WEBVTT 1 00:00:03.439 --> 00:00:07.719 Welcome to Bedtime Astronomy. Explore the wonders of the cosmos 2 00:00:07.759 --> 00:00:12.279 with our soothing Bedtime Astronomie podcast. Each episode offers a 3 00:00:12.359 --> 00:00:16.320 gentle journey through the stars, planets, and beyond, perfect for 4 00:00:16.399 --> 00:00:20.239 unwinding after a long day. Let's travel through the mysteries 5 00:00:20.239 --> 00:00:22.440 of the universe as you drift off into a peaceful 6 00:00:22.480 --> 00:00:23.800 slumber under the night sky. 7 00:00:26.960 --> 00:00:29.719 So on the second of this month, when those artimists 8 00:00:29.719 --> 00:00:32.719 two engines ignited, I mean, if you think about it, 9 00:00:32.960 --> 00:00:36.799 the astronauts strapped inside were protected by aerospace tech that 10 00:00:37.079 --> 00:00:40.119 on a fundamental level hasn't really evolved all that much 11 00:00:40.119 --> 00:00:41.359 since the Apollo missions. 12 00:00:41.520 --> 00:00:45.399 No, it really hasn't. It's surprisingly old school. 13 00:00:45.359 --> 00:00:47.799 Right, because when you look at the schematics for shielding 14 00:00:47.799 --> 00:00:50.960 critical avionics from just the sheer hostility of deep space, 15 00:00:51.560 --> 00:00:54.719 the solution has almost always been brute force. You know, 16 00:00:54.799 --> 00:00:58.840 you use thick plates of aluminum or layers of polyethylene. 17 00:00:58.240 --> 00:00:59.640 Here, water jackets, things like that. 18 00:01:00.679 --> 00:01:05.439 We're taking these incredible twenty first century subanimeter computing architectures 19 00:01:05.840 --> 00:01:09.760 and like burying them behind twentieth century dead weight. And 20 00:01:09.799 --> 00:01:12.439 if you know anything about orbital mechanics, dead weight is 21 00:01:12.480 --> 00:01:13.319 the ultimate enemy. 22 00:01:13.400 --> 00:01:16.480 Oh absolutely, every single ounce of mass we push past 23 00:01:16.560 --> 00:01:19.439 Earth's gravity well costs, you know, thousands of dollars. 24 00:01:19.680 --> 00:01:23.920 We're paying this massive payload penalty just to build dumb walls. 25 00:01:24.640 --> 00:01:28.359 But so what happens when that wall is completely reimagined, 26 00:01:28.959 --> 00:01:31.439 Like what if you could achieve the exact same protection, 27 00:01:31.560 --> 00:01:34.920 the same attenuation of all that cosmic hostility with a 28 00:01:34.959 --> 00:01:37.799 material that is thinner than a single strand of human hair. 29 00:01:38.079 --> 00:01:41.599 Which sounds like science fiction, right, But the mass penalty 30 00:01:41.799 --> 00:01:44.519 isn't just an economic issue anymore. I mean it is 31 00:01:44.560 --> 00:01:49.000 the absolute physical bottleneck for human expansion into the Solar. 32 00:01:48.719 --> 00:01:51.200 System right now, because rockets can only carry so much. 33 00:01:51.359 --> 00:01:54.719 Exactly the Walcket equation is just completely unforgiving. If half 34 00:01:54.760 --> 00:01:58.040 of your available payload is dedicated to structural shielding just 35 00:01:58.040 --> 00:02:01.159 to you know, prevent your on board computers from getting 36 00:02:01.159 --> 00:02:05.439 fried by cosmic radiation. While you've severely restricted the scientific 37 00:02:05.439 --> 00:02:06.200 instruments you can. 38 00:02:06.120 --> 00:02:09.439 Carry, they're leaving behind life support redundancy. 39 00:02:08.840 --> 00:02:13.120 You're leaving behind actual human crew members. The traditional paradigm 40 00:02:13.159 --> 00:02:17.039 relies on macroscopic, really dense materials to block these high 41 00:02:17.120 --> 00:02:19.879 energy threats. But when you hit the absolute limit of 42 00:02:19.919 --> 00:02:22.560 how much mass you can launch. You just can't build 43 00:02:22.599 --> 00:02:23.400 thicker walls. 44 00:02:23.439 --> 00:02:24.319 You literally can't. 45 00:02:24.439 --> 00:02:27.360 Yeah, right, you are forced to look the other way. 46 00:02:27.560 --> 00:02:30.719 You have to manipulate matter at the molecular level to 47 00:02:30.800 --> 00:02:33.960 completely change how the material interacts with those threats in 48 00:02:34.000 --> 00:02:34.639 the first place. 49 00:02:35.120 --> 00:02:37.719 And that brings us to this incredible breakthrough from the 50 00:02:37.840 --> 00:02:42.120 Korea Institute of Science and Technology or KISSED. They've developed 51 00:02:42.120 --> 00:02:47.599 this highly flexible, ultra thin nanomaterial that handles two very 52 00:02:47.639 --> 00:02:50.960 different and visible threats simultaneously. 53 00:02:50.199 --> 00:02:53.080 Electromagnetic interference and neutron radiation. 54 00:02:53.319 --> 00:02:56.319 Right, and before we get into the actual physical chemistry 55 00:02:56.319 --> 00:02:58.319 of how they built this stuff, which is mind blowing 56 00:02:58.360 --> 00:03:01.639 by the way, we really need to establish why these 57 00:03:01.639 --> 00:03:04.840 two specific forces are so destructive to modern technology. 58 00:03:04.919 --> 00:03:06.439 Yeah, that context is crucial. 59 00:03:06.599 --> 00:03:09.960 So let's look at electromagnetic waves first, because we aren't 60 00:03:09.960 --> 00:03:11.680 just talking about static electricity here. 61 00:03:11.759 --> 00:03:14.840 Far from deep space, and honestly, even low Earth orbit 62 00:03:15.080 --> 00:03:19.680 is just saccurated with these highly energetic, constantly fluctuating electric 63 00:03:19.719 --> 00:03:22.960 and magnetic fields. And to really understand why that is 64 00:03:23.080 --> 00:03:25.759 lethal to a spacecraft, you have to look at how 65 00:03:25.879 --> 00:03:29.599 modern semiconductors are built. I mean, we're currently manufacturing silicon 66 00:03:29.680 --> 00:03:33.560 chips with transistor gates that are just a few nanometers. 67 00:03:33.039 --> 00:03:35.199 Wide, which is microscopic, right. 68 00:03:35.080 --> 00:03:39.120 And they operate on incredibly tiny voltage margins. So when 69 00:03:39.159 --> 00:03:43.919 an energetic electromagnetic wave sweeps through an unshielded avionics bay, 70 00:03:44.400 --> 00:03:47.840 it induces parasitic currents in those microscopic circuits. 71 00:03:47.919 --> 00:03:50.439 It's essentially pushing electrons around exactly. 72 00:03:50.560 --> 00:03:53.080 It forces electrons to move where they aren't supposed to, 73 00:03:53.479 --> 00:03:53.960 So it's. 74 00:03:53.800 --> 00:03:58.719 Basically introducing noise into a system that requires like absolute 75 00:03:58.840 --> 00:04:00.840 silence to operate correctly. 76 00:04:00.919 --> 00:04:02.000 That's a great way to put it. 77 00:04:02.080 --> 00:04:06.080 If a stray voltage spike hits a memory register, it 78 00:04:06.120 --> 00:04:09.319 can literally flip a binary zero to a one, and 79 00:04:09.400 --> 00:04:12.159 you end up with what engineers call a single event. 80 00:04:12.000 --> 00:04:14.039 Upset, which can be terrifying in space. 81 00:04:14.159 --> 00:04:16.879 Yeah, I mean, best case scenario, it's a minor sensor glitch. 82 00:04:17.199 --> 00:04:20.519 Worst case it's a catastrophic navigation failure right in the 83 00:04:20.519 --> 00:04:22.439 middle of a critical orbital insertion burn. 84 00:04:22.720 --> 00:04:25.680 And that is just the electromagnetic side of the equation. 85 00:04:25.800 --> 00:04:29.040 That's just a wave of energy flipping logic states. The 86 00:04:29.079 --> 00:04:32.240 other half of this dual thread environment is neutron. 87 00:04:31.879 --> 00:04:34.720 Radiation, which behaves completely differently completely. 88 00:04:34.879 --> 00:04:39.240 Neutrons actually possess mass, but as the name implies, they 89 00:04:39.279 --> 00:04:41.079 carry in neutral electrical. 90 00:04:40.720 --> 00:04:43.519 Charge, meaning they don't care about electronics. Right. 91 00:04:43.560 --> 00:04:46.480 They do not interact with the electromagnetic fields of the 92 00:04:46.519 --> 00:04:50.720 atoms they pass through. They completely ignore the electron cloud. 93 00:04:50.759 --> 00:04:54.360 Which means they fly right through the typical conductive metals 94 00:04:54.360 --> 00:04:58.480 that we would normally use to block electromagnetic interference, like 95 00:04:58.720 --> 00:05:01.920 a copper shield. It might stop a radio frequency wave 96 00:05:02.040 --> 00:05:04.879 dead in its tracks, but a neutron doesn't even notice 97 00:05:04.920 --> 00:05:05.639 the copper is there. 98 00:05:05.759 --> 00:05:08.680 It passes straight through until it makes a direct physical 99 00:05:08.720 --> 00:05:12.160 collision with an atomic nucleus. So when a high velocity 100 00:05:12.199 --> 00:05:15.920 neutron slams into the silicon lattice of a semiconductor, it 101 00:05:15.959 --> 00:05:16.879 is a kinetic event. 102 00:05:16.959 --> 00:05:18.040 It's physical damage. 103 00:05:18.240 --> 00:05:23.199 Yes, physicists call this displacement damage. The neutron acts like 104 00:05:23.240 --> 00:05:27.800 a microscopic billiard ball, you know, transferring its kinetic energy 105 00:05:27.839 --> 00:05:31.800 to a silicon atom and literally knocking it completely out 106 00:05:31.800 --> 00:05:33.879 of its precise crystalline structure. 107 00:05:34.000 --> 00:05:36.600 It leaves behind a physical hole, basically. 108 00:05:36.240 --> 00:05:39.279 Exactly a vacancy in the lattice. It creates what's known 109 00:05:39.319 --> 00:05:40.519 as a frinkal defect. 110 00:05:40.600 --> 00:05:44.160 Yeah, so okay. An electromagnetic wave is an energy fluctuation 111 00:05:44.240 --> 00:05:47.959 that causes electrical chaos and logic errors, while a neutron 112 00:05:48.120 --> 00:05:52.639 is a mass bearing projectile causing permanent physical structural degradation 113 00:05:52.680 --> 00:05:53.759 of the hardware itself. 114 00:05:53.959 --> 00:05:57.079 And this duality is the core engineering nightmare. 115 00:05:56.680 --> 00:05:59.319 Right because to block the electrical chaos, you need highly 116 00:05:59.360 --> 00:06:02.839 conductive matierials, but to block the physical wrecking ball of 117 00:06:02.839 --> 00:06:04.759 the neutron, you need something entirely different. 118 00:06:05.040 --> 00:06:09.720 You need materials rich in low atomic number elements like hydrogen, 119 00:06:09.759 --> 00:06:13.639 dense polymers, or very specialized isotopes that can actually capture 120 00:06:13.639 --> 00:06:14.120 the particle. 121 00:06:14.160 --> 00:06:16.519 So historically, if you want to stop both, you're stuck 122 00:06:16.560 --> 00:06:20.480 trying to bond these disparate materials together, which creates these rigid, bulky, 123 00:06:20.800 --> 00:06:22.519 incredibly heavy composite. 124 00:06:22.160 --> 00:06:25.879 Panels which are prone to delamination under the extreme thermal 125 00:06:25.920 --> 00:06:28.680 cycling of space. By the way, and going back to 126 00:06:28.720 --> 00:06:32.160 our first point, they consume an enormous amount of your mass. 127 00:06:31.879 --> 00:06:35.439 Budget, which brings us back to kiss because this forces 128 00:06:35.480 --> 00:06:38.800 the researchers there to just abandon the macroscopic approach altogether. 129 00:06:39.360 --> 00:06:42.399 If you can't stack distinct layers of heavy materials you 130 00:06:42.439 --> 00:06:44.720 have to find a way to engineer a single material 131 00:06:45.040 --> 00:06:48.839 that possesses both conductivity for the em waves and absorption 132 00:06:48.920 --> 00:06:50.319 capabilities for the neutrons. 133 00:06:50.399 --> 00:06:55.160 And they found that synergy using two very specific nanoscale structures, 134 00:06:55.439 --> 00:07:01.160 carbon nanotubes or CNTs and boron nitride nanotubes BNNTs. 135 00:07:01.399 --> 00:07:03.959 Okay, So, a nanotube, for those trying to picture this 136 00:07:04.360 --> 00:07:07.720 is essentially a single atom thick sheet of material that's 137 00:07:07.720 --> 00:07:09.959 been rolled into a seamless cylinder. Right. 138 00:07:10.000 --> 00:07:13.199 And because they are governed by quantum mechanical properties rather 139 00:07:13.240 --> 00:07:17.680 than you know, classical bulk physics, their characteristics are vastly amplified. 140 00:07:17.720 --> 00:07:19.279 So let's talk about the carbon ones. First. 141 00:07:19.439 --> 00:07:23.160 Carbon nanotubes are renowned for their electron mobility. The electrons 142 00:07:23.160 --> 00:07:25.480 can travel along the tube almost without scattering it all, 143 00:07:25.560 --> 00:07:28.079 making them incredibly conductive, which. 144 00:07:27.879 --> 00:07:31.720 Totally solves the electromagnetic problem. The CNTs basically form this 145 00:07:31.959 --> 00:07:36.439 highly conductive network, creating a nanoscale Faraday cage exactly. So 146 00:07:36.439 --> 00:07:39.360 when an EM wave hits this network, the energy is 147 00:07:39.399 --> 00:07:43.199 coupled into those conductive paths. It's absorbed and then safely 148 00:07:43.240 --> 00:07:46.639 dissipated as just a negligible amount of heat rather than 149 00:07:46.680 --> 00:07:48.959 passing through to the sense of electronics behind it. 150 00:07:49.040 --> 00:07:52.560 So the conductivity handles the wave, but to handle the 151 00:07:52.600 --> 00:07:56.000 neutron we turn to the boron nitride nanotubes. 152 00:07:56.160 --> 00:07:57.399 The bnnt's right. 153 00:07:57.720 --> 00:08:01.639 Structurally, a BNNT looks very similar to a carbon nanotube. 154 00:08:01.639 --> 00:08:04.720 It's that same cylinder shape, but instead of carbon, the 155 00:08:04.759 --> 00:08:08.600 cylinder is composed of alternating boron and nitrogen atoms. 156 00:08:09.040 --> 00:08:12.000 And the really critical component here is the boron right, 157 00:08:12.199 --> 00:08:14.000 specifically the isotope boron ten. 158 00:08:14.199 --> 00:08:17.319 Yes, boron ten is special because it has an unusually 159 00:08:17.399 --> 00:08:19.319 high cross section for thermal neutrons. 160 00:08:19.319 --> 00:08:21.439 Okay, let's unpack cross section for a second, because it's 161 00:08:21.439 --> 00:08:24.079 such a vital concept in nuclear physics and it can 162 00:08:24.079 --> 00:08:26.600 be a little counterintuitive. It isn't a physical measurement of 163 00:08:26.639 --> 00:08:27.279 the atom. 164 00:08:27.079 --> 00:08:29.439 Size, right, No, it's not physical size at all. It 165 00:08:29.480 --> 00:08:32.799 is a measurement of probability, like shooting a basketball exactly 166 00:08:32.840 --> 00:08:35.799 if you don't eedgine shooting a basketball. The nucleus is 167 00:08:35.840 --> 00:08:40.200 the hoop. Most elements have incredibly tiny hoops. A neutron 168 00:08:40.200 --> 00:08:42.879 will just sail right past them without interacting. 169 00:08:42.440 --> 00:08:44.440 But boron ten has a massive hoop. 170 00:08:44.440 --> 00:08:48.279 A massively disproportionate hoop. Yeah, the probability of it actually 171 00:08:48.360 --> 00:08:51.799 capturing a passing neutron is thousands of times higher than 172 00:08:51.799 --> 00:08:52.639 most other elements. 173 00:08:52.679 --> 00:08:54.039 And what happens when it captures it. 174 00:08:54.200 --> 00:08:57.919 When that boron ten nucleus captures the neutron, it undergoes 175 00:08:57.960 --> 00:09:01.000 a nuclear reaction. It absorbs the kinetic energy of the 176 00:09:01.000 --> 00:09:04.840 neutron and transmutates. It actually decays into a stable lithium 177 00:09:04.879 --> 00:09:06.440 ion and an alpha particle. 178 00:09:06.600 --> 00:09:09.799 Wow, so the thread is completely neutralized at the subatomic 179 00:09:09.879 --> 00:09:13.399 level exactly. The theoretical physics of these two materials together 180 00:09:13.519 --> 00:09:15.639 is just beautiful. I mean, you have the CNTs for 181 00:09:15.759 --> 00:09:19.679 conductivity and the BNNTs for neutron capture. Yeah, but here 182 00:09:19.759 --> 00:09:23.000 is the major hurdle in material science, right, Yeah. You 183 00:09:23.000 --> 00:09:27.879 cannot just dump carbon nanotubes and boron nitride nanotubes into 184 00:09:27.919 --> 00:09:31.399 a vat, stir them up and expect them to work together. No. 185 00:09:31.559 --> 00:09:35.080 Absolutely not. At the nanoscale, these materials are incredibly cohesive. 186 00:09:35.120 --> 00:09:37.759 They desperately want to clump together. They iglomerate r they 187 00:09:37.759 --> 00:09:42.639 agglomerate into these totally useless bundles because of Vanderol's forces. 188 00:09:42.200 --> 00:09:46.360 And overcoming that agglomeration is where the Kiss team achieved 189 00:09:46.399 --> 00:09:50.240 something really remarkable. They didn't just mix the two materials together. 190 00:09:51.120 --> 00:09:56.360 They engineered a core shell structure at the individual nanoparticle level. 191 00:09:56.440 --> 00:10:00.600 Yeah, this part is brilliant. Through highly controlled chemical processing, 192 00:10:00.840 --> 00:10:05.039 they managed to sheathe the boron nitride nanotubes within a 193 00:10:05.120 --> 00:10:06.799 layer of carbon nanotubes. 194 00:10:06.879 --> 00:10:10.440 So it's essentially a microscopic coaxial cable. That is the. 195 00:10:10.440 --> 00:10:14.000 Perfect mechanistic analogy. In a coaxial cable, you have an 196 00:10:14.000 --> 00:10:16.879 inner conductor surrounded by an outer shielding. 197 00:10:16.600 --> 00:10:18.480 Layer like the TV cables we used to have. 198 00:10:18.679 --> 00:10:22.799 Exactly here, the outer sheath is the highly conductive carbon 199 00:10:22.879 --> 00:10:27.200 nanotube network and the innercore is the neutron absorbing boron nitride. 200 00:10:27.240 --> 00:10:31.600 So the carbon exterior immediately engages and attenuates the electromagnetic waves, 201 00:10:31.879 --> 00:10:34.919 while that boron core sits inside protected, just waiting to 202 00:10:34.960 --> 00:10:37.639 capture any neutrons that happened to penetrate the outer lattice. 203 00:10:37.679 --> 00:10:40.759 They integrated a dual threat defense mechanism into a single 204 00:10:40.879 --> 00:10:42.679 cohesive architectural unit. 205 00:10:42.879 --> 00:10:43.879 It's so elegant. 206 00:10:44.320 --> 00:10:47.759 But even with this coaxial nanoparticle, you are still dealing 207 00:10:47.799 --> 00:10:52.240 with a fine powder basically, and you cannot coat an 208 00:10:52.240 --> 00:10:55.679 avionics bay or like a lunar habitat with powder. 209 00:10:55.799 --> 00:10:58.240 No, you definitely can't. It has to be suspended in 210 00:10:58.240 --> 00:11:00.799 the matrix, and that matre has to be able to 211 00:11:00.840 --> 00:11:04.720 survive the sheer mechanical violence of a rocket launch plus 212 00:11:04.799 --> 00:11:06.799 the extreme temperature swings of orbit. 213 00:11:07.039 --> 00:11:10.039 The vibrations alone would shake a powder right off exactly. 214 00:11:10.360 --> 00:11:12.720 So the matrix they chose is a polymer known as 215 00:11:12.759 --> 00:11:17.399 PDMS polydimethyl siloxine okay. It is a silicon based organic 216 00:11:17.440 --> 00:11:20.759 polymer that gets heavily utilized in advanced engineering because of 217 00:11:20.799 --> 00:11:24.799 its siloxane backbone. Basically, it's made of alternating silicon and 218 00:11:24.840 --> 00:11:25.799 oxygen atoms. 219 00:11:26.159 --> 00:11:28.600 And what does that specific chemical structure do. 220 00:11:28.799 --> 00:11:32.519 It gives PDMS an incredibly low glass transition temperature, which 221 00:11:32.559 --> 00:11:36.679 means it remains remarkably flexible and elastic even in cryogenic conditions, 222 00:11:36.879 --> 00:11:40.559 which leads to the really astonishing physical specifications of the 223 00:11:40.559 --> 00:11:44.200 final composite. Because the Kiss team took their core shell 224 00:11:44.320 --> 00:11:48.639 nanotubes and embedded them into this PDMS matrix, and the 225 00:11:48.720 --> 00:11:51.679 resulting material is thinner than a human hair, yet it 226 00:11:51.679 --> 00:11:55.320 can strutch to more than twice its original length without tearing, but. 227 00:11:55.440 --> 00:11:58.919 More Importantly, it stretches without breaking the conductive network of 228 00:11:58.919 --> 00:12:00.080 the nanotubes inside it. 229 00:12:00.320 --> 00:12:02.840 Wait, how does it do that? Usually if you stretch 230 00:12:02.879 --> 00:12:05.320 something conductive, it breaks the connection, right. 231 00:12:05.159 --> 00:12:09.000 That's the percolation threshold at work in most conductive elastomers. 232 00:12:09.039 --> 00:12:12.320 If you stretch the material, the conductive particles get pulled apart, 233 00:12:12.360 --> 00:12:16.399 the resistance spikes, and your electromagnetic shielding just completely fails. 234 00:12:16.679 --> 00:12:17.879 But the nanotubes are different. 235 00:12:17.960 --> 00:12:22.440 They are because nanotubes have extremely high aspect ratios, meaning 236 00:12:22.600 --> 00:12:25.320 they are very very long compared to their width, so 237 00:12:25.360 --> 00:12:28.960 they can actually slide and telescope past one another within 238 00:12:29.039 --> 00:12:30.799 the polymer matrix as it stretches. 239 00:12:30.919 --> 00:12:35.519 Oh wow, so they maintain continuous electrical pathways even while 240 00:12:35.600 --> 00:12:36.919 the material is being pulled. 241 00:12:36.679 --> 00:12:41.519 Apart exactly, which means the shielding remains totally viable even 242 00:12:41.600 --> 00:12:44.080 when subjected to severe mechanical deformation. 243 00:12:44.320 --> 00:12:47.120 That is incredible, and we should really look closely at 244 00:12:47.159 --> 00:12:49.639 the performance metrics they achieved with this, because the numbers 245 00:12:49.679 --> 00:12:54.000 are staggering. The material successfully blocks ninety nine point nine 246 00:12:54.120 --> 00:12:56.799 nine nine percent of electromagnetic waves. 247 00:12:57.000 --> 00:12:59.919 Yeah, in signal processing terms, that is an attenuation of 248 00:13:00.080 --> 00:13:03.480 roughly fifty decibels. For a material thinner than a hair, 249 00:13:03.840 --> 00:13:06.480 reducing the transmitted wave energy by a factor of one 250 00:13:06.559 --> 00:13:09.279 hundred thousand is practically total isolation. 251 00:13:09.720 --> 00:13:12.559 It just completely eliminates the threat of induced currents in 252 00:13:12.559 --> 00:13:16.240 the underlying circuitry. It does so the electromagnetic attenuation is 253 00:13:16.320 --> 00:13:20.600 virtually perfect. However, looking at the data on the neutron shielding, 254 00:13:21.039 --> 00:13:23.799 it shows a reduction of seventy two percent. And I 255 00:13:23.799 --> 00:13:25.480 want to focus on this for a second, because if 256 00:13:25.519 --> 00:13:27.759 I am an engineer and I'm designing a redundant life 257 00:13:27.759 --> 00:13:31.200 support system for a deep space habitat, a seventy two 258 00:13:31.240 --> 00:13:34.399 percent reduction implies that over a quarter of the neutron 259 00:13:34.519 --> 00:13:37.320 radiation is still impacting my hardware. That's true. So in 260 00:13:37.360 --> 00:13:40.399 a highly radioactive environment, isn't allowing twenty eight percent of 261 00:13:40.399 --> 00:13:43.480 the threat through considered a pretty catastrophic vulnerability. 262 00:13:43.679 --> 00:13:45.679 Well, you have to look at how it's being used. 263 00:13:46.080 --> 00:13:49.039 If you are evaluating a primary structural shield like the 264 00:13:49.080 --> 00:13:52.600 outer hull of a nuclear reactor, then yes, seventy two 265 00:13:52.679 --> 00:13:55.879 percent is completely insufficient. But we have to look at 266 00:13:55.879 --> 00:14:00.919 the mass attenuation coefficient. Traditional high density poly ethylene shielding 267 00:14:01.000 --> 00:14:05.240 requires several centimeters of thickness and significant mass to achieve 268 00:14:05.240 --> 00:14:09.600 a similar reduction, Kist achieved seventy two percent attenuation with 269 00:14:09.639 --> 00:14:12.240 a layer measured in micrometers. 270 00:14:11.720 --> 00:14:13.159 So it weighs practically nothing. 271 00:14:13.399 --> 00:14:15.200 Its mass is practically negligible. 272 00:14:15.320 --> 00:14:18.279 Okay, So the context is really the application. You wouldn't 273 00:14:18.360 --> 00:14:21.200 use this as the primary outer bulkhead of the space 274 00:14:21.240 --> 00:14:22.000 craft exactly. 275 00:14:22.039 --> 00:14:24.519 You use it as a conformal coating because it is 276 00:14:24.559 --> 00:14:27.639 so incredibly light and flexible. You can apply it directly 277 00:14:27.639 --> 00:14:30.960 to the semiconductor packaging itself, or you wrap it tightly 278 00:14:30.960 --> 00:14:34.240 around the internal wiring iarnesses. Ah. It serves as this 279 00:14:34.480 --> 00:14:38.639 highly efficient localized defense layer that stacks with the broader 280 00:14:38.679 --> 00:14:42.000 structural shielding of the spacecraft. So it allows the engineers 281 00:14:42.000 --> 00:14:44.759 to drastically thin out those heavy outer bulkheads. 282 00:14:44.799 --> 00:14:48.399 You are buying an immense amount of localized protection without 283 00:14:48.440 --> 00:14:52.000 paying the mass of payload penalty precisely. And it does 284 00:14:52.039 --> 00:14:54.960 all of this while remaining thermally stable from what minus 285 00:14:54.960 --> 00:14:57.159 one hundred and ninety six degrees celsius. 286 00:14:56.799 --> 00:14:59.120 Yeah, the temperature of liquid nitrogen all the. 287 00:14:59.080 --> 00:15:01.519 Way up to two hundred fifty degree celsius. Yeah. So 288 00:15:01.559 --> 00:15:05.080 the chemistry of that PDMS polymer matrix is really doing 289 00:15:05.120 --> 00:15:07.960 a lot of heavy lifting to keep those nanotubes functional 290 00:15:08.000 --> 00:15:08.960 in those extremes. 291 00:15:09.080 --> 00:15:12.840 It is, but chemistry alone doesn't solve the integration problem. 292 00:15:13.200 --> 00:15:16.039 You have to be able to manufacture this material into 293 00:15:16.080 --> 00:15:18.639 precise geometries that fit complex. 294 00:15:18.200 --> 00:15:21.080 Hardware, right, because wrapping a wire is one thing, but 295 00:15:21.200 --> 00:15:23.279 coding an intricate sensor array is another. 296 00:15:23.440 --> 00:15:26.559 Exactly, and the transition from a bulk material to a 297 00:15:26.639 --> 00:15:31.960 targeted application relies entirely on the manufacturing methodology. The Kissed 298 00:15:31.960 --> 00:15:35.639 researchers didn't just cast this material into flat sheets. They 299 00:15:35.679 --> 00:15:40.120 actually developed an ink formulation using the nanotube PDMS composite 300 00:15:40.240 --> 00:15:43.559 an ink, yes, and they deployed it using direct ink 301 00:15:43.600 --> 00:15:44.960 writing or DIIW. 302 00:15:45.120 --> 00:15:48.279 Okay, So DIIW is essentially a highly sophisticated form. 303 00:15:48.159 --> 00:15:50.519 Of three D printing, right it is, But it relies 304 00:15:50.519 --> 00:15:53.639 on the precise reeology of the ink. The material has 305 00:15:53.679 --> 00:15:54.559 to be sheer thinning. 306 00:15:54.639 --> 00:15:56.960 Okay, sheer thinning like how ketchup is thick until you 307 00:15:56.960 --> 00:15:57.639 shake the bottle. 308 00:15:57.840 --> 00:16:01.240 That is actually the perfect example. The fluid dynamics are fascinating. 309 00:16:01.559 --> 00:16:03.919 When the composite ink is at rest in the syringe, 310 00:16:04.000 --> 00:16:07.440 it is highly viscous. It acts almost like a solid. 311 00:16:07.360 --> 00:16:10.159 But the moment mechanical pressure is applied to force it 312 00:16:10.240 --> 00:16:12.720 through the microscopic nozzle of the three D printer. 313 00:16:12.960 --> 00:16:16.120 The sheer forces align the polymer chains and the nanotubes, 314 00:16:16.559 --> 00:16:20.519 dropping the viscosity dramatically. It flows smoothly right out of 315 00:16:20.519 --> 00:16:21.360 the nozzle. 316 00:16:21.080 --> 00:16:23.000 But then the second it leaves the nozzle and the 317 00:16:23.039 --> 00:16:27.039 sheer stress is removed, the viscosity instantly recovers. 318 00:16:26.679 --> 00:16:29.759 Right It locks its shape in three dimensional space without 319 00:16:29.799 --> 00:16:31.600 slumping or spreading at all. 320 00:16:31.679 --> 00:16:35.440 And this specific regiological behavior is what allowed the researchers 321 00:16:35.480 --> 00:16:39.399 to print the material into a highly specific architectural geometry, 322 00:16:39.919 --> 00:16:42.519 namely a honeycomb lattice. 323 00:16:42.200 --> 00:16:45.080 Which is where things get really interesting, because they discovered 324 00:16:45.120 --> 00:16:49.000 that engineering the material into a hexagonal honeycomb structure yielded 325 00:16:49.080 --> 00:16:52.639 up to fifteen percent better shielding performance against both em 326 00:16:52.679 --> 00:16:56.200 waves and neutrons compared to a solid flat sheet of 327 00:16:56.240 --> 00:16:57.639 the exact same thickness. 328 00:16:58.039 --> 00:17:01.720 That is wild, a structure that consists largely of empty 329 00:17:01.720 --> 00:17:06.359 space is actually superior at blocking radiation than a solid 330 00:17:06.400 --> 00:17:07.720 wall of dense material. 331 00:17:07.880 --> 00:17:11.440 It's because the geometry is actively doing the work. It 332 00:17:11.480 --> 00:17:15.079 operates on the same physical principles. As an anacoic chamber 333 00:17:15.240 --> 00:17:18.119 the kind they use in acoustic or radio frequency testing, 334 00:17:18.240 --> 00:17:18.640 oh like. 335 00:17:18.559 --> 00:17:20.480 Those rooms with the foam spikes all over. 336 00:17:20.319 --> 00:17:24.759 The walls, Exactly, an anacoic chamber is lined with geometric wedges. 337 00:17:25.160 --> 00:17:28.440 When a wave hits those wedges, instead of bouncing straight 338 00:17:28.440 --> 00:17:31.240 back or pushing straight through, it is forced into a 339 00:17:31.279 --> 00:17:35.200 series of multiple internal reflections. It bounces back and forth 340 00:17:35.200 --> 00:17:36.720 between the walls of the wedge. 341 00:17:37.039 --> 00:17:39.599 So every single time the wave impacts the surface of 342 00:17:39.640 --> 00:17:42.440 the honeycomb cell in this material, a fraction of its 343 00:17:42.519 --> 00:17:46.079 energy is absorbed by the carbon nanotubes and dissipated as heat. 344 00:17:46.400 --> 00:17:50.079 Right by forcing the wave to navigate a three dimensional maze, 345 00:17:50.279 --> 00:17:54.119 you artificially elongate its path length through the lossy material. 346 00:17:54.279 --> 00:17:57.000 You literally drain its energy through geometric impedance. 347 00:17:57.319 --> 00:18:00.799 And that geometric advantage applies to the neutron radio as well. 348 00:18:01.599 --> 00:18:05.720 Fast neutrons entering the honeycomb structure are forced into scattering events. 349 00:18:06.200 --> 00:18:08.519 As they bounce off the walls of the hexagonal lattice, 350 00:18:08.880 --> 00:18:12.160 they lose kinetic energy through moderations. 351 00:18:11.400 --> 00:18:12.799 They slow down, they slow. 352 00:18:12.640 --> 00:18:15.680 Down, and as they enter the thermal energy regime, that's 353 00:18:15.720 --> 00:18:19.559 where the Boron ten cross section is the most effective because. 354 00:18:19.279 --> 00:18:23.880 It drastically increases the probability of capture. The geometry serves 355 00:18:23.920 --> 00:18:27.160 as a mechanism to slow the threat down so the 356 00:18:27.240 --> 00:18:29.359 chemistry can actually neutralize it. 357 00:18:29.359 --> 00:18:34.079 It is a brilliant synergy of material science and mechanical engineering. 358 00:18:33.680 --> 00:18:36.680 It really is. And because it relies on direct ink writing, 359 00:18:37.279 --> 00:18:41.400 the shielding is entirely bespoke. I mean, an aerospace engineer 360 00:18:41.400 --> 00:18:44.200 doesn't have to design their avionics around flat panels of 361 00:18:44.200 --> 00:18:44.960 shielding anymore. 362 00:18:45.039 --> 00:18:47.119 No, not at all. If they have a highly irregular 363 00:18:47.200 --> 00:18:50.279 optical sensor array, they can just three D print a 364 00:18:50.400 --> 00:18:55.000 customized conformal honeycomb structure that perfectly encapsulates the device. 365 00:18:55.119 --> 00:18:57.319 And they could even modify the density of the honeycumb 366 00:18:57.359 --> 00:19:00.759 cells based on the specific radiation vectors that dive will encounter. 367 00:19:01.119 --> 00:19:04.480 The optimization of mass and geometry is total. It's a 368 00:19:04.559 --> 00:19:08.079 complete game changer. But you know, the implications of this 369 00:19:08.319 --> 00:19:13.480 core shell nanotube architecture extend far beyond translunar injection trajectories 370 00:19:13.519 --> 00:19:14.640 and orbital habitats. 371 00:19:14.720 --> 00:19:17.880 Oh absolutely, because the extreme environments we are trying to 372 00:19:17.920 --> 00:19:20.000 master are increasingly terrestrial. 373 00:19:20.119 --> 00:19:23.519 Yeah, Doctor Joe Junghoe of Kissed, who led the research team, 374 00:19:24.000 --> 00:19:27.319 explicitly outlined the terrestrial roadmap for this right. 375 00:19:27.640 --> 00:19:31.160 He categorized this development as a fundamentally new concept in 376 00:19:31.200 --> 00:19:36.240 shielding technology, one that sure establishes critical domestic production infrastructure 377 00:19:36.240 --> 00:19:40.920 for the space age, but also immediately translates to the semiconductor, nuclear, 378 00:19:40.960 --> 00:19:42.640 and medical sectors right here on Earth. 379 00:19:42.839 --> 00:19:46.559 The semiconductor manufacturing industry is perhaps the most immediate beneficiary 380 00:19:46.640 --> 00:19:49.440 of this. The fabrication plants that produce the three and 381 00:19:49.440 --> 00:19:53.880 animator chips we rely on are incredibly noisy electromagnetic environments, right. 382 00:19:53.759 --> 00:19:57.880 Because extreme ultraviolet lithography machines require immense amounts of power, 383 00:19:58.359 --> 00:20:00.880 and they generate massive electric magnetic fields. 384 00:20:01.240 --> 00:20:05.720 And shielding the metrology equipment and the laser alignment sensors 385 00:20:05.720 --> 00:20:11.559 from this interference currently requires massive rigid isolation chambers inside the. 386 00:20:11.519 --> 00:20:13.279 Clean rooms, which take up so much space. 387 00:20:13.480 --> 00:20:17.960 Exactly. A flexible three D printable shield allows for much 388 00:20:18.000 --> 00:20:22.039 tighter integration and significantly smaller clean room footprints. 389 00:20:22.319 --> 00:20:25.839 And the economic implications there are just massive, especially considering 390 00:20:25.880 --> 00:20:30.240 the billions of dollars required to build a single modern fat. 391 00:20:30.039 --> 00:20:31.319 It's a huge cost saver. 392 00:20:31.400 --> 00:20:33.359 But you know, I look at the medical applications and 393 00:20:33.400 --> 00:20:36.799 I see a much more vitual human impact. Like an 394 00:20:37.319 --> 00:20:41.359 interventional radiology or fluoroscopy. Medical professionals are working in close 395 00:20:41.359 --> 00:20:44.880 proximity to actively emitting X ray and radiation sources for 396 00:20:45.000 --> 00:20:45.839 hours at a time. 397 00:20:46.039 --> 00:20:49.240 Yeah, the current standard of care for occupational safety in 398 00:20:49.279 --> 00:20:50.799 those environments relies. 399 00:20:50.440 --> 00:20:52.079 On lead a prints right, the heavy vests. 400 00:20:52.319 --> 00:20:55.079 Lead is highly effective at stopping ionizing radiation because of 401 00:20:55.079 --> 00:20:57.519