tv Lunar Module Landing Operations CSPAN August 11, 2019 9:15am-10:01am EDT
>> next on american history tv, four former apollo era flight controllers discuss the lunar module landing operations. this panel was part of an event hosted by space center houston to mark apollo 11's 50th anniversary. it is a very special day. we are honored to have a panel of important engineers.
all didly 14 when you the miracle back in 1969. i tried to get here and follow in your footsteps as quickly as we could. we have a panel that will talk about lunar module landing operations. the panel here is jack knight, bob nance, hal loden, and bill reeves. instead of me going on about them i will ask them to identify themselves, say a little bit about what they did and then open it for questions. my name is john charles. i am the science in fast scientist in residence at space center houston. i would like to turn the microphone over to mr. knight. to talk about what you did here for apollo 11, what brought you here in the first place and your recollection of that important day. jack: i was the son of an air force family.
we were in various bases around the world. i went to the georgia institute of technology and graduated in 1965. i came directly to the manned space flight center, in particular the apollo systems group. at the time i arrived, apollo had been a program in work, but we were flying the gemini and the gina vehicles. i was in the environmental control, electrical power area. i participated in every lunar flight, including the unmanned one. i was in the ssr staff support room for that. and on all subsequent flights i was in the operational control room, which we called telcom or
telview, depending on the flight. that was for apollo 9, 10, 11 and anything that had a lunar module on it. now i will pass it to bob nance. [applause] bob: good morning. this is a big day. i started this morning with a prayer just like 50 years ago. lord, help me not screw up today. [laughter] i heard president kennedy tell america we were going to go to the moon by the end of that decade. i wanted to be part of that. i also went to georgia tech. i met asked for not bill young -- astronaut there. john young from there i ended up here in lunar module propulsion.
i was so blessed that i got to live my dream of sitting on the console of lunar module propulsion when we landed on the moon. i think we will talk about that later. [applause] hal: good morning. my name is hal loden. i grew up the son of a memphis -- the son of a preacher. i was in florida working on a 1964,program from 1963 to a langley project. a manager was a good friend of mine and he said go to houston for the spacecraft center. i said my wife is from houston, that would be good. i got a job at msc, at the time. i went to the operations directorate.
that was the gemini-gina systems. i am an electrical engineer from texas a&m. [cheers] hal: [laughter] i was a flight controller in the lunar module gnc systems. that area comprises of the descent and a sense systems, and the hardware for the primary and backup computer systems. i flew the apollo missions from glen 1 in australia for that. apollo nine through 10, 11, 12, all the way through 17.
specifically, on apollo 11, i was the main control guy on the console for the ascent on the moon. the descent was exciting. i was there behind our good friend bob carlton. he is no longer with us. he passed away a couple months ago. i was hesitant as to whether or not we would make it when bob was calling out the fuel remaining. we didn't have a lot left. when we got to the ascent, we had problems too. i have heard people say that the asccent was more dangerous. i find that hard to believe. anyway, that's my story. i'll pass it to bill reeves. [applause] bill: my name is bill reeves. i grew up in arkansas and went
to oklahoma to get an electrical engineering degree and went to texas as fast as i could. in football season, i didn't have a chance growing up in arkansas. when i was hired on in 1967, i was hired on as the flight controller operations director. we were in charge of all of the power systems and the power distribution systems. we were also in charge of the pyrotechnic systems, the explosive devices that separate the stages and open valves and deploy the landing gear. i had gotten here right after the apollo 1 fire in january.
i was lucky enough to be in position when we started flying the lunar module. i was in the staff support room. the support rooms are the rooms that support the main control room. we are the people who make the people in the main room look good. [laughter] >> absolutely. >> when you see the control center, when you see it on the movies, that is the tip of an extremely large iceberg. there are a lot of people supporting that. i was flight controller on the lunar module throughout the entire program for all of the
flights. after apollo was over, i flew back seat for nasa for about eight years. i came back for the shuttle and was flight controller on the shuttle and was elected as flight director for 22 shuttle flights. that's it. [applause] [applause] john: this is excellent. a good thumbnail sketch of the lunar activities for apollo. i am derelict in my moderator duties. i forgot to tell you when we first came in that when we are finished please move quickly to the exits. there are 200 people outside waiting for the next presentation. i would like to ask a couple of questions and we will open it up for q1 day.
one is powered descendent howard i want to know any trepidation's you had about the power anding, the propulsion down from lunar orbit and your recommendations or thoughts about the probability , the inevitability of success or any problems you might have. >> there were a lot of sweaty palms. let me try to give an overview. module to send starts after the lunar module comes back down from the backside of the moon. is big surprised we have difficultata was so that we were having trouble getting voice and data, high gain data. the dissent and
the engines firing the first thing that happened was that the data dropped out. we are sitting you're giving goes or no goes without any data. of times you hear the landing and it sounds like everything went really smooth but it was difficult at the beginning. this would drop out and we would get a bit of data and everything is working good. we have our data back. we came to where the crew starts they would rotate 180 degrees and when that happened would lost -- lose data again. we did hear that we were going to be long. that had to do with a slight timing error. everything was going very smoothly.
those thrusters you see on the lunar module as well. a lot of people think you concentrated on the descent engine but we had to have a visual pattern where you look at the accident and rcs area when you are burning an engine the vehicle is shaking and you want to make sure if the engine is working good and it has not sprung a leak. even though you are concentrating you constantly have to look at the other systems in the various propulsion systems. we start off burning at about 98% thrust and then it drops. we had data and everything was looking good. everything was tracking. we had a few computer problems.
everything seems to settle down. everything was going good. one of the things that we were always worried about was that our fuel margin on this mission was running about 4.5% propellant remaining. then we heard attitude hold. that is when the crew decides to take over themselves. normally if they did nothing, the lem would come all the way down to the moment before landing. we already knew with simulations that neil liked to take over early, but this was earlier than we had seen. one of my jobs was the propellant monitoring. are we going to run out of fuel? we had a meeting with neil and buzz and worked out what we would do. we first had an indication of
low-level which is 6.5% remaining. the goal was that you know how much time at that point you have to hover. we got to fight points six and they were not host a hovering. neil realized he had to go over the top of a crater and to get away from a boulder field to try to find smooth ground. we could see this happening because the rcs, those jets, normally a descent engine has a bell. small motions are made with it. that means he is overwriting it putting in a command greater than the descent engine can move. he had leaned over to speed up. when he stopped descending, he leaned down and went up a little bit. i'm sure that was to see whether he could find a clear spot to land. the next call was was 60 seconds. that is 60 seconds until you run
out. the calls were 60, 30, and bingo. 60 seconds, 30 seconds, and bingo. we sat there and my original idea was 60, 30, 15. buzz was active in everything. neil was always very quiet. , i'm aa sudden neil says will make that decision. we said, we know you will, mr. armstrong. said, couldound and you give that another name, please? i believe buzz was a navy pilot. when you are committed to land
you have to land no matter what. neil said bingo works. it was 60, 30 bingo. call 30.xpected to in simulations we normally land after 60 seconds. i have all of those tapes. when i made the 62nd call out, that was passed on, it was 60 seconds. when i made the 32nd call out, it was more like 30 seconds, i couldn't believe we were here. the final number was we landed seconds of fuel remaining. the interesting thing about this, it's really important that the public understand just how brave neil and buzz were.
there were so many things. this was the very first time we had ever landed any spacecraft like this. all of the other missions you had probably heard about, the ranger, the surveyor, they landed directly. if anything happened, you didn't have enough to start -- to stop it to start back up. so we started it by going down slowly. these computers had very little memory. this was the first time that was ever done. if you want to applaud somebody,
applaud neil and buzz. it was amazing. [applause] john: skipping over a lot of interesting stuff. i would like to ask mr. loden about the powered ascent back to orbit. tell us about the unique characteristics of the ascent propulsion system. hal: let's see what i can come up with here. during descent, we had those 12:02 and 12:01 alarms that gave everyone concern. that's because the onboard computer was being overloaded with tasks it did not need to be doing. it had to do with a rendezvous with the radar. when it came to ascent, there was quite a few crew checklist changes that had to be made to take into account that potential
problem again showing up on ascent. we want to keep those alarms from happening. once the changes were made, we came up with a procedure to stall the rendezvous radar antenna and power it off during ascent. there was another issue that i remember working. when they came back in from the eva, buzz noted the circuit breaker panels on both sides of the lunar module, and they are not like the ones you have at your house where you flick it like a light switch. he's are the ones where you push in and pull out -- these are circuit breakers where you push in and pull out. most of them are in the off
position. he noticed that a circuit breaker was broken off. it happened to be the ascent engine arm circuit breaker. that doesn't mean we are not going be -- going to be able to light this engine. that when allowed the computer to automatically light it. we were trying. took out his black ballpoint pen and pushed it in during the countdown at the right time for ascent. the other thing leading up to ascent, on the ascent propulsion system, on the fuel tanks we had two pressurization models for redundancies to pressurize the
fuel tanks. you have to get everything to the right pressure before it goes to the stress chamber. in the simulations, the fire was enough to power the fuel tanks. we would always see both of those tanks drop a couple psi, or pcm counts as we called it. when it came time to do it on the lunar surface, and they fired the valves to pressurize the ascent engines, i only saw one bottle drop, which raised the possibility we only had one bottle of pressurization on the fuel tanks. the normal procedure for ascent
was assuming he had both bottles. we had the ascent engine and the rear thrusters. they had to both use the same propellant. we could use the ascent engine propellant. if we only had one bottle of pressurization, we had to terminate that. we had to alert the crew before liftoff that it was a possibility. we only had one bottle that would pressurize. the countdown to zero zero was done by the computer. the procedure also calls for shortly after takeoff, they would hit this override button, which circumvented the command coming out of the computer, just in case the computer went away for some reason. at liftoff, i told flight, we have both bottles.
very relieved about that. i want to continue on with the ascent feed. i noticed that they had not hit the engine fire override, the second way to keep the engine on. about halfway up, they finally energized the backup route for keeping the engine on. those were the things that occurred for me during the ascent. it wasn't very big, about four feet tall. at the ascent stage, it weighed about 10,000 pounds. it did its job very well. you notice when you are up the window on the films you see it
rocking back and forth. that is the dead man on the altitude control system. those thrusters are keeping that in that dead man. the ascent engine was not give a ball like the descent engine was. once we got back to orbit, they docked with the manned service module. we discarded the eagle which impacted on the moon after they left the moon. a very reliable engine. i was grateful to be part of such a great event. thank you. john: before relieve the topic, how many test firings to the ascent engine have before the flight? hal: that is a question i don't know the answer to.
i would assume it had a lot of test and firings, as well as some in the backup chambers as well. both the descent and the ascent engines were thoroughly checked out. the descent engine with the throttle capability, that was something we had never had on a spacecraft before. the people who put these machines together were very dedicated. the components that went into those spacecraft were the ones who got it done. john: that wasn't a gotcha question. there is a particular aspect i would like you to know about. jack: this is not my area, but it was part of the development process when they felt there was an area that was risky they
would hire two contractors to work on the ascent engine. finally you got to the point where one of them was more successful and then nasa said you are it. you can build ascent engines. the injector was such that erosion during the firing was so bad that they could only fire it once. they did a lot of testing. after that no ascent engine was ever testfired before it was used for lunch. the descent engine was probably different. it was a very -- it is a simple engine. all you had to do was get them to mix. we knew from testing it would work at least once. that was all that it had to
work. hal: that is a good point that i had not remembered. the first time we lit that sucker was on the lunar surface. that is pretty risky when you think about it. >> i was in a meeting for our simulations. i remember neil saying why didn't we just put a big lever on the side. the engine looks like a seat in the middle of the lunar module. he said why didn't we put a big handle on it where you turn it and it starts? hal: that would not necessarily have worked for an abort state during the power off sequence. he had another thing.
bob mentioned the calm. when the lem came around, they had to point through the landing gear. one of the things that was added late in the game was the deflectors on the descent stage that were right underneath the down firing thrusters. they were lighted -- they were added late because thermal analysis said there might be enough erosion that it would damage them on the descent stage. because it was late in the game,
those deflectors were never included in the modeling of antenna pointing, and getting good communications. so the comm guys, i'm pretty sure that's what happened. when you started the descent engine, as you were coming around, the and tenant was trying to point through one or more of those deflectors. you had this until you moved the vehicle a little bit and appointed the antenna. because neil wanted to be looking down at the moon, you had this other maneuver he was talking about after he started the descent engine. he ran it awhile and you had to yaw it over, so when it pitched
forward, armstrong and buzz would be able to see where they were going. all subsequent flights, they didn't need to be looking down. they could get into their anticipated position, and then all they would have to do is pitch forward. you would not have to have a yaw maneuver. that is probably why we ended up with comm problems, until they had pitched forward enough across the surface that the antenna got good enough comm with the ground. hal: this was the first lunar module that had those reflectors installed. when the lunar module would fire, it would impinge on the descent stage. there was an impingement maximum of 15 seconds on the descent stage then we would have to terminate the flight. these eliminated that factor.
we would have avoided it if we did not have those stressors and reflectors on there. bill: there were a lot of great neil armstrong sayings throughout this thing. one of my favorite stories, people remember things differently but this is the way that i remember it, late in the game with the landing radar, there had been some problems in testing. there was a lot of concern about whether it was going to be giving them the data that they needed. they had done a lot of testing on it.
we were in a flight rule meeting. i remember it like it was yesterday. it was a large room with a lot of people in it. it was a long and white table. neil was sitting at the end of the table. there was a discussion about developing a flight rule that said if the computer was not accepting landing radar data by x altitude, then it would be an abort. they targeted for three hours and finally gene says, we have talked about this long enough. that's the rule. if the computer is not accepting radar data by x altitude, it's an abort. everyone was nodding their heads and neil was at the end of the table shaking his head. all of a sudden kranz saw him and said, you don't agree with this?
neil said, you must think i'm going to land with the window shades down. [laughter] bob: i think that is the only mission rule meeting that i remember. hal: i don't remember them because there was nothing but smoke. john: we have time for a few questions from the audience. john: how far downrange to the land from the intended site? bob: it was about 3.7 miles. i was looking all of this up in case you asked. i put it on the website if you want to look up that kind of
stuff. >> [inaudible] john: compared to the smartphone, how much computing power did we have back then? bill: one picture on your cell phone has more bits in it than that computer on the lunar module. >> [inaudible] john: why did the lunar module carry jumper cables? did you know that it carried jumper cables? hal: i guess we had diehard batteries on board but we didn't need them. bill: there weren't any jumper cables but there were some cables that went between the
lunar module to some heaters. we powered some heaters so you wouldn't use any of the power out of the batteries that you needed for the lunar module on the lunar surface. those are the only cables that i'm aware of. hal: those cables, they kept the heaters going on our inertia measurement unit. where you were in space. those cables came to be very important on apollo 13. we were able to use lem battery power to recharge the reentry batteries on the command modules so they could reenter safety. >> [inaudible] john: why was the landers so far
off the lunar surface when they landed? bob: with the landing gear the original intent is that it would automatically land. what was going to happen was that when these probes that were about four-feet tall were to hit, it would shut the engine off and it would drop. we learned quickly in simulation that that was not what neil had in mind. as a pilot i would not want to have done that either. none of the apollo landings were anywhere near as strong, but if the engine had quit at 10 feet, the lamb was -- the lem was designed to survive that fall. john: survived by stroking the landing.
bob: it had a honeycomb that would compress. you did not want the lander to stop it compressing. bill: there was no spring or anything in the landing gear. it was a honeycomb aluminum structure inside the tube. it was a one-shot deal. it would crush, and the strut would compress. he landed so light that it did not compress very far. that is why the latter was as hyatt -- ladder was as high as it was. >> [inaudible] john: who was responsible for picking and packaging and mounting the u.s. flag. the top is straight because of the support arm. what about the bottom? hal: my recollection of that is that was designed by our tech services division here headed by john cocker.
they came up with the concept of unfurling the flag with the support at the top and letting it hang in lunar gravity. that was compressed into a small package to afford us the volume. we fly one in our control center just like that. the one we had in the control center is now on the moon. on some mission they took it from the control center and fluid to the moon. >> on the training vehicles, didn't armstrong typically land with 20 to 30 -- john: did armstrong always have an equivalent of excess fuel at the landing? bill: one of them he didn't land. he ejected out of it. [laughter] bob: i think that is right. the normal landings always had four -- 4% or 5% remaining.
>> [inaudible] john: let me report -- repeat the question first. the question was it is called mission control but who is actually in control? is it the people on the ground or in the spacecraft? bill: control covers a lot of ground. the crew could manually control a lot of things within the vehicle. with the flight ops is constantly doing is keeping track of the flight plan and any changes to the activities that were going to do, and any changes to procedures and working on any anomalies that might occur with the spacecraft.
it is a joint effort between the crew and the ground. you are constantly going back and forth. bob: in those days we did not have a lot of the command capability that we have today. you would put together procedures and the crew would work through the switches. today a lot of that is done by command from the ground. hal: do you mean who is an ultimate command of making a decision? >> i would like to know how much
control was on either end. jack: the ground computer complex did almost all of the trajectory calculations and sent up a set of numbers to the spacecraft which they entered into their computers. without the ground they would not have had enough computational power to do the mission. once you got to descent, there was nothing the ground could do if the crew wanted to keep going. if the ground called and abort -- an abort, there is a good chance they would abort because they would assume the ground saw something that they could not see. bob:, in mission control it is the flight director who makes a timed critical decision, that makes those decisions based on his team on the ground. the overall decision comes from the flight director and goes directly to the crew. hal: there are three consoles that have the abort switch on it. bob: that was almost always associated with the launch
vehicle. john: we have time for one last question. >> [inaudible] john: that is a whole nother seminar. can somebody answer that and five words? jack: my guess would have been the 12:02 alarm. it was unexpected. we had done it in sims, but nobody really expected it would happen. because of the simulations, it set up a situation. we had done a bunch of research to figure out what alarms would
be a real problem and which not. jack garwin had a list that he worked out with m.i.t. who did all of the programming on this thing. >> [inaudible] jack: again, unexpected. during the simulations, he had punched out. since we had all those discussions and reviews, he decided it was ok. bob: that points out that the real unsung heroes, and there are so many all over the country, but the simulations guys were amazing. they had to not only learn the systems, and how they looked at our procedures, but to find
errors. in the last simcoe, the 1201 came up. that is a perfect example of the teamwork that it took to pull this off. hal: another way to describe the simulations people, they were very devious. [laughter] john: on that note, thank you for being here and thank you to these panelists. [applause] [captions copyright national cable satellite corp. 2019] [captioning performed by the national captioning institute, which is responsible for its caption content and accuracy. visit ncicap.org] >> now you are watching american history tv. you 48eekend we bring hours of unique programming exploring our nation's past. american history tv is only on c-span3.
>> next, state university director compares the leadership style of union general george henry thomas and confederate general nathan bedford forrest. >> one of the things i want to make sure before we go into our program, is to thank those of you who have come from other areas and some of our supporters. one of the people not with us today but is a life member an honorary member of our board is james robinson junior. he has had some health issues but he is recovering and i know he is back on the speaker circuit. a guy name nick who has also had a few health issues and not able