142

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 the moon to rest in peace. These brave men, Neil Armstrong and Edwin Aldrin, know that there is no hope for their recovery. But they also know that there ...


67

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 program but was grounded due to a heart issue. Since he had been through astronaut training, but wasn't in competition for a mission assignment himself, he was ...


64

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 in this layer can reach 2,500 °C (4,530 °F) during the day. Even though the temperature is so high, one would not feel warm in the thermosphere, because it is ...


58

Like everything else, the ascent and descent stages were built to be as light as possible. But because they knew they would operate only in a vacuum, many things really didn't need to be sturdy, nor did the shape of it matter. It would never have to deal with aerodynamic drag. In fact, the descent stage was designed to buckle in the right places upon landing,...


55

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 accident which disabled the service module). Once out of power, it would be unable to circulate air or to maintain a comfortable temperature inside. Committing ...


51

The process was a great deal more sophisticated than pointing and thrusting, and the CSM was cooking along at over 1600 m/s, circling the moon every 2 hours. Mission control, however, had fairly precise tracking of the positions of both the CSM and the landing site, and they computed the correct time of launch to begin the rendezvous using powerful Earth-...


41

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 crew left the LM's rendezvous radar, which was used to find their way back to the command module, switched on in the "SLEW" mode, so it would be ready if they had to abort the ...


35

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 as CapCom: 104:59:27 Garriott: Columbia, Houston. Over. 104:59:34 Collins: Columbia. Go. 104:59:35 Garriott: Columbia, Houston. We noticed you are ...


32

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 significant amount of heat from the thermosphere to a spacecraft travelling through it. Spacecraft do need heat protection to survive re-entry, but that is because they'...


24

Neil Armstrong thought they had a 90% chance of survival, but only a 50-50 chance of landing on the first attempt. I've seen one source that says Aldrin was less optimistic, estimating 2/3 chance of survival and 1/3 chance of success. At that time, Apollo spacecraft had flown several missions safely, including two lunar orbit missions, so presumably he was ...


24

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 recorders which were used to store and relay both telemetry and onboard voice data. The CM system was called DSE (Data Storage Equipment) and the LM system was ...


21

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 rocket changes, so escape tower, CM, both interstages. Shockwaves are rarely visible. In the lower atmosphere you can sometimes see condensation in the low-...


21

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 Stage Ignition?, a fully-fueled Saturn V was required to launch Apollo 9. Since the lunar module was extracted before a "TLI burn", the third stage still had lots ...


21

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 powered descent engine burn was initiated at 102:33:05.01. The time was as planned, but the position at which powered descent initiation occurred was about 4 ...


20

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 indicated that the guidance computer was being overloaded with tasks. It was having trouble completing its work in the cycling time available. "We looked down at ...


20

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 touchdown was about 4 miles downrange from the intended landing site: 104:15:13 Duke: Roger. Understand. Omni Charlie. Mike, be advised we have an update for you on ...


19

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 propellant rocket plumes are very faint.


17

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 mode to be used in an emergency. Abort mode IB takes effect at 42 seconds into flight, at about 3km altitude. At 12:55 on the video, the PAO says "altitude is ...


17

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. As far as I know, that was just not something that NASA did or does now. The live TV broadcasts on the way to the moon were not scripted, just as the ISS tours ...


17

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, I think the definitive treatment. Eyles was the LEM descent guidance software programmer! Eyles explains that the problem was actually found on the ground ...


15

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 Earth we perceive orbiting objects: light reflected from the Sun at best. That is, under conditions that the object is large, reflective and properly positioned ...


15

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, the spacecraft decelerates as it moves away from the Earth. Having escape velocity means that your total energy (relative to the Earth in this case) is greater ...


14

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.


14

The shoes of the A7L suit were white with partly-blue "lunar boots" worn over them, but soon were covered in grey-ish dust once on the moon. Have a look at this image on Wikipedia:


14

They absolutely could. The problem is, we don't have high resolution images of the Moon from before those crash dates, and thus it is very difficult to actually tell if a crater is a natural crater or the crash site of Apollo hardware. Bottom line, we've almost certainly imaged it, but we just don't know what we have seen. If you want to take a look, see ...


13

They threw out the PLSS, but that didn't leave them without the use of those space suits entirely. The space suits could be coupled via umbilicals to the LEM ECLSS or to the CM life support system (this was used on Apollo 15-17 for EVAs to retrieve material from the Service Module during the flight back to Earth). The PLSS could store consumables for 4 ...


13

They used the rendezvous radar on the LM to pinpoint the CSM's relative direction, and worked backwards from that info and the CSM's location in order to pinpoint the LM. Here's the commentary from the Apollo 11 Lunar Surface Journal at 121:00:34: [In a 2010 book, From the Trench of Mission Control to the Craters of the Moon, H. David Reed, who was ...


12

The main issue is that the image of the rocket is not taken from the side, but at an angle. We can determine the angle by looking at the apparent length to width ratio of the two stages - note that this screenshot has been taken directly after separation. The first stage seems to be twice as long as wide, the second stage is about three times longer than ...


11

Much of the Flight Journals contains radio communications between the spacecraft and ground control. They were recorded at the control center and transcribed. With kind help from NASA's History Office, the Apollo Flight Journal was prepared from Technical and Public Affairs Office transcripts made at the time. These were converted to electronic text and ...


10

The reasons for that date were: There were a number of considerations which determined the launch windows for a lunar landing mission. These considerations included illumination conditions at launch, launch pad azimuth, translunar injection geometry, sun elevation angle at the lunar landing site, illumination conditions at Earth splashdown, and the number ...


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