WEBVTT - More Apollo and The Soyuz Spacecraft 0:00:04.120 --> 0:00:07.160 Get in touch with technology with tech Stuff from how 0:00:07.200 --> 0:00:13.800 stuff works dot com. Hey there, and welcome to tech Stuff. 0:00:13.840 --> 0:00:17.000 I am your host, Jonathan Strickland. I'm an executive producer 0:00:17.000 --> 0:00:19.799 with how Stuff Works, and I love all things tech. 0:00:19.920 --> 0:00:24.760 And we are, in fact continuing our journey into space, 0:00:26.200 --> 0:00:29.000 or at least the history of space travel. And I 0:00:29.080 --> 0:00:31.159 know we talked a lot about space. We're gonna be 0:00:31.160 --> 0:00:33.880 talking more about space for the next few episodes because 0:00:34.400 --> 0:00:37.839 it's a fascinating topic and I love looking into it 0:00:37.880 --> 0:00:41.400 and there's so much to talk about. The this episode, 0:00:41.400 --> 0:00:45.360 we're going to focus on the later Apollo missions, and 0:00:45.440 --> 0:00:48.120 we will also switch over and talk about the development 0:00:48.120 --> 0:00:52.600 of the Soyuz spacecraft, the Soviet spacecraft that was intended 0:00:52.640 --> 0:00:56.880 to be a competitor to Apollo and is a workhorse 0:00:57.200 --> 0:01:02.840 for space travel now, I mean, it's the only spacecraft 0:01:03.080 --> 0:01:07.440 spoiler alert that will actually bring people back and forth 0:01:07.480 --> 0:01:11.320 between the International Space Station. In upcoming episodes, I'll talk 0:01:11.360 --> 0:01:14.840 more about launch vehicles, which we frequently will refer to 0:01:14.880 --> 0:01:18.160 as rockets, and I will also talk about the Space 0:01:18.200 --> 0:01:21.480 Shuttle program, and then after that we will move on 0:01:21.520 --> 0:01:24.920 to non space related topics. I know it talked a 0:01:24.920 --> 0:01:27.119 lot about it, but I could have gone into even 0:01:27.120 --> 0:01:30.520 more detail about the various spacecraft in their subsystems and 0:01:30.560 --> 0:01:33.399 how they all worked, but I realized that it would 0:01:33.400 --> 0:01:35.000 be over at kill and I didn't want to go 0:01:35.040 --> 0:01:37.320 absolutely nuts. So let's pick up where we left off, 0:01:37.400 --> 0:01:41.119 which was after the return of the Apollo eleven capsule. Now, 0:01:41.640 --> 0:01:46.960 Apollo eleven wasn't just a phenomenal achievement in science, engineering, 0:01:47.240 --> 0:01:50.520 astronaut training, although it was definitely all of those things, 0:01:50.800 --> 0:01:55.520 but it was also effectively the end of the space 0:01:55.640 --> 0:01:58.680 race that had started when the Soviet Union launched sput 0:01:58.760 --> 0:02:01.280 Nick into orbit and put that out as the first 0:02:01.360 --> 0:02:04.600 man made satellite in Earth orbit. The Soviets had won 0:02:04.640 --> 0:02:07.680 those early victories, Sputnik being the first one, but also 0:02:08.080 --> 0:02:10.080 they were the first to put a human into orbit. 0:02:10.120 --> 0:02:13.000 They were the first to put a woman into space, 0:02:13.280 --> 0:02:15.440 but the Americans had managed to be the first two 0:02:15.480 --> 0:02:19.520 docs spacecraft in orbit, and no one else was able 0:02:19.560 --> 0:02:22.680 to put people on the Moon, although the Soviets did 0:02:22.720 --> 0:02:24.840 try to do that too, and I'll talk more about 0:02:24.840 --> 0:02:28.200 those efforts later in this episode. Apollo eleven pretty much 0:02:28.320 --> 0:02:31.880 sealed the deal, and after that success, the space race 0:02:32.000 --> 0:02:35.760 was effectively over. Symbolically, it would not be over for 0:02:35.800 --> 0:02:38.960 a few more years, but the Apollo projects still had 0:02:39.000 --> 0:02:41.840 several more missions before it would end. Apollo eleven was 0:02:41.840 --> 0:02:45.280 not the end of the Apollo program. Apollo twelve was 0:02:45.320 --> 0:02:48.120 the second mission to have a lunar landing. The crew 0:02:48.160 --> 0:02:52.440 would deploy tech called the Apollo Lunar Surface Experiments Package 0:02:52.800 --> 0:02:56.320 or all SEP a l s EP. This was a 0:02:56.360 --> 0:03:00.959 collection of geophysical instruments. Apollo eleven had a more modest 0:03:01.680 --> 0:03:05.080 collection of experiments that they carried. That one was called 0:03:05.400 --> 0:03:10.760 the Early Apollo Surface Experiments Package or a SEP. That 0:03:10.800 --> 0:03:14.560 one had two official experiments and then two additional experiments 0:03:14.560 --> 0:03:17.680 that were not officially part of a SEP. This is 0:03:17.720 --> 0:03:21.040 where I start looking into NASA records and I say, 0:03:21.080 --> 0:03:24.360 what's the difference between officially being part of something and 0:03:24.400 --> 0:03:27.239 not officially being part of something but still going along 0:03:27.280 --> 0:03:29.080 for the ride of being left on the Moon. But 0:03:29.680 --> 0:03:35.480 maybe that's just me getting confused by semantics. NASA on 0:03:35.560 --> 0:03:39.400 Apollo eleven was mostly focused on landing people on the 0:03:39.400 --> 0:03:42.160 freaking Moon and then getting them back home safely, So 0:03:42.200 --> 0:03:45.640 science was sort of a secondary priority, right. It was 0:03:46.120 --> 0:03:49.360 not the highest priority for NASA. For that. For the 0:03:49.400 --> 0:03:53.840 Apollo eleven mission, they had some scientific experiments they wanted 0:03:53.880 --> 0:03:57.840 to include, but mostly they just wanted to concentrate on 0:03:57.920 --> 0:03:59.960 getting people on the Moon and then getting them back 0:04:00.040 --> 0:04:04.360 home safely. The purpose of all SEP was to monitor 0:04:04.440 --> 0:04:08.120 the environment of and a region close to the Apollo 0:04:08.200 --> 0:04:11.040 landing site for at least a year after the end 0:04:11.160 --> 0:04:14.320 of the visit to the Moon. Apollo seventeens version of 0:04:14.320 --> 0:04:18.200 all SEP was designed to to operate for two years, 0:04:19.080 --> 0:04:21.880 and so there The Apollo twelve one was just the 0:04:21.920 --> 0:04:24.680 first all step. All of the other following Apollo missions 0:04:24.680 --> 0:04:27.680 would bring similar packages along. Some of them worked for 0:04:27.920 --> 0:04:30.720 up to eight years before Mission control would shut down 0:04:30.800 --> 0:04:34.679 all remaining all SEP projects on September nineteen seventy seven, 0:04:34.760 --> 0:04:41.120 so some far outlasted their their projected useful lifespan. The 0:04:41.200 --> 0:04:44.120 all SEPs history is pretty darn interesting all in its 0:04:44.120 --> 0:04:48.040 own right. It's it's just the the list of experiments 0:04:48.080 --> 0:04:51.920 is fascinating. The projects started way back in March nineteen 0:04:52.040 --> 0:04:56.039 sixty three, so they knew that the plan was to 0:04:56.040 --> 0:04:58.479 go to the Moon. Kennedy had made the announcement in 0:04:58.560 --> 0:05:01.440 nineteen sixty one, But what could we do once we 0:05:01.520 --> 0:05:05.040 got there, what kind of data would we try to collect? 0:05:05.200 --> 0:05:08.440 And that began a long series of discussions to select 0:05:08.920 --> 0:05:12.320 which experiments would be conducted on the Moon's surface, And 0:05:12.320 --> 0:05:15.120 they had to consider a lot of different factors when 0:05:15.120 --> 0:05:18.320 they were making these choices, not just what was going 0:05:18.320 --> 0:05:21.760 to be the most scientifically interesting, that was obviously one 0:05:21.800 --> 0:05:24.240 of the really important factors, but also what was just 0:05:24.240 --> 0:05:27.520 going to be practical, because the experiments would need to 0:05:27.520 --> 0:05:30.800 be relatively simple in design, because there was no chance 0:05:30.839 --> 0:05:33.520 of sending out a technician to repair a complicated piece 0:05:33.520 --> 0:05:37.039 of equipment once the lunar module would lift off the Moon. 0:05:37.640 --> 0:05:39.240 You know, you can't make a service call and have 0:05:39.279 --> 0:05:42.120 a repairman go to the Moon to fix something. They 0:05:42.240 --> 0:05:45.359 also could not be too heavy, both for the purposes 0:05:45.480 --> 0:05:49.279 of planning out the payload for the launch vehicle, but 0:05:49.680 --> 0:05:54.000 also how you deploy it. How How would you know 0:05:54.120 --> 0:05:57.640 cause the astronauts the how would they actually take it 0:05:57.680 --> 0:05:59.960 out of the lunar module, take it to the rights 0:06:00.000 --> 0:06:01.919 it and set it up it. It was too heavy 0:06:01.920 --> 0:06:05.360 and too complex. Although really heavy wasn't the big problem. 0:06:05.360 --> 0:06:07.000 Bulky was the problem. I mean, on the Moon you 0:06:07.040 --> 0:06:09.640 have one six the Earth's gravity, so it would have 0:06:09.680 --> 0:06:13.400 to be incredibly heavy to be problematic, but bulky was 0:06:13.480 --> 0:06:15.960 an issue that and where the weight was distributed was 0:06:16.000 --> 0:06:19.400 an issue. There were several all steps where astronauts found 0:06:19.400 --> 0:06:23.119 it difficult to carry them, not because necessarily the weight, 0:06:23.160 --> 0:06:26.760 but because there was no convenient way to carry them 0:06:26.800 --> 0:06:31.400 on the Moon's surface. During those discussions, Nassa identified questions 0:06:31.440 --> 0:06:35.200 that scientists felt we should try to answer with these experiments. 0:06:35.240 --> 0:06:40.200 So before designing any equipment or deciding what technology to 0:06:40.360 --> 0:06:43.080 send along, they said, well, what is it exactly do 0:06:43.120 --> 0:06:45.240 we want to learn, and that that will guide us 0:06:45.600 --> 0:06:49.839 into designing these experiments. So those questions included stuff like, 0:06:50.279 --> 0:06:53.560 what is the internal structure of the moon, What is 0:06:53.640 --> 0:06:57.000 the actual geometric shape of the moon? What is the 0:06:57.200 --> 0:07:01.320 present inter internal energy regime sam of the Moon? Where 0:07:01.400 --> 0:07:06.200 where is energy going? Is the Moon shedding energy as 0:07:06.240 --> 0:07:09.640 it absorbing energy? Was the composition of the lunar surface 0:07:09.760 --> 0:07:13.080 wasn't made out of cheese? It turns out no, What 0:07:13.200 --> 0:07:17.920 principal processes were responsible for the present structure of the Moon. 0:07:18.000 --> 0:07:20.480 Why is the Moon the way it is? Was the 0:07:20.520 --> 0:07:23.920 present tectonic pattern and distribution of tectonic activity on the 0:07:23.920 --> 0:07:27.800 Moon are their moon quakes? What are the dominant processes 0:07:27.920 --> 0:07:31.520 of erosion, transport and deposition of material on the lunar surface? 0:07:31.520 --> 0:07:35.320 How does this stuff move around? What volatile substances are 0:07:35.360 --> 0:07:38.960 present on or near the lunar surface? Is there any 0:07:39.040 --> 0:07:43.360 evidence of organic or proto organic molecules on the Moon? 0:07:43.680 --> 0:07:46.160 How old is the Moon? And what is the history 0:07:46.200 --> 0:07:49.320 of dynamic interaction between the Earth and the Moon. A 0:07:49.400 --> 0:07:54.400 follow eleven's ACEP contained a passive seismic experiment package, so 0:07:54.560 --> 0:07:59.280 it would measure essentially moon trimmers, and it had four 0:07:59.320 --> 0:08:02.440 seisometer is that were powered by two solar panels, and 0:08:02.560 --> 0:08:05.600 that would that would study any moon quakes or vibrations 0:08:05.600 --> 0:08:09.400 from meteorite impacts, and it would ultimately record somewhere between 0:08:09.400 --> 0:08:12.640 a hundred and two hundred meteorite impacts during the course 0:08:12.680 --> 0:08:16.560 of its useful lifespan. The second experiment on the ace UP, 0:08:16.680 --> 0:08:21.040 the official experiment, was a lunar dust detector that would 0:08:21.040 --> 0:08:23.720 measure the amount of dust accumulating on the lunar surface 0:08:24.080 --> 0:08:26.680 and would also monitor damage to solar cells caused by 0:08:26.760 --> 0:08:30.840 high energy radiation. Because the Moon does not have the 0:08:30.880 --> 0:08:34.600 same level of protection from radiation as the Earth does. 0:08:35.400 --> 0:08:38.400 Lacking an atmosphere, it doesn't absorb as much of that 0:08:38.480 --> 0:08:42.840 radiation outside of the surface. That is in addition to 0:08:42.960 --> 0:08:46.400 the two official DECEP experiments, they did have two other 0:08:46.480 --> 0:08:51.239 ones I mentioned earlier. Those were a lunar ranging retro reflector, 0:08:51.960 --> 0:08:54.760 which is a fancy way of saying a very reflective surface. 0:08:54.760 --> 0:08:57.440 It was actually an array of one cubes made of 0:08:57.559 --> 0:09:01.200 fused silica, and this reflect the surface was positioned on 0:09:01.200 --> 0:09:03.679 the Moon so that if you had a sufficiently powerful 0:09:03.760 --> 0:09:07.720 laser beam and you knew exactly where that reflective surface was, 0:09:08.080 --> 0:09:10.600 you could aim the laser beam at the surface and 0:09:10.640 --> 0:09:13.920 have it reflect back to the Earth. And if you 0:09:14.040 --> 0:09:17.400 did that with a laser and a sensor, so that 0:09:17.520 --> 0:09:19.640 you've fired the laser and then you had a sensor 0:09:19.679 --> 0:09:23.280 there to detect what the time difference was between firing 0:09:23.320 --> 0:09:26.560 the laser and picking up the reflection, you could get 0:09:26.760 --> 0:09:30.320 very precise measurements of how far away the Moon was, 0:09:30.920 --> 0:09:34.760 to a degree of accuracy of up to eight centimeters, 0:09:35.200 --> 0:09:37.360 which is pretty incredible. You know how close the Moon 0:09:37.440 --> 0:09:43.480 was within eight centimeters. That experiment was operational until June. 0:09:43.679 --> 0:09:47.160 The solar wind composition experiment was the second non ACEP 0:09:47.200 --> 0:09:51.080 experiment deployed by buzz Aldron during Apollo eleven, and it 0:09:51.160 --> 0:09:54.439 used a panel of alunium foil, which was really pretty 0:09:54.520 --> 0:09:56.600 much the same stuff is what you would use to 0:09:56.679 --> 0:10:00.320 wrap up leftovers, and that foil panel was it to 0:10:00.480 --> 0:10:04.200 collect atomic particles that were emitted by the Sun. That 0:10:04.280 --> 0:10:08.560 experiment wasn't left on the Moon, so instead they deployed it. 0:10:08.640 --> 0:10:12.120 They unfolded it and set it up and then left 0:10:12.120 --> 0:10:14.520 it alone for about an hour or so and then 0:10:14.559 --> 0:10:17.520 collected it and stored it in the Lunar Module, and 0:10:17.559 --> 0:10:20.280 they brought it back aboard the Man's Service Module on 0:10:20.320 --> 0:10:23.800 the return trip home, and once they landed, they turned 0:10:23.880 --> 0:10:26.439 over that experiment to a group of scientists from Switzerland. 0:10:26.480 --> 0:10:28.680 It was the group of scientists who had actually designed 0:10:28.760 --> 0:10:33.880 that experiment. The step and the all set packages called 0:10:33.960 --> 0:10:37.640 the Scientific Equipment Bay aboard the Lunar Module their home 0:10:37.760 --> 0:10:40.360 until landing on the Moon. This bay, it's kind of 0:10:40.400 --> 0:10:42.280 like a trunk in a car in a way. It 0:10:42.360 --> 0:10:45.120 was designed so that would allow for easy unloading on 0:10:45.200 --> 0:10:47.480 the Moon's surface, so it's height with such that the 0:10:47.480 --> 0:10:50.040 astronauts didn't have to try and bend far down in 0:10:50.040 --> 0:10:53.079 those big bulky spacesuits to get that things, they could 0:10:53.160 --> 0:10:55.040 kind of reach and grab it and pull it out. 0:10:55.440 --> 0:10:59.000 The bay also had boom arms that would help offload materials, 0:10:59.240 --> 0:11:02.720 particularly the bulky ones that might require both astronauts to 0:11:02.800 --> 0:11:06.400 work together. Remember, the lunar module would have two astronauts 0:11:06.440 --> 0:11:08.880 in it and the command module would have the third 0:11:08.920 --> 0:11:13.440 astronauts still in orbit around the Moon. Uh This was 0:11:13.640 --> 0:11:15.920 important to have those boom arms because sometimes the lunar 0:11:15.960 --> 0:11:17.880 module would land in such a way that it wasn't 0:11:17.880 --> 0:11:21.680 really level on the Moon's surface. You might land at 0:11:21.840 --> 0:11:25.800 the edge of a little dip, or one of the 0:11:25.920 --> 0:11:28.640 legs of the lunar module might sink a little further 0:11:28.800 --> 0:11:32.000 into the dust on the surface, So they wanted to 0:11:32.000 --> 0:11:34.480 make sure they had systems in place to help with 0:11:34.559 --> 0:11:37.400 the unloading in case the lunar module wasn't perfectly level. 0:11:37.840 --> 0:11:40.800 The general procedure for deploying the all set packages was 0:11:40.880 --> 0:11:42.720 that you would have to find a spot about a 0:11:42.760 --> 0:11:46.240 hundred meters to the west of the lunar module and 0:11:46.280 --> 0:11:49.640 make sure that you were not in the shadow the 0:11:49.679 --> 0:11:52.119 path of the shadow of the lunar module for sunrise, 0:11:52.520 --> 0:11:55.640 because solar panels would often be part of those experiments, 0:11:55.679 --> 0:12:00.760 So you needed to have uh unblocked access to sunlight, 0:12:01.640 --> 0:12:04.960 and you had to find someplace that was, you know, 0:12:05.040 --> 0:12:08.800 fairly level, which was always the Finding areas on the 0:12:08.840 --> 0:12:12.240 Moon that met these criteria wasn't always easy. The all 0:12:12.280 --> 0:12:15.200 set aboard Apollo twelve and the ones on each of 0:12:15.240 --> 0:12:20.680 the Apollo missions following until Apollo seventeen included some other 0:12:20.800 --> 0:12:24.880 pieces of equipment. Central to the experiment was a station 0:12:24.960 --> 0:12:26.680 that acted as a power source. It was kind of 0:12:26.679 --> 0:12:30.200 like a a little power generator right in the middle, 0:12:30.520 --> 0:12:34.520 and it had a radio isotope thermoelectric generator. And yet 0:12:34.720 --> 0:12:37.040 that means that the experiments were powered by the heat 0:12:37.200 --> 0:12:43.240 generated by radioactive material undergoing decay. Specifically, they were using 0:12:43.440 --> 0:12:47.360 plutonium to thirty eight in oxide form. The generator could 0:12:47.360 --> 0:12:51.560 produce seventy watts of direct current electricity, and all of 0:12:51.600 --> 0:12:55.080 the generators from Apollo twelve to seventeen are on the Moon, 0:12:55.400 --> 0:12:59.000 with the exception of one, the generator for Apollo thirteen, 0:12:59.679 --> 0:13:01.920 which was forced to abandon its mission in the wake 0:13:01.920 --> 0:13:04.920 of an emergency. That generator is somewhere at the bottom 0:13:04.960 --> 0:13:07.800 of the Pacific Ocean, so they're somewhere in the Pacific 0:13:07.800 --> 0:13:14.320 Ocean is a radioisotope thermoelectric generator with plutonium to thirty 0:13:14.360 --> 0:13:17.120 eight in it. Now that meant that all the experiments, 0:13:17.120 --> 0:13:20.200 and there were many, that these central stations would provide 0:13:20.200 --> 0:13:23.360 power to actually drew less electricity than what would be 0:13:23.400 --> 0:13:26.000 needed to power a seventy five what lightbulb, which is 0:13:26.040 --> 0:13:31.480 pretty incredible. Experiments included stuff like what was uh included 0:13:31.480 --> 0:13:34.280 in the Apollo eleven package that that was in many 0:13:34.320 --> 0:13:36.079 of the other ones as well. But the Apollo twelve 0:13:36.120 --> 0:13:39.960 siometer experiment not only detected when the lunar module crashed 0:13:39.960 --> 0:13:43.560 into the Moon upon being jettisoned from the Command Service Module, 0:13:44.160 --> 0:13:47.440 but found that the Moon vibrated or rang like a 0:13:47.520 --> 0:13:51.280 bell for more than fifty five minutes after that impact. 0:13:52.160 --> 0:13:55.240 So this was done on purpose the jettison the lunar module. 0:13:55.400 --> 0:13:57.640 Everyone else was aboard the Command Service module for the 0:13:57.640 --> 0:14:00.840 return trip home and it was on crash course with 0:14:00.880 --> 0:14:03.800 the Moon, and it was specifically done so that they 0:14:03.800 --> 0:14:08.560 could measure the the seismic activity. So why did it 0:14:08.880 --> 0:14:11.959 vibrate for so long for nearly an hour? Well, according 0:14:11.960 --> 0:14:14.360 to Dr Ross Taylor, the reason is because the lunar 0:14:14.440 --> 0:14:18.360 soil is devoid of moisture, which would literally dampen vibrations. 0:14:18.720 --> 0:14:23.360 Moisture absorbs vibrations, water absorbs them. In fact, when we 0:14:23.360 --> 0:14:25.800 talk about the Space Shuttle program, I'll talk about how 0:14:25.840 --> 0:14:29.800 water was used specifically for that purpose. So without moisture, 0:14:30.040 --> 0:14:33.280 the vibrations could continue much longer than they would on Earth. 0:14:33.960 --> 0:14:38.680 Other experiments would look into stuff like the heat flow 0:14:38.720 --> 0:14:40.920 of the Moon. They found that the interior of the 0:14:40.960 --> 0:14:43.600 Moon is warmer than the surface, so heat flows from 0:14:43.680 --> 0:14:46.360 the center of the Moon out towards the surface and 0:14:46.360 --> 0:14:51.160 then dissipates in space. They also had experiments that had 0:14:52.040 --> 0:14:56.080 magnetoma meters or magnometers if you prefer, but that I'm 0:14:56.120 --> 0:14:59.240 almost certain that's not the right way to say it. Magneto. 0:14:59.440 --> 0:15:02.600 They had the x Man magneto or x Man Villain 0:15:02.640 --> 0:15:05.280 magneto to study the magnetic field of the Moon. They 0:15:05.280 --> 0:15:08.080 had ion detectors to measure the number and types of 0:15:08.080 --> 0:15:11.760 ions on the Moon charged particles on the Moon. Mostly 0:15:12.080 --> 0:15:15.160 those ions were deposited by the solar wind. Other experiments 0:15:15.160 --> 0:15:18.320 would look for charged particles or cosmic radiation, and the 0:15:18.360 --> 0:15:21.840 packages on different Apollo missions contained different experiments. Some would 0:15:21.840 --> 0:15:27.320 be repeated with follow up missions, so you might have 0:15:27.360 --> 0:15:31.120 an experiment that's on Apollo fourteen that's also on Apollo sixteen. 0:15:31.520 --> 0:15:35.520 Others were unique to their specific mission. When we come back, 0:15:35.560 --> 0:15:38.600 i'll talk about an experiment aboard the Apollo seventeen that 0:15:38.640 --> 0:15:40.840 gave astronauts a bit of a headache when they were 0:15:40.840 --> 0:15:43.440 deploying it. But first let's take a quick break to 0:15:43.520 --> 0:15:53.680 thank our sponsor. So one experiment that did not quite 0:15:53.720 --> 0:15:57.760 go as planned was the Lunar Surface Gravimeter aboard the 0:15:57.760 --> 0:16:01.160 Apollo seventeen, and scientists at the University of Maryland designed 0:16:01.240 --> 0:16:04.200 this experiment, and its purpose was to search for evidence 0:16:04.200 --> 0:16:08.040 of gravity waves. Gravity waves were something that Einstein had 0:16:08.080 --> 0:16:11.080 predicted in his theories, but no one at that point 0:16:11.080 --> 0:16:15.640 had found any actual observable evidence of gravity waves, so 0:16:15.720 --> 0:16:18.160 this device was supposed to look out for that kind 0:16:18.160 --> 0:16:20.280 of stuff. It was also meant to study the response 0:16:20.520 --> 0:16:23.680 of the Moon to the Earth's title poll, and it 0:16:23.720 --> 0:16:27.560 could also supplement data gathered by the various seismometers that 0:16:27.640 --> 0:16:31.080 were distributed on the Moon's surface. The business end of 0:16:31.120 --> 0:16:34.960 the experiment, the part that was that at issue was 0:16:35.120 --> 0:16:38.760 a spring balance that was incredibly sensitive and it had 0:16:38.800 --> 0:16:42.440 special mass weights attached to it to provide the proper 0:16:42.480 --> 0:16:47.760 tension on the spring balance. But while designing this particular 0:16:47.880 --> 0:16:51.960 piece of technology, the team made a mathematical error and 0:16:52.400 --> 0:16:56.720 the mass was not correct, so it wasn't actually putting 0:16:56.920 --> 0:17:00.440 enough tension on the spring. The astronauts try to set 0:17:00.480 --> 0:17:04.200 the experiment to null when calibrating it, and they so 0:17:04.440 --> 0:17:08.960 setting it to a neutral position, but they foundly couldn't 0:17:08.960 --> 0:17:13.680 get the meter to register a neutral position, even though 0:17:13.720 --> 0:17:16.439 they verified the experiment was on a level surface and 0:17:16.520 --> 0:17:20.000 that the gimbal inside the device could move freely. Only 0:17:20.040 --> 0:17:22.720 then did NASA realized there was a tiny but sufficiently 0:17:22.760 --> 0:17:26.120 irritating error. The mass weights were two percent lighter than 0:17:26.160 --> 0:17:28.639 what they needed to be in order for the device 0:17:28.680 --> 0:17:33.159 to operate properly. Making things worse, The sensor was adjustable, 0:17:33.520 --> 0:17:36.520 so you could adjust for error, but it would only 0:17:36.560 --> 0:17:39.040 adjust to correct for an error of up to one 0:17:39.119 --> 0:17:43.119 point five cent, and the mass of the weights was 0:17:43.240 --> 0:17:45.840 a two percent error, so it was greater than what 0:17:46.280 --> 0:17:49.960 the device could allow for. So they started using some 0:17:50.040 --> 0:17:52.440 other methods, and one of those methods turned out to 0:17:52.480 --> 0:17:54.560 be what we in the tech business would tend to 0:17:54.600 --> 0:17:59.200 call percussive maintenance, which means an astronaut hit the experiment 0:17:59.240 --> 0:18:02.960 to make it work better. Seriously from a NASA website 0:18:03.000 --> 0:18:07.840 about this alsup experiment, Schmidt, which is a reference to 0:18:07.880 --> 0:18:12.600 Apolo seventeen astronaut Harrison Schmidt, wrapped the exposed top plate 0:18:12.720 --> 0:18:16.520 on the gimble, rocked the experiment in all directions, re 0:18:16.760 --> 0:18:20.640 leveled the experiment, working the base well against the surface, 0:18:20.880 --> 0:18:24.200 and verified the sun shade tilt. These actions were taken 0:18:24.240 --> 0:18:26.879 to free a mass assembly or a sensor beam that 0:18:26.960 --> 0:18:29.959 was suspected of being caught or bound, but no change 0:18:30.000 --> 0:18:32.880 was apparent. The problem was at least partly overcome by 0:18:32.880 --> 0:18:36.159 applying pressure on the beam with the mass changing mechanism 0:18:36.200 --> 0:18:40.400 beyond the design point, by addition of all included masses 0:18:40.720 --> 0:18:44.119 so that it contacted the beam much valuable e v 0:18:44.320 --> 0:18:49.600 A time as extra vehicular activity. About thirty minutes was 0:18:49.760 --> 0:18:52.840 spent on the attempt, which is kind of a polite 0:18:52.840 --> 0:18:54.760 way of saying they wasted half an hour trying to 0:18:54.800 --> 0:18:57.800 get this darn thing to work. All of this is 0:18:57.840 --> 0:19:00.640 to say that the missions after Apollo Oven we're meant 0:19:00.640 --> 0:19:04.720 to further our scientific understanding. Numerous experiments would gather information. 0:19:04.920 --> 0:19:08.240 Some for years after we left the Moon, astronauts would 0:19:08.240 --> 0:19:10.359 gather samples of the dust and the rocks on the 0:19:10.400 --> 0:19:13.840 Moon and bring them back. They deployed equipment starting with 0:19:13.880 --> 0:19:16.199 Apollo fifteen. They also got to tool around on the 0:19:16.240 --> 0:19:18.600 Moon's surface with the lunar rover. I could do a 0:19:18.600 --> 0:19:21.840 full episode just about the lunar rover. The Apollo fifteen 0:19:21.960 --> 0:19:24.520 was the first of Apollo's missions to spend more than 0:19:24.560 --> 0:19:27.080 just a few hours on the Moon's surface. In fact, 0:19:27.280 --> 0:19:31.440 the whole mission for Apollo fifteen lasted about twelve days. 0:19:32.080 --> 0:19:35.440 The CSM pilot spent nearly as much time in lunar 0:19:35.560 --> 0:19:39.359 orbit as the entire length of the Apollo eight mission. 0:19:39.400 --> 0:19:42.760 That was the first Apollo eight mission to orbit the Moon. 0:19:43.240 --> 0:19:46.879 Apollo seventeen, the last of all the missions, launched on 0:19:47.040 --> 0:19:51.720 December seven, ninety and returned to Earth on December nineteenth, 0:19:51.840 --> 0:19:54.920 nineteen seventy two. It would be the last time so 0:19:54.960 --> 0:19:57.600 far that any humans would set foot on the Moon. Now, 0:19:57.600 --> 0:19:59.240 when I say the last mission, I do mean the 0:19:59.320 --> 0:20:05.280 last lunar mission. There was one more Apollo mission that 0:20:05.359 --> 0:20:07.480 I'll talk about a little bit later. Each of these 0:20:07.480 --> 0:20:09.880 missions were really important, and I could do a full 0:20:09.920 --> 0:20:13.720 episode about any single one of them. Now, before I 0:20:13.760 --> 0:20:15.680 transition to talk about the say Us, I thought it 0:20:15.680 --> 0:20:17.320 would be good to at least talk a little bit 0:20:17.359 --> 0:20:21.280 about Apollo thirteen and what happened there, because it had 0:20:21.320 --> 0:20:28.120 the famous malfunction, the subject of many documentaries and films, 0:20:28.119 --> 0:20:32.000 including the film Apollo thirteen. The mission, which carried astronauts 0:20:32.119 --> 0:20:36.439 John Swiggert, Fred Hayes, and James Lovell, had a bumpy start. 0:20:36.520 --> 0:20:39.960 Literally a few minutes after lift off, the astronauts felt 0:20:40.000 --> 0:20:43.160 a little vibration in the command Service module. The Launch 0:20:43.240 --> 0:20:47.280 Vehicles center engine shut down two minutes earlier than planned, 0:20:47.680 --> 0:20:50.720 but the four remaining engines were able to fire for 0:20:50.800 --> 0:20:53.280 a little bit more than half a minute longer than 0:20:53.359 --> 0:20:57.080 planned in order to compensate for that early burnout, and 0:20:57.119 --> 0:21:00.359 the S four B stage had to prepare hell the 0:21:00.440 --> 0:21:04.400 spacecraft and extra nine seconds as well. But despite all that, 0:21:04.720 --> 0:21:07.600 everything else seemed to be going really smoothly, so much 0:21:07.640 --> 0:21:10.600 so that forty six hours into the mission, so nearly 0:21:10.640 --> 0:21:12.840 two days into the mission, ground control said that the 0:21:12.840 --> 0:21:15.600 spacecraft was in such good shape and everything was going 0:21:15.640 --> 0:21:19.320 so smoothly, it was frankly pretty darn boring. Just a 0:21:19.400 --> 0:21:23.240 little before the fifty six hour of the mission, and 0:21:23.400 --> 0:21:27.280 oxygen tank in the service module blew up. A second 0:21:27.280 --> 0:21:31.800 oxygen tank failed, the command module lost electricity, water, and light, 0:21:32.000 --> 0:21:35.640 and that's when we get the famous phrase, Houston, we've 0:21:35.640 --> 0:21:39.280 had a problem here, which typically gets paraphrases Houston, we 0:21:39.320 --> 0:21:42.760 have a problem. The crew would move into the lunar module. 0:21:43.240 --> 0:21:47.080 Remember with these lunar missions, right after going into orbit, 0:21:47.640 --> 0:21:51.000 the Command Service module would detach from the S four 0:21:51.080 --> 0:21:54.120 B and would rendezvous with the S four B two 0:21:54.160 --> 0:21:57.680 dock with the lunar module on the end of the CSM, 0:21:57.800 --> 0:22:00.760 So you have the lunar module kind of kind of 0:22:00.800 --> 0:22:03.480 balanced on the end of the CSM for the rest 0:22:03.480 --> 0:22:05.679 of the journey to the Moon. So it was already 0:22:05.680 --> 0:22:09.560 connected to the CSM. So they had this this lunar 0:22:09.600 --> 0:22:12.560 module where the life support systems were still working. But 0:22:12.760 --> 0:22:15.240 it wasn't ideal to move everyone in there because the 0:22:15.280 --> 0:22:18.840 lunar module was meant to support two crew members for 0:22:19.280 --> 0:22:22.440 less than two days, and instead there would need to 0:22:22.480 --> 0:22:26.040 be three crew members aboard this lunar module for four days. 0:22:26.680 --> 0:22:29.720 They also had to cut way back on water consumption 0:22:30.000 --> 0:22:33.560 because the water was important, not just for them to drink, 0:22:33.800 --> 0:22:36.679 but also to be used as a cooling system for 0:22:36.720 --> 0:22:40.280 the various systems aboard the spacecraft. And as a result, 0:22:40.520 --> 0:22:42.480 because they had to cut so far back on water, 0:22:42.680 --> 0:22:46.560 they all became severely dehydrated. In fact, collectively the crew 0:22:46.600 --> 0:22:50.919 would lose thirty one and a half pounds during this mission, 0:22:51.440 --> 0:22:54.560 almost all of it water weight. So at one point 0:22:54.840 --> 0:22:57.480 Level had to resort to using the Sun as a 0:22:57.560 --> 0:23:00.720 navigational star. He had to align the attitude of the 0:23:00.800 --> 0:23:03.879 lunar module according to the directions he received from ground control, 0:23:03.920 --> 0:23:07.199 which is pretty phenomenal to think about navigating by the 0:23:07.280 --> 0:23:10.679 stars when you're out in space. The conditions in that 0:23:10.800 --> 0:23:15.280 spacecraft were admittedly really tough. The temperature sank down to 0:23:15.359 --> 0:23:18.880 about thirty eight degrees fahrenheit that's about three degrees celsius, 0:23:18.920 --> 0:23:21.440 and no one was sure if the command module would 0:23:21.440 --> 0:23:24.520 power up properly. And the command module was absolutely necessary 0:23:24.520 --> 0:23:28.720 because that was the spacecraft that was outfitted for re entry. 0:23:29.080 --> 0:23:31.439 The heat shielding and everything that was on the command module, 0:23:31.520 --> 0:23:33.520