--- title: "Interesting Things You Didn't Know About the Apollo Program" description: "Imagine stepping into a room lined with rubber, a last resort against the violent uncertainties of space travel. This isn't the setting of a science fiction story; it's a very real chapter in the saga of human ingenuity. From a \"rubber room\" designed to be the ultimate safe haven for astronauts, to ingenious hacks and close calls that were never broadcast, we're about to uncover the hidden gems you didn't know about the missions that took humanity to another world.\n\n## The \"Rubber Room\" Escape Bunkers\n\nThe Apollo program relied on the Saturn V rocket. When adding up the kerosene and liquid hydrogen fuel of all three stages, it carried an insane 42 terajoules of potential explosive energy that it released in a controlled manner to carry the United States' first astronauts to the moon. To understand just how much energy this is, consider that it's a full two-thirds that released by the Little Boy atomic bomb dropped on Hiroshima. That gives it nearly 1,000 times the energy of the US military's most powerful conventional bomb, the MOAB, which releases a measly 46 gigajoules.\n\nIn other words, if that reaction got out of control, it could be one hell of an explosion. And if anyone wanted to survive it, it would take one hell of a bunker. These were the \"Rubber Rooms.\"\n\nLocated underneath the launch pads at Kennedy Space Center, the Rubber Rooms served as last-resort protection for launch-pad crew and the astronauts themselves in case of an explosion. It was capable of supporting 20 people for up to 24 hours.\n\nHowever, the really interesting thing about the Rubber Rooms, and the reason they earned that nickname, was the way in. The launch-pad crew had to slide down a 200-foot chute, around 60 meters, that popped them right into a little rubber-padded reception room of sorts. From there, they had to open a massive steel door to enter the actual bunker which consisted of a domed ceiling and concrete floor suspended on shock-absorbing springs. The astronauts had a longer journey, having to take an elevator down the 320-foot launch tower, around 100 meters, to the launch pad in just 30 seconds from which they'd transfer to the chute.\n\nGetting out wasn't so easy. You either had to exit through a 1,200-foot-long air duct, which is 365 meters, or through an escape hatch in the roof.\n\nObviously the rockets and landers of the Apollo program get all the engineering glory, but the ingenuity of the bunkers was no small feat. They could withstand a fireball 1,400 feet wide, or 430 meters, burning at 2,500 degrees Fahrenheit or 1,370 degrees Celsius. They could also protect their occupants from explosive pressures of 500 pounds per square inch and 75G of acceleration, about 15 times what an untrained human being can normally withstand.\n\nThough an admiral precaution, the Rubber Rooms were never used beyond training. When the Apollo program ended, NASA abandoned them, after which they filled with water and nature promptly took them back as tends to happen in Florida. NASA eventually refurbished the launch pads for the Space Shuttle program but left the Rubber Rooms as they were. Currently, SpaceX rents the pads, but the terms of the lease require them to leave the Rubber Rooms preserved as historical artifacts.\n\n## Apollo 12 Becomes a Lightning Rod\n\nOn 19 November 1969, the Apollo 12 mission crewed by Pete Conrad, Richard Gordon and Alan Bean, made the second ever manned landing on the Moon. Having already beat the Soviets to the Moon with Apollo 11, Apollo 12 was considerably more… relaxed. For example, the launch date was pushed back two months to provide for more training and allow President Richard Nixon to attend. In fact, the astronauts even took hammocks with them to deploy on the lunar surface.\n\nNASA really wanted to make it look like they could now reach the Moon with ease, which is why they didn't publicize many of the unforeseen obstacles. Like the rocket getting struck by lightning… twice.\n\nThe launch was scheduled for 14 November 1969 from Kennedy Space Center in Florida. Because this date coincided with ideal landing conditions on the Moon, there was only a launch window of about three hours. However, it also coincided with stormy weather: overcast and rainy skies as well wind speeds of 175 miles per hour, or 280 kilometers per hour, the strongest faced by any Apollo launch. Plus, there was a cumulonimbus cloud above the launch site, which should have canceled the launch based on NASA rules, but they waived the restriction, and the launch went ahead.\n\nThirty-six seconds after lift-off, a lightning bolt struck the Saturn V rocket, and the voltage surge disconnected all three of the Apollo spacecrafts' fuel cells, which gave power to the internal electrical systems, from the main electrical bus. Yellow caution lights erupted across the control panel for the fuel cells and the master alarm blared in the astronauts' headsets. Yet none of them had noticed any physical disturbances, and the rocket continued lifting them out of the atmosphere with 7.5 million pounds of thrust.\n\nThen, just 16 seconds later at T+52, another bolt struck the rocket. Once again, the three astronauts didn't notice anything but sudden chaos on the control panel. This time it lit up red indicating that the inertial guidance system couldn't be detected. That meant they had no way to judge the position, acceleration and attitude of their ascent through the atmosphere, arguably the most dangerous part of the mission. The Flight Director/Attitude Indicator, nicknamed the \"Eight-Ball,\" began spinning wildly.\n\nThe crew and mission control in Houston couldn't figure out what was wrong, and in fact, everything other than the control panel seemed to be working just fine. Nonetheless, the astronauts could hardly continue flying blind, and anxiety built as mission control scrambled to figure out what exactly was wrong with the apparently malfunctioning spacecraft.\n\nLuckily, John Aaron, the engineer manning the computer receiving electrical data from Apollo, quickly noticed a pattern in the seemingly random readings that reminded him of a telemetry failure during a prior test. He realized the solution and radioed his superior, Flight Director Gerry Griffin. \"Try SCE to AUX,\" he said.\n\nGriffin had no idea what this meant but trusted enough in Aaron's judgment to relay the message to the astronauts who also didn't understand. \"What the hell is that?\" was Pete Conrad's response. However, thinking quickly, they deduced this meant to turn the Signal Conditioning Equipment, SCE, to auxiliary battery power. A simple flip of the switch brought all the instruments back online at T+1:48.\n\nIn the end, the launch was successful, and the three astronauts entered low Earth orbit at T+11:34. After reconnecting the instrument panel to the fuel cells and checking that everything was in working order, they reignited the third stage engine for the four-day journey to lunar orbit. However, even with boots on the Moon, the mission's most notable feat might be astronaut's resetting of their instrument panel in barely over a minute, all while under nearly four Gs of force, about that of your average roller coaster.\n\n## Apollo 11's Missing Tapes\n\nWhen Neil Armstrong took the first steps on the Moon on 20 July 1969, some 650 million people worldwide tuned in to watch the televised video recording. However, few people, especially those used to the ease of modern digital video transmission, realize how much of a feat that was in and of itself.\n\nThat's because Apollo's recording equipment and transmission to Earth was via SSTV, which stands for \"slow-scan television.\" This method transmits static pictures at 10 frames per second over radio waves, ideal for the early lunar missions because it only requires 3 kHz of bandwidth.\n\nHowever, the televisions of the 60s were designed to receive and display in the NTSC standard, which runs at 30 frames per second and requires 6 MHz of bandwidth. The raw video footage from the Moon had to be converted, but NASA couldn't exactly download VLC media player to do it.\n\nInstead, they employed a considerably cruder method. They received the SSTV transmission onto a compatible 10-inch monitor while simply pointing a TV camera at it using the NTSC broadcast standard. This was done in multiple locations all over the globe to allow for worldwide broadcast. Unfortunately, though, this significantly lowered the video quality, particularly the contrast, brightness and resolution, meaning that no one but a few technicians and those doing the video conversion saw the original images.\n\nOf course, we now have much more sophisticated video conversion techniques, right? Surely NASA could feed the original SSTV recording through computer software to remaster it and develop beautiful digital images of the original Moon landing. Well, they could… if they hadn't lost the tapes.\n\nOriginally, NASA recorded the raw SSTV signal on 25mm analog magnetic data tapes. In the early 2000s, once technology emerged that could convert them to higher quality, officials found that they had disappeared, which they finally admitted to the public in 2006. Though it's likely they were erased and reused during a tape shortage in the 80s, and despite an ever shrinking supply of machinery capable of reading the tapes, NASA maintains hope that they'll turn up in one of their many archive centers.\n\n## The Apollo Program Pioneered Modern Computer Engineering\n\nThe internet is filled with memes pointing out that the cell phone in your pocket is several orders of magnitude more powerful than the computer that took the Apollo astronauts to the Moon. It's true—your smart phone does indeed have around a million times the RAM of the Apollo Guidance Computer's four kilobytes and 100,000 times its 0.43 MHz processing power, not to mention some seven million times its 75 kilobytes of permanent storage, which was in the form of core rope memory and read-only.\n\nHowever, this fails to acknowledge just how revolutionary and capable this computer really was. After all, it allowed the Apollo spacecraft to fly almost entirely \"by wire,\" that is, without any manual human control, except during lunar landings.\n\nThe most interesting thing about the AGC was that it was the first computer in the world based on silicon integrated circuits, the basis of the modern microchip. The use of silicon as a semiconductor material provided for much larger numbers of miniaturized transistors in one place than previous computers, which allowed for easy mass production and use in household devices. But first, it let it fit inside a spaceship.\n\nWhere the AGC's limited capacity really came into play was user interface. It was a far cry from you screaming at Siri to find you the nearest Taco Bell. Instead, the astronauts used an interface called \"display and keyboard,\" or DSKY. However, the \"keyboard\" was really just a number pad, and the crew could enter commands consisting of two two-digit numbers, the first representing a verb and the second a noun. For example, pressing Verb, 06, Noun, 62 would display the current velocity, altitude rate and altitude. Interestingly, these would be converted into imperial units even though the computer itself calculated in metric.\n\nDespite this simple input and output, the software, written in a specific AGC assembly language, required 1,400 human-years of work, well over 12.2 million human-hours, or the equivalent of around 18 lifespans. The team was led by Margaret Hamilton, the Director of the Software Engineering Division of the MIT Instrumentation Laboratory. She ended up winning the Presidential Medal of Freedom for her work on the AGC software, which, on paper, formed a stack taller than she was.\n\nThe software went on to play a role in the computers used in the Skylab and Space Shuttle programs as well as fly-by-wire military aircraft. It's also all available on GitHub today if you want to take a crack at flying a rocket ship with little more than a number pad.\n\n## The Snoopy Cap's Hot Mic\n\nAudio communication was key during the Apollo missions, but the space suits made it difficult, not to mention the roar of the rockets. To solve this, NASA designed the \"Communications Carrier Assembly\" to provide each astronaut with two earphones and two microphones for redundancy. The assembly completely wrapped around an astronaut's head with a large white band on top and bulky black housings for the earphones, leading to the nickname \"Snoopy cap\" because of its resemblance to the Peanuts character.\n\nHowever, as interesting as the engineering of the Snoopy cap is itself, more interesting are the candid hot-mic moments captured by it that give us a glimpse into the mind of the Apollo astronauts. Here are some of the best examples.\n\nWhen Apollo 12 took human beings to the Moon for the second time, Pete Conrad, who was just 5'6\" or 168 centimeters tall, considerably shorter than his crewmates, stepped onto the lunar surface with a joking attitude. \"Man, that may have been a small one for Neil, but that's a long one for me.\"\n\nAfter finishing a chat with mission control, Apollo 16 commander John Young informed his crewmate Charlie Duke he was having some digestive problems exacerbated by his enclosed spacesuit. \"I have the farts again,\" he said through the Snoopy cap. \"I got 'em Charlie.\"\n\nAlthough most people know Neil Armstrong's first words on the Moon, the Snoopy cap also captured Buzz Aldrin's particularly poignant reaction to the lunar surface during Apollo 11: \"Beautiful view. Magnificent desolation.\"\n\nIn 1972, during Apollo 17, the last manned mission to the Moon, astronauts Gene Cernan and Harrison Schmitt sang \"The Fountain in the Park\" while strolling across the lunar surface, substituting the word \"Moon\" for \"park.\" Cernan also capped the Apollo program and, to date, humanity's time on the Moon with his final words before lift-off: \"We leave as we came, and God willing, as we shall return, with peace and hope for all mankind.\"\n\n## Key Takeaways\n\n- The Apollo program's Saturn V rocket carried 42 terajoules of potential explosive energy, equivalent to two-thirds of the Little Boy atomic bomb.\n- Rubber Rooms were designed as last-resort bunkers for astronauts and launch-pad crew in case of a rocket explosion.\n- Apollo 12's launch was struck by lightning twice, causing electrical failures that were quickly resolved by mission control.\n- NASA lost the original high-quality tapes of the Apollo 11 moon landing, which were recorded on 25mm analog magnetic data tapes.\n- The Apollo Guidance Computer, based on silicon integrated circuits, was revolutionary for its time and allowed near-autonomous spacecraft control.\n\n## Frequently Asked Questions\n\n### What was the 'Rubber Room' in the Apollo program?\n\nThe 'Rubber Room' was a last-resort escape bunker located underneath the launch pads at Kennedy Space Center. It was designed to protect launch-pad crew and astronauts in case of an explosion. The bunker could support 20 people for up to 24 hours and was accessed via a 200-foot chute that led to a rubber-padded reception room.\n\n### How much energy did the Saturn V rocket carry?\n\nThe Saturn V rocket carried 42 terajoules of potential explosive energy. This is about two-thirds the energy released by the Little Boy atomic bomb dropped on Hiroshima and nearly 1,000 times the energy of the US military's most powerful conventional bomb, the MOAB.\n\n### What happened during the Apollo 12 launch?\n\nDuring the Apollo 12 launch, the Saturn V rocket was struck by lightning twice within 16 seconds. The lightning bolts caused the spacecraft's fuel cells to disconnect from the main electrical bus, leading to chaos on the control panel. The crew and mission control had to quickly resolve the issue to continue the mission.\n\n### What was the issue with the Apollo 11 video tapes?\n\nThe raw video footage from the Apollo 11 Moon landing was recorded on 25mm analog magnetic data tapes. These tapes were later lost, and despite efforts to find them, NASA admitted in 2006 that they had disappeared. It is likely they were erased and reused during a tape shortage in the 1980s.\n\n### What was the Apollo Guidance Computer (AGC) and what made it revolutionary?\n\nThe Apollo Guidance Computer (AGC) was the first computer based on silicon integrated circuits, which allowed for miniaturized transistors and easy mass production. It enabled the Apollo spacecraft to fly almost entirely 'by wire,' without manual human control, except during lunar landings. The AGC's software required 1,400 human-years of work.\n\n### What is the 'Snoopy cap' and what interesting moments did it capture?\n\nThe 'Snoopy cap' was a communications carrier assembly worn by astronauts during the Apollo missions. It captured candid moments, such as Pete Conrad's joke about the lunar surface being a 'long one for me,' John Young's comment about having 'the farts again,' and Buzz Aldrin's description of the Moon as 'magnificent desolation.'\n\n### What was the significance of the Apollo 17 mission?\n\nApollo 17 was the last manned mission to the Moon. During this mission, astronauts Gene Cernan and Harrison Schmitt sang a modified version of 'The Fountain in the Park' while on the lunar surface. Cernan's final words before lift-off were 'We leave as we came, and God willing, as we shall return, with peace and hope for all mankind.'\n\n### What was the purpose of the 'Rubber Rooms' and how were they accessed?\n\nThe 'Rubber Rooms' were escape bunkers designed to protect astronauts and launch-pad crew in case of an explosion. They were accessed via a 200-foot chute that led to a rubber-padded reception room. The bunkers could withstand extreme conditions, including a fireball 1,400 feet wide and explosive pressures of 500 pounds per square inch.\n\n### What was the Apollo 12 mission's notable feat besides the lunar landing?\n\nThe Apollo 12 mission's most notable feat, besides the lunar landing, was the astronauts' quick resolution of a control panel issue caused by lightning strikes. They reset the instrument panel in barely over a minute while under nearly four Gs of force, allowing the mission to continue successfully.\n\n### What was the Apollo 11 mission's video transmission method?\n\nThe Apollo 11 mission used SSTV (slow-scan television) to transmit video from the Moon. This method sent static pictures at 10 frames per second over radio waves, requiring only 3 kHz of bandwidth. The raw video was converted to the NTSC standard for broadcast, but this process significantly lowered the video quality.\n\n## Sources\n\n- [Original Side Projects video: Interesting Things You Didn't Know About the Apollo Program](https://www.youtube.com/watch?v=F3XGMACymlM)\n- [https://www.nasa.gov/history/50-years-ago-apollo-12-on-the-moon-whoopee/](https://www.nasa.gov/history/50-years-ago-apollo-12-on-the-moon-whoopee/)\n- [https://en.wikipedia.org/wiki/Apollo_11](https://en.wikipedia.org/wiki/Apollo_11)\n- [https://en.wikipedia.org/wiki/Apollo_11_missing_tapes](https://en.wikipedia.org/wiki/Apollo_11_missing_tapes)\n- [https://www.nasa.gov/history/apollo-11-mission-overview/](https://www.nasa.gov/history/apollo-11-mission-overview/)\n- [https://en.wikipedia.org/wiki/Apollo_12](https://en.wikipedia.org/wiki/Apollo_12)\n- [https://en.wikipedia.org/wiki/Apollo_17](https://en.wikipedia.org/wiki/Apollo_17)\n- [https://en.wikipedia.org/wiki/Apollo_Guidance_Computer](https://en.wikipedia.org/wiki/Apollo_Guidance_Computer)\n- [https://en.wikipedia.org/wiki/Apollo_program](https://en.wikipedia.org/wiki/Apollo_program)\n- [https://en.wikipedia.org/wiki/Core_rope_memory](https://en.wikipedia.org/wiki/Core_rope_memory)\n- [https://en.wikipedia.org/wiki/GBU-43/B_MOAB](https://en.wikipedia.org/wiki/GBU-43/B_MOAB)\n- [https://en.wikipedia.org/wiki/Integrated_circuit](https://en.wikipedia.org/wiki/Integrated_circuit)\n- [https://en.wikipedia.org/wiki/Kennedy_Space_Center_Launch_Complex_39](https://en.wikipedia.org/wiki/Kennedy_Space_Center_Launch_Complex_39)\n- [https://svtsim.com/moonjs/agc.html](https://svtsim.com/moonjs/agc.html)\n- [https://history.nasa.gov/afj/ap12fj/a12-lightningstrike.html](https://history.nasa.gov/afj/ap12fj/a12-lightningstrike.html)\n- [https://www.space.com/18422-apollo-saturn-v-moon-rocket-nasa-infographic.html](https://www.space.com/18422-apollo-saturn-v-moon-rocket-nasa-infographic.html)\n- [https://en.wikipedia.org/wiki/NTSC](https://en.wikipedia.org/wiki/NTSC)\n- [https://en.wikipedia.org/wiki/Pete_Conrad](https://en.wikipedia.org/wiki/Pete_Conrad)\n- [https://youtu.be/aKdQbsPfWeo](https://youtu.be/aKdQbsPfWeo)\n- [https://en.wikipedia.org/wiki/RP-1](https://en.wikipedia.org/wiki/RP-1)\n- [https://en.wikipedia.org/wiki/Rubber_room_(bunker](https://en.wikipedia.org/wiki/Rubber_room_(bunker)\n- [https://en.wikipedia.org/wiki/Saturn_V](https://en.wikipedia.org/wiki/Saturn_V)\n- [https://en.wikipedia.org/wiki/Slow-scan_television](https://en.wikipedia.org/wiki/Slow-scan_television)\n- [https://en.wikipedia.org/wiki/Snoopy_cap](https://en.wikipedia.org/wiki/Snoopy_cap)\n- [https://history.nasa.gov/computers/Ch2-5.html](https://history.nasa.gov/computers/Ch2-5.html)\n- [https://www.mentalfloss.com/posts/apollo-16-astronaut-john-young-farts-in-space](https://www.mentalfloss.com/posts/apollo-16-astronaut-john-young-farts-in-space)\n- [https://www.realclearscience.com/articles/2019/07/02/your_mobile_phone_vs_apollo_11s_guidance_computer_111026.html](https://www.realclearscience.com/articles/2019/07/02/your_mobile_phone_vs_apollo_11s_guidance_computer_111026.html)\n\n## Related Coverage" url: https://sideprojects.pub/article/interesting-things-you-didnt-know-about-the-apollo-program.md canonical: https://sideprojects.pub/article/interesting-things-you-didnt-know-about-the-apollo-program datePublished: 2026-06-25 dateModified: 2026-06-25 author: - name: Simon Whistler url: https://sideprojects.pub/author/simon-whistler publisher: Side Projects image: "https://media.sideprojects.pub/cdn-cgi/image/width=1600,height=900,fit=cover,quality=80,format=auto/articles/F3XGMACymlM/hero.jpg" type: NewsArticle contentHash: 3201f9bef9c8f78df1cbfdb239a107dec81c6f10a9b62396358598ee84777e1a tokens: 5394 summaryUrl: https://sideprojects.pub/article/interesting-things-you-didnt-know-about-the-apollo-program.md.summary.md --- Imagine stepping into a room lined with rubber, a last resort against the violent uncertainties of space travel. This isn't the setting of a science fiction story; it's a very real chapter in the saga of human ingenuity. From a "rubber room" designed to be the ultimate safe haven for astronauts, to ingenious hacks and close calls that were never broadcast, we're about to uncover the hidden gems you didn't know about the missions that took humanity to another world. ## The "Rubber Room" Escape Bunkers The Apollo program relied on the Saturn V rocket. When adding up the kerosene and liquid hydrogen fuel of all three stages, it carried an insane 42 terajoules of potential explosive energy that it released in a controlled manner to carry the United States' first astronauts to the moon. To understand just how much energy this is, consider that it's a full two-thirds that released by the Little Boy atomic bomb dropped on Hiroshima. That gives it nearly 1,000 times the energy of the US military's most powerful conventional bomb, the MOAB, which releases a measly 46 gigajoules. In other words, if that reaction got out of control, it could be one hell of an explosion. And if anyone wanted to survive it, it would take one hell of a bunker. These were the "Rubber Rooms." Located underneath the launch pads at Kennedy Space Center, the Rubber Rooms served as last-resort protection for launch-pad crew and the astronauts themselves in case of an explosion. It was capable of supporting 20 people for up to 24 hours. However, the really interesting thing about the Rubber Rooms, and the reason they earned that nickname, was the way in. The launch-pad crew had to slide down a 200-foot chute, around 60 meters, that popped them right into a little rubber-padded reception room of sorts. From there, they had to open a massive steel door to enter the actual bunker which consisted of a domed ceiling and concrete floor suspended on shock-absorbing springs. The astronauts had a longer journey, having to take an elevator down the 320-foot launch tower, around 100 meters, to the launch pad in just 30 seconds from which they'd transfer to the chute. Getting out wasn't so easy. You either had to exit through a 1,200-foot-long air duct, which is 365 meters, or through an escape hatch in the roof. Obviously the rockets and landers of the Apollo program get all the engineering glory, but the ingenuity of the bunkers was no small feat. They could withstand a fireball 1,400 feet wide, or 430 meters, burning at 2,500 degrees Fahrenheit or 1,370 degrees Celsius. They could also protect their occupants from explosive pressures of 500 pounds per square inch and 75G of acceleration, about 15 times what an untrained human being can normally withstand. Though an admiral precaution, the Rubber Rooms were never used beyond training. When the Apollo program ended, NASA abandoned them, after which they filled with water and nature promptly took them back as tends to happen in Florida. NASA eventually refurbished the launch pads for the Space Shuttle program but left the Rubber Rooms as they were. Currently, SpaceX rents the pads, but the terms of the lease require them to leave the Rubber Rooms preserved as historical artifacts. ## Apollo 12 Becomes a Lightning Rod On 19 November 1969, the Apollo 12 mission crewed by Pete Conrad, Richard Gordon and Alan Bean, made the second ever manned landing on the Moon. Having already beat the Soviets to the Moon with Apollo 11, Apollo 12 was considerably more… relaxed. For example, the launch date was pushed back two months to provide for more training and allow President Richard Nixon to attend. In fact, the astronauts even took hammocks with them to deploy on the lunar surface. NASA really wanted to make it look like they could now reach the Moon with ease, which is why they didn't publicize many of the unforeseen obstacles. Like the rocket getting struck by lightning… twice. The launch was scheduled for 14 November 1969 from Kennedy Space Center in Florida. Because this date coincided with ideal landing conditions on the Moon, there was only a launch window of about three hours. However, it also coincided with stormy weather: overcast and rainy skies as well wind speeds of 175 miles per hour, or 280 kilometers per hour, the strongest faced by any Apollo launch. Plus, there was a cumulonimbus cloud above the launch site, which should have canceled the launch based on NASA rules, but they waived the restriction, and the launch went ahead. Thirty-six seconds after lift-off, a lightning bolt struck the Saturn V rocket, and the voltage surge disconnected all three of the Apollo spacecrafts' fuel cells, which gave power to the internal electrical systems, from the main electrical bus. Yellow caution lights erupted across the control panel for the fuel cells and the master alarm blared in the astronauts' headsets. Yet none of them had noticed any physical disturbances, and the rocket continued lifting them out of the atmosphere with 7.5 million pounds of thrust. Then, just 16 seconds later at T+52, another bolt struck the rocket. Once again, the three astronauts didn't notice anything but sudden chaos on the control panel. This time it lit up red indicating that the inertial guidance system couldn't be detected. That meant they had no way to judge the position, acceleration and attitude of their ascent through the atmosphere, arguably the most dangerous part of the mission. The Flight Director/Attitude Indicator, nicknamed the "Eight-Ball," began spinning wildly. The crew and mission control in Houston couldn't figure out what was wrong, and in fact, everything other than the control panel seemed to be working just fine. Nonetheless, the astronauts could hardly continue flying blind, and anxiety built as mission control scrambled to figure out what exactly was wrong with the apparently malfunctioning spacecraft. Luckily, John Aaron, the engineer manning the computer receiving electrical data from Apollo, quickly noticed a pattern in the seemingly random readings that reminded him of a telemetry failure during a prior test. He realized the solution and radioed his superior, Flight Director Gerry Griffin. "Try SCE to AUX," he said. Griffin had no idea what this meant but trusted enough in Aaron's judgment to relay the message to the astronauts who also didn't understand. "What the hell is that?" was Pete Conrad's response. However, thinking quickly, they deduced this meant to turn the Signal Conditioning Equipment, SCE, to auxiliary battery power. A simple flip of the switch brought all the instruments back online at T+1:48. In the end, the launch was successful, and the three astronauts entered low Earth orbit at T+11:34. After reconnecting the instrument panel to the fuel cells and checking that everything was in working order, they reignited the third stage engine for the four-day journey to lunar orbit. However, even with boots on the Moon, the mission's most notable feat might be astronaut's resetting of their instrument panel in barely over a minute, all while under nearly four Gs of force, about that of your average roller coaster. ## Apollo 11's Missing Tapes When Neil Armstrong took the first steps on the Moon on 20 July 1969, some 650 million people worldwide tuned in to watch the televised video recording. However, few people, especially those used to the ease of modern digital video transmission, realize how much of a feat that was in and of itself. That's because Apollo's recording equipment and transmission to Earth was via SSTV, which stands for "slow-scan television." This method transmits static pictures at 10 frames per second over radio waves, ideal for the early lunar missions because it only requires 3 kHz of bandwidth. However, the televisions of the 60s were designed to receive and display in the NTSC standard, which runs at 30 frames per second and requires 6 MHz of bandwidth. The raw video footage from the Moon had to be converted, but NASA couldn't exactly download VLC media player to do it. Instead, they employed a considerably cruder method. They received the SSTV transmission onto a compatible 10-inch monitor while simply pointing a TV camera at it using the NTSC broadcast standard. This was done in multiple locations all over the globe to allow for worldwide broadcast. Unfortunately, though, this significantly lowered the video quality, particularly the contrast, brightness and resolution, meaning that no one but a few technicians and those doing the video conversion saw the original images. Of course, we now have much more sophisticated video conversion techniques, right? Surely NASA could feed the original SSTV recording through computer software to remaster it and develop beautiful digital images of the original Moon landing. Well, they could… if they hadn't lost the tapes. Originally, NASA recorded the raw SSTV signal on 25mm analog magnetic data tapes. In the early 2000s, once technology emerged that could convert them to higher quality, officials found that they had disappeared, which they finally admitted to the public in 2006. Though it's likely they were erased and reused during a tape shortage in the 80s, and despite an ever shrinking supply of machinery capable of reading the tapes, NASA maintains hope that they'll turn up in one of their many archive centers. ## The Apollo Program Pioneered Modern Computer Engineering The internet is filled with memes pointing out that the cell phone in your pocket is several orders of magnitude more powerful than the computer that took the Apollo astronauts to the Moon. It's true—your smart phone does indeed have around a million times the RAM of the Apollo Guidance Computer's four kilobytes and 100,000 times its 0.43 MHz processing power, not to mention some seven million times its 75 kilobytes of permanent storage, which was in the form of core rope memory and read-only. However, this fails to acknowledge just how revolutionary and capable this computer really was. After all, it allowed the Apollo spacecraft to fly almost entirely "by wire," that is, without any manual human control, except during lunar landings. The most interesting thing about the AGC was that it was the first computer in the world based on silicon integrated circuits, the basis of the modern microchip. The use of silicon as a semiconductor material provided for much larger numbers of miniaturized transistors in one place than previous computers, which allowed for easy mass production and use in household devices. But first, it let it fit inside a spaceship. Where the AGC's limited capacity really came into play was user interface. It was a far cry from you screaming at Siri to find you the nearest Taco Bell. Instead, the astronauts used an interface called "display and keyboard," or DSKY. However, the "keyboard" was really just a number pad, and the crew could enter commands consisting of two two-digit numbers, the first representing a verb and the second a noun. For example, pressing Verb, 06, Noun, 62 would display the current velocity, altitude rate and altitude. Interestingly, these would be converted into imperial units even though the computer itself calculated in metric. Despite this simple input and output, the software, written in a specific AGC assembly language, required 1,400 human-years of work, well over 12.2 million human-hours, or the equivalent of around 18 lifespans. The team was led by Margaret Hamilton, the Director of the Software Engineering Division of the MIT Instrumentation Laboratory. She ended up winning the Presidential Medal of Freedom for her work on the AGC software, which, on paper, formed a stack taller than she was. The software went on to play a role in the computers used in the Skylab and Space Shuttle programs as well as fly-by-wire military aircraft. It's also all available on GitHub today if you want to take a crack at flying a rocket ship with little more than a number pad. ## The Snoopy Cap's Hot Mic Audio communication was key during the Apollo missions, but the space suits made it difficult, not to mention the roar of the rockets. To solve this, NASA designed the "Communications Carrier Assembly" to provide each astronaut with two earphones and two microphones for redundancy. The assembly completely wrapped around an astronaut's head with a large white band on top and bulky black housings for the earphones, leading to the nickname "Snoopy cap" because of its resemblance to the Peanuts character. However, as interesting as the engineering of the Snoopy cap is itself, more interesting are the candid hot-mic moments captured by it that give us a glimpse into the mind of the Apollo astronauts. Here are some of the best examples. When Apollo 12 took human beings to the Moon for the second time, Pete Conrad, who was just 5'6" or 168 centimeters tall, considerably shorter than his crewmates, stepped onto the lunar surface with a joking attitude. "Man, that may have been a small one for Neil, but that's a long one for me." After finishing a chat with mission control, Apollo 16 commander John Young informed his crewmate Charlie Duke he was having some digestive problems exacerbated by his enclosed spacesuit. "I have the farts again," he said through the Snoopy cap. "I got 'em Charlie." Although most people know Neil Armstrong's first words on the Moon, the Snoopy cap also captured Buzz Aldrin's particularly poignant reaction to the lunar surface during Apollo 11: "Beautiful view. Magnificent desolation." In 1972, during Apollo 17, the last manned mission to the Moon, astronauts Gene Cernan and Harrison Schmitt sang "The Fountain in the Park" while strolling across the lunar surface, substituting the word "Moon" for "park." Cernan also capped the Apollo program and, to date, humanity's time on the Moon with his final words before lift-off: "We leave as we came, and God willing, as we shall return, with peace and hope for all mankind." ## Key Takeaways - The Apollo program's Saturn V rocket carried 42 terajoules of potential explosive energy, equivalent to two-thirds of the Little Boy atomic bomb. - Rubber Rooms were designed as last-resort bunkers for astronauts and launch-pad crew in case of a rocket explosion. - Apollo 12's launch was struck by lightning twice, causing electrical failures that were quickly resolved by mission control. - NASA lost the original high-quality tapes of the Apollo 11 moon landing, which were recorded on 25mm analog magnetic data tapes. - The Apollo Guidance Computer, based on silicon integrated circuits, was revolutionary for its time and allowed near-autonomous spacecraft control. ## Frequently Asked Questions ### What was the 'Rubber Room' in the Apollo program? The 'Rubber Room' was a last-resort escape bunker located underneath the launch pads at Kennedy Space Center. It was designed to protect launch-pad crew and astronauts in case of an explosion. The bunker could support 20 people for up to 24 hours and was accessed via a 200-foot chute that led to a rubber-padded reception room. ### How much energy did the Saturn V rocket carry? The Saturn V rocket carried 42 terajoules of potential explosive energy. This is about two-thirds the energy released by the Little Boy atomic bomb dropped on Hiroshima and nearly 1,000 times the energy of the US military's most powerful conventional bomb, the MOAB. ### What happened during the Apollo 12 launch? During the Apollo 12 launch, the Saturn V rocket was struck by lightning twice within 16 seconds. The lightning bolts caused the spacecraft's fuel cells to disconnect from the main electrical bus, leading to chaos on the control panel. The crew and mission control had to quickly resolve the issue to continue the mission. ### What was the issue with the Apollo 11 video tapes? The raw video footage from the Apollo 11 Moon landing was recorded on 25mm analog magnetic data tapes. These tapes were later lost, and despite efforts to find them, NASA admitted in 2006 that they had disappeared. It is likely they were erased and reused during a tape shortage in the 1980s. ### What was the Apollo Guidance Computer (AGC) and what made it revolutionary? The Apollo Guidance Computer (AGC) was the first computer based on silicon integrated circuits, which allowed for miniaturized transistors and easy mass production. It enabled the Apollo spacecraft to fly almost entirely 'by wire,' without manual human control, except during lunar landings. The AGC's software required 1,400 human-years of work. ### What is the 'Snoopy cap' and what interesting moments did it capture? The 'Snoopy cap' was a communications carrier assembly worn by astronauts during the Apollo missions. It captured candid moments, such as Pete Conrad's joke about the lunar surface being a 'long one for me,' John Young's comment about having 'the farts again,' and Buzz Aldrin's description of the Moon as 'magnificent desolation.' ### What was the significance of the Apollo 17 mission? Apollo 17 was the last manned mission to the Moon. During this mission, astronauts Gene Cernan and Harrison Schmitt sang a modified version of 'The Fountain in the Park' while on the lunar surface. Cernan's final words before lift-off were 'We leave as we came, and God willing, as we shall return, with peace and hope for all mankind.' ### What was the purpose of the 'Rubber Rooms' and how were they accessed? The 'Rubber Rooms' were escape bunkers designed to protect astronauts and launch-pad crew in case of an explosion. They were accessed via a 200-foot chute that led to a rubber-padded reception room. The bunkers could withstand extreme conditions, including a fireball 1,400 feet wide and explosive pressures of 500 pounds per square inch. ### What was the Apollo 12 mission's notable feat besides the lunar landing? The Apollo 12 mission's most notable feat, besides the lunar landing, was the astronauts' quick resolution of a control panel issue caused by lightning strikes. They reset the instrument panel in barely over a minute while under nearly four Gs of force, allowing the mission to continue successfully. ### What was the Apollo 11 mission's video transmission method? The Apollo 11 mission used SSTV (slow-scan television) to transmit video from the Moon. This method sent static pictures at 10 frames per second over radio waves, requiring only 3 kHz of bandwidth. The raw video was converted to the NTSC standard for broadcast, but this process significantly lowered the video quality. ## Sources - [Original Side Projects video: Interesting Things You Didn't Know About the Apollo Program](https://www.youtube.com/watch?v=F3XGMACymlM) - [https://www.nasa.gov/history/50-years-ago-apollo-12-on-the-moon-whoopee/](https://www.nasa.gov/history/50-years-ago-apollo-12-on-the-moon-whoopee/) - [https://en.wikipedia.org/wiki/Apollo_11](https://en.wikipedia.org/wiki/Apollo_11) - [https://en.wikipedia.org/wiki/Apollo_11_missing_tapes](https://en.wikipedia.org/wiki/Apollo_11_missing_tapes) - [https://www.nasa.gov/history/apollo-11-mission-overview/](https://www.nasa.gov/history/apollo-11-mission-overview/) - [https://en.wikipedia.org/wiki/Apollo_12](https://en.wikipedia.org/wiki/Apollo_12) - [https://en.wikipedia.org/wiki/Apollo_17](https://en.wikipedia.org/wiki/Apollo_17) - [https://en.wikipedia.org/wiki/Apollo_Guidance_Computer](https://en.wikipedia.org/wiki/Apollo_Guidance_Computer) - [https://en.wikipedia.org/wiki/Apollo_program](https://en.wikipedia.org/wiki/Apollo_program) - [https://en.wikipedia.org/wiki/Core_rope_memory](https://en.wikipedia.org/wiki/Core_rope_memory) - [https://en.wikipedia.org/wiki/GBU-43/B_MOAB](https://en.wikipedia.org/wiki/GBU-43/B_MOAB) - [https://en.wikipedia.org/wiki/Integrated_circuit](https://en.wikipedia.org/wiki/Integrated_circuit) - [https://en.wikipedia.org/wiki/Kennedy_Space_Center_Launch_Complex_39](https://en.wikipedia.org/wiki/Kennedy_Space_Center_Launch_Complex_39) - [https://svtsim.com/moonjs/agc.html](https://svtsim.com/moonjs/agc.html) - [https://history.nasa.gov/afj/ap12fj/a12-lightningstrike.html](https://history.nasa.gov/afj/ap12fj/a12-lightningstrike.html) - [https://www.space.com/18422-apollo-saturn-v-moon-rocket-nasa-infographic.html](https://www.space.com/18422-apollo-saturn-v-moon-rocket-nasa-infographic.html) - [https://en.wikipedia.org/wiki/NTSC](https://en.wikipedia.org/wiki/NTSC) - [https://en.wikipedia.org/wiki/Pete_Conrad](https://en.wikipedia.org/wiki/Pete_Conrad) - [https://youtu.be/aKdQbsPfWeo](https://youtu.be/aKdQbsPfWeo) - [https://en.wikipedia.org/wiki/RP-1](https://en.wikipedia.org/wiki/RP-1) - [https://en.wikipedia.org/wiki/Rubber_room_(bunker](https://en.wikipedia.org/wiki/Rubber_room_(bunker) - [https://en.wikipedia.org/wiki/Saturn_V](https://en.wikipedia.org/wiki/Saturn_V) - [https://en.wikipedia.org/wiki/Slow-scan_television](https://en.wikipedia.org/wiki/Slow-scan_television) - [https://en.wikipedia.org/wiki/Snoopy_cap](https://en.wikipedia.org/wiki/Snoopy_cap) - [https://history.nasa.gov/computers/Ch2-5.html](https://history.nasa.gov/computers/Ch2-5.html) - [https://www.mentalfloss.com/posts/apollo-16-astronaut-john-young-farts-in-space](https://www.mentalfloss.com/posts/apollo-16-astronaut-john-young-farts-in-space) - [https://www.realclearscience.com/articles/2019/07/02/your_mobile_phone_vs_apollo_11s_guidance_computer_111026.html](https://www.realclearscience.com/articles/2019/07/02/your_mobile_phone_vs_apollo_11s_guidance_computer_111026.html) ## Related Coverage