New answers tagged

1

It was important to increase the sample size for medical tests on the astronauts themselves. These still are the only people that have gone outside of low earth orbit, ever. The data, especially on radiation poisoning and Moon EVA human factors, is vital for new missions to the Moon or Mars.


6

During Project Mercury, NASA's communication network was new, and many of the ground stations did not have dedicated voice communications links back to Houston, so each site needed its own CAPCOM, as described in this QA. During Gemini the network was upgraded; many of the ground stations could provide direct voice links to Houston, but others could not, as ...


3

That structure was just a probe to establish soft dock. Similar to an aerial refueling probe, the probe would latch on to a conical “drogue” element on the lunar module (soft dock). Then, it would retract to precisely align the docking rings to seal together and lock (hard dock). After hard dock, crew would manually remove the probe and drogue and stow them ...


21

This answer is a guess based on NASA Technical Note D-5869: Description and performance of the Saturn launch vehicle's navigation, guidance and control system (referred to as 'D-5869' below), also the Launch Vehicle Digital Computer pages (referred to as 'LVDC' below) and finally the description in the video in the question (referred to as 'the video' below)....


0

For the bonus question, I think I found the answer. They brought with them the Lunar Equipment Conveyor, a nylon strap with a hook and two carabiners: (NASA photo S69-37994) Its intended use was transferring equipment from the LEM down to the surface or back up, but it was also a backup for transferring from the LEM to the CSM if docking had failed: ...


13

EDIT: How about some photographic evidence? This is Pete Conrad, during suit-up for Apollo 12, having a sandwich stashed. From this Popular Science article it appears the whole Apollo 12 crew got sandwiches: After breakfast, the crew went to don their pressure suits. ... At one point, the technician assisting Conrad slipped a sandwich into his leg pocket,...


23

If any of the 12 had a bowel movement and then obeyed procedures, then yes there is poop on the moon My 30+ hour search of Apollo documentation did not reveal a direct answer either way. Perhaps the reason why NASA has never given a direct answer is because "leave poop on the moon" is not good public relations. However, multiple sources indicate detailed ...


3

Here is a list of the flown uncrewed capsules: Mercury Capsules MR-1/MR-1A | NASA Ames Exploration Center, Mountain View, California MR-2 | California Museum of Science and Industry, Los Angeles, California MA-2 | Houston Museum of Natural Science, Houston, Texas MA-5 | North Carolina Museum of Life and Science, Durham, North Carolina BJ-1 | Steven F. ...


1

Yes. By separating with the LM moving away from the moon, and the CSM towards it, the LM would be at a higher altitude than the CSM. As a consequence orbital mechanics cause the LM to start to fall behind the CSM, so when the descent engine was fired to slow the LM it wouldn't bump into the CSM.


8

There's a lot of variations in the astronauts' subjective impressions of the sound: "muffled roar", "gutteral roar", and allusions to infrasonic vibration, for which "rumble" might be a fair description. Collins, in Carrying The Fire: Trust your instruments, not your body, the modern pilot is always told, but this beast is best felt. Shake, rattle, and ...


17

tl;dr: The only source found so far is an article that claims that Charlie Duke claims to have left urine on the Moon. No definitive report about fecal matter on the Moon, though. In total, it's claimed by several sources (probably all copying one article) that 96 bags of poop, urine and puke were left on its surface. By my own count from NASA's list (see ...


6

The rest of the current American crewed capsules. Mercury Capsules MR-3 Freedom 7 | JFK Library, Boston, MA MR-4 Liberty Bell 7 | Kansas Cosmosphere and Space Center Hutchinson, Kansas MA-6 Friendship 7 | National Air and Space Museum Washington D.C. MA-7 Aurora 7 | Museum of Science and Industry Chicago, Illinois MA-8 Sigma 7 | Kennedy Space Center ...


35

I believe used fecal bags from the LM were normally supposed to be transferred back to the CSM and returned with the crew to Earth for analysis. In the Apollo 15 flight journal, in the annotation after 174:14:00, we have this: [As Apollo 15 disappears behind the Moon, Al switches on the Gamma-ray Spectrometer, X-ray Spectrometer and the Alpha Particle ...


2

If we go after lunar pole, there is one more subtlety. NASA reports that most of the known ice aroubd the South Pole, with only sparse distribution at the North Pole. The South Pole and its associated basin (South Pole-Aitken Basin) is on the far side of the the Moon. So an Apollo landing on the South Pole would have needed radio communications relays ...


4

According to W. David Woods' excellent "How Apollo Flew to the Moon", p. 262: Originally a probe had been attached to all four footpads but Neil Armstrong had pointed out the possibility that his descent down the ladder might be impeded by a large length of metal probe that had been bent in some unpredictable way during the landing. The probe below the ...


6

There's a lot of background on VAB design in Moonport. Your "optimistic future" is pretty much spot on - the original projection was for 36 flights a year! An early VAB design to support this had six high bays. (six-bay design with barge instead of crawler) After the annual flight rate prediction was reduced to 24, the design was changed to only have ...


3

Only a partial answer about the medium gray foils. The thermal blanket consists of multiple-layered (at least 25 layers) of aluminized sheet (mylar or H-film). Each layer is only 0.00015 inch thick and is coated on one side with a microinch thickness of aluminum. To make an even more effective insulation, the polymide sheets are hand ...


13

Everything of the Lunar Module should be as light as possible. Therefore no thick-walled, heavyweight, pneudraulic-type struts were used to absorp the landing shock but lightweight aluminum honeycomb cartridges. Shock was absorbed by crushing the honeycomb cartridges. The footpads were build as a sandwich structure of a honeycomb core between two aluminum ...


6

Assuming the counterfactual situation that NASA knew (or expected) that there would be ice in the polar craters, the reason NASA wouldn't do a polar Apollo landing is lighting. In order for the crew to have an easy time judging their height above ground and spotting obstacles, lunar landings were targeted and timed so that the Sun would be between 7 and 20 ...


1

According to NASA Technical Note TN D-6850 the fourth probe was removed because of a concern that the failed probe could inter­fere with crewmen descending the LM ladder. I seem to remember from Gene Kranz' Failure Is Not an Option that Bill Tindall was involved in this somehow, but I can't find the reference to it there or in the Tindallgrams.


2

According to the Apollo 11 Lunar Surface Journal, the probe on the forward/ladder footpad was still installed on Eagle in April of 1969: Aldrin is quoted in the notes at 102:45:40 as saying "we [presumably the crew] asked that they take it [the probe] off."


8

The entire Lunar Roving Vehicle Operations Handbook (PDF, 38 Mb) is in meters. The only mention of "foot" is when talking about the astronauts' footrests, and "feet" does not appear at all. Kinda unexpected, considering that Boeing was the rover contractor. Section 1.5.6 describes the Speed Indicator: The instrument shows LRV velocity from 0 to 20 km/...


8

The LRV was at least partially metric. But they used a mix of metric and US customary units. Temperatures in Fahrenheit. But when you decide to use km for distances, you have to use km/h for speed. Snippets from this paper.


5

Three more missions were planned but canceled to save some money. The lost and forgotten missions 18, 19 and 20. To get moon dust and rocks samples from more than one spot only. To get some samples of hardware from the Surveyor 3 lander during Apollo 12. To place more than one lunar seismometer. To place more than one lunar ranging retro reflector. To have ...


7

The ladder was designed not to be in the way even in a hard landing. The legs are (as stated here in the thread) designed to absorb the energy of the landing by crushing the honeybomb structure within. Now two things happend: 1) the astronauts did touch down much softer than they had planned for and 2) the lunar soil itself absorbed more energy than had been ...


5

The lunar orbit velocity for the Apollo missions was a little over 1600 meters per second (~5300 feet per second, ~3600 mph) according to Apollo By The Numbers (p.104). (h/t DrSheldon for the reference suggestion!)


2

In low orbit, like the one Apollo used, the orbital speed around the moon is about 1.6 km/s. So that is the speed at which both the Command Module and Lander were going. Their speed relative to each other was 0 km/s when they connected ;-) At uhoh's suggestion, here's how to calculate the speed of the spacecraft. Let G be the gravitational constant, M the ...


2

The distance between the foot-pad and the bottom of the outer cylinder represents the maximum amount of compression that the strut can accommodate to absorb landing impact energy. Since it uses a deformable solid material to absorb impact energy (aluminum honeycomb), there is no rebound as you would get from a more conventional (and heavier) type of strut. ...


-8

The ladder stops at that point because base on their theories of the Big Bang, the scientist were expecting several feet of dust. The fact the dust was only an inch or so deep forced them to reevaluate the age of the moon. That is also why it was the first thing Neil discussed when stepping onto the moon.


3

@RussellBorogove's answer addresses the major reasons, but I'll add a minor point: Even though the commander was trained to fly both spacecraft, it was safer to have a pilot dedicated to docking: the command module pilot. The CDR did get practice in simulators for both spacecraft. However, since the CDR was the primary pilot of the LM, he spent an ...


86

They were part of an active seismic imaging experiment (archived version on wayback) By setting up a seismometer and setting off surface explosions of known size, you can get a lot of information about how shockwaves propagate underground, from which you can infer structure.


4

The ALSEP experiment of Apollo 14 measured such a release of oxygen before opening the hatch for the second and third time.


38

Some pictures from Apollo 11 of the landing gear – struts, footpads and contact probes. Three Apollo 12 images: Two Apollo 14 footpad images: An Apollo 16 image: The two probes bend straight up on the left of the left and right footpad. I found no Apollo 17 images with visible contact probes. So yes, some contact probes did bend and stick out sideways. ...


8

This is not a complete answer, because I haven't identified the video directly, but it has some information which I think should help someone interested in finding it. Camera I am now pretty sure (despite my original answer in the photography SE) that this is footage from one of the Apollo TV cameras. The 16mm film footage is simply higher quality than ...


27

There were shock absorbing structures within the landing legs. If the primary shock absorbing strut would be maximally compressed by a hard landing, the lower end of the ladder would be directly above the foot pad. PRIMARY STRUT The upper end of the primary strut is attached to the outboard end of the outrigger; the lower end has a ball joint for the ...


31

It is correct that the probe on the forward footpad was omitted to avoid interfering with the ladder: The probe located on the forward landing gear was deleted because of a concern that the failed probe could interfere with crewmen descending the LM ladder. [p. 8] There was more than one probe for redundancy. In particular, there was no electrical ...


12

It's one of several factors to prevent Earth microorganisms from contaminating the moon. The Apollo Program Summary Report states 8.5.2.1 Lunar-surface contamination.- Nations involved in the exploration of extraterrestrial bodies have agreed to take all steps that are technically feasible to prevent the contam- ination of these bodies during ...


1

Neil Armstrong was also very cool in the first USA in space mishap, tumbling after docking with the Agena But a better explanation: All these astronauts were ultra high achieving, fighter pilots and test pilots with high ranks. The LMP was actually a co-pilot/flight engineer job (and needed said job very much along with a very competent main pilot). But ...


11

This is a double reflection of light between the LM window and the camera lens. There are no two shadows as if they are caused by two light sources. It's the same shadow captured twice in the photograph. 1) Moon craters inside and outside the outer shadow don't line up (especially obvious close to the upper orange line). They wouldn't be affected if the ...


8

Without any time markings, it's impossible to tell if the ground track indicates a "hard left" or very gentle maneuvers over a long period of time. The annotated transcript gives us some hints, though: [Pete is descending very slowly as he flies along the north rim of Surveyor Crater, looking for a good spot to land.] [Conrad, from the 1969 ...


7

What I am interested in is whether Armstrong (or any of the pilots of the subsequent missions) executed any significant "pirouette" or lateral translation maneuvers to locate and fly to their chosen landing sites and/or pirouette to fully inspect a site before touchdown. If not, was it purely unnecessary, was it inadvisable due to stability concerns, ...


6

See Apollo by the Numbers page 35: There is no information about the maneuvered distance to avoid obstacles, only the distance between planned and actual landing spot. 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 ...


9

The excellent monograph by my former colleague Floyd Bennett has this information on Apollo 11 and 12. Here are the Apollo 11 and 12 ground tracks showing lateral maneuvering. Apologies for poor image quality. Some debrief remarks by Pete Conrad - the groundtrack looks like he flew around Surveyor Crater, and sure enough: I saw a suitable landing ...


3

The answer is in the link you provided in your question. Here. The reason they closed the hatch was so that the interior of the LM won't cool down. The hatch can be opened from the outside, if necessary. The reason for almost closing the hatch is, I believe, to prevent radiative cooling of the cabin If they allowed it to cool down, it would require more ...


17

Landing and ascent accelerations were low - 1/3 to 1/2 gee typically. A restraint system was provided, but really more to hold the crew down to the floor, than to support them. Sources Physics of lunar launch Apollo experience report - descent propulsion system LM Handbook


16

It was comfortable to stand for the entire descent and ascent. Accelerations in the lunar module maxed out at around half a gee; descent took around 13 minutes and ascent around 7 minutes. According to Apollo By The Numbers, Apollo 11's ascent stage massed 10776 lbs at launch, and 5928 lbs at cutoff, when the ascent engine cut off; the ascent engine fired ...


4

These are the first words of the 12 astronauts when they physically step on the moon. Not when they are descending on the ladder or on the footpad. Apollo 11 Neil Armstrong, CDR: "That's one small step for [a] man; one giant leap for mankind." Edwin "Buzz" Aldrin, LMP: " Looks like the secondary strut had a little thermal effects on it right here, Neil." ...


4

Upper left: KSC control room for the Instrument Unit during the launch of Apollo 8. I am not sure if this is the Launch Control Center Firing Room or a back room. I think a back room. (reference) Upper right - the Instrument Unit itself as described in this answer Lower left - Launch Control Center Firing Room at KSC, looking away from the window (the ...


5

This is speculation, but a couple features on the site linked in the question stick out as requirements likely to drive the decision to use Boyd bolts instead of other fasteners: "The design flown on Apollo required only a quarter turn for release" (from the patent) "means for preventing the nut and screw from unintentionally separating in response to ...


7

Hobbes' answer is correct, but here is some supplemental information. The Erectable S-Band Antenna was a parabolic dish that was folded and stowed in the descent stage. Page 4-86 of the Apollo Program Summary Report describes the diameter as 10 feet and this NASA webpage says 3 meters. It was carried on Apollo 11-14. Although the LM could broadcast with ...


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