on american history tv. next on american history tv, three former apollo era 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 50th anniversary. good morning and happy lunar landing day. [cheers and applause] >> it's great to have you all here. i'm the chief operating officer at the space center houston. we are a nonprofit entity and smithsonian affiliates and we are the world's first certified autism center as a science center.

there he much in equity inclusion, accessibility, and we take that on as a great badge of honor to establish expert training to ensure that our staff is able to work with people who have any type of learning disabilities or any type of challenges. if you see there is a need we are not meeting, let us know because we always want to improve. welcome today to our first panel discussion. [applause] >> i spent over 20 years of my industry,nasa and the and i tell you, i've been around a lot of folks, and around flight controllers and directors over the last 40 years that i've this has been a fantastic experience for me. gentlemen, they're planning discussions like this or have been a part of the mission control that have been restored as a national historic

landmark where they actually have the missions. through shuttle, but also included the lunar landing for apollo 11 and many other great spaceflights. if you have not gotten your tickets for that, hopefully you will today. they will go quick and i apologize if you are not able to go today because we run that on a quick circuit, but we are going to be open for quite a long time today. hopefully you will be able to get that so that you may be able to do that. there was a great opportunity for us to partner with the nasa space center and we did the fundraising for them as their federal agency could not do that. the city of webster gave a large contribution for that, three point $5 million, $5 million for that restoration. [applause] >> today, with our first panel, we thought it would be best to have a discussion.

as we are talking about the lunar landing, talking about lunar module development start out with, and these are quick presentations and discussions, we really wanted to have commentary from the audience as well. we do have that, we ask that you have a quick question so that we can also have others who can answer and ask questions. them to will allow introduce my name, and i will allow them to give a quick synopsis of what they did when they were in mission control. first is to my right, richard to . [applause] [no audio] -- [applause] bill reeves in the middle. [applause] knight on the far end. [applause] richard, what you start us off? i graduated college in 1966

and went to work for an aircraft company at the time. i started testing the environmental control systems on workedar module and that , that involved atmospheric relation systems which involved getting co2 out of the atmosphere because in a closed environment like that, you have to scrub it otherwise you are in trouble. management, and all the life-support type things are going to focus in the development phases. good morning. , i grew up ins arkansas and got here as fast as i could. [laughter] [applause] i joined here in 1967, and

went straight to the flight control division and was a flight controller on the lunar module in the electrical power assist. we were responsible for all of the power systems which was just batteries, and the distribution system and keeping track of our profile, so we also were in charge of the pyrotechnics license that separated the stages and opened valves. i was in the back room, which is called the vehicle systems support room, and we were the people that made the people in the front rooms look good. [laughter] [applause] anyway, i was 25 years old when on the11 landed and was previous shift and wasn't actually on during the landing, but none of us left shift to

shift, we all hung around and watched it. i will turn it over to jack. knight, i was a member of the air force family that bounced around the world a number of times, a number of places. went to georgia tech, graduated in 1965, and came straight here at the manned space flight center, also in operations. was signed to the lunar module. the lunar module wasn't quite ready at the time, so we participate in the gemini program a little bit. , apolloy were over moved out. the first lunar module was unmanned, i was involved in that. that went around the earth a few times and it automatically executed some of the critical events that had to happen such as trying to burn the engine,

burning an asset engine, and he didn't have any people on board. atmospheric integrity. after that, we started to really pick up and i was involved in all of the manned flights, apollo nine through apollo 17. roomrted out in the back and was out for all of the apollo nine and subsequent. ship -- shiftmy was right after the landing shift so i waited for that to happen. came out immediately thereafter. got to see armstrong step on the moon and the rest. issued,ect of this was

and there were quite a number of them, i think, on all of vehicles. as well as the 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 to get past that, rebuild the interior of the command service module. the liver module is running in parallel with all that. a number of interesting things to me later on, they were in areas that were not my specialty, but in particular, the asset engine. nasa had a process by which, if they had uncertainty in particular areas, they would often put two contractors to work. the first one that came up with a good solution, they said, you are it, you do the rest of it. and the other guy that was paid

moved on to other things. in this particular case of the asset engine, the problem was the eject or. they didn't manage to make it work, it turns out that you can only fire the engine once. no engine was ever tested other than the development by firing the complete parts. until it launched from the moon. to me, that is kind of an interesting thing. [laughter] but it was simple, so you knew it would work once, and that's all it needed to work. every one of them did. -- you want toer speak to that, rich? >> i just wanted to chime in on bill, raise the comment about

being in the ss r. i was in the mission evaluating room working back room to those guys, and we help them look good. [laughter] [applause] >> as you can see, there is a lot of healthy discussion here. they all may had about 50 years to work up to this. >> that is a fact. that was the beauty of the organization, it was a very competitive environment. the always thought that unsung heroes of the program were the training people that and putall of us together the simulations and through all the failures in and all that. those people were behind the scenes and related a great job. -- really did a great job. how many of you all have seen the lunar module described as the lem?

documentation, in fact, when i first got here, there was still a lot of documentation that called it the which stood for a lunar excursion module and the original design of the vehicle was for it to land and move around but that was dropped way early on for cost and weight reasons. so there is your trivia question for the day. [laughter] >> but the power system in the lunar module that i was working on was strictly batteries. main focus was, we would take the checklist that was being developed at the time as to what we were going to do, and we had to resolve the checklist anypower draw that we do at point in time how much power was being drawn out of the batteries, how much time we had left. there were four major batteries

in the decent stage that were on during landing and there were two batteries that power the asset stage when they left the moon to go back to the command module. one design issue that we ran the asset batteries were only parallel on the power buses with the batteries during the landing, in case you had to abort. had to abort the landing, the vehicle would go back. was the you found out batteries which had not been used for quite a while timewise in the mission were sitting on cold plates and they were getting very very cold. and batteries had a characteristic where the voltage was very unstable for the first out of thep hours

battery before the voltage got stable. we found out that if you stage the vehicle without getting that first 10 or 12 and hours out of the battery, the voltage on the bus were dropped during staging to the point it would dump the computer and affect a lot of equipment. we had to come up with a power aheme for the batteries on at certain point in time to get them to pick up the load and get that preconditioning out of the way. that was quite a challenge to do that. during the mission, we found out that they weren't drawing as much as they were supposed to, so we wound up having to play some games with it. all's well that ends well. [laughter] i just wanted to point out and wonder around out here, there's a lunar module and hanging from the sky, that was the test article number eight.

here i accompanied down from where it was located and put it through a full series of thes to validate that environmental control system as well as the thermal control system could manage and keep the vehicle from getting too hot or too cold and help the equipment make sure that the equipment did not get too hot. as i said before in space, there is no atmosphere. heat is carried away only by direct contact with cold plates, and that was what bill was talking to. that vehicle was brought down here and put in the space environment layout on the back part of the center. chamber.ge vacuum vacuum, runull a liquid nitrogen through the

walls, and they also had a number of lights that simulated sunlight. module whichmmand was always in space and was rotating, so it would kind of barbecue and the sun would see different sides of the vehicle constantly, the lunar module, once it sat on the surface, had sat there, and it did not barbecue, so wherever the sun was, it was going to in page on that part of the lunar module all the time it was there. so the thermal design was different and validating that thermal design was done out there in that chamber. among other things. that was done there. another thing that came up, particularly, there was a number of changes that were made to the lunar module.

, oneit arrived at kennedy of which was that during testing down there, they would put it in the chamber down there and the crewmen would get in. one of the things that happened kind of late in armstrong's life, 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 flowing through the suit and out. thatlans always had been we were landing, the crew was completely suited. the only cooling was air flow and he got to warm. so because they were also going to be on the lunar surface, they were wearing a liquid cooling garment which is a fabric that had water tubes running through it.

in a seat with a portable support system, it ran water through that. it did not have enough capacity just for air:. so, after that, they very quickly built a little pump and tubing system and put a heat exchanger in that lunar module and all subsequent ones. that was made available so that moon, itot to the plugged in those little water tubes and use those while they were still in the lunar module. i think there were other changes when certain subjects came up, but that capability was operation, one of the agreements we had was the

age of the contractors for the lunar module in north america was those companies provide technical representatives that had contacts back to the factory to flight operations because we were making drawings and procedures and malfunction procedures, and those contacts were very valuable because they knew the people back at the plant and they a call and get information somewhat easier than a voice nobody had ever heard. key was one of the fairly decisions that was made. another big problem with the lunar module was when it was first built, it turned out to be too heavy. it was way overweight. you heard a lot of stories about

apollo 10 which was a complete dress for her suffer apollo 11. the limb had gone through a massive weight reduction program to get the weight down to where it could land and take back off. apollo 11 was the first lunar module that had gone through that weight reduction program. the lunar module that was on apollo 10 was to have the anyway. heavy -- too heavy anyway. was setrticles that it up so that they would land. [laughter] really not true, it was offloaded to reduce the weight of the vehicle. perspective, the weight reduction program, first of all, affected the thickness of the skin on the loot or module itself, so it was more like an oil can. when we were testing, we could hear the pop of the pressure.

also, in that reduction program, it went from 18 days -- 18 gauge does a 22 gauge wire. ?guess what the people working on the vehicles things, they broke the connections, they broke the wires. it was a massive amount of time spent troubleshooting where the break was. >> another little trivia was the or statement lunar module was a unique vehicle, it only flew in a vacuum and it only had to land on the moon and get back off. and not reenter the earth's atmosphere. a skies always had a motto that heat shields were for sissies. [laughter] [applause] i guess turnabout is fair play. >> that is a hard one to follow.

i do remember that decision, but they had a comeback which escapes me at the moment, i was trying to remember that. i don't remember it, unfortunately. it was 50 years ago. to the effect of you are not getting home without it. drummond at the time made aircraft's for the navy. that thing had to land on carriers. experience andof reputation for structures. structures was part of the lamont module, it had to land on the moon. can't just assume that you are going to land on a nice, last service. youhave to account for might be also falling straight down, you might be going

somewhat forward, somewhat to the left or the right. account for the service might be tilted. all of that had to be built into the design of the struts. the struts were honeycombed aluminum. there was no spring or anything like that. they just would crush. on, there was a scientist named thomas gold, i think he was. reputation,y good but he also had a reputation for assuming certain far out things. one of the things he mentioned was there was a possibility that the lunar dust on the moon would be very deep and it could be 40 feet deep. so the lunar module could just disappear. [laughter] >> now, nobody knew that for certain, and other people

thought differently and designed it differently. out, if you have ever looked back in history, our shots werelite moon called ranger. ranger shot straight from the earth to the moon and went straight in and crash, but while it was going in, it had a camera to his pictures. and so you would post, post, post. you would get a field that might be landing spot. aboutprovided information landing areas. the other one that followed that was surveyor. surveyor landed directly on the moon. it had three landing gears and it had pads that would give you information about whether you were going to sink or not and

how much pounds per square inch the lunar surface would 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. those, we had a pretty good idea there was not going to be a problem, provided the service you landed on -- surface you landed on was designed so you would not kilt over. you could look at apollo 15, or one of those videos, one of those landed with a fairly obvious tilt and it just stayed in their. on jack's point about the structure and the struts, mr. armstrong, put that thing down a stroke ofd it had

about a foot. pads, there was a probe sticking down on each pad that was about five feet long that had a little switch on the end of it. , wheneveral design those probes would touch, it would mean you were five feet off of the surface. so that the, wired if any two of the four probes diagonally tripped that switch, it would shut the engine off so that it would drop in crush those struts. the crew said, nobody is turning my engine off but me. [laughter] >> so they changed the wiring on lightto where it lets a on the dashboard and during the landing, you will hear them say, contact light. when they say contact light,

that meant that that light, the lunar contact light had come on which meant that the probes had touched the surface. and they shut the engine off. probes, there was a concern with the one that was right by the latter. they ended up taking that one stickingse if it is up, it would be a surprise when they jumped down. [laughter] armstrong had pointed that out in one of his visits and they took that one off. so you only had 3, 2 sides and the back. engineering was a little worried, although, again, it wasn't my area. module,ook at the lunar it extends almost down to the bottom of the pads. land with the engine

still running and you are on a rock or some raised area, you that's whylosed -- they have that original design he's talking about, the crew talked him out of it. they would shut the engine off, hopefully before anything like that happened. of course, nothing ever did. but if you hear the actual round, you hear it contact light, engine off, engine arm off, things like that. time that theye actually were on the moon, the first words essentially were engine off. and then it was tranquility base, the eagle has landed. they also had a pretty good reputation for thermal analysis, which turned out to be very good because when you get into the weight reduction and you have to things, there is other

what is remaining, those gold reflected thest sun energy and did a really good job. there's another change that was and that was the theyfiring thrusters, finally determined that if you had enough down firing thrusters, you could damage the thermal protection on the descent stage. so, pretty late in the game, they added these little deflectors on the descent stage right under each of the four down firing rcs thrusters. that turned out because it was pretty late in the game, to may because a bit of a com problem on apollo 11 because those deflectors did not get modeled analysis,munications

,nd so when they came around the descent engine is having essentially toward the earth. so, the antenna has to point down. and if the antenna is pointing right at that deflector, you get multi path and that is probably ratty com early on. the other thing which is unusual wanted toas that neil be looking down at the moon when they started the burn. that meant that somewhere during the dissent, they had to rotate 180 degrees. you got to the point where you pitched over, you would be looking forward. if it stayed where it was, you would have been looking backward. introducedon also

cal -- lost com, and that is why they had him change the antenna for high data rate. the so-called high data rate was 51.2% in. [laughter] >> which is not much now. low was 2.4. when you went to the on the antenna from that distance, you are 2.4. that was pretty low. for my systems, it didn't matter much. for guys looking at the computer, they think they may have lost it all together. was prettycomm back significant. where the crew was, how they were doing. that worked out, but while we were sitting there, there was not a very good feeling. moduleknow, the lunar

and one computer. a firmware back a computer but it was just very small and all it had was some programs to be able to get the asset stage into safe orbit so the command module could pick it up. the main computer in the lunar module, there was just one, and it was a 64 kilobits computer. one picture on your cell phone has more bits on it than that whole thing had. >> and on that point, during the , before the landing occurred, the primary system was called things -- pings. primary navigation system. testingng an lot of the in that stage, prior to shipping it down here, we read what is

called feet tests, full end to end validation. invariably, for many, many tests that were run, whenever we switched to test the ags, the memory was gone. it was one of those self test program that we used to pull memory out and look at it to put it back. glitch that it pulled out and put it back in the wrong spot. bad time it came through, data, bad data, and no memory. they finally figured out how to fix that timing problem. mit did all the programming for both the lunar module computer and the command module computer. they were both essentially the same box built by radeon, but what was in the box a series of

cards that had what they called ropes, but it was a bunch of magnetic doughnuts interlaced with wires and certain directions that made ones and zeros. but those programs were made up at m.i.t., and they had to be separate programs you had a program for landing radar, a program for rendezvous radar. guidance, programs a start to took locate where you were. each one of those programs was called by a master program called an executive. assigned by a was fellow at m.i.t.. you can find this online, by the way, it's an interesting read if you are in that area.

but the great feature was that it would keep running even if one of the other programs had a problem. thatso had a feature allowed for what they call interrupts. would put in a number like p60 eight and was asking for something, that constituted an interrupt. that interrupt over a little bit out that oneigured or two or three of them was p68ciated when he put in a request so he stopped doing that. the other program alarm was because of the way the rendezvous radar had been set up. it was trying to track and the command module, that was the whole purpose of it. but in so doing, it got a set of

angles that caused a high degree of computation to go on. that computation took a little longer than the main program allowed for. it hadn't finished, and it was time to go on to the next thing. an executive overflow and that is what caused a couple of the alarms. those things we didn't know early on, they were simulated prior to apollo 11. aborted, generong asked his flight controllers to go look, we need to understand these things, go back, talk to m.i.t. and figure out what every potential alarm could be and what could cause it, and have that list available. but the main program was the key because unless you got too many of those, it would keep on doing what it's supposed to do.

it would do a program, go to the next one, go to the next one, loopback. and so repeat all of those programs. it was designed, essentially not to crash. so, that turned out to be a really elegant design feature. i think those are still in place today in many areas. dark outlets take some questions. anybody have some questions in the audience? over here on the end? please stand up. >> thank you so much. my question regards the frightening last few minutes of the landing, potentially running out of you'll. the dead man's curve landing long, on a horizontal velocity to escape the fuel. can you tell me as much as you can about that. how did they do it?

>> let me take a shot at that. i think they started the burn slightly late, a couple of seconds. that meant you were going to be long. so they knew pretty well early on they were going to be long. gut there was a long landin ellipse. you mentioned some other things having to do with rate of dissent -- descent. there was a profile and you can find it online, basically when the engine started out, it would run out, it would start about 10% and ramp up to 90%. it would not run very well. they would run it at 90%, between 90% and 100% for most of the fuel burned, and you are just slowing down. lunar gravity is bringing you in.

at a point, highgate or something like that, they start to pitch over. at that point, lunar gravity is bringing you win and the engine is doing two things. it is slowing your velocity plus it is slowing you going down. to crew had a capability what they call a redesignate. so the commander was looking at the window, there were some marks on the window and he could point and look into those marks, line them up at the place he wanted the land, and click if i and the software would say i'm going for that spot. switch thata toggle would change the rate of descent. downyou hear down 2.5, 2.5, some of them were you see down 20 or something like that, that's feet per second in vertical velocity. they control that with a switch. then, they ran across that

boulder field and that is not a very good place, so he arrested the rate of descent and went forward. forward, forward, that's what he's doing, he's flying over that boulder field. the 60 second call and the 32nd call were second calls that said you have 60 seconds to what we call bingo. bingo meant you had 20 seconds of fuel left to go to full and do annch up, abort stage and get out. if you assessed that you weren't going to make it, those were your points to get out. or abort points. well, you are the 60 second call and the 30 second call. it went slightly beyond that when he was here because you heard it picking up dust.

what i heard, i knew he was going to land. [laughter] star question, right here in front. go right ahead. stand up and state your name or at least your question. [laughter] [inaudible] >> 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 again, they were in a different orbit. there wasn't any potential crashing. i think they ended up crashing into a mountain. >> [inaudible]

>> that is a tough one to answer. [laughter] [applause] saying it scientifically. >> let me see, engineering had criteria. in the criteria were what is the maximum pressure differential that you could have between the inside and the outside, and what kind of margin do you want to have? typically, structured margins would be 40%. you would say, what kind of stress is on the send, add 40% to that. five psi or something along those lines. as long as you met that criteria, you were good. >> plus, it was tested in the big vacuum chamber which, the vacuum chamber here could go six,to 10 to the minus

which is pretty close to a perfect vacuum. >> is a national historic landmark, only the second one in addition to the historic mission control that has been restored. >> 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. psiit had to withstand 15 of delta pressure. if it didn't make it, it didn't fly. [inaudible] [laughter] yes, sir, in the red. >> [inaudible] the stages were altogether by quadruples with pyrotechnic devices that flowed.

in between the stages, there were electrical cables and there were gas lines for water and oxygen. and all those lines and cables ran through what is called a guillotine. it was a sharp edged bar with a pyrotechnic device behind that. i think we used abort stage. automatically separate everything. prior to that, however, we put the batteries online, we disconnected dissent batteries -- descent batteries. the crew pushed of fort staged if i remember correctly, and that separated everything. we took advantage of the automatic feature.

>> [inaudible] >> that happened on apollo 14, and i believe it's the only one where they decided they for some reason did not depressurized that cavity between the two tunnels. when you fire the pyrotechnics, there was a pressure in their, and that depressed the lunar module top hatch. that caused it to dump all the gas, so the crew said it took off like a scolded dog. momentarily until the lunar module had automatically regained attitude control and had it pointing back and we thought, there is an empty cabin.

the cabin is empty. none of us, i didn't figure it out at the time. but later on, they got a little nervous because the csn hatch also was subjected to the same pressure weight, but it was a topper, heavier duty hatch, fortunately. so, that is that story, that was apollo 14. >> if i remember right on apollo 11, when they were ready to go spacewalk, you opened a dump valve to dump the pressure out of the limb, and so you could open the door. and that door was a very large store. and i remember they had a lot of difficulty opening the door the weight ofad the delta pressure across the door went to absolutely zero before they could actually open the door. >> i think it's about a 36 inch

door, you can multiply and get nine square feet and so many square inches. multiply that by five and find out it takes a lot of effort to open the door. you don't have very good mechanics. >> last question. >> [inaudible] >> my shot at it would be, i haven't all of it enough, so i don't know what the pressure regime is. we went with five psi or oxygen because you can immediately get into suits and go out. on a spatial in the station, when you are at 14 seven, it is much easier for the human because they are used to it.

but it also means when you are going to go in a spacesuit and drop the pressure down to eight or seven or five psi, you have to do a two or three hour breathing to get the nitrogen out. thing thatbe one would have a difference. the guidance would be different. lotably because it has a more powerful computers. that has pros and cons because. >> i think that the difference would be the amount of processing power that would be carried on these later vehicles. i mean, even on shuttle, the main computers that flew shuttle nothingk, and that is compared to what you are carrying in your pockets. i think acrostic power is going to be the big thing. they will do a whole lot more with computers than they could do on apollo. will be a lot more software involved because the lunar module and the command module back on apollo, it was

all hardwired switches and wires . there wasn't such a thing as data bus. well, there was for the one computer, but today, fly by wire, all aircraft and spacecraft flyby wire. they are all controlled by the computers. you to save a lot of weight. >> [inaudible] >> if you go down and land and use the gateway concept and what lands is supposed to all come back because it has to be refueled. we didn't do that with the lunar module, we just took one part and brought it back and came home with a different vehicle. there's a whole set of design goals that would be different for going back to the moon where to reusea capability

the same vehicle over and over again. the biggest difference, there is a lot of stuff to build on those in the apollo program. like we were winging it a lot and the apollo program, we were. [laughter] were solving problems that nobody had ever thought of before. take all of that knowledge now and incorporated into the new program. i don't know of a better way to end it. please join us in welcoming our panelists today. [applause]

>> ok, the contingency sample is down. to diglittle difficult through. >> there interesting, it's a very soft surface but the contingency sample collected, i've run into a very hard surface, but it appears to be very cohesive material of the same sort. i will try to get a rock in here. announcer: now you're watching american history tv. every weekend beginning saturday at 8 a.m. eastern, we bring you forget hours of unique programming, exploring our nation's past. america history tv is only on c-span3.

>> i believe they are setting up the flag now. neil, this is houston, radio check, over. >> i roger, houston, loud and clear. >> roger, boss. announcer: this weekend on the presidency, former secret service agents talk about protecting the first family and the challenges they face. booners include larry door who prevented a 1975 assassination attempt on president gerald ford. here's a preview. >> my position at the time was right at his left shoulder. as he's walking along shaking hiss, i'm concentrating on

hands in a downward motion because you don't want anybody to grab too long and take his watch or whatever. crowdg down, out in the is a member of the charlie mansion family -- charlie manson family who happened to be carrying a 45 strapped to her ankle. she was back a couple people in he's shaking so as hands, suddenly i see this hand, with something in it and at that time, i didn't know if it was a weapon. front of the in president to stop the hand from coming up because i didn't want him to get hit with whatever it was. the minute i hit it, i knew it was a gun. all my very gun, best friends with the president left with the president. [laughter] >> talk about a training program. you are on your own, but he. -- buddy.

the crowd is screaming and we got the gun. thing, i did have my ist on, so unthinking that, don't know if there's more to this, but i know i'm not letting go of her. i'm pushing her back through the crowd and the crowd is screaming, this girl is screaming. ikeep pushing her away and as said by then, the president has gone with the agents. i dropped her down to the ground , some of the agents and police from the back of the crowd came forward, and i noticed one of the agents from the shift and i hand him the gun and proceed to cover which is half -- cuff her which is happening now, as you see. i turned her over to the agent that was there from our thelligence division and police went back and joined the shift.

seconds, you have a chance to sit back and think about how fast it went down. [applause] announcer: learn more about secret service agents and their challenges sunday at 8 p.m. and midnight eastern on the presidency. you are watching american history tv. tonight on q&a, -- [chanting] >> we were taken out of the hall and confronted with this mob of angry people. >> allison stannard talks about being physically attacked in 2017 after an appearance by charles murray on campus. >> at the end of your discussion with charles murray, you left that room and went where? >> i don't really remember much of it. really tell you what

door we went out. the hallaken out of and confronted with this mob of angry people, some of whom were in masks. they were shoving and jostling. their target was charles murray. >> tonight on q&a. history,n lectures in andrew slap of east tennessee state university teaches a class on abraham lincoln, andrew johnson, and the constitution. he compares how both presidents have been portrayed as either upholding or disregarding the constitution, and whether their reputations match their actions in office. prof. slap: good morning. thank you all for coming. today we are transitioning in the course from civil war to reconstruction. because of that, it is a good

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