Questions tagged [apollo-11]

Apollo 11 landed the first humans, Neil Armstrong and Buzz Aldrin, on the surface of the Moon on July 20, 1969.

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1 answer
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What does a flight path angle of zero degrees mean at launch?

Total beginner here so please be gentle. I'm looking at the Apollo 11 flight path angle plot from Apollo Saturn V Postflight Trajectory AS 506 which shows a zero degree angle at launch. Isn't path ...
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1 answer
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When was Apollo 11 scheduled for July 1969?

I recently read on Wikipedia about Apollo 8's interesting schedule history. Basically, a lunar orbital mission was supposed to be an F mission for 1969, with the LEM tested in lunar orbit. But they ...
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At what point did the Apollo 11's Eagle extend the landing gear?

I am trying to figure out, during Apollo missions, exactly when the lunar-module extended the landing gear. Was it closer to the time the CM and LM connected in the space rendezvous or did they ...
14 votes
4 answers
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What did Charlie Duke mean by "down on the ground"?

When Neil Armstrong gave his iconic report "The Eagle has landed," CAPCOM Charlie Duke responded with, "We copy you down on the ground." What exactly did he mean by this? Was it, ...
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7 votes
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Apollo landing abort times T1, T2, T3,

In the transcript (1 and 2) of Apollo 11 lunar landing we can see ground control and crew talking about "T1" moment and "T2" moment: 102:47:09 Duke: ...T1. Over. Eagle, you are ...
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5 votes
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Where to find Apollo lunar landing checklists?

Is this the only document where I can read the checklists for Apollo lunar landing? They look more sidenotes than real checklists, and they contain hundreds of acronyms; I would expect instead a "...
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12 votes
1 answer
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What did "verb 50 - noun 90" mean during Apollo 11 powered descent? (1202 alarm)

During powered descent a 1202 alarm occurred when LM Pilot Buzz Aldrin asked the Apollo Guidance Computer (AGC) for the difference between computed and measured altitude above ground by typing V16N68 (...
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3 votes
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Apollo 11 throttle telemetry: what is this value?

I cannot find any clue in AGC SW about the value in last column of pages 15-23 of "Apollo 11 LM-5 computer words" document: I think it reads: ...
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10 votes
1 answer
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"Honi soit qui mal y pense"

In the Apollo 11 LEM source code, in the Burn Baby Burn master ignition routine, one of the most emphasized comment is a French citation, HONI SOIT QUI MAL Y PENSE. ...
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Why did a solar eclipse of the sun as seen from Apollo 11 appear to have an elliptical corona?

When asked to recount an experience from the Apollo program, Neil Armstrong stated: [My] most indelible memory was approaching the moon and flying through the moon shadows so that the moon was ...
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1 answer
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Sputnik I and Gagarin's space flight

The US was completely surprised by Sputnik (I) and also by Yuri Gagarin's space flight. Was the USSR equally surprised by the success of Apollo 11? If not, were they expecting/wishing any failure of ...
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1 answer
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Does NASA use UTC for all their missions?

During Apollo 11 launch they said "Liftoff, we have a liftoff, 32 minutes past the hour", which is 01:32 p. m. or 13:32. This is UTC time, because Apollo 11 happened at 08:32 EST. The ...
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1 answer
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How long did the Apollo astronauts spend in the MQF?

After returning to Earth, the Apollo 11 astronauts were placed in a Mobile Quarantine Facility (MQF) to be transported to a NASA facility. How much time did the astronauts spend in the MQF?
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What is the text on Neil Armstrong's space suit's left glove?

I was looking at the Smithsonian National Air and Space Museum's collection, and Neil Armstrong's Apollo 11 spacesuit has some text written on the left glove. It looks like some sort of instructions, ...
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Apollo Cold Welding Mitigation

I am currently debating with someone on a different platform and he brought up the phenomenon "cold welding." I must admit that I had never heard of that before, so I have been reading about ...
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Are the initial conditions for the Apollo PFS objects' orbits known (or knowable) as well as they were for the ascent module?

This answer to Would we have spotted the ascent stage of Apollo 11's Eagle if it was still in orbit around the Moon? and discussion under it suggests that as a check of the orbital propagation ...
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9 votes
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Could the ascent stage of Apollo 11's Eagle still orbit the Moon?

This video: Is Apollo 11's Lunar Module Still In Orbit Around The Moon 52 Years Later? claims, based on orbital simulations, that there is a chanche that the lunar module of Apollo 11 might be still ...
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1 answer
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Does anyone know the source of this video?

I would like to know the source of this video? I cannot find it on youtube, but I think it's from the Apollo 17 launch (because it's night). Any ideas? Is my Apollo 17 guess correct? This is the video:...
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How did "ACA Out of detent" work?

This is a related question about the words said during Apollo 11 as soon as the LM touched the ground. My question is specific to ACA out of detent As soon as the LM touched down on the surface it ...
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7 votes
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Why was a completely new (an "inexperienced" crew, w.r.t. Moon mission) selected for Apollo 11? [duplicate]

Apollo 10 was practically a full dress rehearsal of moon landing, except the landing act. As such, its crew (astronauts) gained all the experience needed for a moon mission. They were best suited to &...
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Why didn't NASA simulate the conditions leading to the 1202 alarm during Apollo 11?

If I understand it, the alarm during the first Lunar descent was due to the computer being overloaded by too much RADAR data. That sounds like something that they would have thought to simulate, but ...
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3 answers
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Lot 345 of Christie's "Voyage To Another World" auction supposedly has the only photo of Armstrong on the Moon, but isn't this one also? [closed]

Christie's press release Christie's Voyage to Another World: The Victor Martrin-Malburet Photograph Collection includes the following: Lot 345, The only photograph of Neil Armstrong on the Moon, July ...
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1 answer
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Astronauts of Apollo 11 facing extreme temperatures

I recently read that temperatures on the moon can vary from -100 °C in the shade to 100 °C in the sunny part. How did astronaut suits cope with these extreme temperatures? Is the same technology used ...
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What are the "18 rescue missions" on Apollo 11, and which 10 of them did Michael Collins not feel comfortable with?

Regarding this tweet from the man himself. I take it to mean abort modes in some form or other for the entire mission? Perhaps just after LM descent? What are the 18 failure modes, and (if there's any ...
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How was a safe tilt angle ensured for liftoff of the Apollo LM?

Recently I read that one of the pre-conditions (among many others) of a successful lift off of the LM ascend stage, from the moon surface, was that the LM ascend stage "axis" should be "...
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What is the constant g-phase in Apollo re-entry, and why does it not show up on the graph?

On the Apollo 11 Flight Journal Day 9: Re-entry and Splashdown, it says something about the "Constant g-phase". This is what the ALSJ says: Planned drag level (deceleration) during the ...
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1 answer
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What were these bent clamps at the top of Apollo 11 CM used for?

An image of the top of Apollo 11 CM from heroicrelics dscc9638 and dscc9660. What were these bent clamps (marked with green arrows by me) used for?
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What was the nature of the communication problems during Apollo 11's Eagle's descent? How were other antennas selected?

In the video of Los Angeles station KTLA's Frank Buckley interviewing astronaut & Apollo 11 CAPCOM Charlie Duke a communication problem and antenna selection is described: BUCKLEY: Many of us who ...
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1 answer
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Apollo 11 first stage separation

Did Apollo 11 climb vertically upwards i.e. radially outwards, or "normal" to earth surface till it separated its first stage (approximately 38 Miles/60 Km or so..), or did it tilt at or ...
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Computers for Apollo Mission

Why did NASA invest so much amount of time and money on developing computers for Apollo Missions? Wouldn't the Man on Moon mission have been far easier and faster if the Astronauts drove the ...
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2 answers
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Why did Apollo 11 land at the sea of tranquility?

As we all know in 1969 Apollo 11 landing made history but, why did it land specifically at the sea of tranquility also known as Mare Tranquilitatis. Probably they would have chosen this because of ...
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How did they access the LM to mount the flag package while the Apollo stack was already on the launch pad?

NASA decided rather late to take a flag to the Moon on the Apollo 11 mission. In fact, they were so late that the package containing the flag was only attached to the leg of the LM on July 9th, two ...
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What happen to the Smithsonian Institutes 3d scan of the Apollo 11 Command Module?

"Since its landing on July 24th, 1969, the Columbia has been kept sealed in plexiglass at the Smithsonian Institute in Washington, DC. That is, until recently, when the software company Autodesk was ...
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Was there any effort made to have Apollo 11 land on July 4? [duplicate]

President Kennedy set a goal of landing a manned mission on the moon by the end of the 1960s, as stated in his well-known speech to Congress on 25 May 1961 ("I believe that this nation should commit ...
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apollo 11 moon landing longitude latitude from PDI to Touchdown

I'm reconstructing the entire apollo 11 mission trajectory. I'm now at the moon landing. Does someone know specific documents specifying longitudes and latitude at the different interfaces starting ...
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Apollo 11 Moon orbital elements [duplicate]

I'm simulating several pieces of the Apollo 11 mission. I'm now at the point of performing lunar landing sequence, and I'm looking for data. I found this report, but it only has partial data, while ...
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9 votes
1 answer
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was Saturn V engine J-2 throttleable?

Were the J-2 engines of the third stage of Saturn V throttable? I know that the F-1 for first was not, but what about J-2? I could not find any information about it. Any reference or info for this? ...
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Apollo 11 trajectory logs [duplicate]

is there any place where to download the log files of the entire Apollo 11 mission? I want to rebuild it in Matlab and I'd use it as reference. I've seen that there is AGI's reconstruition with STK, ...
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What do these Apollo era terms mean?

@Ludo's answer to If I wanted to reconstruct an entire Apollo mission's crewed spacecraft trajectories, what are the key sources of historical data I'd look for? links to Apollo Mission 11, ...
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What was back-up plan in case of Apollo CSM Primary Guidance System IMU went to gimbal lock?

In Apollo-11, during preparations for docking with Command and Service Module in lunar orbit, Armstrong and Aldrin managed to put Lunar Module Primary Guidance System Inertial Measurement Unit (IMU) ...
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How did LM circuit breakers operate? (famous engine arm CB broken by Aldrin)

From Apollo Lunar Surface Journal: "112:56:28 Aldrin: Houston, Tranquility. Do you have a way of showing the configuration of the engine arm circuit breaker? Over. (Pause) The reason I'm asking is ...
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Why was Apollo 11 launched in summer?

The question could seems stupid, but I think that best moment to launch a rocket is when temperature is lowest in order to achieve the best performance in a reaction engine. I do not know if there is ...
6 votes
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Why did a phase mismatch between the Apollo 11 LM's RR and AGC generate a large numbers of interrupts?

A critical aspect of the cause of the famous 1202 and 1201 alarms reported by the Apollo Guidance Computer (AGC) during the decent of the Apollo 11 LM is that the rendezvous radar (RR) was using a "...
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Where in orbit was Michael Collins when the LM landed?

In the NPR podcast On Apollo 11 Anniversary, A Former Crew Member Reflects On The Lunar Trip Scott Simon interviews Michael Collins. Near the beginning is this exchange: SIMON: We asked the man who ...
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Did the 1202 error and associated reboot prevent disaster on Apollo 11 landing?

Most accounts of the famous 1202 error reported by the AGC during landing of the Apollo 11 LM characterize the event as result of the successful operation of the AGC, flushing an resetting an ...
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Help understanding this Apollo 11 docking probe image, what are we looking at, and from where?

The New York Times mix media "article" Apollo 11 As They Shot It shows original photographic images taken by the astronauts and related quotes by them. In one section the text says: ...
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What's the "thump" I hear listening to Apollo 11 playback?

I've been listening to live playback of the Apollo 11 mission at https://apolloinrealtime.org/11/ Besides the expected static and hums, from time-to-time I hear a "thump", sometimes one, sometimes ...
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How much could "sublimator operation" have possibly contributed to Apollo 11's "sizable downrange miss"?

This answer to the question Apollo-11 delta-v “due to residual pressure in the docking tunnel pushing the spacecraft apart” detected as it happened? Was it corrected? quotes from the Apollo 11 Mission ...
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1 answer
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What are "uncoupled attitude maneuvers" and why do them?

This answer to the question Apollo-11 delta-v “due to residual pressure in the docking tunnel pushing the spacecraft apart” detected as it happened? Was it corrected? quotes the following passage from ...
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Apollo-11 delta-v "due to residual pressure in the docking tunnel pushing the spacecraft apart" detected as it happened? Was it corrected?

This answer to How far off did Apollo 11 land? mentions that: Eagle was already 3 miles downrange from the expected position at the start of descent, due to residual pressure in the docking ...
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