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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27
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4answers
6k views

Reasons behind the “Transposition, docking and extraction” maneuver

The Transposition, Docking and Extraction (TD&E) maneuver was done during the Apollo Moon missions right after the translunar injection. The Command/Service Module (CSM) separated from the S-IVB, ...
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Could the Apollo LM abort mode be engaged after touchdown? What would have happened if it was?

The Lunar Module had an abort mode where the crew basically just had to push the ABORT button on the control panel, and the ascent stage would detach from the descent stage, followed by the ascent ...
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Success-fail probabilities for Apollo XI?

Is it known whether probabilities of success vs failure (and specifically fatal failures) were estimated at the time for the Apollo XI mission? Or perhaps some current estimates?
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Apollo re-entry guidance

I am referencing chapter 7 of the book "Spacecraft Navigation and Guidance" by Maxwell Noton. Can anyone tell me how to determine control gains C1 and C2 in equation 7.58 and 7.59 in respective ...
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1answer
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Which astronaut travelled farthest from Earth?

To-date who has flown farthest from the center of the Earth? Is he alive now?
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Why Did Apollo Smoke Twist When Taking Off?

I've been looking at some references of rockets taking off. I came across the Apollo 14 Saturn V launch and noticed that when the rocket was taking off the smoke coming from around the rocket and from ...
190
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6answers
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Can I borrow a lunar rover?

According to Wikipedia there are 3 LRVs sitting on the moon, in very well defined locations. Would China, or whomever gets to the moon with a person next, be able to get in and drive around in an LRV ...
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1answer
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What were the chances of failing the Apollo 11 mission? [duplicate]

What were the chances of the Apollo 11 mission failing? Consider the following scenarios: least one of the crewmembers dying, failing to land on the Moon, unable to return to Earth, the Soviets ...
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769 views

To what extent did Apollo payload mass drive Saturn capability?

Uwe wrote in an answer that The possible payload of Saturn V was carefully planed for the whole mission, but the difference of the payloads of the missions Apollo 11 and 17 was less than 3000 kg. ...
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Was the Apollo 13 CM guidance computer fully shut down?

I was watching the movie Apollo 13, and one thing struck me as quite odd. According to Wikipedia, [Movie director Ron] Howard went to great lengths to create a technically accurate movie, employing ...
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Apollo guidance

I am studying the Apollo Guidance, specifically the derivation of guidance equation. While laying the baseline, a Target-referenced time (T) is chosen as time variable for guidance calculation of the ...
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Why were the two Quindar tones so close in frequency and not apodized?

This and this answer explain the function of the Quindar_tones within Apollo mission comms. At 2525 and 2475 HZ they are only 50Hz or 2% apart in frequency, and the duration is 250 ms or 0.25 seconds....
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What purpose serve the audible “bip” on apollo radio communications? [duplicate]

When looking at moonwalk videos, we can hear bips. What are those bips? Why are there bips? Do this bips still exist in nowaday space missions?
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Why were there beeps punctuating the voice communications during missions such as Apollo?

Voice communication between ground and spacecraft during missions such as Apollo seemed to be always punctuated by beeps. What was the origin of these beeps? Were they some sort of unavoidable ...
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Before the Apollo 1 fire, what was the plan for the missions leading up to a lunar landing?

The actual Apollo flights 2-6 were test launches of the Saturn rocket, the CM and LM (1 was retired due to the fire). What were the original plans? Did they intend to launch people on a Saturn ...
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Was the Apollo spacecraft always gravitationally bound to the Earth-Moon system?

When the Apollo spacecraft was en route to the Moon, was it an escape trajectory from the Earth-Moon system? If not for the burn(s) to enter lunar orbit, would it have continued in an independent ...
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Which Apollo “mystery” was said to be finally solved by a better rendering engine?

I remember reading several years ago about a mystery or puzzle about a photograph from an Apollo moon landing mission that had to do with why someone's suit was as bright as it was in the photo. There ...
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Was an elliptical orbit considered for the CSM when planning the Apollo moon landing missions?

The Apollo moon landing missions used a Lunar Orbit Rendezvous (LRO) approach where the Command Service Module would be in a low lunar orbit (LLO) while the Lunar Module would land on the moon. This ...
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Is it possible to estimate the nozzle characteristics of the Rocketdyne HG3 engine?

Boeing and the Marshall Space Flight Centre brought to pass many studies of improved Saturn V launch vehicles. The rockets proposed under the MLV and ELV projects would feature longer stages for more ...
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1answer
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How is the Rocketdyne J-2S area ratio larger than that of the J-2?

The standard J-2 engine measures 3.38 metres in total length, with a nozzle exit diameter of 2.03 metres, to support its 27.5:1 expansion ratio. However, these dimensions are apparently identical for ...
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659 views

What was the maximum thrust of the Rocketdyne F-1 engine?

Reading through several old reports, I have come across studies conducted by MSFC on improved Saturn V designs with greater payload capacity, and with uprated engines. As a result of increasing launch ...
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Why was Apollo 12 allowed to go up in such bad weather?

I'd always heard the story about how Apollo 12 was struck by lightning and wondered why they let it head up in a storm. They always check the weather before a launch, and if there is any chance of ...
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Were the Apollo CO₂ scrubber canister designs unified after Apollo 13?

After the problem realized when trying to put up three astronauts for an extended stay in the Apollo 13 LEM, namely that the square CM CO₂ scrubbers didn't fit in the LEM's slots, were they redesigned?...
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What's considered the boundary for “earth orbit?” [closed]

According to this CNET article, The last time a human broke free from Earth's orbit was the Apollo 17 mission in 1972. I thought that the moon orbited the Earth, and that visits to it were still ...
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Lunar lander, apollo 11, start position

If i were to simulate a lunar module with: $x_0$, $\dot{x}_0$, $y_0$, $\dot{y}_0$. $x$ is horizontal position, and $y$ is vertical position. What would be appropriate values?
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Moment of inertia of apollo 11 lunar module

I'm currently modeling the lunar landing in 2D. When I set up the momentum balance: $\ddot{\theta} = \frac{dF_l}{J}$ where $d$ is the distance between the sidethruster and the center of mass. $F_l$ ...
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Why did the Apollo program become a MULTIPLE human landing program?

How did JFK's promise of landing one man on the Moon grow into a whole series of landings of 12 men on 7 missions, with even more planned? Given the motivation of the program, shouldn't Apollo have ...
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Using command module as a lander

Question: Why doesn't NASA or SpaceX use the command module as their lander, instead of having another spacecraft as the lander? I was playing Kerbal Space Program the other day, and noticed how many ...
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Combination of liquid hydrogen and liquid oxygen

For the Apollo missions in the 1960s, NASA used a combination of kerosene and liquid oxygen to get the rockets out of Earth's atmosphere. Why did they do that? If you look at the statistics, the ...
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Why did Apollo 11 need someone to stay behind in lunar orbit?

When Neil Armstrong and Buzz Aldrin descended to the moon in the Lunar Module, Michael Collins stayed up in lunar orbit in the Command Module. Why did they need someone to stay behind? At this point,...
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Saturn V Exhaust Plume

When the Saturn V launch vehicles reached high altitudes and speeds, the exhaust plume looks drastically different compared to how it did at launch (it is much larger, and has a cone about halfway ...
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Why does the side of the LEM look almost black in this photo? Did that cause problems?

After reading this answer about the RTGs used on the Lunar surface, I added some of the images from the Wikipdia article Apollo Lunar Surface Experiments Package into this answer, where I noted that ...
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What were the uses of the RTGs in the Apollo spacecrafts?

I was listening to the Plutonium episode of "the Elements" on the BBC, and between 07:00 and 08:30 they talked about uses of plutonium such as spacecraft power and heat. While the returning astronauts ...
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Why did the Apollo Lunar Module have four landing legs?

Why did the Apollo Lunar Module have four landing legs? Is not just three legs enough? Also, three legs guaranties they always form a plane, four does not, as the fourth leg may dangle. To have the ...
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What does 'Switch SCE to AUX' mean?

During the launch of Apollo 12 a major malfunction was caused by 2 lightning strikes. See http://www.realclearscience.com/blog/2013/02/apollo-12-struck-by-lightning.html for more info. The solution ...
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What was the best late Nova rocket design among the request for proposals NASA received?

According to Wikipedia (https://en.wikipedia.org/wiki/Nova_%28rocket%29) the late Nova rocket was a "larger version" of the Saturn 5, meant to send manned missions to Mars. Some requests for proposals ...
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Apollo/Shuttle launch site fuel handling

I read somewhere that fuel was delivered to the Apollo launch site by tanker truck (for cryogenic propellants) and rail cars (for the kerosene). Were the fuels transferred directly from delivery ...
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Apollo LM ascent procedure, computer controlled or manual?

How was the Apollo LM ascent launch procedure controlled? Was it manual, semi-automatic or fully automatic? By "launch procedure" I am talking about the pitch control for the LM. I believe there is no ...
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1answer
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What were the differences on the LM ascent stage engines on Apollo 9, 10, and 11?

According to Apollo By The Numbers, the LM ascent stage of Apollo 11 ("Eagle", LM-5) had maximum rated thrust of 3218 lbf (14.31 kN), and subsequent missions had very similar figures. The engine ...
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Where can I find the amended/improvised checklists for Apollo 13 post-accident?

I have been trying to find this online without too much avail. For my own reference and cross checking, I wanted to know where I could find the emergency checklists and the "made up on the spot" CM ...
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How was time kept on board early manned spaceflights?

I have not been able to find a definitive answer to this. From Mercury to Gemini to Apollo, what was the mechanism for keeping time onboard the spacecraft? Did the Engineers spend energy (and maybe ...
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Where were the various Apollo Lunar Modules (LMs) discarded?

The LEM was comprised of an ascent, and a descent stage. Whilst the descent stage was in most cases left behind on Luna, the ascent stage ferried the astronauts upstairs to the CSM. Where are these ...
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Software development for Apollo [closed]

How was software developed during apollo? From various sources, it can be gleaned that the computer was a ibm system 360, and the language was basically a fortran dialect or fortran. What I'd like ...
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From which Apollo mission is this audio sample?

I found this page where Evgeny Molotov, former head of the Research institute of Space instruments, plays supposed intercepted communication of unknown Apollo mission. Can anyone identify from which ...
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Is long range radio communication possible on the lunar surface?

There are such things as moon-bounce communication whereby radio signals are 'bounced' off the lunar surface to a distant location on Earth. This mechanism may be likened to the way a mirror reflects ...
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1answer
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What was the Apollo service module propellant used for on the LEO missions?

The Apollo service module carried a lot of propellant for performing the following tasks on a Moon mission: Mid-course correction manoeuvres to and from the Moon. Braking the entire CSM/LM stack into ...
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Can landing modules use left over fuel from earlier stages?

I just read a comment by @RussellBorogove about the Apollo 11 abort options that the landing module had about 700 pounds of fuel left on touchdown. I assume that this is the intended behavior for any ...
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Would the Saturn V have been able to send more mass to TLI if it had a lower earth parking orbit?

After reading into the topic a little, I've come across a number of increases to the Saturn V's LEO and TLI performance over the course of the Apollo program. Early moon missions sent between 133t and ...
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Coordination of RCS on Apollo CSM/LM

The RCS thrusters on the Apollo Service Module were positioned approximately around the center of mass of the ship, such that translational maneuvers wouldn't unnecessarily rotate the ship. While the ...
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Are any rockets currently in use capable of putting a man on the Moon?

Apollo 11 used the Saturn V rocket, which is no longer produced. As far as I can tell, Atlas V rockets are not as powerful and would not be able to deliver the lunar lander to the surface of the Moon. ...

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