Claims about A11 oxygen consumption on JREF forums

[grmcdorman]

Over at the James Randi Educational Forums, Dr. Greening (a chemist) has posted a claim about the oxygen consumption in the LM during the Apollo 11 mission. (Note that his username there is Apollo20. Nothing to do with the Apollo 20 hoax on YouTube, as far as I know.)

His post is here: forums.randi.org/showpost.php?p=2764883&postcount=143

My response is here: forums.randi.org/showpost.php?p=2766085&postcount=169

Basically, he's claiming that the consumed oxygen is too low for the known requirements.

I did find that one of his crucial figures - the LM leak rate - was wrong. He gives a figure of 0.2 lb/hr; the Apollo Mission Report states that this is the design rate, and the actual was only 0.05 lb/hr.

The one Apollo figure I can't find a source for is the loss from a cabin depressurization. He quotes 12 lb as being lost in each of the two depressurizations.

The other figure I have no source for is the actual consumption by the astronauts; he quotes a resting basline of 0.05 lb/hr.

Now, using the correct leak rate - 0.05 lb/hr - does balance the numbers at the end.

There is still one oddity, though. In the transmission logs (from ALSJ). At 114:31 GET, there is this exchange:

114:31:45 McCandless: Okay. RCS (Reaction Control System, the steering jets) Alpha is 81 percent: RCS Bravo, 75 percent. Coming up on 115 hours GET, descent oxygen is 31.8 pounds or 59 percent; descent amp hours 858 (remaining), and ascent amp hours 574. Over. (Pause)
114:32:28 Aldrin: Roger. Copy. Thank you very much.

Dr. Greening jumps on this by claiming that this shows there was only 0.9 lb of oxygen consumed in the approximately 10 hours between this transmission and liftoff at GET 124:22:00, and that that value is too low. He doesn't take into account that 1) most of that 10 hours the astronauts slept (or tried to, at least) and 2) at some point prior to liftoff they would have switched to the ascent stage oxygen tanks, so it will be less than 10 hours.

Still, 0.9 lb for 9 or so hours seems a bit low, based on the consumption figures (0.05 lb/hr per astronaut for respiration, 0.05 lb/hr leak rate).

He also implies that the "59 percent" is wrong. However, one can simply show that this is the percentage of the total supply in both stages, so that isn't an error.

He claims to be using SP-2000-4029 as the source for most of his values, and that said values are "inconsistent" with values elsewhere in the Apollo record. He also claimed to be using the Apollo Mission Reports as the source for the O2 consumption rates, but that's exactly what I used (MSC-00171, November 1969), so either he's misreading the document or he's got some other source.

Interestingly, when I continued to look through the ALSJ, I found this transmission:

123:14:45 Evans:And, Tranquility, I have a LM consumables update for you.
123:14:53 Aldrin: Roger. Ready to copy.
123:14:55 Evans: Okay. At plus 123 plus 00, RCS Alpha 78, (repeating) seventy eight percent, PQMD; Bravo is 76 percent PQMD; descent O2 is 62, sixty-two percent. Descent ampere hours are 590...590 remaining; ascent ampere hours are 574, 574 remaining. Over.

Why is the percentage for descent O2 higher here? Is it instrument precision? If so, it would resolve the "only 0.9 lb O2 in ~9 hours" question as well.

Note, by the way, that Dr. Greening is claiming that there are, quote, "there are many undeniable anomalies in the record of the Apollo missions as published by NASA", unquote. However, he refuses to state his thesis; when posters replied to him challenging him as a HB, he said, quote, "Did I say APOLLO was hoaxed? No I didn't!", unquote. Disengenious at best.

He then goes on to bring up the VAB (in the context of the high-altitude nuclear weapon tests), but with no detail linking it to Apollo. When I asked what his point was on that, I got no reply.

I would very much appreciate any additional information I can add to counter his claims.

Note, by the way, there is a lot of other sniping and bickering going on in that thread. If people want any other specific items from the thread, I'd be glad to post direct links.

Thanks.

[alex04]

i'm only a layman with this stuff, but i noticed that there was a cryo-stir at 122:01:26 - would this have any effects on the readings? (2 hours later?)

[Mike will activate small fans in the tanks to stir the contents. According to Gerry Griffin, as the tanks emptied in zero-g, the contents tended toward a "slush", a mixture of liquid oxygen (or hydrogen, depending on the tank in question) and gas. With the content in the slush state, Houston could not be sure of uniform flow out of the tank or of accurate measurements of the amount of oxygen remaining. By stirring the contents with a fan, they homogenized the mixture and got both more uniform flow and better gauge readings.]


i'll quietly disappear if i've made a fool of myself lol

[grmcdorman]

It wouldn't suprise me if the cyro-stir did it. My guess, over at JREF, was that the remaining O2 was measured based on the tank pressure. (Can't think of any other mechanism, in fact, but I'm not an engineer). I overlooked that item, though (I do recall now going past it, but it didn't click).

[grmcdorman]

Um, wait. That's referring to Mike - that is, Mike Collins, in the CM. I don't see a stir being done in the LM. So that's not it.

[alex04]

grmcdorman said:

Um, wait. That's referring to Mike - that is, Mike Collins, in the CM. I don't see a stir being done in the LM. So that's not it.

ah yep, my mistake, sorry about that

But the point of the cryo-stir (in my understanding) is to help give accurate measurements of the oxygen readings. If the LM had no cryo-stir, then how can we be certain of the accuracy? And if we are somehow confident of the readings of the LM, then why do they need to do cryo-stirs on the CM?

At this point (return to orbit) during I'm not sure how long the LM would have been at zero Gs, but it's a point worth looking into.

Another thing looking into, is that the Astronauts' oxygen rate was increased substantially during the EVA's - when they were resting in the LM, would this affect the readings enough to cause the aforementioned discrepancy?

Aldrin, from the 1969 Technical Debrief - "I think that the fact that you're well cooled off enables you to absorb a fair amount in an increase of activity before it manifests itself. The oxygen flow rate concerned me a little bit pre-flight because I found, in doing some fairly strenuous exercise in the thermal vacuum chamber, that the first indication I got was that there was not quite enough circulation of oxygen to breathe. It tended to get a little stuffy in the helmet. (Here, Buzz changes the subject to the workload involved in launch and rendezvous) I think all of us who have been through this business (in the simulators) know a good bit about the pace of activities following insertion (into lunar orbit), which is rather leisurely taken. However, you can get wrapped around the axle doing a lot of different things that aren't required (in a normal launch and rendezvous) - many of them are doing things just to say you can add more and more solutions. Therefore, to carry out a minimum-rendezvous effort is not, as I would see it, a very tiring task to look forward to after descent and a prolonged EVA. I think we would have been fully capable of carrying out a lift-off and rendezvous (right after the EVA, had one been required)."]

[Bob B.]

grmcdorman said:

The one Apollo figure I can't find a source for is the loss from a cabin depressurization. He quotes 12 lb as being lost in each of the two depressurizations.

I think he calculates 12 lbm total for the two depressurizations, not 12 lbm per each. I calculated nearly this same number a few years ago in a thread at BAUT. Here is the thread and specifically see my post #25. I calculated 23.6 lbm for four depressurizations, or 11.8 lbm for two.

grmcdorman said:

The other figure I have no source for is the actual consumption by the astronauts; he quotes a resting basline of 0.05 lb/hr.

In my post #33 I calculated the rest oxygen consumption rate for a 75 kg person to be 1.10 lbm/day, or about 0.046 lbm/hour.

Both of his numbers seem to be essentially correct, though be hedges a bit on the conservative side.

grmcdorman said:

There is still one oddity, though. In the transmission logs (from ALSJ). At 114:31 GET, there is this exchange:

114:31:45 McCandless: Okay. RCS (Reaction Control System, the steering jets) Alpha is 81 percent: RCS Bravo, 75 percent. Coming up on 115 hours GET, descent oxygen is 31.8 pounds or 59 percent; descent amp hours 858 (remaining), and ascent amp hours 574. Over. (Pause)
114:32:28 Aldrin: Roger. Copy. Thank you very much.

Dr. Greening jumps on this by claiming that this shows there was only 0.9 lb of oxygen consumed in the approximately 10 hours between this transmission and liftoff at GET 124:22:00, and that that value is too low. He doesn't take into account that 1) most of that 10 hours the astronauts slept (or tried to, at least) and 2) at some point prior to liftoff they would have switched to the ascent stage oxygen tanks, so it will be less than 10 hours.

I don’t know about this case, but I do know that in some cases what the astronauts read on their instruments was not always what not always the same as what was transmitted to the ground in the downlink telemetry. Before anyone can claim a discrepancy here it is necessary to make sure we aren’t comparing apples and oranges.

Regarding the ascent stage supply, the initial load was 4.74 lbm and the amount remaining at LM jettison was 3.8 lbm. I don’t know what the reading was at liftoff from the Moon. (Edit: Based on Table 8 of Report M-932-69-11 dated 24-July-69)

EDIT: I also agree with those who question the accuracy of the readings. I don’t think the sensor could supply an accurate enough reading to back up this Greening fellow’s conclusion that something is wrong with the data.

EDIT 2: I just realized the 31.8 lbm reading was being read to the astronauts from the ground (I thought it was the other way around). It is therefore likely all the quantities are based on telemetered data, so that makes my point about the possibility of conflicting readings moot.

grmcdorman said:

Still, 0.9 lb for 9 or so hours seems a bit low, based on the consumption figures (0.05 lb/hr per astronaut for respiration, 0.05 lb/hr leak rate).

If we assume the 0.9 lbm number drawn from the descent stage is correct, then the total consumed between both the descent and ascent stage supplies was 1.84 lbm. This occurred between the 114:31:35 GET transmission and LM jettison at 130:09:55 GET, a period of 15.64 hours. Also note that CSM/LM docking occurred at 128:03:00 GET, or about 13.52 hours after the 114:31:35 GET transmission.

Using the 0.05 lbm/hr leak rate and the 0.046 lbm/man-hour rest consumption rate, then the total oxygen consumption was 0.142 lbm/hr. This adds up to 1.92 lbm for 13.52 hours or 2.22 lbm for 15.64 hours. I don’t think the 2.22 lbm figure is credible because the hatch between the LM and CSM was opened and the crew transferred to the CSM prior to LM jettison. The 1.92-lbm figure is probably closer to the correct number, which is very close to the 1.84-lbm number. Since the crew slept during part of the time, we would expect a lower oxygen consumption rate. The 1.84-lbm number therefore does not seem to be out of line with what we would expect.

EDIT: On second thought, I don't suppose we can't say for sure the 0.94 lbm from the ascent stage was consumed after 114:31:35 GET since we don't have a reading at that point. Although they would not have begun to draw oxygen from this system until they were preparing for departure, I suppose it is possible there could have been a small amount of loss prior to 114:31:35 GET.

[JayUtah]

The exact purpose of stirring the cryogenic tanks was to give accurate quantity readings. The sensor transducer runs the whole dimension of the tank and is spoofed by stratification of temperatures along its length. Measuring the quantity of cryogenic oxygen was known to be problematic; hence there is no one measurement that should be considered the One True quantity at that point in time. To put it in simple terms: the O2 quantity measurement is a "noisy" signal. You can't discuss the quantity measurements from any source without understanding the statistical basis on which they are made in each case. That goes for snapshot readings as well as computed trends.

[grmcdorman]

Bingo; the expert speaks. Thanks JayUtah.

[alex04]

ah well, i was sort of on-track (in a non-technical way) ;D

i'll be interested to see how that discussion progresses!

[Bob B.]

grmcdorman,

I notice in you reply to Dr. Greening that you corrected him on many of the quantities he quoted. Just for your information, Greening’s numbers come from Table 8 of Post Launch Mission Operation Report No. M-932-69-11 dated July 24, 1969. This is also the report I used when putting together my reply #5.

The report that you reference is dated November 1969. Being the later and more extensive report, I tend to believe the one you used. However I’d go a little easy on Greening in criticizing his data since he is using figures published in a NASA report. Correct him when necessary but don’t treat him like he’s using bogus data.

[grmcdorman]

Ah. I wondered where Dr. Greening's numbers came from. Thank you; I can use that when I pull this all together in a summary. (What I intend to do, if it's alright with the people here, is summarize the responses here, with links back here - and of course attributions [which is naturally implied in linking].)

His main statement is that the numbers are "inconsistent" in this and many other areas in the Apollo documents. However, he seems to take offense when I and others infer that he is, therefore, implying that Apollo was hoaxed. But if this is not the conclusion he's aiming for, then I'm not sure what his point is.

[Bob B.]

grmcdorman said:

His main statement is that the numbers are "inconsistent" in this and many other areas in the Apollo documents.

Yes there are inconsistencies. When dealing with something that is as data intensive as Apollo there are going to be inconsistencies. I see it often in other things as well; it is a fact of life. If the inconsistency causes a problem, the proper thing to do is reconcile the inconsistency. Jumping to outlandish conclusions is certainly the wrong approach.

[grmcdorman]

Exactly, Bob B.

I - and others on the JREF forums - can't quite figure Dr. Greening out. When posting in his area of expertise, chemistry, he can post quite lucid and rational posts. Outside of that, though, his posts can be, um, touchy complaints, attacks on the JREF posters as "conformist" and "group thinkers" - and often verging on woo. For example, he recently posted a proposition that HIV/AIDS was created by the CIA as, apparently, an attack on U.S. black men (same thread as the post quoted here on Apollo). I'm not sure if he's fond of arguing, is a troll (which is nearly the same thing), or is truly a woo believer on these other topics.

With respect to the Apollo information, I don't know precisely what he's trying to achieve. He refuses to be pinned down on anything other than he's pointing out "inconsistencies". Unfortunately, that's all to close to some other conspiracy theorists' habit of "just asking questions".

Ah well. The exercise, in part, is for my own edification (and the other observers); I don't expect I'll get very far with Dr. Greening.

ETA: The other problem with this sort of thing is that the HBs are going to latch on to it, if they haven't already. (For the O2 consumption, it looks like it hasn't been raised before; web searches turned up essentially nothing either way.) So having a counter-argument already ready is probably a good thing, as well.

[Bob B.]

grmcdorman said:

The other problem with this sort of thing is that the HBs are going to latch on to it, if they haven't already. (For the O2 consumption, it looks like it hasn't been raised before; web searches turned up essentially nothing either way.)

The only other time I can recall seeing an oxygen consumption argument was in the BAUT thread from over three years ago that I referenced earlier (read here – the O2 argument starts with post #15). The HB didn’t mention any particular mission and didn’t provide figures to support his claim; he just said the LM lacked the tank capacity to hold the required volume of oxygen. After I performed the calculations showing how wrong he was, the HB made one more post, changing the subject, and then disappeared never to be heard from again.

[grmcdorman]

Yeah - typical of CT/HBs of all stripes, isn't it?