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 --> 00:00:25.839 slumber under the night sky. 7 00:00:26.879 --> 00:00:33.439 We've all seen the pictures from Mars, right, It's incredible rovers, curiosity, perseverance. 8 00:00:34.679 --> 00:00:37.320 They're just engineering marvels. 9 00:00:36.920 --> 00:00:42.479 Absolutely peak technology, nuclear powered, incredibly complex systems, some of 10 00:00:42.479 --> 00:00:43.560 the size of a small car. 11 00:00:43.759 --> 00:00:46.600 And the science they send back is I mean, it's priceless. 12 00:00:46.679 --> 00:00:49.320 But there's always that butt, isn't there. The cost is 13 00:00:49.719 --> 00:00:52.320 enormous billions of dollars. 14 00:00:52.359 --> 00:00:54.679 That's one side, yeah, billions permission. 15 00:00:55.119 --> 00:00:57.520 And the other thing is they're slow. They cover ground 16 00:00:57.520 --> 00:01:01.759 really slowly. We measure their progress in what kilometers per year? 17 00:01:01.920 --> 00:01:04.560 That's pretty much it. And that's the fundamental trade off 18 00:01:04.599 --> 00:01:07.000 you make with that kind of traditional exploration. You get 19 00:01:07.319 --> 00:01:12.120 incredible precision, amazing longevity at one specific spot, but you 20 00:01:12.239 --> 00:01:15.959 totally sacrifice scale. Our picture of Mars, you know, the geography, 21 00:01:16.079 --> 00:01:18.920 the climate, It's been shaped for decades by what these 22 00:01:19.040 --> 00:01:21.959 very expensive wheeled robots can see right where they happen to. 23 00:01:21.920 --> 00:01:24.079 Be, which leaves a pretty big gap, doesn't it. What 24 00:01:24.120 --> 00:01:27.319 if you want to understand something huge like planet wide 25 00:01:27.359 --> 00:01:31.519 climate patterns, or I don't know, track geological futures over 26 00:01:31.959 --> 00:01:34.599 hundreds thousands of kilometers. 27 00:01:34.079 --> 00:01:40.000 Exactly, a single rover, however advanced, just crawling along it 28 00:01:40.040 --> 00:01:43.680 can't give you that big picture, that systemic, distributed view. 29 00:01:44.200 --> 00:01:46.799 And that's precisely why this other idea, the one we're 30 00:01:46.799 --> 00:01:50.079 looking at today is well, it's so radical, the tumbleweed 31 00:01:50.159 --> 00:01:51.040 rover concepts. 32 00:01:51.120 --> 00:01:52.840 Tumbleweed, Okay, Yeah. 33 00:01:52.680 --> 00:01:55.560 The idea is basically to ditch all that complex propulsion 34 00:01:55.640 --> 00:01:59.120 that motors the heavy wheels, the nuclear core, and instead 35 00:01:59.519 --> 00:02:01.959 use the most abundant resource on Mars. 36 00:02:01.959 --> 00:02:05.000 Which is the wind. You're talking about these sort of spherical, 37 00:02:05.159 --> 00:02:08.599 lightweight things just getting blown across the surface like giant 38 00:02:08.680 --> 00:02:10.000 planetary dandelions. 39 00:02:10.120 --> 00:02:12.560 That's a pretty good analogy, actually. Yeah, And look, we've 40 00:02:12.599 --> 00:02:15.360 just gotten some really critical results back from wind tunnel tests, 41 00:02:15.360 --> 00:02:18.479 field tests. This isn't just some sci fi fantasy anymore. 42 00:02:18.560 --> 00:02:23.120 It's quickly moving towards being a real possibility for future missions. 43 00:02:23.159 --> 00:02:23.680 Wow. 44 00:02:23.879 --> 00:02:26.159 Okay, so the really big question here is, you know, 45 00:02:26.199 --> 00:02:29.199 how can a massive ball we're talking five meters across 46 00:02:29.280 --> 00:02:33.280 just push by guts of when become this transformative technology? 47 00:02:33.560 --> 00:02:36.439 How does that let us explore Mars on a continental scale? 48 00:02:36.560 --> 00:02:40.000 It sounds more like a giant, very sophisticated beach ball 49 00:02:40.319 --> 00:02:41.039 than a rover. 50 00:02:41.319 --> 00:02:45.680 Huh. Well, it might look simple, but the science behind 51 00:02:45.680 --> 00:02:49.039 making it work is anything. But it seems simple, but 52 00:02:49.120 --> 00:02:54.199 it's actually more pragmatic and scientifically robust then you might 53 00:02:54.199 --> 00:02:55.039 think at first glance. 54 00:02:55.120 --> 00:02:57.400 Okay, let's unpack this then, because yeah, it sounds like 55 00:02:57.439 --> 00:03:00.960 it relies on radical simplification, but simplicity has to be 56 00:03:00.960 --> 00:03:02.919 grounded in some pretty solid physics. 57 00:03:02.599 --> 00:03:04.719 Right, absolutely, Let's start with the machine itself. 58 00:03:04.759 --> 00:03:08.280 Okay, define this tumble weed rover physically. What are we 59 00:03:08.319 --> 00:03:10.039 talking about? Size construction? 60 00:03:10.159 --> 00:03:14.319 Physically? Yeah, they're designed as ultra light weight spheres and 61 00:03:14.479 --> 00:03:17.840 the scale is well, it's kind of astonishing. Fully deployed, the 62 00:03:17.879 --> 00:03:20.520 target size is five meters in diameters five. 63 00:03:20.479 --> 00:03:22.800 Meter Wait a minute, perseverance is about three meters long. 64 00:03:23.319 --> 00:03:26.599 That's huge, like giraffe height rolling on Mars. 65 00:03:26.840 --> 00:03:30.039 Pretty much. Think about that visual. The structure itself is 66 00:03:30.080 --> 00:03:33.120 basically an advanced, very durable shell, maybe like a tough 67 00:03:33.159 --> 00:03:36.719 balloon made from extremely light but really resilient materials. The 68 00:03:36.759 --> 00:03:40.039 whole design is about maximizing that surface area while keeping 69 00:03:40.039 --> 00:03:41.439 the mass incredibly low. 70 00:03:41.680 --> 00:03:45.439 But why so big? Why five meters wouldn't something smaller 71 00:03:45.520 --> 00:03:48.479 be I don't know, easier to handle, easier to launch. 72 00:03:49.039 --> 00:03:52.039 Ah, But the size is actually the secret sauce. It's 73 00:03:52.080 --> 00:03:55.400 directly linked to the challenge of moving anything in Mars's 74 00:03:55.439 --> 00:03:59.400 atmosphere because it's so thin exactly compared to Earth, Mars 75 00:03:59.400 --> 00:04:02.400 has almost no atmosphere, less than one percent of ours 76 00:04:02.439 --> 00:04:06.280 at the surface. So to actually catch enough wind to move. 77 00:04:06.280 --> 00:04:07.400 You need a big sale. 78 00:04:07.439 --> 00:04:09.800 You need a huge surface area for that thin wind 79 00:04:09.800 --> 00:04:13.240 to push against. Combined with the absolute minimum possible weight, 80 00:04:13.800 --> 00:04:16.720 A five meters sphere seems to hit that sweet spot 81 00:04:16.759 --> 00:04:20.000 that optimal ratio of sail area to mass. It gives 82 00:04:20.040 --> 00:04:23.040 you enough oomph, enough rolling torque from the Martian wind. 83 00:04:23.240 --> 00:04:26.000 It's all engineered around fluid dynamics in that specific environment. 84 00:04:26.079 --> 00:04:29.759 Okay, so the entire mobility system is just harnessing Martian wind, 85 00:04:29.800 --> 00:04:31.920 Like you said, like the tumblewheez we see rolling across 86 00:04:32.000 --> 00:04:34.439 deserts on Earth as a model, which means you're basically 87 00:04:34.480 --> 00:04:37.600 swapping out the need for well for power sources, no 88 00:04:37.720 --> 00:04:39.800 complex motors, no RTGs. 89 00:04:39.399 --> 00:04:41.800 Precisely, and that leads straight to the core goal, the 90 00:04:41.839 --> 00:04:46.240 really revolutionary part, large scale and low cost exploration. When 91 00:04:46.279 --> 00:04:50.000 you use the wind that's already there, you sidestep massive 92 00:04:50.000 --> 00:04:54.360 engineering headaches. Think about traditional rovers, they often rely on 93 00:04:54.399 --> 00:04:57.959 those RTGs, radioisotope, thermoelectric generators. 94 00:04:57.480 --> 00:04:58.519 Some nuclear batteries. 95 00:04:58.600 --> 00:05:02.680 Yeah, basically nuclear batteries, super high cost, very heavy, politically 96 00:05:02.759 --> 00:05:06.199 tricky to get approved for launch. By taking RTGs out 97 00:05:06.240 --> 00:05:10.839 of the equation, along with motors, complex gears, heavy wheels, 98 00:05:10.879 --> 00:05:15.639 the cost just plummets. The whole platform becomes almost disposable, 99 00:05:15.839 --> 00:05:18.959 relatively speaking, and that opens the door to mass production. 100 00:05:19.199 --> 00:05:21.839 And if you cut the cost and complexity that much, 101 00:05:21.959 --> 00:05:24.360 suddenly you can think about not just sending one precious 102 00:05:24.439 --> 00:05:26.040 billion dollar machine exactly. 103 00:05:26.079 --> 00:05:29.079 You can employ the swarm strategy. The goal isn't one rover, 104 00:05:29.439 --> 00:05:32.720 it's deploying entire swarms of these relatively inexpensive rovers all 105 00:05:32.720 --> 00:05:33.079 at once. 106 00:05:33.600 --> 00:05:37.240 Swarm. Okay, now that changes things. What's the scientific advantage 107 00:05:37.240 --> 00:05:39.000 of having a whole bunch of these rolling around. 108 00:05:39.160 --> 00:05:42.800 That's where this mission concept really truly shines. The scientific 109 00:05:42.839 --> 00:05:46.120 payoff of a distributed swarm. You shift from measuring things 110 00:05:46.160 --> 00:05:47.279 at just one point. 111 00:05:47.160 --> 00:05:48.759 Like Curiosity does now. 112 00:05:49.439 --> 00:05:54.360 To systemic distributed sensing. The strategy allows for an unprecedented 113 00:05:54.480 --> 00:05:58.120 simultaneous view. As the team puts it of atmospheric and 114 00:05:58.199 --> 00:06:02.879 surface processes from different locations on Mars. We could track 115 00:06:03.319 --> 00:06:06.959 dynamic things happening across the planet that are basically invisible 116 00:06:07.000 --> 00:06:08.399 to us right now. 117 00:06:08.000 --> 00:06:11.120 That distributed sensing, Yeah, I can see how that's a 118 00:06:11.120 --> 00:06:14.800 game changer, especially for climate science, maybe large scale geology too. 119 00:06:15.279 --> 00:06:18.519 What kind of questions could you actually answer with, say, 120 00:06:19.319 --> 00:06:21.839 dozens of these spread across the continent and things we 121 00:06:21.920 --> 00:06:23.000 just can't tackle. 122 00:06:22.680 --> 00:06:25.759 Now, Okay, think about planetary climate modeling. Yeah, we know 123 00:06:25.879 --> 00:06:30.360 Mars has these huge, sometimes planet encircling dust storms, right, Yah, 124 00:06:30.399 --> 00:06:33.279 the massive ones and powerful atmosphere pressure waves sort of 125 00:06:33.279 --> 00:06:36.120 like big weather fronts moving cross Earth. With one rover 126 00:06:36.439 --> 00:06:39.079 like perseverance, you can see a wave pass over you. 127 00:06:39.079 --> 00:06:41.240 You get a snapshot in time at one place, right, 128 00:06:41.360 --> 00:06:43.839 But imagine you have fifty tumbleweeds spread out over a 129 00:06:43.879 --> 00:06:47.639 thousand kilometers. Suddenly you can map the pressure gradients, the 130 00:06:47.680 --> 00:06:51.160 temperature changes within the wave. Simultaneously, you can track its speed, 131 00:06:51.199 --> 00:06:54.959 how it evolves in real time across a huge area. Wow, 132 00:06:55.240 --> 00:06:59.319 that's just impossible. With single point sampling or thing geologically 133 00:07:00.240 --> 00:07:03.519 could give you statistical data on soil composition or magnetic 134 00:07:03.560 --> 00:07:07.240 fields over a vast region. You move beyond just finding 135 00:07:07.319 --> 00:07:11.439 one interesting rock. You start understanding planetary scale trends. 136 00:07:12.040 --> 00:07:14.800 Okay, so the rolling phase is obviously crucial for spreading 137 00:07:14.800 --> 00:07:17.240 them out and gathering that kind of data, But you 138 00:07:17.360 --> 00:07:21.399 mentioned there's more to it. The mission isn't just about rolling, that's. 139 00:07:21.319 --> 00:07:23.120 Right, and this is where it gets, as you said, 140 00:07:23.120 --> 00:07:26.680 really interesting. The rolling is the deployment method, getting the 141 00:07:26.720 --> 00:07:31.079 instruments distributed across strategic target areas. But once they reach 142 00:07:31.120 --> 00:07:35.279 those spots, maybe preplan zones or areas of interest identified 143 00:07:35.360 --> 00:07:38.480 during the traverse, they stop rolling. The plan is for 144 00:07:38.519 --> 00:07:41.759 them to actually collapse into fixed positions. Collapse, Yeah, they 145 00:07:41.759 --> 00:07:46.360 transform into permanent measurement stations dotted strategically across the Martian surface. 146 00:07:46.439 --> 00:07:50.199 Hold on, how does a five meter lightweight ball just 147 00:07:50.279 --> 00:07:53.319 stop and anchor itself? Does the source material give any 148 00:07:53.360 --> 00:07:55.800 clues about that mechanism, how do you deflate it or 149 00:07:55.839 --> 00:07:56.279 stick it to. 150 00:07:56.319 --> 00:08:00.319 The ground that specific mechanism. The how is likely still 151 00:08:00.319 --> 00:08:04.079 part of the team's ongoing development, probably proprietary at this stage, 152 00:08:04.439 --> 00:08:08.480 but the core concept involves a controlled deflation or maybe 153 00:08:08.560 --> 00:08:12.519 retraction of that outer shell. Okay, The key is that 154 00:08:12.560 --> 00:08:16.319 the interior payload bay, the part with the actual science instruments, 155 00:08:16.680 --> 00:08:20.160 needs to be secured to the ground somehow. This transition 156 00:08:20.240 --> 00:08:23.839 from mobile to static is absolutely essential for the long 157 00:08:23.920 --> 00:08:24.839 term science value. 158 00:08:24.879 --> 00:08:26.959 So they become little weather stations. 159 00:08:26.560 --> 00:08:31.319 Or something exactly, or size mix stations, radiation monitors. They 160 00:08:31.319 --> 00:08:35.440 can provide sustained measurements from fixed points over potentially years, 161 00:08:36.039 --> 00:08:40.759 tracking atmospheric pressure changes, temperature cycles, maybe detecting marsquakes, monitoring 162 00:08:40.879 --> 00:08:43.759 radiation levels. Long term, they can form a kind of 163 00:08:43.840 --> 00:08:45.639 data backbone across the planet. 164 00:08:45.519 --> 00:08:48.240 Or even communication relays for other future missions. 165 00:08:48.320 --> 00:08:51.159 That's definitely a potential application. So yeah, the movement phase 166 00:08:51.200 --> 00:08:53.960 is the deployment strategy getting them spread out. But the 167 00:08:54.000 --> 00:08:56.879 static phases where you get that really long term scientific 168 00:08:56.919 --> 00:08:57.840 return on investment. 169 00:08:58.080 --> 00:09:02.480 Okay, the concept is well, it's brilliant, but the practical 170 00:09:02.519 --> 00:09:07.399 side still feels daunting. We established Mars's atmosphere is incredibly thin. 171 00:09:08.000 --> 00:09:11.360 Trying to roll a giant, super lightweight ball in that 172 00:09:11.480 --> 00:09:14.919 low pressure, even with strong winds. It feels like it 173 00:09:14.960 --> 00:09:16.200 needed some serious proof. 174 00:09:16.559 --> 00:09:19.919 Hard evidence, absolutely essential. You can't just assume Earth physics 175 00:09:19.919 --> 00:09:24.159 scales directly to Mars, especially with atmospheres. The staling factors 176 00:09:24.159 --> 00:09:27.679 are notoriously tricky. So yes, The source material details two 177 00:09:27.879 --> 00:09:31.320 main experimental phases that have now provided that crucial proof 178 00:09:31.320 --> 00:09:32.919 of concept, right the tests. 179 00:09:33.159 --> 00:09:35.080 Let's start with phase one. That was the wind tunnel 180 00:09:35.080 --> 00:09:39.559 physics right July twenty twenty five at RHUs University's Planetary 181 00:09:39.639 --> 00:09:42.559 Environment Facility. They basically had to build a little piece 182 00:09:42.600 --> 00:09:43.159 of Mars on. 183 00:09:43.120 --> 00:09:45.919 Earth pretty much. They used scaled down prototypes for this, 184 00:09:46.399 --> 00:09:50.200 specifically models with diameters of thirty, forty and fifty centimeters. 185 00:09:50.240 --> 00:09:52.240 They put these inside a special wind tunnel. 186 00:09:51.960 --> 00:09:54.679 Chamber, and the key was the atmosphere, the absolute key. 187 00:09:54.720 --> 00:09:56.759 The tests were run under a very low atmosphere and 188 00:09:56.799 --> 00:09:58.039 pressure seventeen. 189 00:09:57.600 --> 00:10:01.799 Millibars seventeen okay, remind us Earth's atmosphere at sea level is. 190 00:10:02.000 --> 00:10:05.200 About one thy thirteen millibars, so seventeen is less than 191 00:10:05.240 --> 00:10:08.120 two percent of earth pressure. It's practically a near vacuum environment. 192 00:10:08.279 --> 00:10:11.879 Why is simulating that low pressure so vital and I 193 00:10:11.879 --> 00:10:14.320 imagine technically quite hard to do. 194 00:10:14.559 --> 00:10:17.000 It's vital because the way air interacts with the surface, 195 00:10:17.559 --> 00:10:21.399 the whole fluid dynamics picture changes dramatically at such low pressures. 196 00:10:21.799 --> 00:10:25.440 Air becomes highly rarefied, how wind actually pushes the sphere, 197 00:10:25.480 --> 00:10:27.879 how the sphere interacts with the ground through that thin air. 198 00:10:28.360 --> 00:10:31.200 It's just fundamentally different physics in here. Okay, if the 199 00:10:31.279 --> 00:10:34.480 rover design can roll efficiently at seventeen millibars, it tells 200 00:10:34.480 --> 00:10:37.240 you the basic aerodynamic and structural design works for Mars. 201 00:10:38.120 --> 00:10:41.320 And yeah, maintaining that low pressure while also generating controlled 202 00:10:41.320 --> 00:10:44.240 wind inside a chamber is definitely a technical challenge. 203 00:10:44.279 --> 00:10:46.080 Did they just test it on a flat surface? 204 00:10:46.759 --> 00:10:49.200 No, that was another critical part. They ran tests over 205 00:10:49.240 --> 00:10:52.919 five different simulated Mars terrains, things like smooth planes, rough 206 00:10:53.039 --> 00:10:57.919 rocky areas, fine sand surfaces with pebbles, even simulated boulder fields. 207 00:10:58.240 --> 00:10:59.919 They want to make sure it wasn't just a con 208 00:11:00.039 --> 00:11:02.000 set that worked on a perfectly smooth lab. 209 00:11:01.840 --> 00:11:05.039 Floor, right, because Mars isn't smooth, and the goal is 210 00:11:05.080 --> 00:11:08.639 to find that magic number right, the minimum wind speed 211 00:11:08.639 --> 00:11:12.440 needed to actually get these things rolling consistently across different terrains. 212 00:11:12.679 --> 00:11:13.440 What did they find? 213 00:11:13.639 --> 00:11:17.799 The results were really positive and remarkably consistent across the 214 00:11:17.840 --> 00:11:21.519 different setups. They found that sustained wind speeds of nine 215 00:11:21.559 --> 00:11:24.159 to ten meters per second were enough to set the 216 00:11:24.159 --> 00:11:25.559 models into continuous motion. 217 00:11:26.000 --> 00:11:28.080 Nine to ten meters per second. Okay, is that fast 218 00:11:28.360 --> 00:11:29.960 like hurricane speeds. 219 00:11:29.799 --> 00:11:32.720 Not hurricane No. On Earth, ten meters is about twenty 220 00:11:32.720 --> 00:11:36.279 two miles per hour, a strong breeze, maybe a moderate gale. 221 00:11:36.600 --> 00:11:39.080 But remember on Mars the ear is so thin you 222 00:11:39.200 --> 00:11:40.960 need dead speed to get enough force. 223 00:11:41.440 --> 00:11:44.399 And that threshold nine ten meters it worked even on 224 00:11:44.480 --> 00:11:46.399 the rough terrain, the pebbles, the boulders. 225 00:11:46.519 --> 00:11:49.559 That's what they found. It held true across all those 226 00:11:49.639 --> 00:11:53.320 Mars like terrains they simulated, which is a huge finding. 227 00:11:53.720 --> 00:11:56.360 It proves the basic mechanism is robust. It can handle 228 00:11:56.360 --> 00:11:58.919 different geological settings you'd expect to find on Mars. 229 00:11:58.960 --> 00:12:01.360 Okay, so it rolls, but that's only part of the puzzle. 230 00:12:02.039 --> 00:12:04.720 If this thing is tumbling end over end, how does 231 00:12:04.759 --> 00:12:08.399 the science package inside stay working? Can it even collect 232 00:12:08.399 --> 00:12:10.360 accurate data while it's bouncing? 233 00:12:10.399 --> 00:12:13.480 Around, great question, And that was the other major validation 234 00:12:13.559 --> 00:12:16.360 for the wind tunnel tests. Yeah, they had sensors on 235 00:12:16.440 --> 00:12:20.480 board the prototypes, and yes, the successfully recorded data even 236 00:12:20.559 --> 00:12:25.399 during that vigorous tumbling motion. Okay, and maybe even more critically, 237 00:12:25.679 --> 00:12:29.120 the actual physical behavior of the rover, how it accelerated 238 00:12:29.200 --> 00:12:32.440 its rolling speed, how it reacted to wind gusts. That 239 00:12:32.559 --> 00:12:36.559 behavior closely matched the complex computer models, the fluid dynamics 240 00:12:36.559 --> 00:12:38.919 simulations the team had previously developed. 241 00:12:39.039 --> 00:12:41.679 Why is matching the models so important? Is it just 242 00:12:41.759 --> 00:12:43.919 about proving their math was right. 243 00:12:44.399 --> 00:12:46.840 It's much more profound than just checking the math. It 244 00:12:47.039 --> 00:12:52.559 validates their ability to reliably predict where these things will go. Ah, Okay, 245 00:12:52.639 --> 00:12:54.559 think about it. If you're a mission control trying to 246 00:12:54.559 --> 00:12:56.919 manage a whole swarm of these things being blown around 247 00:12:56.960 --> 00:12:59.639 by the wind, you can't just rely on luck. You 248 00:12:59.720 --> 00:13:01.679 need high fidelity predictive. 249 00:13:01.240 --> 00:13:03.320 Model, right, You need to know roughly where they'll end 250 00:13:03.399 --> 00:13:04.320 up exactly. 251 00:13:04.440 --> 00:13:07.240 The our host results basically prove that the physics engine 252 00:13:07.279 --> 00:13:09.799 they're using to calculate, Okay, if the wind blows this 253 00:13:09.879 --> 00:13:14.279 way tomorrow, where will tumbleweed number seven likely be? That 254 00:13:14.399 --> 00:13:18.200 engine is accurate. That's absolutely fundamental for planning emission, for 255 00:13:18.320 --> 00:13:21.559 coordinating the swarm, for actually achieving the science goals. 256 00:13:21.600 --> 00:13:25.679 Okay, prediction is key. Now another practical thought. Mars isn't flat. 257 00:13:25.960 --> 00:13:30.039 It has hills, slopes, crater rims. A strong wind might 258 00:13:30.080 --> 00:13:33.159 push you up a gentle slope maybe, but what happens 259 00:13:33.159 --> 00:13:35.960 if the train gets steep? Can a wind blown ball 260 00:13:36.080 --> 00:13:37.279 actually climb up hill? 261 00:13:37.440 --> 00:13:39.559 That was a specific thing they tested in our house, 262 00:13:40.159 --> 00:13:42.840 and the results were pretty impressive. The scaled models showed 263 00:13:42.840 --> 00:13:45.399 they could climb a slope of eleven point five degrees 264 00:13:45.480 --> 00:13:46.879 inside that low pressure. 265 00:13:46.600 --> 00:13:48.120 Chamber eleven and a half degrees. 266 00:13:48.240 --> 00:13:50.519 Now, because of the differences in gravity between Earth and 267 00:13:50.559 --> 00:13:54.320 Mars and that low atmospheric density they calculator, they climbing 268 00:13:54.399 --> 00:13:57.639 eleven point five degrees in the chamber is equivalent to 269 00:13:57.879 --> 00:14:00.559 climbing roughly a thirty degree slope on the actual surface 270 00:14:00.559 --> 00:14:00.960 of Mars. 271 00:14:01.159 --> 00:14:05.279 Thirty degrees. Seriously, that's incredibly steep for any vehicle, let 272 00:14:05.279 --> 00:14:07.960 alone one that doesn't have powered wheels or direct steering. 273 00:14:08.360 --> 00:14:11.200 It is. It really pushes the boundaries of what we 274 00:14:11.360 --> 00:14:16.200 thought possible for passive mobility, and it dramatically increases the 275 00:14:16.240 --> 00:14:19.879 amount of Martian terrain that would theoretically be accessible to 276 00:14:19.919 --> 00:14:22.759 these rovers, fewer places they could get permanently stuck. 277 00:14:22.879 --> 00:14:24.360 That's a big deal for mission planning. 278 00:14:24.519 --> 00:14:29.600 Huge And get this, the lead scientist, Mario Yuaso Carvolio 279 00:14:29.679 --> 00:14:34.159 dipinto Balsamasso. He noted that these results are probably conservative, 280 00:14:34.279 --> 00:14:36.960 how so, because the small prototypes they used in the 281 00:14:37.000 --> 00:14:41.879 wind tunnel they were actually deliberately made heavier relative to 282 00:14:41.919 --> 00:14:45.120 their size than the final full scale five meter rover 283 00:14:45.320 --> 00:14:46.000 is designed to be. 284 00:14:46.240 --> 00:14:48.600 Ah So they were testing a harder to move version. 285 00:14:48.759 --> 00:14:51.639 Exactly, if they had perfectly scaled down the weight to 286 00:14:51.679 --> 00:14:55.000 surface area ratio, the actual threshold wind speed needed to 287 00:14:55.000 --> 00:14:57.559 get the real thing rolling on Mars might be even 288 00:14:57.639 --> 00:15:00.480 lower than that nine ten meters per second they measure, So. 289 00:15:00.440 --> 00:15:03.000 The reel rover might be even more responsive to the 290 00:15:03.039 --> 00:15:04.519 wind than these tests showed. 291 00:15:05.120 --> 00:15:08.200 That's the suggestion, which is very encouraging. 292 00:15:08.360 --> 00:15:11.039 Okay, so Phase one in the wind tunnel nailed down 293 00:15:11.039 --> 00:15:15.080 the physics, the mobility threshold, the slope climbing, and validated 294 00:15:15.080 --> 00:15:18.240 their predictive models. What was phase two about? That moved 295 00:15:18.240 --> 00:15:19.320 things out of the lab right right? 296 00:15:19.519 --> 00:15:22.679 Phase two is about real world operational data gathering. This 297 00:15:22.759 --> 00:15:25.279 was the field campaign. Back in April twenty twenty five, 298 00:15:25.879 --> 00:15:28.519 they took it to an inactive quarry in Mastricht in 299 00:15:28.600 --> 00:15:29.279 the Netherlands. 300 00:15:29.399 --> 00:15:30.679 Corey why there. 301 00:15:30.480 --> 00:15:35.039 Good analog for rough, rocky, irregular terrain, more realistic than 302 00:15:35.080 --> 00:15:37.639 a controlled lab surface, and for this test they used 303 00:15:37.639 --> 00:15:40.720 a larger prototypes a two point seven meters diameter version 304 00:15:41.000 --> 00:15:42.720 called the Tumbleweed Science Test. 305 00:15:42.559 --> 00:15:45.960 Bit so bigger, closer to the real scale. And the 306 00:15:46.039 --> 00:15:49.720 focus here wasn't if it rolls, but could the electronics 307 00:15:49.879 --> 00:15:51.759 survive and work exactly? 308 00:15:52.120 --> 00:15:54.919 The primary goal was proving that the internal science package 309 00:15:54.960 --> 00:15:58.120 the electronics could not only survive the chaotic tumbling motion 310 00:15:58.240 --> 00:16:02.200 over natural ground, but also rather clean usable scientific data 311 00:16:02.240 --> 00:16:02.879 while tumbling. 312 00:16:03.080 --> 00:16:05.480 What kind of instruments did this testbed carry? Was it 313 00:16:05.519 --> 00:16:07.440 just dummy weight or actual sensors? 314 00:16:07.840 --> 00:16:11.320 Actual sensors. It had a modular payload bay designed to 315 00:16:11.320 --> 00:16:14.960 fit standard off the shelf components, which helps keep costs 316 00:16:15.000 --> 00:16:18.240 down too. For this test. It carried a camera, a 317 00:16:18.240 --> 00:16:22.639 magnetometer for measuring magnetic fields, a GPS obviously for tracking 318 00:16:22.639 --> 00:16:25.799 his path on Earth during the test, and critically, an 319 00:16:25.840 --> 00:16:28.559 inertial measurement unit or IMU. 320 00:16:28.720 --> 00:16:32.240 Okay an IMU on a normal rover that helps with navigation, 321 00:16:32.799 --> 00:16:36.639 knowing its orientation precisely. But what does an IMU do 322 00:16:36.960 --> 00:16:40.080 inside something that's constantly spinning and tumbling. Seems like it 323 00:16:40.080 --> 00:16:41.000 would just be chaos. 324 00:16:41.240 --> 00:16:44.559 Well, the IMU is maybe the most critical piece for 325 00:16:44.840 --> 00:16:48.320 getting good data in this unique situation. It measures the 326 00:16:48.399 --> 00:16:52.399 rover's acceleration and its angular velocity. Basically, attracks exactly how 327 00:16:52.440 --> 00:16:54.639 fast and in which direction the sphere is rotating at 328 00:16:54.679 --> 00:16:55.360 every single moment. 329 00:16:55.440 --> 00:16:55.720 Okay. 330 00:16:55.960 --> 00:16:59.000 With that raw motion data, the onboard computer can then 331 00:16:59.039 --> 00:17:02.000 mathematically comp and state for the spin. It can essentially 332 00:17:02.080 --> 00:17:04.400 despin the readings from the other instruments. 333 00:17:04.480 --> 00:17:06.880 Ah, so it lets the camera take a stable picture 334 00:17:07.000 --> 00:17:09.200 or the magnetometer get a consistent reading even while the 335 00:17:09.240 --> 00:17:10.160 whole thing is rolling. 336 00:17:10.559 --> 00:17:15.400 Precisely, it allows you to extract stable, scientifically meaningful data 337 00:17:15.400 --> 00:17:18.599 streams from the chaos of the tumbling motion. And the 338 00:17:18.640 --> 00:17:22.559 mostric tests confirmed it worked. The platform successfully gathered and 339 00:17:22.599 --> 00:17:26.039 processed environmental data in real time while tumbling over that 340 00:17:26.200 --> 00:17:27.920 rough natural quarry terrain. 341 00:17:28.480 --> 00:17:30.799 Okay, so we have proof they can roll if the 342 00:17:30.799 --> 00:17:33.799 wind hits nine ten meters per second, they can climb 343 00:17:33.839 --> 00:17:37.799 surprisingly steep slopes, and they can actually collect scientific data 344 00:17:37.839 --> 00:17:40.359 while they're rolling. That brings us back to the big 345 00:17:40.440 --> 00:17:43.680 question about the fuel source you mentioned earlier. Near surface 346 00:17:43.720 --> 00:17:46.279 winds on Mars. We don't actually know that much about them. 347 00:17:46.440 --> 00:17:49.839 That's been the historical challenge. Yes, our understanding is patchy. 348 00:17:50.160 --> 00:17:53.599 Near surface winds are officially described as not well understood. 349 00:17:53.960 --> 00:17:57.720 Why because most of our data comes from landers or rovers. 350 00:17:57.480 --> 00:17:59.920 Which tend to land in relatively safe calm air. 351 00:18:00.359 --> 00:18:05.119 Exactly. We pick landing sites for safety primarily not necessarily, 352 00:18:05.160 --> 00:18:08.240 because they're the windiest places on Mars. So our data 353 00:18:08.240 --> 00:18:09.759 has been sparse and localized. 354 00:18:10.279 --> 00:18:13.039 That sounds like a potential achilles heel for the whole concept, 355 00:18:13.119 --> 00:18:15.440 doesn't it relying entirely on a power source that we 356 00:18:15.480 --> 00:18:17.079 admit we don't fully understand. 357 00:18:17.400 --> 00:18:19.799 It definitely would be except for some more recent data 358 00:18:19.839 --> 00:18:23.599 that's come in from let's say, non traditional wind sensors. 359 00:18:24.680 --> 00:18:28.279 And this new data really seems to bolster the tumbleweed 360 00:18:28.359 --> 00:18:30.160 idea quite significantly. 361 00:18:30.279 --> 00:18:32.240 Oh like what well. 362 00:18:32.319 --> 00:18:36.039 NASA's Insight Lander, for instance, its main job with seismology 363 00:18:36.359 --> 00:18:39.599 listening for marsquakes, but its seismometer. 364 00:18:39.160 --> 00:18:42.319 Was so sensitive it kicked up vibrations from the wind exactly. 365 00:18:42.559 --> 00:18:45.720 It recorded ground vibrations generated by the wind blowing across 366 00:18:45.720 --> 00:18:48.160 the lander in the surface, and it did this for 367 00:18:48.240 --> 00:18:51.480 over two Martian years, giving us a much longer baseline 368 00:18:51.480 --> 00:18:53.119 of wind activity at one location. 369 00:18:53.519 --> 00:18:55.680 Interesting any other sources, Yes. 370 00:18:55.599 --> 00:18:58.839 And perhaps even more directly relevant measurements taken during the 371 00:18:58.880 --> 00:19:02.799 flights of the Ingenuity Hell helicopter ah the little drone. Yeah. 372 00:19:02.839 --> 00:19:06.200 As it flew, it sensors gathered data on air density, temperature, 373 00:19:06.200 --> 00:19:09.000 and wind speeds much closer to the surface than orbiting 374 00:19:09.079 --> 00:19:12.480 satellites can measure. And what both Insight and Ingenuity showed 375 00:19:12.960 --> 00:19:15.799 was that higher wind speeds the kind cumble wheat needs 376 00:19:16.039 --> 00:19:19.480 seem to occur to hear the surface surprisingly frequently, more 377 00:19:19.519 --> 00:19:22.440 often than the older, lower average speeds typically reported. 378 00:19:22.599 --> 00:19:25.400 Okay, so we're getting better evidence that strong winds near 379 00:19:25.440 --> 00:19:28.160 the ground aren't just rare flukes. They might be a 380 00:19:28.240 --> 00:19:31.720 regular part of the Martian weather cycle. How does this 381 00:19:31.799 --> 00:19:34.920 new data line up with that ten meter per second 382 00:19:34.920 --> 00:19:35.920 threshold they need? 383 00:19:36.400 --> 00:19:39.720 The analysis, particularly of the Insight data by Mario's team, 384 00:19:40.440 --> 00:19:44.759 is really encouraging. They suggest that, especially in Mars's northern 385 00:19:44.839 --> 00:19:48.279 hemisphere during its summer season, the daytime wind speeds show 386 00:19:48.319 --> 00:19:52.000 a wide distribution, but it skewed towards those higher speeds. 387 00:19:52.039 --> 00:19:55.839 Needed Around ten meters per second isn't uncommon during the day. 388 00:19:55.759 --> 00:19:59.440 So it's like a reliable daily power source during summer days. 389 00:19:59.480 --> 00:20:02.440 That seems to be the pattern. And interestingly, even the nights, 390 00:20:02.559 --> 00:20:06.000 which are generally calmer, aren't always dead calm. They found 391 00:20:06.039 --> 00:20:09.400 that sometimes even at night, speeds can spike above ten 392 00:20:09.440 --> 00:20:12.200 meters per second, maybe due to atmospheric shifts or cold 393 00:20:12.240 --> 00:20:14.839 air drainage, winds flowing down slopes or canyon walls. 394 00:20:14.960 --> 00:20:17.119 Okay, so the fuel seems to be there, and maybe 395 00:20:17.119 --> 00:20:20.079 more reliably than we used to think. That's great news 396 00:20:20.079 --> 00:20:23.000 for planning emission. Now let's get to the numbers that 397 00:20:23.079 --> 00:20:26.880 really show why this is such a different approach the range. 398 00:20:26.960 --> 00:20:29.319 If you take that r who's wind tunnel data feed 399 00:20:29.359 --> 00:20:32.720 it into their validated prediction models, what kind of distances 400 00:20:32.799 --> 00:20:34.640 could these things actually cover on Mars. 401 00:20:34.960 --> 00:20:38.160