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.
710
questions
4
votes
0
answers
119
views
Was Apollo 8 lunar orbit entry speed intentional at 7,777 ft/s?
When Apollo 8 first went behind the back side of the Moon, it was traveling at 7,777 feet per second (https://history.nasa.gov/afj/ap08fj/12day3_lunar_encounter.html). Was the speed being all 7s (the ...
- 41
6
votes
1
answer
76
views
Apollo ALSEP RTG shorting switch to prevent overheat of the RTG?
I found these lines in the Apollo 14 Lunar Surface Journal:
116:07:37 Mitchell: Houston, the current reading is 8.
116:07:42 McCandless: Understand 8 amperes before pressing the
(shorting) switch.
...
- 46.6k
2
votes
1
answer
94
views
Understanding the Viewgraph by Dr. John Houbolt and the probability of success calculation of a Lunar Landing
The well known Dr. John Houbolt used a viewgraph to explain the much higher probability of success with LOR in comparison to EOR and Direct Flight for a lunar landing.
I used Python to check the ...
- 46.6k
2
votes
0
answers
120
views
What is the most efficient method of landing for space capsules returning to earth? [closed]
I have read that the Russians don't land on water because they don't have access to a large warm-water coastline like the US. US has large swaths of land and water and most US capsules (Apollo, Dragon,...
- 71
6
votes
4
answers
884
views
Were Hasselblad cameras used in space after the Apollo mission?
Analog Hasselblad cameras with photochemical film were used extensively during the Apollo mission to the Moon.
Were they used later for Spacelab, Space Shuttle and Mir or ISS?
- 46.6k
6
votes
2
answers
1k
views
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 ...
- 61
4
votes
0
answers
120
views
Reference request: Rocketdyne Document R-3896-4 "F-1 Rocket Engine Illustrated Parts Breakdown"
Various sections of the Rocketdyne F-1 document R-3896 can be found scattered about the web, but I can't find R-3896-4. It's described as
R-3896-4 F-1 Rocket Engine Illustrated Parts Breakdown
This ...
- 159k
12
votes
1
answer
294
views
What does it mean to tune the Saturn F-1 engine to a frequency, and how is the tuning done?
Chapter 10 of Chariots For Apollo remarks the following in discussing the pogo problem of Apollo 4 and 6 and the role of the first stage F-1 engines in that:
The mission analysts later discovered ...
- 12.1k
13
votes
1
answer
1k
views
What kind of signals and encodings were used to send tilt/pan commands to TV cameras on the Moon (up through Apollo)?
This answer to Has anyone in space beyond LEO seen or has anything photographed a non-pointer laser from Earth? shows a frame from video shot by Surveyor 7 on the Moon, looking at Earth, and ...
- 148k
6
votes
0
answers
90
views
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 ...
- 2,823
4
votes
2
answers
510
views
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 "...
- 2,823
4
votes
2
answers
207
views
How did "STOP" button work on Lunar Module?
The button to stop the descent engine of Lunar Module was not "just a button": it evolved and changed multiple times during development, and this is one of the many existing designs:
What ...
- 2,823
39
votes
3
answers
5k
views
Why did the Lunar Module have such an irregular shape? Didn't it add weight and complexity?
Given the very stringent mass requirements, why was such a complex design choosen? I think an irregular shape weights a lot more than a squared box, not to mention the complexity to build it.
I saw in ...
- 2,823
12
votes
1
answer
1k
views
Would the free return trajectories of Apollo 8 to Apollo 11 have made them reenter Earth's atmosphere?
Apollo 8 to Apollo 11 flew on a free return trajectory (later missions left the free return trajectory during a mid course correction after TLI).
If those spacecraft had just stayed on that trajectory,...
- 1,153
10
votes
3
answers
2k
views
Apollo Guidance Computer (AGC) Compiler?
I found a brochure by Raytheon about the Apollo Guidance Computer.
A compiler was announced for the AGC.
As far as I know the AGC was programmed in assembler only. What kind of high level language ...
- 46.6k
3
votes
0
answers
106
views
How to "decode" this ancient log of Apollo Guidance Computer (AGC)?
I found this interesting document:
https://www.ibiblio.org/apollo/Documents/apollo_11_computer_words.pdf
But the scan quality is very very poor!
I tried interpreting the headers, but some characters ...
- 2,823
21
votes
3
answers
3k
views
Why are unused launch abort rockets jettisoned rather than used to augment thrust?
Launch abort rockets use powerful rockets. For a pad abort, they must have enough thrust to lift the capsule to an altitude where parachutes can function.
The Apollo launch escape rocket had a 155,...
- 6,450
8
votes
2
answers
855
views
How long would it have taken to launch an Apollo contingency flight?
How long would it have taken to launch an Apollo contingency flight, if, for example, the lunar lander couldn't have got back up to orbit? Could the lander have held three astronauts?
- 81
1
vote
0
answers
65
views
Fuel profile for Apollo 11
I downloaded a dozen of NASA documents about post-flight analysis of Apollo 11 mission, but I cannot find a table or a plot of fuel usage and remains;
Some of the documents which I found:
http://www....
- 2,823
4
votes
0
answers
126
views
Two additional Saturn V flights planned in 1967 - but for what?
Per this question, there was no "cancelled" second run of Saturn Vs: only the first fifteen were ordered, and no second batch was ordered and then later cancelled. This had always been my ...
- 7,406
11
votes
3
answers
2k
views
Docking in space
I read about the mechanism of "docking" of Command Modules & Lunar Modules of the Apollo missions (the probe & drouge). It seems it was far too complex & had too many parts. I ...
- 3,272
12
votes
1
answer
1k
views
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 ...
- 1,091
8
votes
2
answers
257
views
How was AS-212 (Saturn 1B) supposed to carry both a CSM and LM?
I recently came across this overview image of Saturn 1B missions:
(source: NASA)
AS-212 is asterisked with the note (bottom-left of the image) that it is "scheduled to carry both a CSM and LM.&...
- 12.1k
1
vote
1
answer
92
views
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 ...
- 19
15
votes
1
answer
2k
views
What does the ATOLL programming language look like?
During the Apollo program, checkout tests of launch vehicle and spacecraft systems were gradually being automated, moving away from the manual processes during the early years of the space program to (...
- 12.1k
13
votes
2
answers
2k
views
Where did AS-206 go between 1967 and 1973?
The Apollo program was a bit stressful. In 1967 a lot of things went wrong, especially with the delivery of the lunar module:
General Phillips's office originally planned to launch the first lunar ...
- 12.1k
5
votes
0
answers
145
views
Would deorbiting a crippled Apollo spacecraft using the Saturn V third stage have been a reasonable contingency?
In the event of the loss of all fuel cells in an Apollo mission, would reaching orbit with the third stage, then using the relight to de-orbit somewhat near the normal location in the pacific be a ...
- 834
9
votes
2
answers
1k
views
How were registers in the Apollo Guidance Computer implemented?
I'm having a hard time finding information on the composition of the AGC's registers. Were they also Magnetic Core Memory or something else?
- 193
10
votes
2
answers
294
views
Could Apollo's Sextant navigation use similar geometry as Marine Navigation?
Could Apollo's Sextant navigation for Cislunar Celestial Navigation use similar geometry as Marine Navigation?
My grandfather would be familiar with the instrument in this astronaut’s hands, although ...
- 6,450
12
votes
0
answers
187
views
What space capsule is this part from?
One of my relatives has this metal component sitting in their backyard. It was a souvenir that my grandfather got to keep from his days working in the aerospace industry (primarily for Boeing). My ...
- 221
12
votes
1
answer
1k
views
What distance did the Apollo CSM go before turning round to pick up the Lunar module?
I have looked for quite a while to find this out, and as yet have not been able to work out the answer.
On the Apollo missions 10 to 17 the CSM had to turn round to pick up the lunar module between ...
- 121
2
votes
1
answer
69
views
What was the size and mass limit of a PPK for Apollo?
Astronauts are allowed to take a personal preference kit (PPK) with them to space. The Wikipedia page for PPKs states how they are defined by the Federal Aviation Regulations as of January 2001. This ...
- 4,820
0
votes
1
answer
124
views
Star visibility from space
During the Apollo missions the astronauts of the Apollo 15,16,and 17 performed cislunar space EVAs to check on experiments located in an external bay but said they could see no stars:
Transcript from ...
- 35
14
votes
3
answers
2k
views
How did the lunar module avoid problems with flying regolith when taking off?
In November 2020, a SpaceX rocket suffered damage due to a problem with the launchpad, and future missions to the Moon and Mars could suffer similar problems since there won't be a launchpad at all.
...
- 4,820
5
votes
0
answers
65
views
Were there backup routes planned for the Apollo LRV?
I just finished reading "A Man on the Moon" by Andrew Chaikin, an amazing read. For the missions involving the Lunar Roving Vehicle (LRV, Apollo 15-17), there are some mentions of astronauts ...
- 483
20
votes
2
answers
1k
views
How Did One Stand in The LEM Before Descent? [duplicate]
This is really simple, but i've never seen it discussed. One piloted the Apollo LEM standing up, without many restraints. But before the LEM ignited the descent engine, it was practically in free fall....
- 1,301
4
votes
1
answer
101
views
Was the Lunar Topographic Camera ever used?
From the APOLLO EXPERIENCE REPORT -
PHOTOGRAPHIC EQUIPMENT AND OPERATIONS
DURING MANNED SPACE-FLIGHT PROGRAMS
NASA TN D-69
However, more detailed photography was required to evaluate the
...
- 46.6k
0
votes
1
answer
278
views
What would have happened if all Apollo computers failed?
Let's assume all available computers in the command module and the lunar module failed and the astronauts were unable to repair them in flight.
Would they have been able to return back home safely ...
- 654
3
votes
1
answer
108
views
Saturn 1 booster performance/structures
I was recently comparing some basic performance stats and noted that the Saturn 1/ 1B has very similar load to orbit figures to the Falcon 9.
This seemed interesting to me, which brings up several ...
- 31
37
votes
1
answer
6k
views
What if Apollo Lunar Rover failed on the Moon?
Let's assume that our Apollo astronauts are on the Moon, driving their Lunar Rover and they are far away from the LM. What if LRV failed during the mission? Would they be able to get back to the LM on ...
- 654
0
votes
1
answer
144
views
How long was Apollo put on hold after Apollo 1?
After Apollo 1, the Apollo program was put on hold while the accident could be investigated. How long was the program put on hold? How much did it delay the actual Moon landing?
- 4,820
9
votes
2
answers
490
views
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 ...
- 686
4
votes
1
answer
182
views
Why did Apollo missions open the propulsive Hydrogen vents during the coast phase?
According to Figure 2-1 of the SA-503 flight manual the LH2 continuous vent was opened during the coast phase, and closed during the ullage stage of the S-IVB restart T_6 + 0:00:42.0 (but open for ...
- 141
5
votes
1
answer
202
views
Are there any markings that uniquely identify each Saturn-Apollo combination?
This question made me wonder: are there any markings on the Saturn I/IB/V launch vehicle, Apollo service module or command module that uniquely identify each vehicle (i.e. AS-5xx)?
It doesn't have to ...
- 12.1k
2
votes
1
answer
147
views
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:...
- 21
4
votes
1
answer
571
views
Did any Apollo missions have enough fuel left to bring back the LM ascent stage?
A recent question asks why the Apollo lunar module wasn't routinely brought back when returning from the Moon, so it could be used as an Apollo 13 style lifeboat. The answers correctly state that ...
- 46.5k
16
votes
3
answers
7k
views
Apollo 14-17 - Why didn't they keep the Lunar Module docked as a lifeboat for the way back to Earth?
During Apollo 13, the Lunar Module had to be used as a lifeboat in order to save the astronauts. Then, it was only jettisoned from the Command Module shortly before Earth re-entry (even after the ...
- 279
6
votes
1
answer
157
views
How did the Carbon Dioxide gauges work on Apollo?
The book Lost Moon by Jim Lovell and Jeffrey Kluger had this interesting description in Chapter 10 (page 254 in my copy) regarding the CO2 gauges (emphasis added):
Carbon dioxide concentrations in ...
- 16.8k
12
votes
2
answers
2k
views
Would've the CO2 scrubbers failed before the O2 supply ran out during an Apollo moonwalk?
This absurd video on Reddit of the Earth blowing up while Apollo astronauts were walking on the Moon got me thinking.
Assuming something catastrophic happened to the Lunar Module the moment the two ...
- 6,747
3
votes
1
answer
284
views
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 ...
- 2,809