Editing Apollo Lunar Module (section)

===Descent stage===
[[File:Scale model of the Apollo Lunar Module.jpg|thumb|Scale model of the Apollo Lunar Module at the [[Euro Space Center]] in Belgium]]
The descent stage's primary job was to support a powered landing and surface extravehicular activity. When the excursion was over, it served as the launch pad for the ascent stage. Its octagonal shape was supported by four folding landing gear legs, and contained a [[throttle]]able [[Descent Propulsion System]] (DPS) engine with four [[hypergolic propellant]] tanks. A [[continuous-wave radar|continuous-wave]] [[Doppler radar]] antenna was mounted by the engine [[heat shield]] on the bottom surface, to send altitude and rate of descent data to the guidance system and pilot display during the landing.

Almost all external surfaces, except for the top, platform, ladder, descent engine and heat shield, were covered in amber, dark (reddish) amber, black, silver, and yellow aluminized [[Kapton]] foil blankets for [[thermal insulation]]. The number 1 (front) landing leg had an attached platform (informally known as the "porch") in front of the ascent stage's extravehicular activity hatch and a ladder, which the astronauts used to ascend and descend between the cabin and the surface. The landing pad of each leg incorporated a {{convert|67|in|m|adj=mid|-long}} surface contact sensor probe, which signaled the commander to switch off the descent engine.  The probe was omitted from the number 1 leg of every landing mission, to avoid a suit-puncture hazard to the astronauts, as the probes tended to break off and protrude upwards from the surface.  For suspension, each leg incorporated an aluminum honeycomb shock absorber that would crumple on impact; the actual landings were softer than anticipated, using less of the compression range and leaving the leg's attached ladder higher off the surface than intended.

Equipment for the lunar exploration was carried in the modular equipment stowage assembly (MESA), a drawer mounted on a hinged panel dropping out of the lefthand forward compartment. Besides the astronaut's surface excavation tools and sample collection boxes, the MESA contained a television camera with a tripod;<ref>{{Cite web |last=Donnell |first=Ivy |date=2019-07-16 |title=50 Years After the Moonwalk: Looking Back at Apollo 11's Broadcast from the Moon |url=https://unwritten-record.blogs.archives.gov/2019/07/16/50-years-after-the-moonwalk-looking-back-at-apollo-11s-broadcast-from-the-moon |access-date=2024-12-18 |website=The Unwritten Record |language=en-US}}</ref><ref name=":1">{{Cite web |title=Camera, Television, Lunar Surface, Apollo |url=https://airandspace.si.edu/collection-objects/camera-television-lunar-surface-apollo/nasm_A19720828000 |access-date=2024-12-18 |website=National Air and Space Museum |language=en}}</ref> as the commander opened the MESA by pulling on a lanyard while descending the ladder, the camera was automatically activated to send the first pictures of the astronauts on the surface back to Earth.<ref name=":1" /> A [[Lunar Flag Assembly|United States flag]] for the astronauts to erect on the surface was carried in a container mounted on the ladder of each landing mission.

The Early Apollo Surface Experiments Package<ref>{{Cite web |last=Lindsay |first=Hamish |date=30 September 1977 |title=Apollo Lunar Surface Experiments Package |url=https://www.honeysucklecreek.net/msfn_missions/ALSEP/hl_alsep.html |access-date=2024-12-18 |website=www.honeysucklecreek.net}}</ref> (later the [[Apollo Lunar Surface Experiments Package]]) was carried in the opposite compartment behind the LM. An external compartment on the right front panel carried a deployable [[S band|S-band]] antenna which, when opened, looked like an inverted umbrella on a tripod. This was not used on the first landing due to time constraints, and the fact that communications were being received using the LM's S-band antenna but was used on Apollo 12 and 14.<ref>{{Cite web |title=Antenna Assembly, S-Band, Lunar Module #2 |url=https://airandspace.si.edu/collection-objects/antenna-assembly-s-band-lunar-module-2/nasm_A19711598018 |access-date=2024-12-18 |website=National Air and Space Museum |language=en}}</ref> A hand-pulled [[Modular Equipment Transporter]] (MET), similar in appearance to a golf cart, was carried on Apollo 14 to facilitate carrying the tools and samples on extended moonwalks.<ref>{{Cite web |last=Muir-Harmony |first=Teasel |date=2021-02-12 |title=Lessons from Apollo 14 |url=https://airandspace.si.edu/stories/editorial/lessons-apollo-14 |access-date=2024-12-18 |website=National Air and Space Museum |language=en}}</ref> On the extended missions ([[Apollo 15]] and later), the antenna and TV camera were mounted on the [[Lunar Roving Vehicle]], which was carried folded up and mounted on an external panel.<ref>{{Cite web |title=Lunar Roving Vehicle |url=https://www.nasa.gov/wp-content/uploads/static/history/alsj/a17/A17OTM17-19.PDF |page=18}}</ref> Compartments also contained replacement [[Primary life support system|Portable Life Support System]] (PLSS) batteries and extra [[lithium hydroxide]] canisters to purge [[carbon dioxide]] from the LM.<ref>{{Cite web |date=March 23, 2008 |title=Apollo 13 Lunar Module 'Mail Box' |url=https://www.nasa.gov/image-article/apollo-13-lunar-module-mail-box/ |access-date=2024-12-18 |website=NASA |language=en-US}}</ref>

* Height: {{convert|10|ft|7.2|in|m|abbr=on}} (plus {{convert|5|ft|7.2|in|m|abbr=on}} landing probes)
* Width/depth, minus landing gear: {{convert|13|ft|10|in|m|abbr=on}}
* Width/depth, landing gear extended: {{convert|31.0|ft|m|abbr=on}}
* Mass including propellant: {{convert|22,783|lb|kg|abbr=on}}
* Water: one {{convert|151|kg|lb|adj=on|abbr=on}} storage tank
* DPS propellant mass: {{convert|18,000|lb|kg|abbr=on}} stored in four {{convert|67.3|ft3|m3|adj=on|sigfig=4}} propellant tanks
* DPS engine: [[TRW Inc.|TRW]] [[Descent Propulsion System|LM descent engine (LMDE)]]<ref>{{cite web |url=http://www.astronautix.com/engines/tr201.htm |title=TR-201 for Delta rocket second stage derived from LMDE |date=1972 |url-status=dead |archive-url=https://web.archive.org/web/20080706190928/http://astronautix.com/engines/tr201.htm |archive-date=July 6, 2008 }}</ref><ref name="NASA"/>
* DPS thrust: {{convert|10,125|lbf|N|abbr=on}}, throttleable between 10% and 60% of full thrust
* DPS propellants: Aerozine 50 fuel / nitrogen tetroxide oxidizer
* DPS pressurant: one {{convert|49|lb|kg|adj=on}} supercritical helium tank at {{convert|1555|psi|MPa|abbr=on}}
* DPS [[specific impulse]]: 311 s (3,050 N×s/kg)
* DPS [[Delta-v|delta-V]]: {{convert|8,100|ft/s|m/s|abbr=on}}
* Batteries: four (Apollo 9–14) or five (Apollo 15–17) 28–32 V, 415 [[Ampere-hour|Ah]] silver-zinc batteries; {{convert|135|lb|kg|abbr=on}} each