WEBVTT 1 00:00:03.399 --> 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 00:00:27.000 --> 00:00:29.920 If you've ever pictured what a truly sustainable energy future 8 00:00:30.000 --> 00:00:34.079 might look like, chances are space based solar power or 9 00:00:34.159 --> 00:00:36.240 SBSP was part of that picture. 10 00:00:36.320 --> 00:00:39.679 Oh absolutely, It's this ultimate high tech vision, isn't it. 11 00:00:39.679 --> 00:00:43.320 These gigantic solar arrays up in orbit, way above the clouds, 12 00:00:43.640 --> 00:00:46.159 soaking up sunshine twenty four seven. 13 00:00:45.920 --> 00:00:49.960 Unlimited sunshine, no night, no clouds, just pure energy beamed 14 00:00:50.000 --> 00:00:50.799 back down to Earth. 15 00:00:50.880 --> 00:00:53.200 It really is seen as a kind of holy grail 16 00:00:53.359 --> 00:00:56.159 for clean energy. I mean, think about it. Solar power 17 00:00:56.200 --> 00:00:58.960 down here on the ground is always dealing with nighttime, 18 00:00:59.079 --> 00:01:03.880 bad weather, the atmosphere, scattering light. It all cuts down efficiency. 19 00:01:04.439 --> 00:01:08.840 But a satellite parked in geostationary orbit GEO that's bathed 20 00:01:08.879 --> 00:01:12.519 in intense sunlight constantly, it could provide reliable base load 21 00:01:12.560 --> 00:01:13.400 power day. 22 00:01:13.239 --> 00:01:15.760 In day out, and you know, this isn't just science 23 00:01:15.799 --> 00:01:18.920 fiction anymore. It's moving towards reality pretty fast. We've seen 24 00:01:18.959 --> 00:01:21.680 some big steps lately, definitely like the Celtics based Solar 25 00:01:21.760 --> 00:01:26.040 Power Project, the SSPP demo that really showed it's possible 26 00:01:26.120 --> 00:01:30.079 fundamentally to send usable power wirelessly from orbit down to 27 00:01:30.120 --> 00:01:31.159 a receiver on the ground. 28 00:01:31.439 --> 00:01:34.280 That was a huge proof of concept. And it's not 29 00:01:34.439 --> 00:01:38.480 just Caltech. There are pilot projects bubbling up elsewhere too, China, 30 00:01:38.640 --> 00:01:42.239 the UK, Japan, They're all looking seriously at this. 31 00:01:42.439 --> 00:01:44.560 So the whole conversation has shifted, hasn't. 32 00:01:44.280 --> 00:01:47.480 It Exactly the basic physics they work. The question isn't 33 00:01:47.480 --> 00:01:50.239 really if we can do it anymore. It's more like, okay, 34 00:01:50.280 --> 00:01:54.159 how much power can we actually realistically deliver, you know, 35 00:01:54.200 --> 00:01:56.840 considering the costs, the logistics, which brings. 36 00:01:56.680 --> 00:01:59.359 Us perfectly to the analysis we're looking at today. We're 37 00:01:59.359 --> 00:02:02.120 diving into this really interesting new paper it's in acta 38 00:02:02.200 --> 00:02:06.519 astronautica by some Italian and German researchers, right, and. 39 00:02:06.439 --> 00:02:09.759 They set out to do something specific, calculate the absolute 40 00:02:09.960 --> 00:02:13.159 maximum potential power you could get from a whole constellation 41 00:02:13.280 --> 00:02:17.199 of these SBSP satellites up in geo designed purely for energy. 42 00:02:17.360 --> 00:02:19.960 And what's fascinating, what really caught my eye is how 43 00:02:19.960 --> 00:02:22.639 their findings kind of flipped the script on what we 44 00:02:22.680 --> 00:02:23.960 thought the main problems would be. 45 00:02:24.080 --> 00:02:26.120 Yeah, that's the core of it. For decades, I think 46 00:02:26.199 --> 00:02:29.599 most people, even engineers, assumed the big hurdles would be, 47 00:02:29.840 --> 00:02:32.159 you know, up their technical stuff. 48 00:02:32.000 --> 00:02:35.000 Like dodging space junk, or just the challenge of building 49 00:02:35.080 --> 00:02:37.439 these enormous structures in zero G. 50 00:02:37.639 --> 00:02:41.080 Or the efficiency of the power beaming itself getting microwaves 51 00:02:41.080 --> 00:02:43.439 through the atmosphere without losing too much. 52 00:02:43.520 --> 00:02:46.199 Okay, so let's unpack this study because it challenges all that. 53 00:02:46.800 --> 00:02:51.000 The researchers basically argue the biggest roadblocks aren't technical or 54 00:02:51.039 --> 00:02:56.560 even orbital. No, they're down here logistical, geographical, ground based problems. 55 00:02:57.120 --> 00:03:00.199 They actually call it the grounding reality of space power. 56 00:03:00.319 --> 00:03:02.919 That's the crux of it. Yeah. They modeled the whole 57 00:03:02.919 --> 00:03:06.240 thing systematically, looking at four different scenarios. They started with 58 00:03:06.360 --> 00:03:09.639 just pure space, very theoretical, and then layered in more 59 00:03:09.680 --> 00:03:11.240 and more real world limits. 60 00:03:11.360 --> 00:03:14.039 So our plan here is to follow their steps, go 61 00:03:14.080 --> 00:03:17.479 through these scenarios one by one and really understand why 62 00:03:17.680 --> 00:03:20.319 the ceiling for space solar power seems to be set 63 00:03:20.360 --> 00:03:24.000 by things like land use and electrical grids, not rocket 64 00:03:24.039 --> 00:03:25.000 science exactly. 65 00:03:25.360 --> 00:03:27.919 It turns out the real bottleneck forces us to look 66 00:03:27.960 --> 00:03:29.719 down at the Earth, not up at the stars. 67 00:03:29.800 --> 00:03:32.120 Okay, let's start at the beginning. Then, how do they 68 00:03:32.120 --> 00:03:33.159 set up this calculation? 69 00:03:33.360 --> 00:03:37.800 The methodology, so the goal was precise, they weren't after 70 00:03:37.879 --> 00:03:42.199 a vague guess. They wanted the maximum possible power delivered 71 00:03:42.240 --> 00:03:46.599 by a fleet of SBSP satellites in geostationary orbit and. 72 00:03:46.639 --> 00:03:49.360 GEO Just a quick reminder for you listening, that's the 73 00:03:49.439 --> 00:03:53.879 orbit about thirty six thousand kilometers up. Satellites there orbit 74 00:03:53.919 --> 00:03:55.400 of the same speed the Earth. 75 00:03:55.199 --> 00:03:58.960 Turns, meaning they appear fixed over one spot on the ground, 76 00:03:59.319 --> 00:04:02.400 which is if you want to beam power down continuously 77 00:04:02.479 --> 00:04:03.360 to the same receiver. 78 00:04:03.520 --> 00:04:04.000 Makes sense. 79 00:04:04.360 --> 00:04:07.199 So their whole calculation really boiled down to two main questions, 80 00:04:07.199 --> 00:04:10.039 which kind of gives us a roadmap. First, how many 81 00:04:10.080 --> 00:04:13.360 satellites can you physically fit into that GEO ring given 82 00:04:13.400 --> 00:04:14.479 the rules of the road up. 83 00:04:14.360 --> 00:04:16.079 There, okay, the physical space available. 84 00:04:16.399 --> 00:04:19.040 And second, for each of those satellites, how much power 85 00:04:19.040 --> 00:04:21.000 can actually make it down and get fed into our 86 00:04:21.040 --> 00:04:24.360 existing electrical grids? Considering all the losses along the way. 87 00:04:24.480 --> 00:04:27.120 Right, So, starting with that first question, how many satellites fit, 88 00:04:27.279 --> 00:04:29.240 they needed some kind of rule for spacing them. 89 00:04:29.120 --> 00:04:33.639 Out exactly, and they applied one single consistent constraint across 90 00:04:33.680 --> 00:04:37.480 all their orbital scenarios, the minimum distance angle or MDA. 91 00:04:37.680 --> 00:04:39.279 MDA minimum distance angle. 92 00:04:39.480 --> 00:04:42.959 Yeah, it's the smallest angular gap you need between any 93 00:04:43.040 --> 00:04:46.439 two satellites in GEO. It's there for two main reasons. 94 00:04:46.560 --> 00:04:50.360 One is obvious to stop them physically crashing into each other. 95 00:04:50.439 --> 00:04:51.519 Definitely want to avoid that. 96 00:04:51.800 --> 00:04:54.399 But maybe even more critical for these high power systems, 97 00:04:54.399 --> 00:04:58.319 it's about preventing radio frequency interference. You can't have these 98 00:04:58.519 --> 00:05:02.759 massive microway power beams crossing or messing with each other 99 00:05:03.319 --> 00:05:06.079 or with existing communication satellite signal. 100 00:05:06.199 --> 00:05:08.920 Ah okay, so it's not just about collisions, is about 101 00:05:08.959 --> 00:05:11.720 signal integrity too. What angle did they actually use? 102 00:05:11.959 --> 00:05:16.519 They use point one degrees, which you know sounds incredibly small, KINI, 103 00:05:16.639 --> 00:05:18.839 But when you're talking about the scale of GEO thirty 104 00:05:18.839 --> 00:05:21.720 six thousand kilometers out, that translates into a huge amount 105 00:05:21.720 --> 00:05:22.639 of physical distance. 106 00:05:22.680 --> 00:05:24.079 How much space are we talking about? 107 00:05:24.199 --> 00:05:26.800 Well, they noted point one degrees is actually pretty conservative. 108 00:05:26.800 --> 00:05:29.959 It gives a decent buffer at that altitude. Point one 109 00:05:30.000 --> 00:05:32.920 degrees gives each satellite what they call an aperture range, 110 00:05:33.199 --> 00:05:35.920 basically a guaranteed clear zone of one hundred and forty 111 00:05:35.959 --> 00:05:36.959 seven kilometers. 112 00:05:37.000 --> 00:05:40.120 Wow, one hundred and forty seven kilometers for each satellite. 113 00:05:40.480 --> 00:05:43.319 That's enormous. Yeah, how big are these post satellites meant 114 00:05:43.360 --> 00:05:43.519 to be? 115 00:05:43.800 --> 00:05:46.639 Current designs are often talking maybe what two to five 116 00:05:46.720 --> 00:05:49.879 kilometers across for the solar rays somewhere in that ballpark. 117 00:05:50.319 --> 00:05:53.839 So the required clear space is like thirty times bigger 118 00:05:53.879 --> 00:05:54.920 than the satellite itself. 119 00:05:54.959 --> 00:05:57.519 Easily. That one hundred and forty seven kilometers accounts for 120 00:05:57.600 --> 00:06:00.560 all sorts of things, potential drifting of the beam, small 121 00:06:00.680 --> 00:06:04.480 navigation errors, making sure heat plumes don't interfere, room to 122 00:06:04.519 --> 00:06:08.079 maneuver if needed. It's all about safe operations based on 123 00:06:08.160 --> 00:06:10.399 let's say, cautious regulations. 124 00:06:10.480 --> 00:06:13.920 Okay, so this MDA, this point one degree rule, giving 125 00:06:14.040 --> 00:06:16.959 one hundred and forty seven kilometers of space, that's a 126 00:06:17.000 --> 00:06:20.120 fundamental starting point for figuring out how many could theoretically 127 00:06:20.120 --> 00:06:20.759 fit up there. 128 00:06:21.160 --> 00:06:25.759 That's the baseline physical and regulatory constraint for the space 129 00:06:25.839 --> 00:06:27.879 part of the equation before we even think about what's 130 00:06:27.879 --> 00:06:28.360 already there. 131 00:06:28.439 --> 00:06:30.879 All right, So with that point one degree rule established, 132 00:06:30.920 --> 00:06:33.319 let's look at their first couple of scenarios. These focus 133 00:06:33.439 --> 00:06:34.959 just on the orbital capacity itself. 134 00:06:34.959 --> 00:06:38.879 Fare Yeah, scenario one is pure theory, the absolute simplest calculation. 135 00:06:39.000 --> 00:06:41.040 You just take the full three hundred and sixty degrees 136 00:06:41.079 --> 00:06:43.879 of the GEO circle and divide it by that point 137 00:06:43.879 --> 00:06:45.360 one degree minimum separation. 138 00:06:45.519 --> 00:06:46.720 Okay, simple division. 139 00:06:46.759 --> 00:06:50.800 What's the number the math gives you, three thousand, six hundred. Theoretically, 140 00:06:50.839 --> 00:06:55.120 you could fit three thousand, six hundred SBSP satellites into 141 00:06:55.160 --> 00:06:57.600 geostationary orbit if that was the only rule. 142 00:06:57.759 --> 00:07:01.600 Three thousand, six hundred. That's that's a lot of power stations. 143 00:07:01.600 --> 00:07:04.120 That's the absolute ceiling, assuming you could pack them in 144 00:07:04.199 --> 00:07:06.199 right next to each other with just that minimum clearance. 145 00:07:06.279 --> 00:07:08.800 It's a huge number. Yeah, it represents the sort of 146 00:07:08.959 --> 00:07:11.720 raw capacity of that orbital shell itself. 147 00:07:11.759 --> 00:07:16.160 But of course space isn't empty, especially not GEO exactly. 148 00:07:16.240 --> 00:07:20.120 GEO is prime real estate. It's already got tons of satellites, communications, 149 00:07:20.199 --> 00:07:23.680 whether military, they've been launching stuff up there for decades. 150 00:07:23.959 --> 00:07:26.680 So that brings us to scenario two. They had to 151 00:07:26.720 --> 00:07:28.480 account for the existing traffic. 152 00:07:28.160 --> 00:07:32.800 I assume precisely scenario two models, putting these new SBSP 153 00:07:33.000 --> 00:07:36.319 units into the gaps around all the existing satellites already 154 00:07:36.360 --> 00:07:38.079 operating in GEO, still. 155 00:07:37.920 --> 00:07:40.199 Using the same point one degree spacing rule. 156 00:07:40.199 --> 00:07:43.120 Still using the same point one degree MDA clearance from 157 00:07:43.120 --> 00:07:46.480 any neighbor, whether it's another SBSP station or an existing 158 00:07:46.560 --> 00:07:49.680 COMM satellite. You have to play nice with everyone already there, right, And. 159 00:07:49.600 --> 00:07:51.120 Does that make a big difference? How much does the 160 00:07:51.199 --> 00:07:51.800 number drop? 161 00:07:52.079 --> 00:07:55.279 It makes a significant difference, as you'd expect. Accounting for 162 00:07:55.319 --> 00:07:59.680 that existing orbital congestion. The total potential number of SPSP 163 00:07:59.839 --> 00:08:03.000 SEVE satellites falls from three thousand, six hundred down to 164 00:08:03.120 --> 00:08:04.600 two thousand, five hundred and nine. 165 00:08:04.759 --> 00:08:08.600 Okay, so a drop of nearly eleven hundred potential spots 166 00:08:08.720 --> 00:08:10.199 just lost to existing traffic. 167 00:08:10.399 --> 00:08:13.360 That's right. Almost a third of the theoretical capacity is 168 00:08:13.399 --> 00:08:15.720 already in effect occupied or blocked. 169 00:08:16.439 --> 00:08:19.639 Still, twenty five hundred and nine is a very substantial number. 170 00:08:19.879 --> 00:08:22.240 If that was the end of the story, If orbital 171 00:08:22.279 --> 00:08:24.839 slots were the only real constraint. 172 00:08:24.519 --> 00:08:28.399 Then yeah, the focus would just be on launch cause, manufacturing, deployment, speed, 173 00:08:28.439 --> 00:08:29.879 that sort of thing. How do we fill those twenty 174 00:08:29.920 --> 00:08:31.120 five hundred slots sufficiently. 175 00:08:31.319 --> 00:08:33.399 But this is where the study takes that turn. All right, 176 00:08:33.519 --> 00:08:35.519 this is where it gets really interesting because the focus 177 00:08:35.519 --> 00:08:37.639 shifts completely down to Earth. 178 00:08:37.759 --> 00:08:40.559 Exactly, if space was the only limit, we'd be talking 179 00:08:40.559 --> 00:08:43.600 about two thy five hundred and nine stations. But the 180 00:08:43.639 --> 00:08:46.799 researchers then start layering on the terrestrial realities, and this 181 00:08:46.879 --> 00:08:49.000 is where we see that the Earth's own limitations, not 182 00:08:49.159 --> 00:08:52.000 orbital physics, are really what dictate the final number. 183 00:08:52.320 --> 00:08:55.399 So let's move to scenario three. What's the first big 184 00:08:55.440 --> 00:08:57.080 ground based problem they introduce. 185 00:08:57.519 --> 00:09:01.519 Scenario three brings in the absolute necessity of the ground station, 186 00:09:01.639 --> 00:09:03.159 the receiver. It's usually called a. 187 00:09:03.120 --> 00:09:06.080 Rectenna, rectenna, rectifier and antenna combined. 188 00:09:06.240 --> 00:09:08.840 Exactly, it's this huge facility on the ground that has 189 00:09:08.879 --> 00:09:11.679 to capture the microwave power being coming down from space 190 00:09:11.960 --> 00:09:15.240 and convert it back into usable electricity for the grid. 191 00:09:15.799 --> 00:09:20.279 Without a rectennas site, the satellite is useless, just orbiting hardware. 192 00:09:20.480 --> 00:09:22.960 And these are tennas. They have to be pretty enormous, 193 00:09:22.960 --> 00:09:25.159 don't they to catch that beam efficiently? 194 00:09:25.519 --> 00:09:29.600 Massive, which leads directly to the first set of major 195 00:09:29.679 --> 00:09:33.759 geographical constraints the authors applied. They identified three big ones 196 00:09:33.799 --> 00:09:36.399 dictating where you could even possibly put one of these things. 197 00:09:36.440 --> 00:09:37.200 Okay, what are they? 198 00:09:37.240 --> 00:09:41.559 Constraint number one is pretty straightforward. For now, rectennas have 199 00:09:41.600 --> 00:09:44.159 to be built on land, not over the ocean. 200 00:09:44.279 --> 00:09:46.960 Okay, That immediately rules out what seventy percent of the 201 00:09:47.000 --> 00:09:47.720 planet's surface. 202 00:09:47.879 --> 00:09:51.840 Pretty much a huge limitation, especially since many optimal orbital 203 00:09:51.879 --> 00:09:54.080 slots might be over the Pacific or Atlantic. 204 00:09:54.240 --> 00:09:55.399 Right. What's constraint too? 205 00:09:55.759 --> 00:09:59.360 Constraint too relates to the basic geometry of geo since 206 00:09:59.399 --> 00:10:01.919 those satellite are parked directly above the equator. 207 00:10:02.200 --> 00:10:04.360 Ah, they have to be received near the equator too. 208 00:10:04.320 --> 00:10:06.879 Pretty much. Yeah, there's a limit to how far north 209 00:10:06.919 --> 00:10:10.840 or south you can realistically place the rectenna. The study 210 00:10:10.879 --> 00:10:14.679 constrained placement to within thirty degrees of the equator latitude 211 00:10:14.720 --> 00:10:16.559 thirty north to latitude thirty south. 212 00:10:16.919 --> 00:10:20.399 Why that specific limit. What happens if you go further away, 213 00:10:20.480 --> 00:10:23.759 say to forty or fifty degrees latitude, Well. 214 00:10:23.639 --> 00:10:27.840 The geometry gets difficult. From a satellite directly over the equator, 215 00:10:28.080 --> 00:10:30.679 the beam coming down to a receiver at a higher 216 00:10:30.759 --> 00:10:33.679 latitude has to travel at a much shallower angle through 217 00:10:33.720 --> 00:10:37.679 the atmosphere, almost skimming the horizon from the satellite's. 218 00:10:37.120 --> 00:10:39.559 Perspective, okay, and that causes problems. 219 00:10:39.600 --> 00:10:43.159 Two big ones. First, the longer path through the atmosphere 220 00:10:43.159 --> 00:10:47.559 means more potential for energy loss scattering absorption. But the 221 00:10:47.600 --> 00:10:50.919 bigger issue is beam spread. That shallow angle means when 222 00:10:50.960 --> 00:10:53.720 the beam finally hits the ground, it's spread out over 223 00:10:53.759 --> 00:10:55.600 a much much larger area. 224 00:10:55.360 --> 00:10:57.720 Which ties it to the third constraint. I'm guessing land 225 00:10:57.799 --> 00:10:58.559 use exactly. 226 00:10:58.600 --> 00:11:02.759 Constraint three size and land use. The further your rectenna 227 00:11:02.840 --> 00:11:05.639 is from the equator, closer to that thirty degree limit, 228 00:11:05.960 --> 00:11:07.720 the bigger the beemut print is on the. 229 00:11:07.679 --> 00:11:09.720 Ground, meaning you need a bigger rectenna. 230 00:11:09.799 --> 00:11:12.840 You need a vastly larger clear land area for the 231 00:11:12.879 --> 00:11:18.320 rectenna to capture that diffuse energy efficiently. We're talking possibly ten, 232 00:11:18.440 --> 00:11:21.440 maybe even fifteen kilometers wide in some of those higher 233 00:11:21.519 --> 00:11:25.679 latitude cases. Just finding that much completely unencumbered land. 234 00:11:25.919 --> 00:11:28.799 And it has to be accessible near the equator, not 235 00:11:28.840 --> 00:11:32.200 already used for cities or farms or protected nature reserves. 236 00:11:32.279 --> 00:11:35.639 Right, you need huge plots of suitable real estate us. 237 00:11:35.480 --> 00:11:37.519 Putting those three things together, needs to be on land, 238 00:11:37.600 --> 00:11:40.240 needs to be within thirty degrees of the equator, and 239 00:11:40.279 --> 00:11:43.600 the required land area gets huge near that limit. How 240 00:11:43.679 --> 00:11:46.279 much did that reduce the number of possible stations from 241 00:11:46.279 --> 00:11:48.919 the twenty five hundred and nine we had in scenario two? 242 00:11:49.360 --> 00:11:51.879 This is where the numbers really start to fall. Applying 243 00:11:52.039 --> 00:11:55.799 just those terrestrial geographical constraints drops the number of potentially 244 00:11:55.840 --> 00:11:58.600 viable stations all the way down to one thy seven 245 00:11:58.679 --> 00:11:59.559 hundred and seventy one. 246 00:11:59.600 --> 00:12:02.360 Wow, from two thousand, five hundred and nine down to 247 00:12:02.399 --> 00:12:04.720 a one thousand, seven hundred and seventy one. So that's 248 00:12:04.720 --> 00:12:07.600 another what seven hundred plus potential site's gone just because 249 00:12:07.639 --> 00:12:09.279 of geography and land availability. 250 00:12:09.360 --> 00:12:12.080 Exactly. It proves pretty starkly that finding the right spot 251 00:12:12.120 --> 00:12:14.360 on Earth is already a much bigger constraint than finding 252 00:12:14.399 --> 00:12:15.279 a slot in orbit. 253 00:12:15.519 --> 00:12:18.559 It really reframes the problem, doesn't it. It becomes less 254 00:12:18.600 --> 00:12:22.240 about space engineering and more about like global real estate 255 00:12:22.240 --> 00:12:26.320 and land management policy, finding one thousand, seven hundred and 256 00:12:26.320 --> 00:12:30.000 seventy one suitable massive plots near the equator. 257 00:12:30.080 --> 00:12:34.159 It's a massive geopolitical and logistical challenge. And incredibly, that's 258 00:12:34.200 --> 00:12:36.080 still not the tightest bottleneck they found. 259 00:12:36.159 --> 00:12:38.399 That's another level Scenario four. 260 00:12:38.679 --> 00:12:41.519 Scenario four introduces what turns out to be the most 261 00:12:41.559 --> 00:12:45.240 restrictive constraint of all, and maybe the most insightful one, 262 00:12:45.360 --> 00:12:48.639 it's the bottleneck caused by existing electrical infrastructure. 263 00:12:48.840 --> 00:12:53.279 Ah okay, So finding the perfect huge equatorial plot of 264 00:12:53.360 --> 00:12:56.159 land is pointless if you can't actually plug the power 265 00:12:56.159 --> 00:12:56.919 into the grid there. 266 00:12:57.000 --> 00:13:00.320 Precisely you need the infrastructure of the high capacity substation, the 267 00:13:00.360 --> 00:13:04.360 heavy duty transmission lines, the distribution networks capable of handling 268 00:13:04.360 --> 00:13:08.559 a sudden, massive influx of power. We're talking gigawatt scale 269 00:13:08.559 --> 00:13:09.080 per station. 270 00:13:09.360 --> 00:13:09.559 Right. 271 00:13:09.679 --> 00:13:12.279 You can't just plug a power plant's output into local 272 00:13:12.320 --> 00:13:15.159 neighborhood power lines. It would blow the system exactly. 273 00:13:15.200 --> 00:13:18.360 It would overload everything instantly. So the challenge for the 274 00:13:18.360 --> 00:13:22.240 researchers was how do you measure or estimate where that 275 00:13:22.320 --> 00:13:25.720 kind of heavy duty grid infrastructure already exists. They couldn't 276 00:13:25.799 --> 00:13:27.519 map every power line. 277 00:13:27.519 --> 00:13:30.559 Globally, so they needed some kind of stand in a proxy. 278 00:13:30.759 --> 00:13:35.279 They did. They used a really clever, the quite restrictive proxymetric. 279 00:13:35.440 --> 00:13:39.759 They decided to limit potential rectenna locations only to areas 280 00:13:39.759 --> 00:13:43.039 that already have a significant level of human development measured 281 00:13:43.039 --> 00:13:44.240 by population density. 282 00:13:44.360 --> 00:13:47.799 Population density as a proxy for grid capacity. What density 283 00:13:47.879 --> 00:13:48.600 level did they use? 284 00:13:48.720 --> 00:13:51.840 They set the threshold at three thousand people per square. 285 00:13:51.639 --> 00:13:54.799 Kilometer three thousand people per square kilomber, So that excludes 286 00:13:54.960 --> 00:13:58.480 like most rural areas, even if they were geographically perfect. 287 00:13:58.600 --> 00:14:01.480 It excludes huge swaths of l and yes, the thinking 288 00:14:01.559 --> 00:14:03.600 is pretty logical. Though an area with that kind of 289 00:14:03.600 --> 00:14:06.519 density thing maybe dense suburbs, the edges of large cities 290 00:14:06.519 --> 00:14:09.879 may be very intensely farmed areas is highly likely to 291 00:14:10.000 --> 00:14:14.559 already have the kind of sophisticated high capacity electrical grid. 292 00:14:14.320 --> 00:14:18.639 Needed because serving that many people already requires significant power 293 00:14:18.639 --> 00:14:20.320 infrastructure investment over decade. 294 00:14:20.399 --> 00:14:23.840 That's the rationale. They basically assumed that you wouldn't build 295 00:14:23.840 --> 00:14:26.879 the massive grid upgrades needed just for an SBST station. 296 00:14:27.399 --> 00:14:30.120 The power has to land where a robust grid already 297 00:14:30.120 --> 00:14:33.240 exists or is very nearby. If the density is lower, 298 00:14:33.360 --> 00:14:35.679 the local grid is probably too weak to handle a 299 00:14:35.679 --> 00:14:36.799 sudden gigawatt input. 300 00:14:36.879 --> 00:14:39.519 Okay, that's a major constraint. So when they apply that 301 00:14:39.600 --> 00:14:43.720 rule only placing rectennas in areas with three thousand plus 302 00:14:43.720 --> 00:14:46.600 people per square kilometer on top of all the previous 303 00:14:46.720 --> 00:14:50.200 orbital and geographical limits, what happened to the number. 304 00:14:50.440 --> 00:14:53.440 This is where the number collapses. The final most restricted 305 00:14:53.480 --> 00:14:57.240 count of potential fully viable SBSP stations. Considering all the 306 00:14:57.279 --> 00:15:01.360 constraints orbital traffic, geography, land use, and grewed readiness, it 307 00:15:01.480 --> 00:15:03.480 drops to just three hundred and sixty. 308 00:15:03.120 --> 00:15:05.960 Four Wow, three hundred and sixty four from one thousand, 309 00:15:06.000 --> 00:15:07.840 seven hundred and seventy one down to three hundred and 310 00:15:07.879 --> 00:15:10.960 sixty four, a huge drops. That's an almost ninety percent 311 00:15:11.000 --> 00:15:13.600 reduction from the original theoretical maximum of three thousand, six 312 00:15:13.679 --> 00:15:14.080 hundred In. 313 00:15:14.080 --> 00:15:16.799 Scenario one, it is eighty nine point nine percent reduction. 314 00:15:16.840 --> 00:15:19.679 To be precise, the orbit could hold thousands, but Earth's 315 00:15:19.679 --> 00:15:23.200 current infrastructure using their proxy, can only really support receiving 316 00:15:23.240 --> 00:15:25.879 power at three hundred and sixty four locations, so. 317 00:15:25.799 --> 00:15:29.720 The conclusion seems pretty unavoidable. Then, the ultimate limit on 318 00:15:30.000 --> 00:15:34.120 SBSP capacity, at least based on this analysis, isn't set 319 00:15:34.159 --> 00:15:38.120 by space. It's set by the ground, specifically by where 320 00:15:38.120 --> 00:15:41.799 we've already built dense populations in high capacity power grids. 321 00:15:41.879 --> 00:15:45.440 That's the core finding the bottleneck isn't rocket science, it's 322 00:15:45.480 --> 00:15:48.120 city planning and electrical engineering essentially. 323 00:15:48.320 --> 00:15:52.440 Okay, so we have the final most constrained number three 324 00:15:52.559 --> 00:15:56.240 hundred and sixty four potential stations Now, what about the 325 00:15:56.279 --> 00:15:58.879 second part of their calculation? How much power could this 326 00:15:58.960 --> 00:16:00.399 constellation actually deliver? 327 00:16:00.759 --> 00:16:03.519 Right, so, first they had to estimate how much power 328 00:16:03.559 --> 00:16:06.559 each station could collect in space before you account for 329 00:16:06.600 --> 00:16:08.080 all the losses getting it down here. 330 00:16:08.159 --> 00:16:09.639 What assumptions did they make for that? 331 00:16:09.679 --> 00:16:13.159 They used a few key variables based on plausible near 332 00:16:13.240 --> 00:16:16.279 term technology. They looked at the solar panel area, the 333 00:16:16.279 --> 00:16:18.919 efficiency of the cells, the angle to the sun, which 334 00:16:18.960 --> 00:16:21.919 is pretty constant in GEO, and the solar irradiance of that. 335 00:16:22.120 --> 00:16:23.960 How big did they assume the solar panels would be. 336 00:16:24.159 --> 00:16:28.480 They assumed a very substantial area ten square kilometers per satellite. 337 00:16:28.639 --> 00:16:31.879 Ten square kilometers that's hard even picture what's that equivalent to. 338 00:16:32.600 --> 00:16:37.879 Let's see, it's roughly fourteen hundred standard football fields, or 339 00:16:38.039 --> 00:16:41.480 think about the entire area of a major international airport complex. 340 00:16:41.519 --> 00:16:43.360 It's truly enormous. 341 00:16:43.039 --> 00:16:45.360 Okay, massive scale. And the efficiency. 342 00:16:45.440 --> 00:16:48.799 They assumed a twenty percent conversion efficiency for the solar 343 00:16:48.840 --> 00:16:51.960 cells themselves, which is pretty reasonable, maybe even a bit 344 00:16:51.960 --> 00:16:54.320 conservative for future tech, but achievable now. 345 00:16:54.440 --> 00:16:57.519 So ten square kilometers of panels at twenty percent efficiency 346 00:16:57.639 --> 00:17:01.720 in constant GEO sunlight, which power does that collect per station? 347 00:17:02.000 --> 00:17:05.160 The number is staggering. Two hundred and seventy two gigawatts 348 00:17:05.319 --> 00:17:07.440 generated in orbit per station. 349 00:17:07.240 --> 00:17:09.960 Two hundred and seventy two gigawatts. Yeah, each, If you 350 00:17:09.960 --> 00:17:11.400 could get even a fraction of that. 351 00:17:11.400 --> 00:17:13.880 Down exactly, if all three hundred and sixty four stations 352 00:17:13.880 --> 00:17:17.039 collected that, you're talking almost one hundred thousand gigawatts collected 353 00:17:17.039 --> 00:17:20.000 in space. World energy solved, right, But here come the losses. 354 00:17:20.359 --> 00:17:22.519 This is the big question mark. Isn't it converting that 355 00:17:22.599 --> 00:17:26.000 DC power to microwaves, beaming it thirty six thousand kilometers, 356 00:17:26.039 --> 00:17:28.960 get through the atmosphere, catching it, converting it back to AC. 357 00:17:29.240 --> 00:17:31.680 This is the critical step and honestly the point where 358 00:17:31.680 --> 00:17:34.119 the authors applied really extreme conservatism. 359 00:17:34.160 --> 00:17:36.200 How much did they estimate would actually get delivered to 360 00:17:36.240 --> 00:17:38.279 the grid out of that two hundred and seventy two 361 00:17:38.319 --> 00:17:39.240 gw collected. 362 00:17:39.519 --> 00:17:42.160 Their final estimate for power delivered to the grid per 363 00:17:42.240 --> 00:17:45.079 station was just one giglewyy. 364 00:17:44.559 --> 00:17:48.039 One one gigawatt delivered from two hundred and seventy two 365 00:17:48.039 --> 00:17:51.680 gigawats collected. Yes, that's an overall efficiency of what less 366 00:17:51.680 --> 00:17:52.799 than half a percent. 367 00:17:52.720 --> 00:17:55.720 Round point three percent or put point three seven percent. Yeah, 368 00:17:55.799 --> 00:17:58.839 it's an incredibly low number. It implies absolutely massive losses 369 00:17:58.839 --> 00:18:02.839 in the conversion beaming atmosphere transit and rectena conversion process. 370 00:18:03.119 --> 00:18:07.720 That seems almost unrealistically pessimistic. Does the paper justify that 371 00:18:07.839 --> 00:18:10.599 huge loss factor in detail or is it more of 372 00:18:10.640 --> 00:18:13.720 a placeholder for we expect very large losses. 373 00:18:13.960 --> 00:18:16.599 It's acknowledged in the source material itself that this assumption 374 00:18:16.680 --> 00:18:21.119 is extremely conservative and lacks extensive, detailed justification. Within the paper, 375 00:18:21.599 --> 00:18:24.519 they were effectively building in the largest possible buffer against 376 00:18:24.519 --> 00:18:28.759 any technological optimism regarding transmission efficiency. It assumes a near 377 00:18:28.799 --> 00:18:29.519 total loss. 378 00:18:29.680 --> 00:18:32.720 Okay, well, let's run with our ultra conservative number for now, 379 00:18:32.759 --> 00:18:34.359 just to see where it leads. If you have three 380 00:18:34.440 --> 00:18:36.799 hundred and sixty four stations and each only delivers one 381 00:18:36.839 --> 00:18:38.200 gigaw to the grid. 382 00:18:38.039 --> 00:18:41.079 Then the total power provided by this horse case constellation 383 00:18:41.319 --> 00:18:43.759 is three hundred and sixty four gigawats of reliable base 384 00:18:43.799 --> 00:18:44.720 load power. 385 00:18:44.640 --> 00:18:48.319 Three hundred and sixty four gigawatts globally. How does that 386 00:18:48.359 --> 00:18:51.839 compare to say, total world electricity consumption? 387 00:18:52.200 --> 00:18:54.519 It works out to be enough to cover approximately three 388 00:18:54.559 --> 00:18:56.920 percent of total global power usage. 389 00:18:57.200 --> 00:19:00.920 Three percent After all that effort, one hundred and sixty 390 00:19:00.920 --> 00:19:06.000 four massive satellites, huge ground stations. Three percent doesn't immediately 391 00:19:06.039 --> 00:19:08.799 sound like a game changer. Why is that figure still 392 00:19:08.839 --> 00:19:11.759 considered significant enough for companies and countries to be pouring 393 00:19:11.799 --> 00:19:12.440 money into this? 394 00:19:13.000 --> 00:19:16.240 That's a fair question. The key is that it's baseload power. 395 00:19:16.359 --> 00:19:20.000 It's not intermittent like wind or ground based solar. It's 396 00:19:20.079 --> 00:19:23.920 three percent that's available twenty forty seven constantly, reliably, regardless 397 00:19:23.960 --> 00:19:25.160 of weather or time of day. 398 00:19:25.400 --> 00:19:28.480 Uh okay, So it's about the quality and reliability of 399 00:19:28.519 --> 00:19:30.279 that power, not just the raw amount. 400 00:19:30.440 --> 00:19:32.920 Exactly, in global energy markets, adding three hundred and sixty 401 00:19:32.920 --> 00:19:36.920