weird and very mass-inefficient.  Do you have a precise reference, or any information about when a more conventional throttling approach was finally adopted?

Offline the_other_Doug

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Re: Lunar Module panels
« Reply #33 on: 12/29/2014 06:27 pm »
The DPS design issues, as well as many other decisions made in re the LM's design, are discussed in great detail in the late Tom Kelly's excellent book "Moon Lander: How We Developed the Apollo Lunar Module".

Kelly was the Grumman engineer mainly responsible for the design of the LM (though he worked with a large design team), and after the design had been fully patted into shape, Kelly was transferred to oversee the construction phase.  As Kelly put it (paraphrasing from memory), he had suffered the worst nightmare of the aircraft designer -- "now I had to figure out how to build the thing I had designed."

:)
-Doug  (With my shield, not yet upon it)

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