we stayed in the cabinet room throughout the day. the windows were dark. we were into nighttime. at 4:15 in theed afternoon than the astronauts did not walk until later. >> explore our nations passed on american history tv every weekend on c-span3. in 1970 nine a small network with an unusual name pulled out a big idea. let the viewers make up their own minds. topan opened the door washington policymaking for all to see bringing you unfiltered content from congress and beyond. a lot has changed in 40 years but today that idea is more relevant than ever. on television and online, c-span is your unfiltered view of government so you can make up your own mind. brought to you by your cable or satellite provider. tv,ext on american history three former flight controllers

and engineers discuss the design and development of the lunar module and how it operated during the apollo 11 moon landing. this panel was part of an event hosted by space center houston to mark apollo 11's anniversary. and happy lunar landing day. [applause] it's great to have you all here. i am the chief operating officer here at the space center houston. we are a smithsonian affiliate. world's first certified autism center as a science center. we believe very much in equity, inclusion, accessibility, and we take that honesty great badge of honor that our staff has had extra training to ensure that

our staff is able to work with people who have any type of learning disability or challenge or anything like that. if you see that there is a needed that we are not meeting, please let us know because we always want to improve. welcome today for our first panel discussion. [applause] i spent 20 years of my life now's the end of the industry. i have been around a lot of .olks this is been a fantastic experience for me. many of these gentlemen we have been involved with planning discussions like this or have been a part of mission control that has been restored as a national historic landmark where they actually have the missions from mid-gemini up through shuttle but also the lunar landing for apollo 11 and many other great race flights.

if you have not got your ticket should do that. it they will go quick. if you're not able to go today werun a quick circuit but will be open for quite a long time today so hopefully you will be only get that and see if you can be back tomorrow. it was great for us to partner with nasa johnson space center. we did the hundreds and for them -- we did the fund raising for them. [applause] today without first panel, we thought it would be best to have a discussion as we are talking about the lunar landing. talk about the lunar module and issues to start off with. presentationsk and discussions. we just wanted to have some

commentary from the audience as well. we ask that you have a quick question so that we can also have others who can ask questions and our gentlemen are able to answer those. nameoing to introduce by and i will allow them to give a quick synopsis of what they did and they were in mission control. first is richard to go. [applause] middle.the jack on the far end. richard please start us off. i graduated college in 1966 and went to work for grumman at the time.

i started testing the environmental control systems on the lunar module. that involved getting co2 out of the atmosphere because in a closed environment, you have to scrub it otherwise you are in trouble. all the life support tech things were my focus during the testing and development phases. bill? >> good morning. i grew up in arkansas and got here as fast as i could. [laughter] [applause] joined here in 1967 and went straight to the flight control division and was a flight controller on the lunar module and on the electrical power system group.

we were responsible for all the power systems which was just batteries and the distribution system and keeping track of power profiles. we were also in charge of the power -- pyrotechnic devices that separated the stages and opened valves in the kind of stuff. room called back the vehicle system staff support rim. we were the people that made the people in the front room look good. [laughter] [applause] anyway, i was 25 years old when apollo 11 landed. ands on the previous shift wasn't actually on during the landing but none of us left from shift to shift. we all hung around and watched it. i will turn it over to jack area. >> i was a member of an air

force family that bounced around the world a number of times. i went to georgia tech, graduated in 1965 and came straight here. also in operations. i was assigned to the lunar module but it wasn't quite ready at the time so i participated in the gemini and a gina programs a little bit. over, apolloe group doubt. the first lunar module was an unmanned and i was involved in that. it was launched on the saturn one b. it automatically executed some of the critical events that had to happen such as burning dissent and i sent engines. keeprents were just to atmospheric integrity because there were no people on board.

that, we started to pick up and i was involved in all of the manned flights of apollo nine through 17. roomrted out in the back for apollo nine and all subsequent. michelle was 11, right after the landing shift. happen then that to i came out immediately eva.after for the i got to see armstrong step on the moon and the rest of the eva. the subject of this was issues and there were quite a number of vehicles, the the command service module as well as lunar module. of course everyone is probably

aware we had the apollo one fire that set things back a little bit. we kept progressing and managed rebuild thethat, interior of the command service module. the lunar module was running in parallel with all that. number of interesting things to meet later on and they were in areas that were not my specialty but in particular, the ascent engine. at nasa had a process by which there was uncertainty in a particular area, they would put two contractors to work. the first one to come up with a , yousolution, you're it will do the rest of it and the other guy was paid and moved on to other things. in this particular case of this engine, the problem was the

injector. they did manage to make it work but as it turns out, you could only fire the engine once. engine was ever tested other than the development time by firing its complete parts until it launched from the moon. to me, that is interesting thing. [laughter] >> i just wanted to chime in on bills, about being in the ussr. i was in the mission evaluation room working the back room to those guys. we help them look good.

[laughter] [applause] >> you can see there's a lot of healthy discussion here. [laughter] they'd only had about 50 years to work up to this area. >> that is a fact. that was the beauty of the flight ops organization. it was a very competitive environment. i always thought that the unsung heroes of the program were the training people trained all of us and put together the simulations and all the failures and. those people were behind the scenes and did a great job. talking about issues, how many of you all have heard or seen the lunar module described as the lem? documentation in fact when i first got here there was a lot of documentation that call it that which stood for

lunar excursion module. the original design of the vehicle was to be able to move around but that was dropped early on for cost and weight reasons. so they took the name and changed it to the lunar module. the power system in the lunar module that i was working on was strictly batteries. focus -- we would take the checklist that was being developed as to what we were going to do and we had to resolve the checklist into power draw so we knew at any point how much power was being drawn out of the batteries and how much we had left area there were four major batteries and the dissent and there were two that powered the ascent stage.

one of the big design issues we ran into was the ascent batteries were on parallel on the powered buses the dissent arteries during the landing in case you had to abort. stage vehicle and go back to the command module. what we found out was the ascent batteries which is not in use for quite a while timewise in the mission were sitting on cold plates and they were getting very cold. silver zinc batteries at a characteristic where the voltage was very under table for the first 10 or 12 and hours before the voltage that stable. we found out that if you stage the vehicle without getting the first 10 or 12 amp hours out of

the batteries, the voltage would drop during the staging to the point that it would dump the computer and affect a lot of equipment areas we had to come up with a power scheme to put the batteries on a certain point in time to get that preconditioning out of the way. that was quite a challenge to do that and during the mission, we found out that they were drawing as much as they were supposed to so we wound up having to play some games. all is well that ends well. [laughter] [applause] out that ifto point you wonder around out here, there is a lunar module thing hanging from the sky. that was the test article number eight. hereompanied that down from where government was located and through a full thats of tests to validate

the environmental control system as well as the thermal control keep theuld manage and vehicle for getting too hot or too cold and to help the equipment to make sure the equipment didn't get too hot. space, thereore in is no atmosphere. heat gets carried away only by direct contact with cold plates. that is what bill was talking to. vehicle was brought down here and put in the space environment lab out on the back part of the center. it is a huge vacuum chamber. vacuum, runbably liquid nitrogen through the walls, and they also had a number of lights that simulated sunlight. unlike the command module that

was always in space and rotating so it would barbecue until the sun would see a different side or it would see the sun on different sides of the vehicle constantly. the lunar module with a set on sat there andnd did not barbecue so wherever the sun was, it was going to impinge on that part of the lunar module all the time. it's thermal design was different and validating the design was done out there in the chamber. among other things. another issue -- another thing there was a -- number of changes made to the lunar module fairly minor once it arrived at kennedy. which was the during testing down there, the paper

would be the chamber down there and its crewmen would get in it and one of the things that happened kind of late and armstrong's flight apollo 11 was he indicated he was too warm. in the lunar module in the chamber and at that time, it was only air cooled, air blowing through the suit and out. our plans had always been when we were landing that the crew was completely suited. airflow andling was he got to warm. toause they were also going be on the lunar surface, they were wearing a liquid cooling garment which is a fabric that had water tubes running through it. with au're in a suit support system, it ran water through that for cooling it just didn't have enough capacity just for air cooling and the crew would be working too hard.

and veryt, graham quickly built a little pump and tubing system and put a heat exchanger and that lunar module and all subsequent ones while it was at the cape. so that made available when we got to the moon, the crew could plug in those little water tubes and use those while they were still in the lunar module. late inre other changes the game when certain subjects came up. that capability was there. i am on aeration, slightly different tack. one of the agreements we had was that each of the contractors graham and the north american was those programs provided

technical representatives that had contact to the factory to flight operations. we were making drawings and procedures and malfunction procedures, normal procedures. very contacts were valuable because they knew the people back at the plant. they could call and get thanmation somewhat easier a voice no one had ever heard. key was one of the fairly decisions that was made in the program. another big problem with the lunar module was that when it was first built, it turned out to be too heavy. it was way overweight and you have heard stories about apollo 10 which was a complete dress rehearsal for apollo 11. it did everything except land. it had gone through a weight reduction program to get the

weight down to work it could land and take back off. apollo 11 was the first lunar module that had gone through the weight reduction program. the lunar module on apollo 10 was to have the anyway. about fuel articles offloaded so they wouldn't land. [laughter] that's really not true. use theffloaded to vehicle until we got through the where reduction program. >> that weight reduction program affected the thickness of the skin on the lunar module itself so it was more like an oil can than anything else. we would hear a pop will be pressured it up. in the weight reduction program they went from 18 gauge to 22 gauge wire. guess what.

when the people working on the vehicle touched those things, they broke. they broke the wires. it was a massive amount of time spent troubleshooting where the break was. question orrivia statement was the lunar module was a unique vehicle. it only flew a vacuum and only had to land on the moon and get back off. and not reenter the earth's atmosphere. we had a motto that heat shields were for sissies. [laughter] [applause] i guess turnabout is fair play. >> that was a hard one to follow. i do remember that heat field had aon which -- they

comeback which escapes me at the moment i'm trying to remember. [laughter] i don't remember it unfortunately it was 50 years ago. [laughter] something to the effect that you're not getting home about it. drummond at the time made aircraft for the navy. those things had to land on carriers. they had a lot of experience and reputation for structures. lunaras a part of the module -- it had to land on the moon. assume thatst you're going to land on a nice flat surface. you had to account for you might be falling straight down. you might be going so much forward to the left or right. then some rate of dissent. the surface might be tilted.

all of that had to be built into the design of the struts. the struts were honeycombed. aluminum. they just crushed. there was no spring or anything like that they would just crushed. on, there was a scientist named thomas gold. he had a very good habitation but he also had a ruby tatian forassuming -- reputation assuming certain fallout things. that he realized the lunar dust would be very loose and very deep. if the lunar module it could just disappear in the dust. [laughter] anddy knew that for certain other people thought differently and designed it differently. if you have ever

oured back in history, first moon shots were called ranger. ranger shot straight from the earth to the moon, went straight in and crashed but while it was going in, it had a camera and it's not teachers. you get closer and closer and get the feel that might be a landing spot. informationed landing areas. the other ones that followed that was surveyor. surveyor landed directly on the lip -- moon. it had three landing gear and it heads that would give you information about whether or not you would sink and how much pounds per square inch the service with support. we found out what the reality was with those missions.

when the lunar module was designed, they put pads and took that kind of thing into account so the area of those pads, we had a good idea there was not going to be a problem provided the service was within the it was designed to secure would not tilt over. if you look at maybe apollo 15, you see that one of those landed with a fairly obvious tilt. the tilt just stayed there until you took off. jack's point about the honeycomb structure and the mr. armstrong put that thing down so gently i don't think he crushed one but about two inches area. also, on the pads there was a

probe sticking down on each pad that was about five feet long and it had a little switch on the end of it. design, whatever those probes would touch, it would mean you are five feet off of the service. they were wired so that diagonally, if any two of the four probes dagley tripped that switch, it would shut the engine would drop the last five feet and crush the struts. he said nobody's turning my engine off of me. [laughter]

they shut the engine off. on those probes. there was a concern with the one that was right by the latter. i think they ended up taking was went off because if it sticking up it would be a surprise when they jumped down. [laughter] >> i think armstrong that pointed that out on one of his visits and i took that one off. so you only had three. a sides and it back. the engineering was a little i -- it was not my area so i didn't care that much about it. module,ook at the lunar the engine bell expense -- extends to the bottom of the pad. if you land with the engine still running and you're on them you haven'tthing, enclosed engine. the engineers worried about that that's what he had the original

design he was talking about. they would shut the engine off hopefully before anything like that happened. if you hear the actual air to ground, contact like, engine off, engine arm off, if you count the time that they were on the moon the first words were engine off. [laughter] then there was a moment of silence and then it was tranquility base here the eagle has landed. they also had a pretty good indication for thermal analysis which turned out to be very good because when you get into the weight reduction and you have to take out various and sundry things, what is remaining, those sheet just reflected the sun fantasy and did a very

good job. it was another change that was late and that was the down firing thrusters they finally determined that if you had enough down firing thrusters, it could damage the thermal percent -- thermal protection on the descent stage. so they added to collectors under each of the four down firing thrusters. game,e it was late in the that turned out to me because a bit of a communication problem on apollo 11. modeldeflectors to docket -- did not get modeled in the communication analysis. when they came around to do the deorbit burn, the descent engine is pointed toward the earth.

the antenna has to point down. if the antenna is pointing right get multipath you hadthat is probably why we ready communication early on. the other thing which was unusual was that neil wanted to be looking down at the moon when they started the burn. duringant that somewhere the descent, they had to rotate 180 degrees. when you got to the point when you pitched over, he would be looking forward. also reduced the reduce of communication and that's why they had a call to go up and get him to new angles for his steerable antenna to regain

high data rates. wasso-called high data rate 51.2 kilobits per second. [laughter] that's not much now. at low data rate 2.4. when you went to the antennas from that distance, you are at 2.4 kilobits and that was pretty low. for my systems, it didn't matter too much but for guys looking at the computer now, he might have lost it all. getting communication back was pretty significant. for evaluating where the crew was and how they were doing. that worked out but while we were sitting there lost a calm that was not a good feeling. had oneunar module computer. there was a firmware backup computer but it was very small.

all it has was some programs to get the ascent stage into orbit. the main computer in the lunar module there was just one and it was a 64 kilobits computer. one picture and your cell phone has more bits in it than the whole vehicle. >> or to the testing -- prior to systemting, the primary was called the primary guidance navigation system and the backup abort system was called the ags. testing,lot of the was a full end-to-end validation of all the software and hardware.

invariably, for many tests that whenever we switched to test the ax, the memory was gone. it was one of the self test programs that used to pull the memory out and look at it and if you put it back and back again, there was a timing glitch that it put it in the wrong spot. at the next time i came through, the data was bad. they finally fixed in a timing problem. [laughter] m.i.t. did all the programming for lunar module computer and the command module computer. they were both essentially the same box by raytheon but what was in the box were a series of rogues but it was a bunch of magnetic core donuts

interlaced with wires in certain directions that made ones and zeros. those programs were made up at m.i.t. and they had to be separate programs or you had a program for landing radar, rendezvous radar, the descent if they took ae, star trek to locate where you were, and each one of those called by a master program called an executive. that executive was designed by a fellow at m.i.t. his name was herb fanning. it's great feature was that it would keep running even if one of the other programs had a and also had a feature

that allowed for interrupts. number,z would put in a it was asking for something that constituted an interrupt. that interrupt took a little bit of time. that one or two or three of the alarms was he put in a d68 request. so he stopped doing that. wasother program alarm because of the way that -- i think the rendezvous radar had been set up and it was trying to attract the command module, that was the whole purpose of it. doing, they got a set of angles that got a high degree of copy tatian to go on. that copy tatian took longer than the main program allowed

for it. it had not finished and it was time to go on to the next thing and that caused executive overflow and that's what caused a couple of the alarms. those things we didn't know early on. they were simulated prior to apollo 11. aborted, jean asked his flight controllers to go look at -- to understand these things. they talked to m.i.t. and figured out what every potential alarm could be. the name of that list available. key unlessogram was it was decimal if it got too many it was doing what was supposed to do. it would do to a program finger to each next. it would repeat all those

programs and it was designed not to crash. elegantned out to be an design feature and those are still in place today. in many areas. >> let's take some questions. does anybody have a question in the audience? please stand up. [indiscernible] my question regards the frightening last few minutes of the landing. fuel,ially running out of the dead man's curve, landing long, taking on horizontal velocity to take on the boulder field. can you talk about that? i am fascinated about how they i think they>> started the burn a little bit late.

that meant you were going to be long. they knew pretty early on for they were going to be long. there was a long landing so it was still going to be in the but at the far end of it. there is a profile and you can find it online. basically when the engine it would start 10%, rep. tipton: 90%. it would not run very well. it was stable between 60 and 90. if they would run it at 90% or between 90 and 100% for most of the deorbit burn. the ornate -- orbit is bringing you in. then they start to pitch over.

it slowing your far velocity than it's also slowing you going down. the crew had a capability to redesignate. if the commander was looking out the window, there were some marks on the window and he could put -- point the limb and line them up where he wanted to land and click a button and the software would say ok i will go for that spot. a toggle switch that would change the rate of descent. them say numbers, some of the readings where it -- they would run across that cavity that boulder field and armstrong said that's not a good place so the rested rate of descent and went forward. so when you hear forward

forward, that's what he is doing. he's flying over the boulder field. the 32nd calland for calls that said you now have 60 seconds to bingo. 30 seconds to bingo. bingo meant you had 20 seconds of fuel left to go to fuel for -- full thrust, punch up, and do an aborted stage and get out. if you assessed that you are not going to make it, those were your points. to get out. or abort that they were the abort points. you heard the 62nd call and the 32nd call then he went slightly beyond that. he was there because you heard picking up dust. that. heard i knew he was going to land. [laughter] question.

don't state your name gesture question. [laughter] [indiscernible] >> i wasn't. [laughter] that was all in a different orbit. we didn't worry about that. i imagine there were some people looking at that but they were -- they were in different orbit so there wasn't any intentional of crashing they ended up crashing into a mountain. >> [indiscernible] >> that is a tough question to answer. [laughter]

>> you are saying scientific then. [laughter] criteriae engineering that were what is the maximum pressure differential? do you could have between the inside and outside? and what kind of margin do you want to have? typically structural margins would be 40%. what kind of stress is on the skin? and 40% to that. p. a five psi delta as long as you met the criteria, you are good. >> it was tested in the big vacuum chamber. there is one here that could go down to 10 to the minus six doors. that is pre-close to a perfect vacuum. part of the test process was

to take the lunar module vehicles out to a field and pump them up to three times operating pressure. it had to withstand routine psi -- 15 psi. if it didn't make it, it didn't fly. [indiscernible] [laughter] [indiscernible] >> the stages were held together by four bolts with power -- arotech devices they would blow the bold and the nut. stages,between the two there were electrical cables and there were gas lines for water and oxygen.

cablesthose lines and ran through what's called a guillotine. and a sharpimal edged bar. there was a pyrotechnic device behind that. i think we used abort stage. which was automatically separate everything. prior to that however, for a normal one would put the essence batteries and the -- disconnected the decent batteries and counted down and the crew pushed abort stage and that separated everything and let the ascent engine. we took advantage of the automatic feature. >> [indiscernible]

>> that happened on apollo 14. i believe it was the only one where they decided for some reason did not depressurized that cavity between the two tunnels. and when you fired the pyrotechnics, there was a pressure wave in their and that depressed the lunar module top hatch. that caused it to dump all of it took off like a scolded dog. [laughter] we lost data momentarily until the vehicle the lunar module had regained attitude control and had its antennas pointing back. time.on at the i suppose the cabin is empty. timen't figure out at the thethey later on had

service hatch that was that had the same pressure weight but it was a tough year heavier duty hatch fortunately. that was apollo 14. >> if i remember right on apollo 11, when they were ready to go , you open a dump valve to dump the pressure out of the limb so you can open the door. that was a very large door. i remember they had a lot of difficulty opening the door because they had to wait until the pressure change across the door went to zero before they could open the door. >> i thinks it's about a 36 inch , it so if you can multiply takes a lot of effort to open the door.

you don't have very good mechanics. >> last question. >> [indiscernible] have shot at it would be i not followed it enough so i don't know what their pressure regime is area we went with five psi your oxygen because you can immediately get into suits and go out area on the space shuttle seven, it ist 14 easier for a human because they are used to it. it also means and you have to go in a space in and drop your pressure down to eight or seven or five psi, you have to do a two or three hour thing to get all the night you can out.

that might be one thing that would have a difference. the guidance would be different because it has a lot more powerful computers area that has its pros and cons. >> i think the big difference would be the amount of processing power that would be carried on these later vehicles. even on shuttle, the main computers that flew shuttle were 512 k. that is nothing compared to what you are carrying in your pocket. the processing power is going to be the big thing that will be able to do a whole lot more with the computers than they could do on apollo and shuttle. >> there will be a lot more software involved because the lunar module and the command module in apollo, it was all hardwired switches and wires going from the switch to the relay. there wasn't such a thing as a data bus.

today, fly by wire all of that aircraft and spacecraft are fly by wire and controlled by the computers. that enables you to save a lot of weight in the vehicle. >> if you go down and land and whathe gateway concept, lance is supposed to all come back because it has to be refueled. we just took one part of it, took it back and brought it back on a different vehicle. there's a whole set of design goals that would be different for going back to the moon ryu expect to have a capability were you reuse the same vehicle over and over again. isthe biggest difference there is a lot of stuff to build on that was developed in the

apollo program. if it seems like we were winging it, we were. i don't know of a better way to end it. weree join us and welcoming our panelists today. [applause] >> american history tv is on social media. follow us at c-span history.

here is the reason program. >> this is an icon for traverse city. having two bays and it is the end of a peninsula. the peninsula is north of downtown traverse city. the peninsula divides each and west -- east and west bay. this lighthouse is needed here for shipping traffic that would go to elk rapids and also traverse city. at the end of the peninsula, out from the beach is a very shallow shoal.