# How dangerous were the Apollo missions? **URL:** \ **Category:** Great Debates\ **Created:** [November 15, 2008, 6:46pm UTC](https://boards.straightdope.com/t/how-dangerous-were-the-apollo-missions/472888 "2008-11-15T18:46:45Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![sinical\_brit](https://avatars.discourse-cdn.com/v4/letter/s/48db29/32.png) [@sinical\_brit](https://boards.straightdope.com/u/sinical_brit)\ **Post date:** [November 17, 2008, 2:25pm UTC](https://boards.straightdope.com/t/how-dangerous-were-the-apollo-missions/472888/21 "2008-11-17T14:25:55Z")
As the probablity of death, failure and international embarasment was so high, together with the need for a lot of luck in order to succeed, why did they name a mission 13 and not just skip to 14 ? ---
**Author:** ![mks57](https://avatars.discourse-cdn.com/v4/letter/m/b9bd4f/32.png) [@mks57](https://boards.straightdope.com/u/mks57)\ **Post date:** [November 17, 2008, 2:46pm UTC](https://boards.straightdope.com/t/how-dangerous-were-the-apollo-missions/472888/22 "2008-11-17T14:46:55Z")
One of the Saturn Vs was hit by lightning shortly after lift-off. That could easily have been a very bad day. There were other launch vehicle problems that were not widely publicized. > **[Pogo oscillation](https://en.wikipedia.org/wiki/Pogo_oscillation)** > > Pogo oscillation is a self-excited vibration in liquid-propellant rocket engines caused by combustion instability. The unstable combustion results in variations of engine thrust, causing variations of acceleration on the vehicle's flexible structure, which in turn cause variations in propellant pressure and flow rate, closing the self-excitation cycle. The name is a metaphor comparing the longitudinal vibration to the bouncing of a pogo stick. Pogo oscillation places stress on the frame of th NA... ---
**Author:** ![Icerigger](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/icerigger/32/432_2.png) [@Icerigger](https://boards.straightdope.com/u/Icerigger)\ **Post date:** [November 17, 2008, 3:00pm UTC](https://boards.straightdope.com/t/how-dangerous-were-the-apollo-missions/472888/23 "2008-11-17T15:00:17Z")
That was Apollo 12, SCE to AUX.😉 ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [November 17, 2008, 5:53pm UTC](https://boards.straightdope.com/t/how-dangerous-were-the-apollo-missions/472888/24 "2008-11-17T17:53:48Z")
> [@](#): > > As the probablity of death, failure and international embarasment was so high, together with the need for a lot of luck in order to succeed, why did they name a mission 13 and not just skip to 14 ? Ah, yes, let’s take something that has a chance of being an international embarassment, and deliberatly make it an international embarassment. You don’t think a meaningless superstition like that wouldn’t have gotten laughed at, do you? ---
**Author:** ![Moirai](https://avatars.discourse-cdn.com/v4/letter/m/96bed5/32.png) [@Moirai](https://boards.straightdope.com/u/Moirai)\ **Post date:** [November 17, 2008, 6:04pm UTC](https://boards.straightdope.com/t/how-dangerous-were-the-apollo-missions/472888/25 "2008-11-17T18:04:11Z")
> [@Sam\_Stone](#): > > Apollo was more dangerous than those stats would suggest. You also have to consider the close calls - Apollo 13 came within a whisker of losing the crew. On Apollo 11 the guidance computer for the LEM failed. Other non-moon Apollo missions had various failures that could have been life threatening. I actually got to talk to Gene Kranz about this once. He said flat-out that _every single mission_ was seconds and inches away from total disaster, multiple times per mission. Yeah. :eek: ---
**Author:** ![Cliffy](https://avatars.discourse-cdn.com/v4/letter/c/59ef9b/32.png) [@Cliffy](https://boards.straightdope.com/u/Cliffy)\ **Post date:** [November 17, 2008, 10:40pm UTC](https://boards.straightdope.com/t/how-dangerous-were-the-apollo-missions/472888/26 "2008-11-17T22:40:31Z")
> [@sinical\_brit](#): > > As the probablity of death, failure and international embarasment was so high, together with the need for a lot of luck in order to succeed, why did they name a mission 13 and not just skip to 14 ? Comes after 12, **sinical**. –Cliffy ---
**Author:** ![user\_hostile](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/user_hostile/32/474_2.png) [@user\_hostile](https://boards.straightdope.com/u/user_hostile)\ **Post date:** [November 17, 2008, 10:56pm UTC](https://boards.straightdope.com/t/how-dangerous-were-the-apollo-missions/472888/27 "2008-11-17T22:56:14Z")
> [@mks57](#): > > One of the Saturn Vs was hit by lightning shortly after lift-off. That could easily have been a very bad day. There were other launch vehicle problems that were not widely publicized. > > [Pogo oscillation - Wikipedia](http://en.wikipedia.org/wiki/Pogo_oscillation) Yeah, Apollo 13 survives the pogo oscillations on the 2nd stage only to later suffer from a sticky, welded thermostat. Presuming the deflagration of the second stage, the results would have been as spectacular as the Challenger tragedy, but survival would have been fairly likely given the launch abort system. The Q-ball in the front nose would have detected an off-course anomaly in a matter of milliseconds and issued an abort to the command module. The CM in turn would ignite the solid fuel motor and detached from the service module and flown off to a happier place. I’ve often wondered what the public’s reaction had the pogo pre-empted the blowout in space. Wouldn’t have made much of a movie now…😉 Incidentally, where I worked at yesterday, I walked by an area and noticed various pieces of the Orion LAS. The abort motor nozzles were a lot larger then I thought they would be. Should ever be used in an actually emergency with astronauts, this will definitely be the double E-ticket ride of their lives. [QUOTE=lumpy] I have no knowledge of the designs so I couldn’t say; I was speaking generically of the consequences of engine failure for any reason. I have heard that the LEM engines especially were designed to be “too simple to fail”. [/QUOTE] The LEM used hypergolic fuels which ignite spontaneous on contact–hence no ignition source is needed (along with the electronics, wiring, etc.). This helps reduce the overall weight of rocket motor and increases the reliability. The trade-off is a lower impulse rate with respect to other types of types of fuels (LH2 & LO2), but those are far more complex to use (pumps, cryogenics, etc.) and the hypergolics had enough margin to make it practical for use on the moon. ---
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [November 18, 2008, 4:31am UTC](https://boards.straightdope.com/t/how-dangerous-were-the-apollo-missions/472888/28 "2008-11-18T04:31:30Z")
> [@](#): > > I actually got to talk to Gene Kranz about this once. He said flat-out that every single mission was seconds and inches away from total disaster, multiple times per mission. So is my ten minute drive to work every day. Realistically, what was his definition of being close to a total disaster? A fifty percent chance of an event that would cause the mission to be aborted would seem a relatively loose definition. But if that were true and it happened “multiple times per mission” (let’s define that as once per day) than a typical Apollo mission would have been aborted over 99% of the time. ---
**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:** [November 18, 2008, 5:20am UTC](https://boards.straightdope.com/t/how-dangerous-were-the-apollo-missions/472888/29 "2008-11-18T05:20:37Z")
> [@Chronos](#): > > NASA isn’t a single monolithic whole. It’s my understanding that before Challenger, the NASA administration talked about a 1/4000 rate, but most of the actual engineers did say something more like 1%. NASA program managers may have talked in terms of fractional percentages for failure (Dick Feynman wrote that during the _Challenger_ IFRB that one manager claimed a 1:100,000 failure rate) the best technical estimates of STS mortality by prime contractor engineering leads were between 1:50 and 1:100, which nicely brackets the actual failure rate. Even a simple rocket has thousands of potential failure modes, a small percentage of which are unavoidably catastrophic single point failures (SPF). The Saturn V launch vehicle and Apollo capsule could legitimately be described as being at the edge of failure during any major mission flight event, such as motor ignition, staging, separation, and atmospheric re-entry, and failures at those modes would be essentially unrecoverable. The Shuttle STS, which its massive increase in complexity, is even worse, and the fact that it works at all is an amazing testament to the ability of engineers who were working with computers and software hardly more complex than your average modern scientific calculator. Shamefully, however, the modes that resulted in the flight failures of _Challenger_ and _Columbia_ weren’t some kind of unforeseen, unavoidable events; the problems that led to these disaster were well-known, documented, and entirely avoidable (or at least capable of significant mitigation). The failures in these cases are largely due to human error of judgment and bureaucratic inertia. Ditto is arguably true for the Apollo I pad fire and the Apollo XIII failure. Comparisons to terrestrial hazards like driving are not apropos; while the odds that you might get in an accident due to driver error are not insignificant, the actual incidence of accidents is quite low compared to the amount of time spent in transit, and the severity of most accidents is limited to reparable damage to cars and passengers. Failure in flight of a space launch vehicle, on the other hand, is frequently catastrophic and without useful mitigation. Stranger ---
**Author:** ![sinical\_brit](https://avatars.discourse-cdn.com/v4/letter/s/48db29/32.png) [@sinical\_brit](https://boards.straightdope.com/u/sinical_brit)\ **Post date:** [November 18, 2008, 1:03pm UTC](https://boards.straightdope.com/t/how-dangerous-were-the-apollo-missions/472888/30 "2008-11-18T13:03:06Z")
Yeh - i realise its the next number after 12 etc. Very good. Well done everyone. But its not as if 13 isnt generaly considered to be unlucky. Many US buildings dont have a 13th floor, some airports dont have gate13, many aircraft dont have seat / row 13. In fact some of your streets arnt even numberd 13. You DO [have a history](http://en.wikipedia.org/wiki/Triskaidekaphobia) of not being 100 % comfortable with it as a nation ! ---
**Author:** ![Sailboat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sailboat/32/461_2.png) [@Sailboat](https://boards.straightdope.com/u/Sailboat)\ **Post date:** [November 18, 2008, 2:16pm UTC](https://boards.straightdope.com/t/how-dangerous-were-the-apollo-missions/472888/31 "2008-11-18T14:16:49Z")
> [@sinical\_brit](#): > > Yeh - i realise its the next number after 12 etc. Very good. Well done everyone. But its not as if 13 isnt generaly considered to be unlucky. > > Many US buildings dont have a 13th floor, some airports dont have gate13, many aircraft dont have seat / row 13. In fact some of your streets arnt even numberd 13. You DO [have a history](http://en.wikipedia.org/wiki/Triskaidekaphobia) of not being 100 % comfortable with it as a nation ! Allow me to note that we occasionally have found [13](http://en.wikipedia.org/wiki/Thirteen_Colonies) to be [just the right number](http://en.wikipedia.org/wiki/United_States_Declaration_of_Independence), my **sinical \*brit** ish\* friend. 🙂 ---
**Author:** ![user\_hostile](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/user_hostile/32/474_2.png) [@user\_hostile](https://boards.straightdope.com/u/user_hostile)\ **Post date:** [November 18, 2008, 3:13pm UTC](https://boards.straightdope.com/t/how-dangerous-were-the-apollo-missions/472888/32 "2008-11-18T15:13:19Z")
> [@Stranger\_On\_A\_Train](#): > > … The Shuttle STS, which its massive increase in complexity, is even worse, and the fact that it works at all is an amazing testament to the ability of engineers who were working with computers and software hardly more complex than your average modern scientific calculator. > …Stranger And tested far more exhaustively. > [@](#): > > From “[The They Write the Right Stuff](http://www.fastcompany.com/magazine/06/writestuff.html)” > But how much work the software does is not what makes it remarkable. What makes it remarkable is how well the software works. This software never crashes. It never needs to be re-booted. This software is bug-free. It is perfect, as perfect as human beings have achieved. Consider these stats : the last three versions of the program – each 420,000 lines long-had just one error each. The last 11 versions of this software had a total of 17 errors. Commercial programs of equivalent complexity would have 5,000 errors. One set of bugs is listed [here.](http://www.cs.berkeley.edu/~bonachea/294-8/hw1.html) ---
**Author:** ![SmackFu](https://avatars.discourse-cdn.com/v4/letter/s/53a042/32.png) [@SmackFu](https://boards.straightdope.com/u/SmackFu)\ **Post date:** [November 18, 2008, 4:02pm UTC](https://boards.straightdope.com/t/how-dangerous-were-the-apollo-missions/472888/33 "2008-11-18T16:02:05Z")
Another close call was Gemini 8. Uncontrolled spin due to a thruster being stuck on. > **[Gemini 8](https://en.wikipedia.org/wiki/Gemini_8)** > > Gemini 8 (officially Gemini VIII) was the sixth crewed spaceflight in NASA's Gemini program. It was launched on March 16, 1966, and was the 14th crewed American flight and the 22nd crewed spaceflight overall.\[a\] The mission conducted the first docking of two spacecraft in orbit, but also suffered the first critical in-space system failure of a U.S. spacecraft which threatened the lives of the astronauts and required an immediate abort of the mission. The crew returned to Earth safely. > Flown by... ---
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [November 18, 2008, 4:10pm UTC](https://boards.straightdope.com/t/how-dangerous-were-the-apollo-missions/472888/34 "2008-11-18T16:10:54Z")
> [@](#): > > Many US buildings dont have a 13th floor, some airports dont have gate13, many aircraft dont have seat / row 13. In fact some of your streets arnt even numberd 13. You DO have a history of not being 100 % comfortable with it as a nation ! Those are all open to the public and there are people who have irrational superstitions. But Apollo missions didn’t have to sell tickets. ---
**Author:** ![Darth\_Sensitive](https://avatars.discourse-cdn.com/v4/letter/d/58956e/32.png) [@Darth\_Sensitive](https://boards.straightdope.com/u/Darth_Sensitive)\ **Post date:** [November 18, 2008, 4:20pm UTC](https://boards.straightdope.com/t/how-dangerous-were-the-apollo-missions/472888/35 "2008-11-18T16:20:31Z")
Man - that Armstrong guy on Gemini 8. Sounds like he had a pair of big brass ones. So big that they’d probably throw off any calculations made for space travel - whatever happened to him? ---
**Author:** ![BJMoose](https://avatars.discourse-cdn.com/v4/letter/b/5fc32e/32.png) [@BJMoose](https://boards.straightdope.com/u/BJMoose)\ **Post date:** [November 18, 2008, 5:30pm UTC](https://boards.straightdope.com/t/how-dangerous-were-the-apollo-missions/472888/36 "2008-11-18T17:30:36Z")
> [@Little\_Nemo](#): > > I once read that solar flares were a big concern. If there had been flares during an Apollo mission, the astronauts would have received a lethal dose of radiation. There was no practical way to shield the spacecraft, so the plan was “hope we don’t have any solar flares for the next twelve days.” You’re right. Just the other day I heard something (think it was the History Channel) about this possibility. In fact, there was a big solar storm between two of the moon missions. Regarding the explosion on 13: I suspect that what saved their hides when tank two blew was that it happened in a vacuum - as soon as the tank ruptured, The Void eagerly sucked up most of the energy released. Sounds plausible, anyway. ---
**Author:** ![Madd\_Maxx](https://avatars.discourse-cdn.com/v4/letter/m/5f9b8f/32.png) [@Madd\_Maxx](https://boards.straightdope.com/u/Madd_Maxx)\ **Post date:** [November 18, 2008, 5:34pm UTC](https://boards.straightdope.com/t/how-dangerous-were-the-apollo-missions/472888/37 "2008-11-18T17:34:46Z")
The size and physical properties of Mr. Armstrong’s testicles were taken into account during his selection into NASA’s astronaut program. ---
**Author:** ![user\_hostile](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/user_hostile/32/474_2.png) [@user\_hostile](https://boards.straightdope.com/u/user_hostile)\ **Post date:** [November 18, 2008, 10:08pm UTC](https://boards.straightdope.com/t/how-dangerous-were-the-apollo-missions/472888/38 "2008-11-18T22:08:27Z")
> [@BJMoose](#): > > You’re right. Just the other day I heard something (think it was the History Channel) about this possibility. In fact, there was a big solar storm between two of the moon missions. For what it’s worth, I heard the contingency plan was to turn the bottom end of the Service Module with the nozzle pointing towards the Sun and hope that the re-entry shield would attenuate the primary radiation. How well would it work? Beats me. The following suggest not much: The astronauts that went to the moon were on average suffering cataracts about four years earlier then average non-lunar voyager (I have no cite for this other than reading it in a magazine in the last millennium.) > [@BJMoose](#): > > Regarding the explosion on 13: I suspect that what saved their hides when tank two blew was that it happened in a vacuum - as soon as the tank ruptured, The Void eagerly sucked up most of the energy released. Sounds plausible, anyway. Another way of saying this is that there was no compressible media in front of the shock wave to build up the hammer effect. Interesting, I’d never thought of what the differences between detonating a conventional high explosive at sea level vs. 250,000 feet, and what kind of damage would result to objects near and far away. Anyone got a link to information like that? Don’t bother with nuclear explosives. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [November 18, 2008, 11:06pm UTC](https://boards.straightdope.com/t/how-dangerous-were-the-apollo-missions/472888/39 "2008-11-18T23:06:22Z")
> [@](#): > > Those are all open to the public and there are people who have irrational superstitions. But Apollo missions didn’t have to sell tickets. Addendum to that, you’ve got to realize that an astronaut is a person who will knowingly and willingly sit on top of a three hundred foot tall pile of explosives and deliberately set it off. Forget about irrational fears; these guys don’t even have _rational_ fears. ---
**Author:** ![jsc1953](https://avatars.discourse-cdn.com/v4/letter/j/5daacb/32.png) [@jsc1953](https://boards.straightdope.com/u/jsc1953)\ **Post date:** [November 19, 2008, 12:11am UTC](https://boards.straightdope.com/t/how-dangerous-were-the-apollo-missions/472888/40 "2008-11-19T00:11:51Z")
Partly my own teenage perception; partly media filters – but I don’t think the US public had any real appreciation for how dangerous manned spaceflight really was. I remember hearing & reading about glitches (like Gemini 8), but never felt that anyone was in any real danger. As a whole, every flight was so successful that I personally felt the US space program was bullet-proof. Even during Apollo XIII, I never really doubted they’d return safely. We’re Americans, after all – we can do 100 impossible things before breakfast. [Previous page](https://boards.straightdope.com/t/how-dangerous-were-the-apollo-missions/472888.md?page=1) [Next page](https://boards.straightdope.com/t/how-dangerous-were-the-apollo-missions/472888.md?page=3)