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156 votes

If the astronauts on Apollo 11 had landed safely on the moon but could not take off, would there have been a rescue mission?

The following is a speech written for President Nixon, in the event that the Apollo 11 mission did not succeed. Fate has ordained that the men who went to the moon to explore in peace will stay on ...
Fred's user avatar
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69 votes
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How did NASA choose who descended in the LEM during the Apollo missions?

During the Apollo era, Deke Slayton, as chief of the astronaut office, was the primary decision maker when it came to choosing who was assigned to which crews. Slayton was chosen for the Mercury ...
Russell Borogove's user avatar
65 votes

Why didn’t the Spacecraft used for the Apollo 11 mission melt in the Earth’s Atmosphere?

Although the temperature at altitude can be several thousands of degrees, the atmosphere is so thin it does not transfer heat efficiently. Wikipedia explains it very well - The highly diluted gas ...
david_c's user avatar
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56 votes

If the astronauts on Apollo 11 had landed safely on the moon but could not take off, would there have been a rescue mission?

The Apollo lunar module was battery powered, so could only maintain a livable environment for a few days (this was a major concern for Apollo 13, since the crew was reliant on the LM after the ...
Russell Borogove's user avatar
49 votes
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What is the text on Neil Armstrong's space suit's left glove?

It's called, appropriately enough, the "sewn-on cuff checklist". Aldrin's tasks are in parentheses as shown by the (LMP) annotation at the top. It's a checklist of pretty much everything ...
Organic Marble's user avatar
42 votes
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What were the problems on the Apollo 11 lunar module?

These were the "1202" and "1201" program alarms, which were warning signals that the lunar module's computer was becoming overloaded. During Apollo 11's descent to the moon, the ...
Russell Borogove's user avatar
41 votes
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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?

They used the Mobile Service Structure (MSS), which for some reason is rarely shown in Apollo pre-launch photos. The large work platforms at upper right completely surrounded the spacecraft and ...
Organic Marble's user avatar
36 votes
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Did Michael Collins ask for a fourth gimbal for Christmas? Is there a recording or transcript?

A transcript exists in the Apollo 11 Lunar Surface Journal, Postlanding Activities, with extensive annotations. The exchange begins at Mission Elapsed Time 104:59:27. Owen Garriott has just taken over ...
GNiklasch's user avatar
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33 votes

Why didn’t the Spacecraft used for the Apollo 11 mission melt in the Earth’s Atmosphere?

It's not the temperature that matters, it's the heat transfer. The density of the atmosphere up in the thermosphere is very very thin. There simply isn't nearly enough mass to transfer any ...
gerrit's user avatar
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33 votes
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What did Charlie Duke mean by "down on the ground"?

Based solely on my long experience working behind the scenes in the Mission Control Center (as an instructor, not a flight controller) "on the ground" is unlikely to mean anything other than ...
Organic Marble's user avatar
30 votes

Why did Apollo 11 land at the sea of tranquility?

The set of landing sites considered for all the Apollo missions was driven by a desire to sample a wide variety of lunar geology, but the order for them was chosen to make the first landings easiest ...
Russell Borogove's user avatar
29 votes
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Why didn't NASA simulate the conditions leading to the 1202 alarm during Apollo 11?

They did simulate the debugging alarms, such as the 1201 and 1202. From Apollo: The Race to the Moon*: On July 5, just eleven days before the launch, [...] the scenario included one of the computer ...
DylanSp's user avatar
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25 votes

Why didn't NASA simulate the conditions leading to the 1202 alarm during Apollo 11?

As DylanSp's answer notes, the 1201/1202 alarms were simulated, but the details of the computer overload that caused them on the Apollo 11 flight were complex, and were not specifically simulated ...
Russell Borogove's user avatar
24 votes
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How were the Flight Journals of the Apollo missions originally transcribed/recorded?

Besides the recording equipment Earth-side, which picked up the "air-to-ground loop" (i.e. voice transmissions between the spacecraft and mission control), both the CM and the LM had multitrack tape ...
Russell Borogove's user avatar
23 votes

The speed of Apollo 11 at first stage separation was apparently only about 40% of what NASA claims? What does this indicate?

That is not a shockwave. It looks like the edge of the second stage engine exhaust plume. If it were a shockwave, more shockwaves should be visible: one at each point where the diameter of the ...
Hobbes's user avatar
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23 votes
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Who filmed the Apollo 11 trans-lunar injection?

The "TLI burn" was filmed by the crew of Apollo 9 - an Earth-orbit test of the lunar module. As explained in Scott Manley's video on Youtube, How Did The Apollo 11 Documentary Get Film Of The Upper ...
JohnHoltz's user avatar
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22 votes

Why did a solar eclipse of the sun as seen from Apollo 11 appear to have an elliptical corona?

Answer: The sun has an outrageously strong magnetic field. The corona is highly ionized and interacts with the magnetic field. This produces corona symmetry around the magnetic pole axis. The corona ...
Woody's user avatar
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21 votes
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How far off did Apollo 11 land?

The distance is noted in Apollo by the Numbers. 22,500 feet, that is 6.858 km or 3.7 nautical miles or 4.26 statute miles. From the Apollo 11 Summary, link from called2voyage: The 756.39-second ...
Uwe's user avatar
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21 votes

How far off did Apollo 11 land?

Eagle was already 3 miles downrange from the expected position at the start of descent, due to residual pressure in the docking tunnel pushing the spacecraft apart when they undocked. Final ...
Russell Borogove's user avatar
21 votes

What are the "18 rescue missions" on Apollo 11, and which 10 of them did Michael Collins not feel comfortable with?

The 18 rescue cases are detailed in the CMP Solo Book and they are all for the undocked phase of the mission after the LM undocks from the CSM in lunar orbit. In most cases the LM can not do or can't ...
indy91's user avatar
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20 votes

Would Luna 15 have been visible to any of the members of the Apollo 11 crew?

It's unlikely. They made no report of seeing it, although it was mentioned as a news item at several points during the mission. The sky is big, the moon's surface is big, rockets are fast, hypergolic ...
Russell Borogove's user avatar
20 votes
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Why did Neil Armstrong alone, not NASA, end up coming up with the first words uttered on the moon?

I don't have a definitive answer to this question because I have never come across any discussion of NASA even considering the idea of giving the astronauts a script to read for part of the mission. ...
Mark Foskey's user avatar
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20 votes

What were the problems on the Apollo 11 lunar module?

What happened: With just seven and a half minutes remaining before they were set to touch down on the moon, Armstrong and Aldrin reported a program alarm. "It's a 1202." The 1202 alarm ...
Hobbes's user avatar
  • 128k
18 votes

Apollo 11 mission report shows velocity well below escape velocity thousands of km on the way to the Moon

As @Rikki-Tikki-Tavi points out escape velocity is the velocity you would need at (or near) the surface of Earth to make out out of Earth orbit. Of course, just like anything thrown up into the air, ...
uhoh's user avatar
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17 votes
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Apollo 11 ascent data/observation mismatch

Liftoff in the video you link is at 12:00. 13:00 on the video is one minute after the launch, not 107 seconds. At 12:42 on the video, the "one bravo" call is heard, indicating a change in the abort ...
Russell Borogove's user avatar
17 votes
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Would Luna 15 have been visible to any of the members of the Apollo 11 crew?

On Earth, most of visibility of objects coming from space is created by interaction with the atmosphere. As Moon has no atmosphere, an approaching space object would appear in a similar way to how on ...
Agent_L's user avatar
  • 414
17 votes

If the astronauts on Apollo 11 had landed safely on the moon but could not take off, would there have been a rescue mission?

There was no chance to get them back alive - no ready to launch rocket, no ready to launch spaceship, no lunar module capable to take 3 persons (or land automatically) - just nothing.
Pavel Bernshtam's user avatar
17 votes

What were the problems on the Apollo 11 lunar module?

Supplementary answer (these answers cover it well, but there are a few other things of interest): For anyone interested in the details of this issue, the book Sunburst and Luminary by Don Eyles has, ...
Organic Marble's user avatar
17 votes

What did Charlie Duke mean by "down on the ground"?

Looking over the mission transcript, the term 'the ground' always seems to refer to the various people speaking from Earth to the people up in space. 00 07 46 30 CC: "11, Houston. Those shaft ...
Richard's user avatar
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17 votes
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What does a flight path angle of zero degrees mean at launch?

In this plot from Apollo Saturn V Postflight Trajectory AS 506 the confusion arises because this is the inertial flight path angle (in Apollo documents "space-fixed" == "inertial")...
Organic Marble's user avatar

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