Editing Moon landing conspiracy theories (section)

=== Mechanical issues ===
[[File:Apollo11 under LM.jpg|right|thumb|Lunar surface under the [[Lunar Module Eagle|Lunar Module ''Eagle'']]]]

1. The Lunar Modules made no blast craters or any sign of dust scatter.<ref>[[#Kaysing|Kaysing 2002]], p. 75</ref>

:* ''No crater should be expected. The {{convert|10000|lb|kg|adj=on|order=out|abbr=on}} thrust [[Descent Propulsion System]] was throttled down very far during the final landing.<ref>[[#Harrison|Harrison 2012]], p. 96</ref> The Lunar Module was no longer quickly decelerating, so the descent engine only had to support the lander's own weight, which was lessened by the Moon's gravity and by the near exhaustion of the descent propellants. At landing, the engine thrust divided by the nozzle exit area is only about {{convert|10|kPa|psi|lk=on|abbr=on|order=flip}}.<ref>[[#Plait|Plait 2002]], p. 164</ref><ref>{{cite journal |last1=Metzger |first1=Philip |author-link1=Philip T. Metzger |last2=Smith |first2=Jacob|last3=Lane |first3=John |date= June 30, 2011 |title=Phenomenology of soil erosion due to rocket exhaust on the Moon and the Mauna Kea lunar test site |journal=Journal of Geophysical Research |volume=116 |issue=E06005 |pages=5–8|doi=10.1029/2010JE003745 |bibcode=2011JGRE..116.6005M |doi-access=free }}</ref>''

::''Beyond the engine nozzle, the plume spreads, and the pressure drops very quickly. Rocket exhaust gasses expand much more quickly after leaving the engine nozzle in a vacuum than in an atmosphere. The effect of an atmosphere on rocket plumes can be easily seen in launches from Earth; as the rocket rises through the thinning atmosphere, the exhaust plumes broaden very noticeably. To lessen this, rocket engines made for vacuums have longer bells than those made for use on Earth, but they still cannot stop this spreading. The lander's exhaust gases, therefore, expanded quickly well beyond the landing site. The descent engines ''did'' scatter a lot of very fine surface dust as seen in 16mm movies of each landing, and many mission commanders spoke of its effect on visibility. The landers were generally moving horizontally as well as vertically, and photos do show scouring of the surface along the final descent path. Finally, the lunar [[regolith]] is very compact below its surface dust layer, making it impossible for the descent engine to blast out a crater.<ref name=ba-pg163-165>[[#Plait|Plait 2002]], pp. 163–165</ref> A blast crater was measured under the Apollo 11 lander using shadow lengths of the descent engine bell and estimates of the amount that the landing gear had compressed and how deep the lander footpads had pressed into the lunar surface, and it was found that the engine had eroded between {{convert|4|and|6|in|order=flip|abbr=on}} of regolith out from underneath the engine bell during the final descent and landing.<ref name="as11psr">{{cite web |url=http://www.hq.nasa.gov/alsj/a11/as11psr.pdf |title=Apollo 11 Preliminary Science Report |pages=93–101 |year=1969 |publisher=NASA |id=NASA SP-214 |access-date=May 1, 2013}}</ref>''

2. The second stage of the launch rocket or the Lunar Module [[Apollo Lunar Module#Ascent stage|ascent stage]] or both made no visible flame.

:* ''The Lunar Modules used [[Aerozine 50]] (fuel) and [[dinitrogen tetroxide]] (oxidizer) propellants, chosen for simplicity and reliability; they ignite [[hypergolic propellant|hypergolically]] (upon contact) without the need for a spark. These propellants produce a nearly transparent exhaust.<ref>[[#Woods|Woods 2008]], p. 191</ref> The same fuel was used by the core of the American [[Titan II GLV|Titan II]] rocket. The transparency of their plumes is apparent in many launch photos. The plumes of rocket engines fired in a vacuum spread out very quickly as they leave the engine nozzle (see above), further lessening their visibility. Finally, rocket engines often run "rich" to slow internal corrosion. On Earth, the excess fuel burns in contact with atmospheric oxygen, enhancing the visible flame. This cannot happen in a vacuum.''

<gallery class="center">
File:Ap17-ascent.ogv|Apollo 17 [[Apollo Lunar Module|LM]] leaving the Moon; rocket exhaust visible only briefly
File:Apollo8Launch.ogg|[[Apollo 8]] launch through the first stage separation
File:Apollo6Interstage.jpg|Exhaust flame may not be visible outside the atmosphere, as in this photo. Rocket engines are the dark structures at the bottom center.
</gallery>
<gallery class="center">
File:Gemini-Titan 11 Launch - GPN-2000-001020.jpg|The launch of a [[Titan II GLV|Titan II]], burning [[Hypergolic propellant|hypergolic]] Aerozine-50/N<sub>2</sub>O<sub>4</sub>, {{convert|430000|lbf|MN|abbr=on|order=flip}} of thrust. Note the near-transparency of the exhaust, even in air (water is being sprayed up from below).
File:Atlas missile launch.jpg|[[Atlas (rocket family)|Atlas]] uses non-hypergolic kerosene ([[RP-1]]) fuel which gives a bright and very visible exhaust, {{convert|340000|lb-f|MN|abbr=on|order=flip}} of thrust
File:Apollo 11 launch.jpg|Bright flame from first stage of the [[Saturn V]], burning RP-1
</gallery>

3. The Lunar Modules weighed 17 tons and made no mark on the Moondust, yet footprints can be seen beside them.<ref>[[#René|René 1994]] pp. n, 11</ref>

:* ''On the surface of the Earth, Apollo 11's fueled and crewed [[Lunar Module Eagle]] would have weighed approximately {{convert|17|short ton|kg|lk=on|abbr=on}}. On the surface of the Moon, however, after expending fuel and oxidizer on its descent from lunar orbit, the lander weighed about {{convert|2700|lb|kg|abbr=in|order=flip}}.<ref>{{cite book|url=https://history.nasa.gov/SP-4029/SP-4029.htm |title=Apollo by the Numbers: A Statistical Reference |last=Orloff |first=Richard W. |orig-year=First published 2000 |date=September 2004 |publisher=[[NASA]] |isbn=016050631X |id=NASA SP-2000-4029 |access-date=May 31, 2013}} See Statistical Tables: [https://history.nasa.gov/SP-4029/Apollo_18-37_Selected_Mission_Weights.htm "Selected Mission Weights (lbs)"] and [https://history.nasa.gov/SP-4029/Apollo_18-28a_LM_Descent_Stage_Propellant_Status.htm "LM Descent Stage Propellant Status"].</ref> The astronauts were much lighter than the lander, but their boots were much smaller than the lander's approximately {{convert|3|ft|cm|adj=on|abbr=on|order=flip}} diameter footpads.<ref>{{cite web|url=http://www.hq.nasa.gov/alsj/LM_Landing%20Gear1973010151.pdf |title=Apollo Lunar Module Landing Gear |last=Rogers |first=William F. |work=Apollo Lunar Surface Journal |publisher=NASA |access-date=May 31, 2013}}</ref> Pressure (or force per unit area) rather than mass determines the amount of regolith compression. In some photos, the footpads did press into the regolith, especially when they moved sideways at touchdown. (The bearing pressure under Apollo 11's footpads, with the lander being about 44 times the weight of an EVA-configured astronaut, would have been of similar magnitude to the bearing pressure exerted by the astronauts' boots.)''<ref>[[#Heiken|Heiken 1991]], pp. 475–476</ref>

4. The air conditioning units that were part of the astronauts' spacesuits could not have worked in an environment of no atmosphere.<ref name="cooper">{{cite web |url=http://www.williamcooper.com/majestyt.htm |title=MAJESTYTWELVE |last=Cooper |first=William |year=1997 |website=williamcooper.com |archive-url=https://web.archive.org/web/20000815194854/http://www.williamcooper.com/majestyt.htm |archive-date=August 15, 2000 |access-date=May 31, 2013}}</ref>

:* ''The cooling units could <u>only</u> work in a vacuum. Water from a tank in the backpack flowed out through tiny pores in a metal [[Sublimation (phase transition)|sublimator]] plate where it quickly vaporized into space. The loss of the heat of vaporization froze the remaining water, forming a layer of ice on the outside of the plate that also sublimated into space (turning from a solid directly into a gas). A separate water loop flowed through the LCG ([[Liquid Cooling and Ventilation Garment|Liquid Cooling Garment]]) worn by the astronaut, carrying his metabolic waste heat through the sublimator plate where it was cooled and returned to the LCG. The {{convert|12|lb|kg|abbr=on|order=flip}} of feedwater gave about eight hours of cooling; because of its bulk, it was often the limiting consumable on the length of an EVA.''

[[File:Surveyor 3-Apollo 12.jpg|thumb|right|[[Surveyor 3]] with [[Apollo 12]] lander in background]]