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Questions tagged [apollo-program]

NASA's Apollo program was a 17-mission program that focused on landing a human on the lunar surface. The program was the third human spaceflight by NASA, after Mercury and Gemini.

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How do we know the Apollo Moon landings are real?

Since about 1976, conspiracy theories denying the Moon landing and claiming it was all faked have cropped up. As a website devoted to answering questions about space exploration, we receive questions ...
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Apollo communication between the Earth and Moon

How was it possible for astronauts to send back tv/radio signals to earth from the moon? I have just been teaching my son about waves behavior and understand that radio waves are reflected back to ...
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Launch window for the Apollo Lunar Module?

If something would have gone wrong after a successful Moon landing requiring to ascent as soon as possible, what about the launch window for the lunar rendezvous maneuver? Could they ascent at any ...
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How close did Apollo 16 astronaut Charles M. Duke Jr. get to the edge of Plum crater?

The New York Times article What Happened to Earth’s Ancient Craters? Scientists Seek Clues on the Moon’s Pocked Surface includes a NASA photo with the caption: Astronaut Charles M. Duke Jr., of the ...
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Left behind photo

After several trips to moon there were several items left behind on the moon's surface, including foot prints. Is there any photo or registry of any of those items taken recently?
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What was this Ziploc bag used for on an Apollo 14 moonwalk?

And how the heck would an astronaut have opened it with his gloves on? Is that bag likely to still be there in good condition, or would it have been broken down by radiation by now? Was it normal to ...
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Why did Apollo have a crew of 3?

Why did Apollo have a crew of three when only two actually reached the surface of the moon? I can see it makes sense for the Lunar Module only to seat two astronauts. Less mass to land softly on the ...
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How did NASA choose who descended in the LEM during the Apollo missions?

Referring to the Apollo missions, As many know, during Apollo 11, Michael Collins didn't descend with Neil Armstrong and Buzz Aldrin towards the moon. I can only begin to imagine the sadness of not ...
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How many Lunar Surface Hasselblad cameras were left on the Moon?

There were six Apollo missions that landed on the Moon. Each mission was equipped with at least two Lunar Surface Hasselblad cameras left on the lunar surface before ascent. But the total number of ...
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Why does the Apollo-8 Trans-Lunar Injection burn appear to be pulsing in this photo?

This tweet called my attention to The Smithsonian National Air and Space Museum story Photographing Apollo 8's Orbit Toward the Moon. The story is quite an interesting bit of space history and worth a ...
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Did Apollo's velocity slow down after TLI due to Earth's gravity?

I assume Apollo's velocity slowed down after it left Earth orbit, for how long was it decelerating. Did it start accelerating as it approached the Moon. What was the rate of deceleration due to ...
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Has in-space refueling been done?

Before the Apollo program committed to the lunar orbit rendezvous mode, one of the Earth orbit rendezvous proposals involved launching two Saturn Vs, one with the Apollo spacecraft and large lunar ...
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Looking for Apollo 11 powered descent video

At a science museum I visited on my 2018 fall vacation (I think it was the Chicago MSI), I saw a video loop that looked and sounded very much like part of the moon landing multimedia show at the ...
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Apollo-SLA & LM air pressures at launch

At the time of launch what was the air pressure in the Apollo LM, and the spacecraft-LEM adapter section (SLA)? Was the air vented from the SLA as the vehicle entered orbit?
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Docking of CSM with LM

After separation from the SLA (by about 50-100 feet), the CSM "turned around" and docked with the LM to pull it out. This turning around was done by a 180 degree change in orientation. This could have ...
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Docking of Command and Service module with Lunar module

Is there any video available which is shot inside CSM during the process of docking with LM to pull it out of adapter?
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What do you call the Apollo LEM plus CM (Command Module) when they are connected?

In the question How far away can spacecraft be seen with an optical telescope? I used ...Apollo 14 CM & LEM and the Saturn IV B..." for lack of better words. Unlike some people I (don't) ...
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How did NASA get the video camera on the Moon to track the LM ascent stage, considering the substantial delay?

The Moon's distance can be as much as about 406,000 km from Earth. That's a round trip light time of roughly 2 x 406,000 / 300,000 = 2.7 seconds or more, depending on how the signal was relayed to ...
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At what time in the Apollo 14 mission did the maneuver shown in this image happen, and what exactly was happening?

In a search for information for this answer I received this google books link of Comment: The Relevance of Space, by Arthur Kantrowitz, Bulletin of the Atomic Scientists 197, 4 April 1971, pp 32-33. ...
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Exit film of moon landing departure

On Apollo 15, 16, and 17 NASA filmed the Lunar Module taking off and leaving the moon. With no-one on the moon how could the the camera move to follow it and who brought the exposed film back to ...
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Puzzler: Precisely what maximum distance from the Earth did the Apollo 13 astronauts achieve?

tl;dr: Both this answer and this answer quote Wikipedia to state that the Apollo 13 astronauts reached 404,171 km from Earth. I'm not able to reproduce that value. According to JPL's Horizons the ...
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How far from Earth were the Apollo astronauts when they left the Earth's magnetosphere?

I am assuming the Apollo missions recorded radiation levels as they travelled to the Moon. Have those records ever been released, as a way of determining when the Apollo astronauts left the ...
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What's the closest that an Apollo mission passed GEO on it's way to the moon?

@Uwe's comment No astronaut ever visited geostationary orbit at 22-23k miles to maintain or deploy satellites. The Apollo astronauts just rushed by on their way to the Moon and back. below the ...
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What was the view from the Apollo spacecraft while travelling to the moon?

From what I read on the internet, I took around 3 days for Apollo 11 to get to the Moon. I'm curious what was the view from the windows of the spacecraft during the journey. What did the astronauts ...
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Bits per core for the different versions of the Apollo guidance computer core rope memory?

The first version of the Apollo guidance computer had a ROM of only 12 K words of 16 bit. Later it was doubled to 24 K and finaly tripled to 36 K words. The first version of core rope read only ...
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If the astronauts on Apollo 11 had landed safely on the moon but could not take off, would there have been a rescue mission?

Say they landed on the moon but discovered the ship was damaged during the landing and they could not launch again. What would have been the plan? Would another crew have been sent to rescue them? ...
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Was there fuel consumption budgeting for Apollo 11 Lunar module?

Did the astronauts aboard Apollo 11's Lunar Module have any stated or imposed limitation or restriction on the amount of fuel they could use while in lunar orbit and performing landing maneuvers? I am ...
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How does the efficiency of the Rocketdyne F-1A compare to the F-1?

The Rocketdyne F-1 was to be updated with a new turbopump and gas generator assembly, without other major component redesign. This was to result in a thrust increase from around 1,522,000 pounds force ...
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Was splashing down on the USSR-controlled territory a possibility for Apollo missions?

From what I understand, the planned landing areas for Apollo command modules were pre-programmed beforehand and happened in the South Pacific. Was there any remote possibility of an emergency ...
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Did the Apollo astronauts hear any external sounds during a lunar EVA?

Did any sounds resonate through their boots or any part of their environmental suit? Could they hear the folding or rubbing of the material of their suits? Did anything impact their boots that might ...
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What modifications constituted the ‘reorificing’ of F-1 engines on later Saturn V flights?

The topic of uprating the Saturn V’s first stage engines appears to have been widely discussed, and yet there is little agreement as to how it was done. Early Rocketdyne F-1 engines quote lower ...
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Apollo guidance computer ROM addressing using the ROM bank register, what is the bank register size?

The Apollo guidance computer had 36 K words of core rope ROM. To address 36864 words, a 15 bit memory address for up to 32768 words is not enough, 16 bits are needed. This Wikipedia article describes ...
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How accurate is this Apollo Command Module replica, and why would it be copper-colored?

Reading the Quartz article How do you design an office for robots? I saw what is certainly a replica of most likely an Apollo command module ("space capsule") in several of the photos, the largest of ...
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What was the nature of the visible part of the viscous wake trailing the Apollo CM during reentry?

This diagram suggests a helix in the wake, was it a single-helix, a multiple helix, or a superhelix? Is there any other part of the wake that would be visible?
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Did the Apollo lunar module descent stage have a role as a sort of service module?

To minimize the re-entry mass of the Apollo command module, essentially all of the mission supply of command module consumables was stored in the service module. Was there a similar arrangement ...
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Launch Accelerations: Values, history

This topic: What G-forces do different launchers cause? indicates that current satellite launchers are limiting peak acceleration to about 4g. I'm pretty sure the STS (Shuttle) did the same. My ...
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Did the Apollo astronauts ever describe reentry deceleration?

Did the Apollo astronauts describe any differences in how it felt in the CM as it passed between the hypersonic, supersonic, transonic and the subsonic zone? Did the CM shake more or less in ...
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How long is the Apollo Lunar Module extraction window?

In Apollo lunar missions, the Command/Service Module extracts the Lunar Module after S-IVB's translunar injection burn. Since all three spacecraft were on a transfer orbit, they would be in the ...
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Apollo recovery zone(s)

For the Apollo missions that left Earth orbit, were there multiple recovery zones for each splashdown? How big was each zone?
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Hypersonic Inflatable Aerodynamic Decelerator entry to Mars' atmosphere

Is it known whether or not a Hypersonic Inflatable Aerodynamic Decelerator inflation and entry into Mars' atmosphere would produce more violent vibrations and lateral movements than was experienced by ...
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For an Apollo Lunar Module Ascent Stage launch, what is the optimal profile of $\beta$ (or $\gamma$) vs time?

When Apollo astronauts departed the lunar surface in the Lunar Module's Ascent Stage, it appeared to rise vertically ($\beta$ = 0) for ~10 seconds and then begin the "tipover" (videos of Apollo 15, 16 ...
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What was the colour of the shoes used by the Apollo astronauts in moon landing?

The pictures from Apollo landing despite being in high resolution, does not reveal the right colour of the shoes used by the astronauts during the EVA on the moon. An example - Buzz Aldrin picture ...
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How did the Apollo Service Module reenter?

I always assumed that after the Apollo Command Module separated from the Service Module, the SM was effectively inert and was simply left to re-enter of its own accord. However, from the Apollo 11 ...
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How does the Apollo LM ascent guidance program P12 actually work?

P12 is the AGC guidance program for normal ascent from the lunar surface to orbit. According to the mission planning documents, after separation and ignition, the ascent stage holds its initial ...
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How many minutes of Lunar Sim did Neil Armstrong get?

A quick follow-up to What were the differences between the LLRV and LLTV? These craft were provided with a zero-zero ejection seat. The above reverenced article on wikipedia mentions Neil Armstrong ...
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How easy would opening an Apollo capsule following dry landing be?

To help frame the problem, I have written the following scenario: It's December 19, 1972 and the Apollo 17 has returned to Earth, but something went wrong and they landed in the middle of the Outback....
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What coordinate system was used for the Apollo missions?

This is specifically about the Apollo missions, which are not touched in this related question. Did they use one coordinate system throughout the entire mission, or did they switch depending on the ...
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What was the mascon “fix” used by Apollo 12?

According to the mascon entry on wikipedia: At that time, one of NASA's highest priority "tiger team" projects was to explain why the Lunar Orbiter spacecraft being used to test the accuracy of ...
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How do you find lunar flyby using Apollo 13 mission report data?

Link to mission report: https://www.hq.nasa.gov/alsj/a13/A13_MissionReport.pdf So Im trying to do analysis on the mission phases of Apollo 13 but my part is to only focus on the flyby part. My ...
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Did astronauts on the moon poop in front of each other?

I know about the Apollo pooping bag. The question is, in the CSM, was there any space to use it privately? I suppose while coasting towards the Moon they could use the LM, but on the return trip? Any ...