A Significant Moment for Apollo 16
A Significant Moment for Apollo 16:
Inconsistency in the audio recordings
Luis E. Bilbao, PhD
Relative size of the Earth and the Moon during the journey
The Earth has a radius of 6,371 km, which is about 3.66 times larger than the radius of the Moon (1,737 km). Viewing an object in space, the Angular size (the angle subtended by an object) depends on its actual size and the distance at which it is observed. Thus, on a trip from Earth to the Moon, starting from an Earth orbit, the Earth will initially appear much larger than the Moon, but as the spacecraft moves away, the apparent size of the Earth will decrease and that of the Moon will increase, until, on reaching a lunar orbit, the Earth will appear much smaller than the Moon.
During the lunar mission trajectory attributed to Apollo 16, astronaut John Young makes a specific mention of the comparative size of the Earth relative to the Moon. In the Apollo 16 Flight Journal, section Day 2, Part 1: Electrophoresis Experiment and Midcourse Correction Burn1 the following conversation is transcribed alongside the audio of this exchange. (The corresponding instant in the audio, a16 0234103.mp3, has been added at the end of each speech block.
Public Affairs Officer – This is Apollo Control, Houston at 23 hours, 42 minutes Ground Elapsed Time. [GET] That was Lunar Module Pilot Charlie Duke talking to CapCom Tony England here in Mission Control clarifying one point in the post-sleep report. We presently show Apollo 16 at a distance of 99,923 nautical miles [185,057 km*] from the Earth, and traveling at a speed of 5,238 feet per second [1,596 m/s]. [1m 24s]
023:43:54 – Young: Okay. We can see the Earth out there, and it’s getting a good deal smaller. It’s about the same size as the Moon almost, out the other window. And Africa is clear this morning – at least the part that we can see, which is what’s usually clear, right around from the Canaries on. [2m 51s]
023:44:24 – England: Very good. We’ve got you about a little over well, you just passed 100,000 miles [185,200 kilometres] on our chart here. [3m 20s]
From this dialogue it is clear that astronaut Young observes that the Earth and the Moon are almost the same visual size (i.e. same angular size), and that this observation was made 1 minute 56 secs after the distance of 99,923 nautical miles (NM) from Earth was noted by the PAO. The position of the ship mentioned immediately before and immediately after Young’s observation.* The translation into 185,057 km has been inserted by the editors of the ALSJ.
Considering that the distance to lunar orbit for the Apollo 16 flight was 207,161NM (383,632 km), at the time of the comment the craft should be about halfway through the flight, though slightly closer to Earth, which means that the visual size of the Earth should be about 4 times larger than the Moon.
A composite of photographs in Fig. 1 show the relative visual size at 185,057 km from Earth, similar to what Young would have seen, and also using as a reference on the same scale the size that the Moon would be, seen from a low Earth orbit.
These two images below are a composite to show the relative visual size of the Moon and Earth.
As seen in Fig 1a, in low Earth orbit, and at 170 km altitude, with the angular size of the Moon ≈ 0.5º and of the Earth ≈ 154º), the Moon appears to be 308 times smaller than the Earth.
Fig 1b. At 185,057 km from Earth, the Moon appears 4 times smaller than the Earth.
Fig 1b. demonstrates that when seen at the distance of 185,057 km, mentioned in the transcript above, with an angular size of the Moon ≈ 1º and of the Earth ≈ 4º , the Moon is 4 times smaller than the Earth.
While John Young’s expression “about the same size” is subjective and does not indicate exact precision (for example, in purely colloquial terms it could perhaps refer to differences of up to a factor of 2 without necessarily appearing incorrect). However, in a technical or scientific context this expression usually implies a smaller difference, perhaps within 10-20% difference. But under no circumstances would it apply to a size difference of 4:1 as seen in Fig 1b.
It should be kept in mind that Commander Young was not only an astronaut, he was also a naval aviator and test pilot. With a strong background in aeronautical engineering,2 he was essentially competent in technical and descriptive observations. Given his knowledge and training, it is reasonable to assume that his comment about the apparent sizes of the Earth and Moon was not a careless observation, but should be a fairly reliable estimate of what he was seeing at the time. It is unlikely that such a trained observer would make such a large error in his visual assessment by saying that two objects such as the Moon and Earth (Fig 1b) are “about the same size”. It’s like an airline pilot saying that the two planes seen in Fig 2 are almost the same size.
Fig 2: Size comparison of two planes, one of which is about 3 times longer than the other. Could you say that they are “about the same size”?
It is also surprising that neither the PAO at the Apollo Control Center, Houston, nor the CapCom at the Cape in Florida had asked precisely what the spacecraft commander meant by ”about the same size”.3 Especially given that it could indicate that for some reason astronaut Young’s visual perceptions were altered, which would surely indicate further investigation post-flight. However, the dialogue that immediately follows simply continues with the evaluation of distance traveled:
023:44:32 Young: I would guess we’re about 100,000 miles out. Yes.
023:44:40 England: Well, sounds like a milestone. [Long pause.]
023:44:56 England: [Laughter.] They say you’re only 14 miles off, John.
You’re going to have to recalibrate your eyeball. [Long pause.]
That is, although they jokingly discuss how for a difference of 0.01% in distance, Young must recalibrate his eye, but for a difference of 400% they say nothing.
Conclusion
All of the above shows that Young’s comment cannot correspond to an observation made at 185,057 km from Earth, when the Earth is 4 times larger than the Moon. Both the immediately preceding comment and the immediately following comment specifically mention that the distance is around 185,057km.
Nor does Young’s observation correspond to later on in the trajectory, because it is only at a distance of just over 300,000 km from Earth that the Moon and the Earth appear to be the same size. (At just over 162,000NM, that’s nearly 2/3rds further on from Young’s observational position of some 99,923NM.)
In short, the only possible conclusion is that this audio does not correspond to a recording made on a trip to the Moon. It would seem to be a fake audio of a poorly written script.
Luis E. Bilbao
Aulis Online, April 2025
About the Author
Luis Ernesto Bilbao has a PhD in Physics from the University of Buenos Aires, is Adjunct Professor, and Independent Researcher, INFIP CONICET, UBA (the Faculty of Exact and Natural Sciences, University of Buenos Aires, Argentina).
The Institute of Plasma Physics (INFIP), dependent on the CONICET and the FCEyN-UBA, is a center carrying out pure and applied research in a wide variety of subjects of this discipline. The INFIP researchers have extensive knowledge and many years of experience in this branch of physics, with the publication of more than 600 works since 1983.
References
- The Apollo Flight Journal, retrieved January 2025
- for example Wikipedia, retrieved January 2025
- Link to the Apollo 16 journal listing of crew & CapCom: Apollo 16 Crew Information,
Editor’s Note
Before and After that Significant Moment
This entire sequence is scientifically incorrect to the point that it was simply begging to be noticed. This draws us towards an alternative conclusion: aware of the fact that the inconsistencies noted by noted by Luis Bilbao would not become apparent to the wider public until decades later, (due to the political & technical circumstances prevalent in the 1960s and ’70s) this whole sequence had been deliberately organised as yet another whistle-blow by those unable to speak out for fear of severe consequences.
The clues to this hypothesis lie in the preamble that went on immediately before the Earth-Moon discussion, as well as in the subsequent conversation noted by Luis Bilbao, to which we can add further comment.
Before
In the lead up to the Earth/Moon segment, there was another discussion, between CapCom and astronaut Charlie Duke, concerning weights and measures, and the designation of terms for their food and drink consumption. All of it equally unnecessary from any sort of planning point of view, since such important details would have been tied down months before launch.
The original 1972 PDF audio transcript1 used the terms PAO for the public affairs Officer at Apollo Control Center in Houston. It also used SC for the spacecraft, and reading this first exchange from the SC, the cynically inclined might think of SC Houston, as Space Center Houston.
This is the dialogue as recorded in the ALSJ:
PAO This is Apollo Control, Houston; 23 hours, 32 minutes Ground Elapsed Time. Apollo 16 now 99,379 nautical miles [184,050 km] away from the Earth. Now traveling at a speed of 5,261 feet per second [1,603 m/s].
023:32:36 Duke: Houston, we're charging Battery A. [Pause.] And on that food, Tony, add my apricot cubes, I just ate them. [Long pause.]
023:33:04 England: Okay, Charlie.
023:41:03 England: Charlie, Houston.
023:41:08 Duke: Go ahead
023:41:10 England: Okay. On that fluid consumption there, the numbers you gave were in ounces. Could you verify that's ounces and not bags? [Pause.]
023:41:25 Duke: Say that again, Tony.
023:41:28 England: In the fluid you've consumed - the drinks, you gave the numbers in ounces, and I guess the blank here is listed in number of bags and partial bags, and they just want to verify the fact that the number you have was in ounces and also to check and see what unit you want to use for the rest of the mission on that so everybody will have it straight.
023:41:50 Duke: Okay, we'll use - we'd like to use ounces, and that's what we'll go with.
023:41:56 England: Okay.
023:41:57 Duke: That's what I read.
023:41:58 England: Okay. Understand. Thank you. [Pause.]
023:42:07 Duke: Tony, the - the menu side of it, the things that are in the menus are in, of course, bags.
023:42:16 England: Okay, we understand.
Given that earlier on Duke had referred to solid items as ‘food’, why then is he now referring to these as ‘menu items’? Because a menu consists of all types of nourishment including drinks. Although, it is true there is another sort of menu on board the spacecraft, and that is the list of commands within the software programs of the spacecraft’s Apollo Guidance Computer (AGC). Here we come to another fact, relatively unknown to the public at the time of these missions. In the 1960s The US and the UK both used the imperial system of measurement and the proposition of changing to the metric system was not popular with the public of either nation. Especially when it came to road distances. However the advent of computing required the use of the SI System and this was used discreetly by NASA for all its computing.2
For the public usage and the display consoles on the AGC, Houston converted their SI units into various measuring systems: readouts of distance were displayed in nautical miles (converted from metres); altitude in imperial feet (converted from metres); time was displayed in minutes and seconds (converted from centiseconds) and altitude rates in imperial feet per second (converted from metres per centisecond).3
The reason offered for those variable AGC displays was that most of the pilots were former Navy or Air Force pilots and were familiar with those systems. Not said, was that many of the rocket engineers, like their leader Von Braun, had come from Europe and were more familiar with the metric system. Nor was it mentioned that their astronauts were sufficiently well educated to be able to understand the metric system. Conveniently and confusingly, the public were served up with various systems of measuring, thereby drawing yet another veil across the Apollo missions.
And by the way, this discussion of fluid ounces should have been expressed in millilitres back at Houston, not bags. However if this is a whole other conversation about matters of mass and gravitational forces, those bags become grams. But then encoding the coding was nothing new: interestingly given the political seriousness of the Apollo Project, the programmers at MIT had thought it necessary to inserted jokes and quotes into their coding of the AGC source code.
This hidden messaging system was noted by Keith Collins in the July 9, 2016 article for Quartz titled The code that took America to the moon was just published to GitHub, and it’s like a 1960s time capsule, 4 when he wrote:
“Many of the comments in the AGC code go beyond boring explanations of the software itself. They’re full of light-hearted jokes and messages, and very 1960s references.”
He draws attention to several examples, one of which includes a quote from Shakespeare.
Image extract source Chris Garry5
As Shakespeare wrote it, that reference should read like this: Henry the Sixth, the Second Part, Act Four, Scene VII. In modern terms that would be Henry 6, part 2, Act 4 scene 7.
Tracking this down the MIT programmers’ reference of Henry 6 Act 2 Scene 4 will produce nothing, because it is revealed to be both incorrect and inadequate. Parts are missing and acts and scenes numbered wrongly so you have to dig deeper to find the context of this quote. Which is a message in itself. Especially since the section referred to actually refers to the rebel Jack Cade and his gripe with the authorities of England.6
After
This section on weights and measures was followed by the visual evaluation of the Earth Moon dialogue between Young and England dealt with by Luis Bilbao. Then came the follow-up dialogue some of which was noted by Luis Bilbao. As you will recall it went like this:
023:44:32 Young: I would guess we’re about 100,000 miles out. Yes.
023:44:40 England: Well, sounds like a milestone. [Long pause.]
023:44:56 England: [Laughter.] They say you’re only 14 miles off, John.
You’re going to have to re calibrate your eyeball. [Long pause.]
To which we can now add these questions: Why is Young simply using that American idiom “I would guess”? (In the UK that is I would think”), but in any idiom he should be able to know by looking at the display on the spacecraft’s Apollo Guidance Computer (AGC) to see the readout telling him see precisely where he is. However, Imperial miles were NOT used, so when the ALSJ chooses to use Tony England’s surname, rather than his title of CAPCOM, the possibility of confusion arises. If you didn’t know the surname of the CapCom, given the discussion, it would be easy for someone reading the ALSJ to think that someone from England was talking to the astronauts at that juncture.
For the uninitiated, that country across the Atlantic is the nearest to the USA where historically the Romans erected milestones every thousand paces (in Latin: mille passus) along their roads.7 In Roman times the mille passus was of 1480m (4855.584ft) Centuries later (that long pause) in Tudor England, the distance was changed from 1480m to 1609.344m(5280ft). 100,000 mille passus at 1480m per 1000, equates to 92 statute miles altitude. And that distance, is within 14% of the low earth orbital distance seen in Fig 1a of Luis Bilbao’s article.
While Tony England’s ‘sounds like a milestone’ could be referring to an emotionally ‘significant moment’ it could equally well be an attempt to draw attention to all these discrepancies of time and place. Tellingly, the final three lines of that follow-up discussion went like this:
023:45:17 Young: Okay. From our point of view, you only got a little more than half an Earth.
023:45:23 England: Oh, that's right. We forgot; you're kind of handicapped.
023:45:28 Young: Right.
Whether that handicap is related to where these astronauts actually were, or it is related to not being able to actually see what they are describing, the point is laboured. Essentially, the crossover of so many different evaluation systems combined with the inadequacies of much of the technology extant at the time of Apollo, (especially that AGC,8 enabled these extraordinary conversations to convey far more information than the words on the pages of this Apollo 16 transcript. While available to us now, at the time these clues would not be seen either by the public who had not enough knowledge of the inner workings of NASA, nor by the instigators of the Apollo missions, who themselves had not enough time to adequately parse these mission scripts, or indeed those computer readouts.
Keith Collins notes that, the PINBALL_GAME_BUTTONS_AND_LIGHTS.s file, is described as “the keyboard and display system program … exchanged between the AGC and the computer operator.”
Well, that takes us to the pinball machines and possibly the whole notion of gambling, Las Vegas, and much, much more, but that’s another story.
M. Bennett, April 2025
Editor’s Note References
- The original 1972 audio record pp124-125
- UK Metric Association: The Moon Landings
- AGC source code referred to as Colossus 2A was the overall name for the Apollo programming prepared by the Instrumentation Laboratory, Massachusetts Institute of Technology, in Cambridge, Mass. Margaret Hamilton, the Colossus Programming Leader Apollo Guidance and Navigation submitted it for approval on 28 March 1969. The Command Module part of this source code was designated Comanche055. The Lunar Module part of the source code was designated Luminary099. https://github.com/chrislgarry/Apollo-11 And http://www.ibiblio.org/apollo/assembly_language_manual.html
- Keith Collins’ must read article on Quartz
- Pinball Game Buttons and Lights
- Henry 6th quote https://en.wikipedia.org/wiki/Jack_Cade%27s_Rebellion
- The Roman Mileage system
- Was the Apollo Computer flawed? An investigation into the Apollo Guidance Computer documentation, Xavier Pasca, Aulis Online, 2012 Updated October 2013
and Apollo Guidance Computer Memory update May 2019
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