# Apollo 11 Question **URL:** \ **Category:** Factual Questions\ **Created:** [December 30, 2015, 1:30am UTC](https://boards.straightdope.com/t/apollo-11-question/741695 "2015-12-30T01:30:00Z")\ **Posts on this page:** 20\ **Page:** 4
**Author:** ![Hail\_Ants](https://avatars.discourse-cdn.com/v4/letter/h/dc4da7/32.png) [@Hail\_Ants](https://boards.straightdope.com/u/Hail_Ants)\ **Post date:** [May 21, 2016, 10:57pm UTC](https://boards.straightdope.com/t/apollo-11-question/741695/61 "2016-05-21T22:57:13Z")
> [@joema](#): > > The Lunar Module ascent stage was designed with extreme simplicity, even at a significant performance cost. The propulsion system had no pumps or igniters. There were no fuel cells like failed on Apollo 13 – only batteries. Unlike the Service Module it used only pressurized gaseous oxygen, not cryogenic oxygen (which blew up on Apollo 13). The propulsion plumbing used double redundant valves. It had double redundant computers and could probably reach orbit without any computer whatsoever – that was a practiced contingency. The reaction control thrusters had a separate non-computerized analog electrical path, and separate contingency activation solenoids. The engine had no complex regenerative cooling, thereby greatly simplifying plumbing. The engine was not gimbaled like on the Service Module, just bolted in a fixed position. In the great documentary series _[Moon Machines](https://youtu.be/VhUGNaLgDJ8?t=1130)_, which focuses on just the hardware, in the episode about the LM one of the engineers points out that because of all this, every LM ascent engine flown was essentially completely brand-new, shrink-wrapped from the factory. IOW those individual units were never tested, never fired, nothing, until their use on the Moon’s surface. ---
**Author:** ![Isilder](https://avatars.discourse-cdn.com/v4/letter/i/cc9497/32.png) [@Isilder](https://boards.straightdope.com/u/Isilder)\ **Post date:** [May 22, 2016, 3:25am UTC](https://boards.straightdope.com/t/apollo-11-question/741695/62 "2016-05-22T03:25:57Z")
> [@Sailboat](#): > > Unlike the Wikipedia article I cited, the program emphasized that Cooper splashed down closer to his target point than any other Mercury astronaut. Not the only parameter… so he had a good safety margin in terms of distance from target… What about all the other margins ? How close was he to burning up ? How close was he to running out of fuel ? How close was he to smashing into the water too fast ? ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [May 22, 2016, 4:30am UTC](https://boards.straightdope.com/t/apollo-11-question/741695/63 "2016-05-22T04:30:44Z")
> [@Hail\_Ants](#): > > When I was a teenager and learned all the details of the Apollo mission profiles I couldn’t help but wonder if Collins, ya know, while orbiting the Moon all alone, the most remote human ever in all of human history, if he, ah, spanked it. Well, it would have been obvious from the readings of blood pressure monitors that he was wearing. Also, the ondom catheter that he wore might have been a bit of an interferance. ---
**Author:** ![Johnny\_Ace](https://avatars.discourse-cdn.com/v4/letter/j/6bbea6/32.png) [@Johnny\_Ace](https://boards.straightdope.com/u/Johnny_Ace)\ **Post date:** [May 22, 2016, 5:03am UTC](https://boards.straightdope.com/t/apollo-11-question/741695/64 "2016-05-22T05:03:30Z")
This is one of the few vivid memories I have from early childhood: So I’m a few months from my fifth birthday, and the family and I are all sitting around the TV watching the moon landing. My three-year-old sister says, “Daddy, you _never_ take us to the Moon!” (I don’t remember her saying that; my mother used to regale us with it when we were older. But I clearly recall the TV ‘show’ itself.) ---
**Author:** ![Ranger\_Jeff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ranger_jeff/32/2065_2.png) [@Ranger\_Jeff](https://boards.straightdope.com/u/Ranger_Jeff)\ **Post date:** [May 22, 2016, 9:25am UTC](https://boards.straightdope.com/t/apollo-11-question/741695/65 "2016-05-22T09:25:54Z")
> [@Leo\_Bloom](#): > > I responded to that by asking about “Russian” spaceflght to half cover my ass in case I was being whooshed, which I sensed in (mistakenly) reading as a joke an Apollo “misplaced splash landing” over a jungle. > > I’m still not clear–it was for _only_ a scenario of an off-coast mislanding? But now that I think of it, could it/the Apollo astronauts survive a land landing? Water is more incompressible than a lot of land areas. The couches the Apollo crews sat/laid in had shock absorber struts holding them to the CM. So they’d lessen the shock from an on land landing if that happened. ---
**Author:** ![JKellyMap](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jkellymap/32/15880_2.png) [@JKellyMap](https://boards.straightdope.com/u/JKellyMap)\ **Post date:** [May 22, 2016, 11:16am UTC](https://boards.straightdope.com/t/apollo-11-question/741695/66 "2016-05-22T11:16:36Z")
> [@Johnny\_Ace](#): > > This is one of the few vivid memories I have from early childhood: > > So I’m a few months from my fifth birthday, and the family and I are all sitting around the TV watching the moon landing. My three-year-old sister says, “Daddy, you _never_ take us to the Moon!” > > (I don’t remember her saying that; my mother used to regale us with it when we were older. But I clearly recall the TV ‘show’ itself.) Sorry to continue the hijack…but just yesterday, my five-year-old was confused, and wondered if I were going to outer space tomorrow. Turns out he heard me mention I will be taking a shuttle (bus) to the airport, and he’d only heard that word in the context of the Space Shuttle. 🙂 ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [May 23, 2016, 12:30am UTC](https://boards.straightdope.com/t/apollo-11-question/741695/67 "2016-05-23T00:30:11Z")
> [@joema](#): > > The Lunar Module ascent stage was designed with extreme simplicity, even at a significant performance cost. The propulsion system had no pumps or igniters. There were no fuel cells like failed on Apollo 13 – only batteries. Unlike the Service Module it used only pressurized gaseous oxygen, not cryogenic oxygen (which blew up on Apollo 13). Nitpick; both the LM Descent Propulsion System and Ascent Propulsion System used nitrogen tetraoxide as the oxidizer and a mixture of hydrazine and unsymmetrical dimethylhydrazine (UDMH), which were selected because of decent performance combined with being hypergolic (ignite upon contact), thereby eliminating the possible failure point of an ignition system. > [@joema](#): > > So the Apollo lunar missions were risky but the chance of the “stranded alive on the moon and can’t take off” scenario mentioned in the William Safire draft speech was probably relatively low. While everything was done to simplify the LM propulsion systems and make them as robust as possible, the ignition of a rocket propulsion system always has many potential failure modes. Even with redundant valves, the possibility of FOD obstructing flow, rupture of propulsion feed lines, a higher than expected ignition transient, latent failure in the combustion chamber, thermal fracture of the nozzle throat or bell, loss of TVC control, et cetera all pose a risk that could have stranded the astronauts on the Lunar surface with no practicable means of rescue or recovery. Mission baselines for hypothetical future Mars missions (and presumably hypothetical Lunar missions, although I’ve never worked on a study for one) indicate that only complete redundancy, e.g. two separate spacecraft and descent/ascent propulsion systems can achieve the required mission reliability threshold (NASA typically assumes 98% to 99% end to end mission reliablity requirement for crewed interplanetary mission studies depending on who is driving the study; a single spacecraft and descent/ascent vehicle generally comes in at around 85% to 93% mission reliability depending on the assumptions of the study and degree of maturity of the system, although there are certain architectures where consumables and backup systems are prestaged that can up the reliability significantly.) The problem of achieving this redundancy is twofold; cost and logistics. Launching a separate, parallel mission isn’t quite twice the price of a single spacecraft because there are economies of scale to be had but it is fairly close; given the cost of a single mission with good reliablity (\>95%) is a minimum of around US$200B even for a short duration opposition-class mission, and a full fledged dual exploratory mission on a conjunction-class trajectory (two separate landing objectives, or a scientific crew of 12+ and ability to transit to remote sites) typically costs in at around US$500B. Practically speaking, without a standard transportation infrastructure and an ability to produce at least some consumables by in situ resource extraction and manufacture, there is always the possibility of being stranded on a planetary body without sufficent propellants or materials to affect any kind of repair, nor a means of rescue or recovery. This willl remain the case for the foreseeable future for any missions which have less than full redundancy, and is yet another argument against crewed interplantary surface missions, although there are some persuasive arguments for sending a crew on an orbital control vessel to operate surface probes and rovers in near real time rather than with many minutes of delays. > [@Hail\_Ants](#): > > In the great documentary series _[Moon Machines](https://youtu.be/VhUGNaLgDJ8?t=1130)_, which focuses on just the hardware, in the episode about the LM one of the engineers points out that because of all this, every LM ascent engine flown was essentially completely brand-new, shrink-wrapped from the factory. IOW those individual units were never tested, never fired, nothing, until their use on the Moon’s surface. It really isn’t accurate to say that the propulsion systems were “never tested”; every propulsion component on a rocket launch vehicle or spacecraft undergoes a regime of component and subsystem level acceptance testing, as well as design qualification testing of a representative selection of articles, and for one shot devices, lot acceptance testing. It is true that the engines were not static fired after installation on the LM, but this is true of many systems and especially those using hypergolic propellants. (I believe the DPS underwent a cold gas test prior to final integration, but the APS was in fact sealed and integrators could only perform limited continuity and polarity checkouts.) Stranger ---
**Author:** ![joema](https://avatars.discourse-cdn.com/v4/letter/j/a9adbd/32.png) [@joema](https://boards.straightdope.com/u/joema)\ **Post date:** [May 23, 2016, 1:10pm UTC](https://boards.straightdope.com/t/apollo-11-question/741695/68 "2016-05-23T13:10:17Z")
> [@Stranger\_On\_A\_Train](#): > > …While everything was done to simplify the LM propulsion systems and make them as robust as possible, the ignition of a rocket propulsion system always has many potential failure modes. Even with redundant valves, the possibility of FOD obstructing flow, rupture of propulsion feed lines, a higher than expected ignition transient, latent failure in the combustion chamber, thermal fracture of the nozzle throat or bell, loss of TVC control, et cetera all pose a risk that could have stranded the astronauts on the Lunar surface with no practicable means of rescue or recovery… I disagree with this part. The LM ascent stage engine was as simple and reliable as could be devised. There was no Thrust Vector Control (TVC) – it was bolted directly to the vehicle frame. Unlike the descent engine, it was fixed thrust – not throttleable. It had already been tested many times in the J-2A altitude chamber at AEDC, including long-term thermal hot and cold soak in vacuum space conditions (similar test cell shown): [Welcome nimr.org - BlueHost.com](http://www.nimr.org/systems/rockets/96-07001.jpg) It was tested in space including staging on Apollo 9 and 10. The ascent stage and propulsion system worked perfectly. Something could easily have gone fatally wrong during powered lunar descent or ascent. However it is unlikely those failure modes would have produced a “stranded alive and able to communicate with earth” scenario – which is the _sole_ scenario discussed in the William Safire speech. Any significant rupture of propellant feed lines would have likely caused an explosion – they were hypergolic – or it would have quickly poisoned the astronauts in the cabin. There are lots of cases where workers have been exposed to Aerozine-50 or N204 – they don’t live long. A slight trace of this penetrated the Command Module during atmospheric descent from the Apollo/Soyuz mission, and it essentially knocked out the astronauts. They were hospitalized for weeks and fortunate to survive. When rocket engines or criticality 1 pyros fail, it typically does not produce a gentle result. That’s why you never see a launch vehicle with a buckled skin, trailing smoke like a wounded WWII bomber, which somehow limps into orbit. It either works to near perfection or the failures rapidly cascade to total destruction. The Apollo lunar missions were very risky but the single scenario mentioned in the Safire speech – stranded alive on the moon and able to communicate – seems much less likely than the other fatal failure modes. ---
**Author:** ![Elendil\_s\_Heir](https://avatars.discourse-cdn.com/v4/letter/e/7cd45c/32.png) [@Elendil\_s\_Heir](https://boards.straightdope.com/u/Elendil_s_Heir)\ **Post date:** [October 18, 2018, 7:57pm UTC](https://boards.straightdope.com/t/apollo-11-question/741695/69 "2018-10-18T19:57:34Z")
Bumped. Some cool ground-level, slow-mo video of the Apollo 11 liftoff: [Apollo 11 Saturn V Launch Camera E-8 - YouTube](https://www.youtube.com/watch?v=DKtVpvzUF1Y) ---
**Author:** ![Aji\_de\_Gallina](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aji_de_gallina/32/260_2.png) [@Aji\_de\_Gallina](https://boards.straightdope.com/u/Aji_de_Gallina)\ **Post date:** [October 18, 2018, 9:08pm UTC](https://boards.straightdope.com/t/apollo-11-question/741695/70 "2018-10-18T21:08:15Z")
I remember a, not particularly good, movie where the objective was to send a man to the moon before the Soviets, but they couldn’t bring him back. He landed and had to find to pod with his stuff and it was difficult. He finds two dead cosmonauts. The last scene in him seeing the pod. Does anyone know the movie? ---
**Author:** ![ohiomstr2](https://avatars.discourse-cdn.com/v4/letter/o/82dd89/32.png) [@ohiomstr2](https://boards.straightdope.com/u/ohiomstr2)\ **Post date:** [October 18, 2018, 10:24pm UTC](https://boards.straightdope.com/t/apollo-11-question/741695/71 "2018-10-18T22:24:38Z")
> **[Countdown (1967) - Plot - IMDb](https://www.imdb.com/title/tt0062827/plotsummary/)** > > Countdown (1967) - Plot summary, synopsis, and more... Sounds like what you are looking for. ---
**Author:** ![Bijou\_Drains](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bijou_drains/32/2814_2.png) [@Bijou\_Drains](https://boards.straightdope.com/u/Bijou_Drains)\ **Post date:** [October 18, 2018, 11:20pm UTC](https://boards.straightdope.com/t/apollo-11-question/741695/72 "2018-10-18T23:20:11Z")
people die climbing Mt. Everest and those bodies are not brought down , too risky. one body has been up there since 1996 [Green Boots - Wikipedia](https://en.wikipedia.org/wiki/Green_Boots) ---
**Author:** ![kaylasdad99](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kaylasdad99/32/3398_2.png) [@kaylasdad99](https://boards.straightdope.com/u/kaylasdad99)\ **Post date:** [October 19, 2018, 2:37am UTC](https://boards.straightdope.com/t/apollo-11-question/741695/73 "2018-10-19T02:37:00Z")
> [@Stranger\_On\_A\_Train](#): > > The Soviets descended onto land for the opposite reasons; they have plenty of open space (and little concerns about the liability for crushing some Kazakhstani peasant’s hovel) and don’t have an extensive naval force suitable for recover operations. > [@AK84](#): > > Here is a (not very good)[translation](http://www.thelivingmoon.com/47john_lear/02files/Soyuz_TMA-11_Not_So_Perfect_Landing.html) of the rentry of the [Soyuz TMA-11](https://en.wikipedia.org/wiki/Soyuz_TMA-11#Ballistic_reentry) reentry where they landed in some Kazakh farm field. They caused crops to catch fire and IIRC per Chris Hadfield, they _did_ pay compensation. That is commendable, but it doesn’t really speak to **Stranger** ’s comment, as it occurred _after_ there was no Soviet space program (or any Soviets, because there was no Soviet Union). ---
**Author:** ![ElvisL1ves](https://avatars.discourse-cdn.com/v4/letter/e/5daacb/32.png) [@ElvisL1ves](https://boards.straightdope.com/u/ElvisL1ves)\ **Post date:** [October 19, 2018, 11:10am UTC](https://boards.straightdope.com/t/apollo-11-question/741695/74 "2018-10-19T11:10:48Z")
> [@Aji\_de\_Gallina](#): > > I remember a, not particularly good, movie where the objective was to send a man to the moon before the Soviets, but they couldn’t bring him back. > He landed and had to find to pod with his stuff and it was difficult. He finds two dead cosmonauts. The last scene in him seeing the pod. > Does anyone know the movie? [Countdown](https://en.wikipedia.org/wiki/Countdown_(1968_film)), starring James Caan. And you’re being kind. ---
**Author:** ![mako88sb](https://avatars.discourse-cdn.com/v4/letter/m/9de0a6/32.png) [@mako88sb](https://boards.straightdope.com/u/mako88sb)\ **Post date:** [October 19, 2018, 7:58pm UTC](https://boards.straightdope.com/t/apollo-11-question/741695/75 "2018-10-19T19:58:43Z")
> [@Elendil\_s\_Heir](#): > > Bumped. > > Some cool ground-level, slow-mo video of the Apollo 11 liftoff: [https://www.youtube.com/watch?v=DKtVpvzUF1Y](https://www.youtube.com/watch?v=DKtVpvzUF1Y) Love watching that video. One thing I only found out about a few years ago was the system designed to reduce transient stresses that could be caused by a too sudden release of the Saturn V from it’s hold down posts. They used tapered pins & dies to control & slow the release for about the first 6" of the lift-off. The tapered pins were basically drawn through the dies and it was a bit of trial and error solution that saw the number of tapered pins being reduced from the 16 used on SA-502 to eventually only 8 on later launches. ---
**Author:** ![Siam\_Sam](https://avatars.discourse-cdn.com/v4/letter/s/d78d45/32.png) [@Siam\_Sam](https://boards.straightdope.com/u/Siam_Sam)\ **Post date:** [October 23, 2018, 5:09am UTC](https://boards.straightdope.com/t/apollo-11-question/741695/76 "2018-10-23T05:09:42Z")
Seems like a good place to mention the new Neil Armstrong movie _First Man_ is very good. ---
**Author:** ![Elendil\_s\_Heir](https://avatars.discourse-cdn.com/v4/letter/e/7cd45c/32.png) [@Elendil\_s\_Heir](https://boards.straightdope.com/u/Elendil_s_Heir)\ **Post date:** [October 23, 2018, 3:44pm UTC](https://boards.straightdope.com/t/apollo-11-question/741695/77 "2018-10-23T15:44:52Z")
> [@Siam\_Sam](#): > > Seems like a good place to mention the new Neil Armstrong movie _First Man_ is very good. I was underwhelmed, myself. Movie thread here: [https://boards.straightdope.com/sdmb/showthread.php?t=861376](https://boards.straightdope.com/sdmb/showthread.php?t=861376) ---
**Author:** ![Just\_Asking\_Questions](https://avatars.discourse-cdn.com/v4/letter/j/ba9def/32.png) [@Just\_Asking\_Questions](https://boards.straightdope.com/u/Just_Asking_Questions)\ **Post date:** [October 23, 2018, 6:07pm UTC](https://boards.straightdope.com/t/apollo-11-question/741695/78 "2018-10-23T18:07:29Z")
> [@Elendil\_s\_Heir](#): > > Bumped. > > Some cool ground-level, slow-mo video of the Apollo 11 liftoff: [https://www.youtube.com/watch?v=DKtVpvzUF1Y](https://www.youtube.com/watch?v=DKtVpvzUF1Y) For god’s sake, don’t read the comments! If one can afford them, I highly recommend [Spacecraft FIlms](https://www.amazon.com/Apollo-11-Moon-Spacecraft-Films/dp/B00009XYYF). There is a whole series of these collected footage discs. Tons of good video. All the launch camera footage. Everything. Pricey, but mega-cool. ---
**Author:** ![Reindeer\_Flotilla](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/reindeer_flotilla/32/3024_2.png) [@Reindeer\_Flotilla](https://boards.straightdope.com/u/Reindeer_Flotilla)\ **Post date:** [October 23, 2018, 7:20pm UTC](https://boards.straightdope.com/t/apollo-11-question/741695/79 "2018-10-23T19:20:40Z")
Another great video and a favorite of mine is [this montage of different camera angles](https://www.youtube.com/watch?v=wvWHnK2FiCk) for the Apollo 11 launch. What’s awesome is that it also shows the dozens (hundreds?) of events around the rocket that all occur within the few seconds between ignition and launch. Things like the disconnection of umbilical systems to all the individual booster stages, the release of the hold-downs (as also shown in the video referenced by \*\* Elendil’s Heir\*\*), the gantry supports detaching and swinging clear, and so on. It really shows the amazing choreography and genius engineering involved just to get a Saturn 5 off the pad. ---
**Author:** ![Elendil\_s\_Heir](https://avatars.discourse-cdn.com/v4/letter/e/7cd45c/32.png) [@Elendil\_s\_Heir](https://boards.straightdope.com/u/Elendil_s_Heir)\ **Post date:** [November 9, 2018, 8:17pm UTC](https://boards.straightdope.com/t/apollo-11-question/741695/80 "2018-11-09T20:17:49Z")
The U.S. Postal Service is offering some cool new NASA-style mission patches, including for Apollo 11, as tie-ins to the recent Sally Ride stamp: [https://store.usps.com/store/product/stamp-gifts/sally-ride-mission-patch-set-S\_477329](https://store.usps.com/store/product/stamp-gifts/sally-ride-mission-patch-set-S_477329) [Previous page](https://boards.straightdope.com/t/apollo-11-question/741695.md?page=3) [Next page](https://boards.straightdope.com/t/apollo-11-question/741695.md?page=5)