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If you are capable, please help us to create good quality subtitles: https://c3subtitles.de/talk/504 Thanks! 1 00:00:09,150 --> 00:00:11,279 To introduce this next talk, I will 2 00:00:11,280 --> 00:00:14,099 first ask you another question 3 00:00:14,100 --> 00:00:16,409 has anyone here ever had the chance 4 00:00:16,410 --> 00:00:17,940 to send something into space? 5 00:00:20,010 --> 00:00:22,410 One person, two persons, three? 6 00:00:23,460 --> 00:00:26,039 Well, more than I expected, 7 00:00:26,040 --> 00:00:27,179 less than I hoped for. 8 00:00:28,410 --> 00:00:30,659 This next talk might be giving 9 00:00:30,660 --> 00:00:33,119 you a small introduction 10 00:00:33,120 --> 00:00:35,219 to how how to do 11 00:00:35,220 --> 00:00:36,369 that. 12 00:00:36,370 --> 00:00:38,489 So our next speaker, 13 00:00:38,490 --> 00:00:39,819 let's just call him Uncle 14 00:00:40,830 --> 00:00:43,259 Um, has studied first 15 00:00:43,260 --> 00:00:45,359 in Brunswick and pulled 16 00:00:45,360 --> 00:00:47,429 hypertrophic the Eric, which 17 00:00:47,430 --> 00:00:49,679 I am proudly representing here, not 18 00:00:49,680 --> 00:00:50,680 an advertisement, 19 00:00:51,810 --> 00:00:54,359 and then moved over to Cohuna, 20 00:00:54,360 --> 00:00:56,819 where he studied space science 21 00:00:56,820 --> 00:00:59,010 and then designed a CubeSat. 22 00:01:01,080 --> 00:01:03,149 For the next hour, he will introduce 23 00:01:03,150 --> 00:01:04,289 you to this topic. 24 00:01:04,290 --> 00:01:06,419 And I hope he will answer 25 00:01:06,420 --> 00:01:08,459 this one important question. 26 00:01:08,460 --> 00:01:10,439 How hard can it be? 27 00:01:10,440 --> 00:01:12,539 Audience give a warm applause to 28 00:01:12,540 --> 00:01:14,879 with. So you want to build the satellite. 29 00:01:24,660 --> 00:01:26,789 Yeah, thanks for the introduction, as 30 00:01:26,790 --> 00:01:29,159 has been said. I've studied in Kiruna 31 00:01:29,160 --> 00:01:31,709 and up there we have reindeer's 32 00:01:31,710 --> 00:01:34,109 iron ore mining and space research. 33 00:01:34,110 --> 00:01:35,999 And I just want to give you a brief 34 00:01:36,000 --> 00:01:37,979 glimpse of the complexities of designing 35 00:01:37,980 --> 00:01:41,399 a spacecraft, especially a CubeSat. 36 00:01:41,400 --> 00:01:42,659 So what is the CubeSat? 37 00:01:42,660 --> 00:01:44,969 And CubeSat is a picture on our satellite 38 00:01:44,970 --> 00:01:46,149 phone to keeps us and people. 39 00:01:46,150 --> 00:01:48,389 Now, satellite is a satellite which 40 00:01:48,390 --> 00:01:50,489 folds in the arbitrary weight class of 41 00:01:50,490 --> 00:01:52,109 one to 10 kilograms. 42 00:01:52,110 --> 00:01:54,509 And the special thing about CubeSat 43 00:01:54,510 --> 00:01:56,079 is inside the picture. 44 00:01:56,080 --> 00:01:58,109 And NASA just launched not only as a 45 00:01:58,110 --> 00:02:00,779 secondary payload, but as a containerized 46 00:02:00,780 --> 00:02:03,149 payload data to tell you what 47 00:02:03,150 --> 00:02:04,349 this means. 48 00:02:04,350 --> 00:02:06,449 And the interesting thing about CubeSat 49 00:02:06,450 --> 00:02:09,119 are that they provide a relatively 50 00:02:09,120 --> 00:02:10,709 low entry hurdle into satellite 51 00:02:10,710 --> 00:02:11,969 technology. 52 00:02:11,970 --> 00:02:14,639 So a short history about CubeSat. 53 00:02:14,640 --> 00:02:16,919 There were small satellites before, 54 00:02:16,920 --> 00:02:18,299 especially amateur radio satellites, 55 00:02:18,300 --> 00:02:20,519 which acted as relay stations for amateur 56 00:02:20,520 --> 00:02:21,509 radio users. 57 00:02:21,510 --> 00:02:23,309 But most of them didn't follow any 58 00:02:23,310 --> 00:02:24,719 standard. So there was a lot of 59 00:02:24,720 --> 00:02:27,389 reinventing the wheel with 60 00:02:27,390 --> 00:02:29,519 progressing miniaturization of electronic 61 00:02:29,520 --> 00:02:31,619 components. It was possible to 62 00:02:31,620 --> 00:02:33,619 shrink these small satellites that 63 00:02:33,620 --> 00:02:36,239 formerly had about a cubic meter, maybe 64 00:02:36,240 --> 00:02:38,429 in size, down to just 65 00:02:38,430 --> 00:02:39,959 the CubeSat form factor. 66 00:02:39,960 --> 00:02:42,089 And therefore chipsets were invented 67 00:02:42,090 --> 00:02:44,549 mostly as a way to for students 68 00:02:44,550 --> 00:02:46,679 to learn how to build a full fledged 69 00:02:46,680 --> 00:02:48,759 satellite without having to a long delay 70 00:02:48,760 --> 00:02:51,419 with previous small satellite projects. 71 00:02:51,420 --> 00:02:53,309 But since then, CubeSat has not only been 72 00:02:53,310 --> 00:02:54,310 used in educational 73 00:02:56,880 --> 00:02:59,399 context, but also in scientific research 74 00:02:59,400 --> 00:03:01,529 and technology demonstrations and even as 75 00:03:01,530 --> 00:03:03,929 commercial applications. 76 00:03:03,930 --> 00:03:05,459 So what is in the CubeSat design 77 00:03:05,460 --> 00:03:06,599 specifications? 78 00:03:06,600 --> 00:03:08,339 And most importantly, it defines the 79 00:03:08,340 --> 00:03:10,619 CubeSat shape and Mars, but 80 00:03:10,620 --> 00:03:12,929 also defines what makes the CubeSat 81 00:03:12,930 --> 00:03:14,999 so easily transportable as a 82 00:03:15,000 --> 00:03:16,199 secondary payload. 83 00:03:16,200 --> 00:03:17,789 So, for example, it ensures that the 84 00:03:17,790 --> 00:03:20,549 launch vehicle is safe from the CubeSat, 85 00:03:20,550 --> 00:03:22,739 but also that the launch provider 86 00:03:22,740 --> 00:03:24,839 doesn't have to worry about any 87 00:03:24,840 --> 00:03:27,569 liability for not 88 00:03:27,570 --> 00:03:28,739 adhering to regulations. 89 00:03:28,740 --> 00:03:31,169 So mostly with 90 00:03:31,170 --> 00:03:33,269 regards to radio communication and all 91 00:03:33,270 --> 00:03:34,270 to degree. 92 00:03:34,920 --> 00:03:37,139 But in general, these standards inside 93 00:03:37,140 --> 00:03:38,579 the CubeSat design specifications, which 94 00:03:38,580 --> 00:03:40,199 is the official document you can 95 00:03:40,200 --> 00:03:42,599 download, is just a 96 00:03:42,600 --> 00:03:44,549 minimum, the minimum common denominator 97 00:03:44,550 --> 00:03:47,129 between a different launch providers 98 00:03:47,130 --> 00:03:49,019 of CubeSat. So if you adhere to this 99 00:03:49,020 --> 00:03:50,729 standard, you will definitely be fine. 100 00:03:50,730 --> 00:03:52,859 But often you can handle 101 00:03:52,860 --> 00:03:54,509 waveforms which give you a small 102 00:03:54,510 --> 00:03:55,679 exceptions, or you can accuse the 103 00:03:55,680 --> 00:03:58,229 provider of more volume 104 00:03:58,230 --> 00:03:59,400 in certain directions or something. 105 00:04:00,750 --> 00:04:02,999 So the CubeSat envelope, 106 00:04:03,000 --> 00:04:04,979 basically almost a 10 by 10 by 10 107 00:04:04,980 --> 00:04:06,329 centimeter block. 108 00:04:06,330 --> 00:04:08,399 I had chosen to teach the 109 00:04:08,400 --> 00:04:09,990 metric system to American students. 110 00:04:12,150 --> 00:04:14,249 It's not really 10 centimeters in height 111 00:04:14,250 --> 00:04:16,559 because we have small standards here, 112 00:04:16,560 --> 00:04:18,539 but close enough. 113 00:04:18,540 --> 00:04:20,669 And on the edges you have these guideway 114 00:04:20,670 --> 00:04:22,799 which have a defined minimum 115 00:04:22,800 --> 00:04:24,929 hardness because they're so important 116 00:04:24,930 --> 00:04:27,000 to hold the CubeSat in place and later 117 00:04:28,140 --> 00:04:29,140 put them into space. 118 00:04:30,210 --> 00:04:32,429 So from these space units, you 119 00:04:32,430 --> 00:04:34,289 have different defined form factors, 120 00:04:34,290 --> 00:04:36,869 usually whole multiples 121 00:04:36,870 --> 00:04:38,639 of the base one unit. 122 00:04:38,640 --> 00:04:40,799 So one, two, three, four and so 123 00:04:40,800 --> 00:04:41,099 on. 124 00:04:41,100 --> 00:04:43,139 But sometimes you also see half units, 125 00:04:43,140 --> 00:04:44,490 CubeSat or one and a half units. 126 00:04:45,730 --> 00:04:47,859 So another standard you might encounter 127 00:04:47,860 --> 00:04:50,229 is to keep the kids thus 128 00:04:50,230 --> 00:04:52,029 PCB, which follows the P.S. 129 00:04:52,030 --> 00:04:54,129 104 standard for the shape of the 130 00:04:54,130 --> 00:04:55,839 PCB and the mounting holds, but has a 131 00:04:55,840 --> 00:04:58,689 special, uh, follow connector. 132 00:04:58,690 --> 00:05:00,220 And on the smaller connectors, you have 133 00:05:01,390 --> 00:05:03,969 common voltages, better voltages, 134 00:05:03,970 --> 00:05:06,609 Digital BOCES general-purpose 135 00:05:06,610 --> 00:05:08,619 and a lot of commercial CubeSat 136 00:05:08,620 --> 00:05:10,719 components and substances you can buy for 137 00:05:10,720 --> 00:05:12,369 to this form. Of course, this is a 138 00:05:12,370 --> 00:05:14,739 pretty, pretty big PCB and some 139 00:05:14,740 --> 00:05:16,809 manufacturers have gone on 140 00:05:16,810 --> 00:05:19,209 to define proprietary formats for 141 00:05:19,210 --> 00:05:21,549 fitting more functions in this same 142 00:05:21,550 --> 00:05:22,550 PCB 143 00:05:23,740 --> 00:05:25,989 form factor with supports and so on, 144 00:05:25,990 --> 00:05:28,179 and something which you might find 145 00:05:28,180 --> 00:05:29,739 and is that the mounting holes are not 146 00:05:29,740 --> 00:05:30,579 really symmetric. 147 00:05:30,580 --> 00:05:32,110 So, yeah, 148 00:05:34,050 --> 00:05:36,159 it's, uh, you have to pay attention how 149 00:05:36,160 --> 00:05:38,739 to mount a strong intellectual structure. 150 00:05:38,740 --> 00:05:40,779 And these PCBs are then stacked. 151 00:05:40,780 --> 00:05:42,849 And the connector here is just for the 152 00:05:42,850 --> 00:05:43,899 electrical connection. 153 00:05:43,900 --> 00:05:45,339 The real mechanical connection which 154 00:05:45,340 --> 00:05:47,169 holds the PCB inside the CubeSat 155 00:05:47,170 --> 00:05:49,749 structure is done via threated what's 156 00:05:49,750 --> 00:05:51,189 inserted here in the edges. 157 00:05:51,190 --> 00:05:53,379 And then the piece holds 158 00:05:53,380 --> 00:05:54,459 together with spacers. 159 00:05:55,790 --> 00:05:57,889 So how is it keeps that launched ships 160 00:05:57,890 --> 00:05:59,209 that are integrated in so-called pot 161 00:05:59,210 --> 00:06:01,309 dispensers so you can see six 162 00:06:01,310 --> 00:06:04,099 pot dispensers in a bigger box and just 163 00:06:04,100 --> 00:06:05,779 dispensers that are mounted on the upper 164 00:06:05,780 --> 00:06:06,799 stage of the rocket. 165 00:06:06,800 --> 00:06:09,139 So, for example, on the payload adapter, 166 00:06:09,140 --> 00:06:11,329 somewhere in between or even below 167 00:06:11,330 --> 00:06:13,639 near the engine and after 168 00:06:13,640 --> 00:06:15,859 the main payload is gone and it had a 169 00:06:15,860 --> 00:06:17,869 good head start, so you can't hit it 170 00:06:17,870 --> 00:06:18,619 anymore. 171 00:06:18,620 --> 00:06:20,929 These pots are opened and the chipsets 172 00:06:20,930 --> 00:06:21,930 are released. 173 00:06:22,610 --> 00:06:24,889 You can see such a 174 00:06:24,890 --> 00:06:26,509 pot. So the most important 175 00:06:27,710 --> 00:06:30,049 will to work this pot does is it contains 176 00:06:30,050 --> 00:06:31,099 the CubeSat during launch. 177 00:06:31,100 --> 00:06:32,449 So it holds it in place. 178 00:06:32,450 --> 00:06:34,219 And even if something breaks inside the 179 00:06:34,220 --> 00:06:36,289 CubeSat, it will not hurt the 180 00:06:36,290 --> 00:06:38,449 main satellite because this is 181 00:06:38,450 --> 00:06:40,309 all the rocket operator. 182 00:06:42,050 --> 00:06:44,209 So you integrate 183 00:06:44,210 --> 00:06:46,069 it into this port and this is the last 184 00:06:46,070 --> 00:06:47,749 time you see a satellite. 185 00:06:47,750 --> 00:06:50,399 It has some access hatches to remove 186 00:06:50,400 --> 00:06:52,999 and safety plugs after integration, 187 00:06:53,000 --> 00:06:55,429 but then it's integrated 188 00:06:55,430 --> 00:06:57,019 a chip to launch site and you don't see 189 00:06:57,020 --> 00:06:59,089 them inside this CubeSat, 190 00:06:59,090 --> 00:07:00,919 this case, a three year old CubeSat is 191 00:07:00,920 --> 00:07:03,019 hosted by whales and sitting on top 192 00:07:03,020 --> 00:07:05,209 of a spring-loaded push a plate. 193 00:07:05,210 --> 00:07:07,309 And then when time comes and you're in 194 00:07:07,310 --> 00:07:09,379 space, the box opens and the push 195 00:07:09,380 --> 00:07:11,569 up just pushes out a satellite into 196 00:07:11,570 --> 00:07:12,570 space. 197 00:07:13,520 --> 00:07:16,729 So some about payload safety, 198 00:07:16,730 --> 00:07:19,669 the CubeSat design specifications 199 00:07:19,670 --> 00:07:20,689 have a couple of them. 200 00:07:20,690 --> 00:07:22,009 So, for example, the payload has to be 201 00:07:22,010 --> 00:07:24,259 dead doing 202 00:07:24,260 --> 00:07:25,729 doing launch. 203 00:07:25,730 --> 00:07:28,249 So there is no power going anywhere 204 00:07:28,250 --> 00:07:29,599 inside your satellite. 205 00:07:29,600 --> 00:07:31,729 The batteries and solar panels are 206 00:07:31,730 --> 00:07:34,189 physically via launch switches 207 00:07:35,630 --> 00:07:37,709 separated from the electronics. 208 00:07:37,710 --> 00:07:40,399 This means that you get no communication 209 00:07:40,400 --> 00:07:41,599 after integration. 210 00:07:41,600 --> 00:07:43,669 You also can't emit 211 00:07:43,670 --> 00:07:45,799 any RF frequencies 212 00:07:45,800 --> 00:07:48,199 or magnetic fields by accident and 213 00:07:48,200 --> 00:07:50,359 therefore ensure that you're a good 214 00:07:50,360 --> 00:07:51,499 passenger. 215 00:07:51,500 --> 00:07:53,599 Also, of course, because the airport 216 00:07:53,600 --> 00:07:55,789 has to contain your satellite, you 217 00:07:55,790 --> 00:07:57,559 are also not allowed to have very high 218 00:07:57,560 --> 00:07:59,719 density of energy inside 219 00:07:59,720 --> 00:08:01,009 your satellite because that has the 220 00:08:01,010 --> 00:08:03,529 potential of getting out of the port. 221 00:08:03,530 --> 00:08:04,669 Let's put it this way. 222 00:08:04,670 --> 00:08:06,979 And so this is especially important 223 00:08:06,980 --> 00:08:08,119 if you want to have some pressurized 224 00:08:08,120 --> 00:08:10,369 containers on board or if you would have 225 00:08:10,370 --> 00:08:11,569 if you wanted to have a kind of 226 00:08:11,570 --> 00:08:14,209 propulsion, for example, the chemical 227 00:08:14,210 --> 00:08:16,099 propulsion, this is usually not possible 228 00:08:16,100 --> 00:08:18,679 because of this energy limit, 229 00:08:18,680 --> 00:08:19,909 therefore, the limits, for example, on 230 00:08:19,910 --> 00:08:21,169 hazardous substances. 231 00:08:21,170 --> 00:08:23,269 So the workers on the ground say from 232 00:08:23,270 --> 00:08:25,399 your satellite, also on volatile 233 00:08:25,400 --> 00:08:26,929 materials which evaporate from your 234 00:08:26,930 --> 00:08:29,059 satellite, and might we condense on 235 00:08:29,060 --> 00:08:30,979 other people's satellite on their optics 236 00:08:30,980 --> 00:08:31,999 or something like that? 237 00:08:32,000 --> 00:08:33,000 So it is not allowed. 238 00:08:35,120 --> 00:08:37,399 So I just want to go over the most 239 00:08:37,400 --> 00:08:39,350 important subsystems of CubeSat, 240 00:08:40,549 --> 00:08:42,168 which you can see here, they are mostly 241 00:08:42,169 --> 00:08:43,408 similar to big satellites. 242 00:08:43,409 --> 00:08:45,049 It's just the difference is that they're, 243 00:08:45,050 --> 00:08:47,239 uh, miniaturized and you 244 00:08:47,240 --> 00:08:48,889 have a much tighter integration between 245 00:08:48,890 --> 00:08:50,659 different components. So you see that 246 00:08:50,660 --> 00:08:53,479 there are some a lot of interdependencies 247 00:08:53,480 --> 00:08:55,369 between these systems. 248 00:08:56,420 --> 00:08:57,529 So starting with mechanisms and 249 00:08:57,530 --> 00:08:58,339 structure. 250 00:08:58,340 --> 00:09:00,409 So a mechanism and structures, 251 00:09:00,410 --> 00:09:02,839 everything that holds things in place 252 00:09:02,840 --> 00:09:04,399 of makes things move. 253 00:09:04,400 --> 00:09:06,859 And you have to see that mechanisms 254 00:09:06,860 --> 00:09:08,449 are common points of failure in space 255 00:09:08,450 --> 00:09:10,789 project. So it's important that if you 256 00:09:10,790 --> 00:09:12,979 don't want to be one of the 50 percent 257 00:09:12,980 --> 00:09:15,319 of first time satellites, CubeSat first 258 00:09:15,320 --> 00:09:17,539 CubeSat would fail without doing anything 259 00:09:17,540 --> 00:09:18,739 significant in orbit. 260 00:09:18,740 --> 00:09:20,419 You have to verify them. 261 00:09:20,420 --> 00:09:21,919 And the common mechanisms include, for 262 00:09:21,920 --> 00:09:23,449 example, antenna deployment. 263 00:09:23,450 --> 00:09:25,279 If you have external, uh, deployable 264 00:09:25,280 --> 00:09:27,529 solar panels that can be deployed and 265 00:09:27,530 --> 00:09:29,239 this is usually just done by spring, 266 00:09:29,240 --> 00:09:31,039 loading them and holding them back by a 267 00:09:31,040 --> 00:09:32,869 burn wire, which you burn in orbit and 268 00:09:32,870 --> 00:09:33,889 then it releases. 269 00:09:35,620 --> 00:09:37,779 So verification, what are common 270 00:09:37,780 --> 00:09:39,759 verification methods, for example, for 271 00:09:39,760 --> 00:09:41,529 launch vibration, the vibration during 272 00:09:41,530 --> 00:09:43,269 launch are much more severe for your 273 00:09:43,270 --> 00:09:45,699 satellite than just a static Gillard's. 274 00:09:45,700 --> 00:09:47,829 So how do you find 275 00:09:47,830 --> 00:09:49,899 out what kind of vibrations do 276 00:09:49,900 --> 00:09:51,809 you expect? You could read the manual. 277 00:09:51,810 --> 00:09:54,159 Nearly nearly any major 278 00:09:54,160 --> 00:09:56,349 commercial satellite launcher 279 00:09:56,350 --> 00:09:58,239 has a publicly available user manual 280 00:09:58,240 --> 00:10:00,049 search area and five soldiers and so on. 281 00:10:00,050 --> 00:10:01,689 So you can just find it on the Internet. 282 00:10:01,690 --> 00:10:03,459 The promise they give you a vibration 283 00:10:03,460 --> 00:10:05,699 profile, which is meant for the main 284 00:10:05,700 --> 00:10:08,379 main payload and your mountainside put 285 00:10:08,380 --> 00:10:10,509 on somewhere else on the upper 286 00:10:10,510 --> 00:10:12,939 stage. So you would need to know 287 00:10:12,940 --> 00:10:15,189 the behavior of the port and amounting 288 00:10:15,190 --> 00:10:17,079 to really know what your satellite feels. 289 00:10:17,080 --> 00:10:18,879 So it's better to just look at your 290 00:10:18,880 --> 00:10:19,869 CubeSat launch provider. 291 00:10:19,870 --> 00:10:21,969 They also have documents and they specify 292 00:10:21,970 --> 00:10:23,589 an acceptance level of operations you 293 00:10:23,590 --> 00:10:26,049 have to withstand 294 00:10:26,050 --> 00:10:28,119 before and during launch. 295 00:10:28,120 --> 00:10:30,789 So that's usually what you test for 296 00:10:30,790 --> 00:10:33,249 and for the mechanisms. 297 00:10:33,250 --> 00:10:35,259 Of course, it's usually easy to get it 298 00:10:35,260 --> 00:10:37,239 working on Earth under ambient 299 00:10:37,240 --> 00:10:38,199 temperature and so on. 300 00:10:38,200 --> 00:10:39,879 And so it's very important if you have a 301 00:10:39,880 --> 00:10:41,499 crucial mechanism that you test under the 302 00:10:41,500 --> 00:10:43,419 conditions that you might actually 303 00:10:43,420 --> 00:10:45,939 encounter in space. So, for example, 304 00:10:45,940 --> 00:10:48,339 after it has been shaken from the launch 305 00:10:48,340 --> 00:10:51,249 or the temperature 306 00:10:51,250 --> 00:10:53,439 profile to a counter in space, 307 00:10:53,440 --> 00:10:55,749 so it might have different extensions 308 00:10:55,750 --> 00:10:57,819 and much stuck or a 309 00:10:57,820 --> 00:10:59,829 vacuum might be affected and also low 310 00:10:59,830 --> 00:11:01,749 battery levels because of her wires. 311 00:11:01,750 --> 00:11:03,729 And you want to deploy solar panels and 312 00:11:03,730 --> 00:11:04,729 you don't have enough battery. 313 00:11:04,730 --> 00:11:06,339 How do you get more battery power? 314 00:11:06,340 --> 00:11:08,859 Because you can't play with solar panels, 315 00:11:08,860 --> 00:11:11,079 so please test them also under these 316 00:11:11,080 --> 00:11:12,729 circumstances. 317 00:11:12,730 --> 00:11:14,979 So a next few words about 318 00:11:14,980 --> 00:11:15,980 thermal. 319 00:11:16,420 --> 00:11:18,789 So there was often a question of space, 320 00:11:18,790 --> 00:11:20,859 hot or cold. It totally depends, 321 00:11:20,860 --> 00:11:22,959 because in space, due to the lack of 322 00:11:22,960 --> 00:11:25,149 atmosphere, the 323 00:11:25,150 --> 00:11:27,429 heat can only be transported 324 00:11:27,430 --> 00:11:29,349 over conduction inside the satellite 325 00:11:29,350 --> 00:11:30,789 radiation and such a satellite. 326 00:11:30,790 --> 00:11:33,369 And so the outside only radiation. 327 00:11:33,370 --> 00:11:35,559 And due to the small thermal 328 00:11:35,560 --> 00:11:37,749 mass of CubeSat, you can get 329 00:11:37,750 --> 00:11:39,909 very high temperature variations 330 00:11:39,910 --> 00:11:40,959 even over one orbit. 331 00:11:40,960 --> 00:11:43,209 So from the eclipse you had inside 332 00:11:43,210 --> 00:11:44,619 the shadow of the Earth and then in the 333 00:11:44,620 --> 00:11:45,129 sun. 334 00:11:45,130 --> 00:11:46,779 So, for example, the Sun Cube satellite 335 00:11:46,780 --> 00:11:49,099 published its data online, 336 00:11:49,100 --> 00:11:51,939 has surface temperatures from 337 00:11:51,940 --> 00:11:54,489 minus 20 degrees to 40 degrees, 338 00:11:54,490 --> 00:11:56,350 just maybe over one orbit. 339 00:11:58,170 --> 00:12:00,299 And so what you get is a radiation 340 00:12:00,300 --> 00:12:02,489 balance between solar 341 00:12:02,490 --> 00:12:04,559 radiation, also some reflected solar 342 00:12:04,560 --> 00:12:06,899 radiation from Earth, also emission 343 00:12:06,900 --> 00:12:08,489 of some radiation from Earth. 344 00:12:08,490 --> 00:12:09,839 And then, of course, your satellites 345 00:12:09,840 --> 00:12:12,209 heats up, also emits some radiation, 346 00:12:12,210 --> 00:12:14,789 and then you get a kind of balance 347 00:12:14,790 --> 00:12:17,099 or let's say a 348 00:12:17,100 --> 00:12:18,100 budget. 349 00:12:18,940 --> 00:12:21,369 So what can you do for externally, 350 00:12:21,370 --> 00:12:23,559 usually you can just on 351 00:12:23,560 --> 00:12:26,629 keep that level change to 352 00:12:26,630 --> 00:12:28,869 and inner the values of the of 353 00:12:28,870 --> 00:12:29,289 the surface. 354 00:12:29,290 --> 00:12:31,449 So let's say the color of the 355 00:12:31,450 --> 00:12:33,639 surface for irradiation and so 356 00:12:33,640 --> 00:12:34,929 on. The problem is that the large 357 00:12:34,930 --> 00:12:36,159 contribution of the surface will be 358 00:12:36,160 --> 00:12:37,419 covered in solar panels because you 359 00:12:37,420 --> 00:12:38,679 really need this power. 360 00:12:38,680 --> 00:12:40,719 So you can't really just make it 361 00:12:40,720 --> 00:12:42,309 reflective. That would be not a good 362 00:12:42,310 --> 00:12:43,310 idea. 363 00:12:44,110 --> 00:12:44,829 What you can do. 364 00:12:44,830 --> 00:12:46,299 For example, if you have a problem with 365 00:12:46,300 --> 00:12:48,069 uneven heating, if you have one side of 366 00:12:48,070 --> 00:12:49,839 the satellite which might always face the 367 00:12:49,840 --> 00:12:51,699 sun and overheat while the other one is 368 00:12:51,700 --> 00:12:53,589 relatively cool, you can go in something 369 00:12:53,590 --> 00:12:55,449 we call the barbecue mode, which 370 00:12:55,450 --> 00:12:57,069 basically means you rotate your 371 00:12:57,070 --> 00:12:58,929 satellites and make it crispy from all 372 00:12:58,930 --> 00:12:59,930 from outside. 373 00:13:01,540 --> 00:13:03,879 Uh, yeah, but internally, 374 00:13:03,880 --> 00:13:05,799 if you have some very sensitive, heat 375 00:13:05,800 --> 00:13:08,049 sensitive components, you might 376 00:13:08,050 --> 00:13:10,149 want to insulate them to keep 377 00:13:10,150 --> 00:13:11,709 them away from this huge temperature 378 00:13:11,710 --> 00:13:13,929 swings you see on the outside of the, 379 00:13:13,930 --> 00:13:15,459 uh, of the satellite. 380 00:13:15,460 --> 00:13:16,809 So, for example, you can start by 381 00:13:16,810 --> 00:13:18,309 insulating the side panels. 382 00:13:18,310 --> 00:13:20,559 So these most important things are kept 383 00:13:20,560 --> 00:13:22,089 away from your inside. 384 00:13:22,090 --> 00:13:24,189 But then you also have to see that the 385 00:13:24,190 --> 00:13:26,289 heat you generate with electronics inside 386 00:13:26,290 --> 00:13:28,659 or a fetus inside has to go somewhere. 387 00:13:28,660 --> 00:13:30,549 So you need some kind of conduction path 388 00:13:30,550 --> 00:13:31,779 to the outside. 389 00:13:31,780 --> 00:13:33,960 This is a very complex tradeoff. 390 00:13:35,020 --> 00:13:36,729 So how can you verify it? 391 00:13:36,730 --> 00:13:39,189 First thing you could do would be just 392 00:13:39,190 --> 00:13:41,319 think about if the satellite would just 393 00:13:41,320 --> 00:13:43,389 be masked with a surface in 394 00:13:43,390 --> 00:13:44,769 orbit under certain illumination 395 00:13:44,770 --> 00:13:47,079 conditions. Would it heat up to a certain 396 00:13:47,080 --> 00:13:49,179 temperature or would it cool down 397 00:13:49,180 --> 00:13:50,619 to a certain temperature? 398 00:13:50,620 --> 00:13:52,869 So what is the radiation really balance 399 00:13:52,870 --> 00:13:54,549 temperature? So it just gives you a first 400 00:13:54,550 --> 00:13:56,619 idea of what problems 401 00:13:56,620 --> 00:13:58,419 you're facing. But in the end, you 402 00:13:58,420 --> 00:14:00,669 usually do a fine 403 00:14:00,670 --> 00:14:02,799 analysis and try 404 00:14:02,800 --> 00:14:04,599 to just calculate what is the temperature 405 00:14:04,600 --> 00:14:06,739 difference, temperature distribution and 406 00:14:06,740 --> 00:14:08,529 such a satellite, especially because with 407 00:14:08,530 --> 00:14:11,109 this earth shattering 408 00:14:11,110 --> 00:14:12,819 time and time and sunlight, you really 409 00:14:12,820 --> 00:14:15,239 have a transient behavior you want to do 410 00:14:15,240 --> 00:14:18,159 you want to know about, and then to 411 00:14:18,160 --> 00:14:20,409 finally verify it, you usually 412 00:14:20,410 --> 00:14:21,399 do a thermal vacuum test. 413 00:14:21,400 --> 00:14:23,649 Also to know if the models you did 414 00:14:23,650 --> 00:14:25,629 here have anything to do with reality 415 00:14:25,630 --> 00:14:27,129 that isn't always the case. 416 00:14:28,420 --> 00:14:30,549 So thermal vacuum 417 00:14:30,550 --> 00:14:32,409 vacuum because of course, if you would 418 00:14:32,410 --> 00:14:34,779 have convection, this changes the physics 419 00:14:34,780 --> 00:14:36,549 a lot because it's much more prominent. 420 00:14:36,550 --> 00:14:38,259 So we want to do it in a vacuum 421 00:14:38,260 --> 00:14:39,219 environment. 422 00:14:39,220 --> 00:14:41,319 And of course, you might think, OK, 423 00:14:41,320 --> 00:14:42,999 this is relatively late in the 424 00:14:43,000 --> 00:14:44,409 development schedule because you always 425 00:14:44,410 --> 00:14:45,579 need your components. 426 00:14:45,580 --> 00:14:47,529 And maybe if there was a major problem, 427 00:14:47,530 --> 00:14:49,809 this gives you a lot of problems 428 00:14:49,810 --> 00:14:51,009 because everything else is already 429 00:14:51,010 --> 00:14:51,639 developed. 430 00:14:51,640 --> 00:14:53,499 So maybe in the early stages of your 431 00:14:53,500 --> 00:14:55,639 development, you want to test just 432 00:14:55,640 --> 00:14:58,029 the structural model with resistible 433 00:14:58,030 --> 00:15:00,399 heaters as Camelot's basically 434 00:15:00,400 --> 00:15:01,400 for heat. 435 00:15:02,470 --> 00:15:04,909 So, too, the attitude, determination, 436 00:15:04,910 --> 00:15:07,419 control subsystem, so darned 437 00:15:07,420 --> 00:15:08,949 attitude is the orientation of the 438 00:15:08,950 --> 00:15:11,559 CubeSat in space, you can define 439 00:15:11,560 --> 00:15:13,899 different frames. Want to know your 440 00:15:13,900 --> 00:15:15,879 orientation and inertial frames for non 441 00:15:15,880 --> 00:15:18,039 rotating pages with regards to 442 00:15:18,040 --> 00:15:20,709 the stars of Central Frame is 443 00:15:20,710 --> 00:15:21,219 interesting. 444 00:15:21,220 --> 00:15:23,349 If you want to do Earth observations, Sun 445 00:15:23,350 --> 00:15:24,669 Center frame, it's interesting if you 446 00:15:24,670 --> 00:15:26,829 want to know something about the thermal 447 00:15:26,830 --> 00:15:28,629 conditions or your power generation 448 00:15:30,190 --> 00:15:31,929 and for control, what do we have to work 449 00:15:31,930 --> 00:15:32,319 against? 450 00:15:32,320 --> 00:15:34,569 So we have to work against radiation 451 00:15:34,570 --> 00:15:37,339 pressure from the sun magnetic torque. 452 00:15:37,340 --> 00:15:40,059 Uh, we've got the cleanest 453 00:15:40,060 --> 00:15:41,559 basically means if you have built your 454 00:15:41,560 --> 00:15:43,929 satellite, launched into orbit, you might 455 00:15:43,930 --> 00:15:46,299 not have built a satellite into 456 00:15:46,300 --> 00:15:48,459 it. You might, but that comes later. 457 00:15:48,460 --> 00:15:50,919 But if you don't want to have magnets 458 00:15:50,920 --> 00:15:52,359 in your cell that you still have some 459 00:15:52,360 --> 00:15:53,589 kind of magnetic field. 460 00:15:53,590 --> 00:15:54,649 So, for example, of course, you have 461 00:15:54,650 --> 00:15:56,649 connected magnetic, magnetized materials 462 00:15:56,650 --> 00:15:58,449 inside or just because of the currents 463 00:15:58,450 --> 00:15:59,739 flowing inside your satellite. 464 00:15:59,740 --> 00:16:01,809 And this creates a talk with, uh, 465 00:16:01,810 --> 00:16:03,579 with the magnetic field and gives you a 466 00:16:03,580 --> 00:16:05,169 disturbance. 467 00:16:05,170 --> 00:16:07,239 But also, if you have a baby a little 468 00:16:07,240 --> 00:16:09,459 larger CubeSat, you might encounter and 469 00:16:09,460 --> 00:16:11,019 even drag, for example, if you have a 470 00:16:11,020 --> 00:16:13,149 deployable solar panel or something like 471 00:16:13,150 --> 00:16:15,309 that. So even though not very 472 00:16:15,310 --> 00:16:17,289 dense atmosphere might give you some kind 473 00:16:17,290 --> 00:16:19,149 of disturbance, and if you would have a 474 00:16:19,150 --> 00:16:20,679 really big satellite or maybe have a 475 00:16:20,680 --> 00:16:23,079 tether or something, just a change 476 00:16:23,080 --> 00:16:24,969 in gravity with height, induce us to 477 00:16:24,970 --> 00:16:27,579 talk. Uh, we are trying to reorient 478 00:16:27,580 --> 00:16:28,580 the satellite. 479 00:16:29,850 --> 00:16:31,589 So how do we determine our attitude in 480 00:16:31,590 --> 00:16:32,489 space? 481 00:16:32,490 --> 00:16:34,479 The simplest way would be just use the 482 00:16:34,480 --> 00:16:35,519 illumination. 483 00:16:35,520 --> 00:16:37,679 So this just measures the 484 00:16:37,680 --> 00:16:40,439 elimination of the sun, the solar flux 485 00:16:40,440 --> 00:16:42,869 on your sensor, and then says, OK, 486 00:16:42,870 --> 00:16:44,489 I have a sensor on each side of my 487 00:16:44,490 --> 00:16:46,679 CubeSat, and then I try to 488 00:16:46,680 --> 00:16:48,449 determine from where the sun comes. 489 00:16:48,450 --> 00:16:49,559 Of course, you always have a degree of 490 00:16:49,560 --> 00:16:51,479 freedom rotating around the direction 491 00:16:51,480 --> 00:16:53,159 where some comes from because this 492 00:16:53,160 --> 00:16:54,869 doesn't change your reading, but this 493 00:16:54,870 --> 00:16:57,089 gives you a reading in the sun centered 494 00:16:57,090 --> 00:16:58,899 frame. Then you have the magnetic field 495 00:16:58,900 --> 00:17:01,049 so everyone knows 496 00:17:01,050 --> 00:17:02,009 who has a smartphone. 497 00:17:02,010 --> 00:17:03,750 You can use a compass 498 00:17:04,920 --> 00:17:07,078 to determine your, uh, the 499 00:17:07,079 --> 00:17:08,459 way you are heading. 500 00:17:08,460 --> 00:17:10,469 You can use a more sophisticated sansone. 501 00:17:10,470 --> 00:17:12,209 So this is different from inflation 502 00:17:12,210 --> 00:17:14,249 sensors and sensors that you usually have 503 00:17:14,250 --> 00:17:16,078 some kind of powerful system which 504 00:17:16,079 --> 00:17:18,358 projects like a slit 505 00:17:18,359 --> 00:17:21,088 of light on a sensor, and then you can 506 00:17:21,089 --> 00:17:23,189 determine directly an angle where 507 00:17:23,190 --> 00:17:25,139 this light came from. 508 00:17:25,140 --> 00:17:26,789 So this is more accurate. 509 00:17:26,790 --> 00:17:28,799 You can use Earth's horizon sensors, 510 00:17:28,800 --> 00:17:31,079 which basically try to detect the Earth 511 00:17:31,080 --> 00:17:33,299 or just the line where Earth 512 00:17:33,300 --> 00:17:35,579 meets space. And then you get a reference 513 00:17:35,580 --> 00:17:37,949 in the earth centered frame and 514 00:17:37,950 --> 00:17:40,019 the highest class, usually our star 515 00:17:40,020 --> 00:17:42,149 cameras, this little camera cameras 516 00:17:42,150 --> 00:17:43,799 looking at the stars. 517 00:17:43,800 --> 00:17:46,019 And then from the picture they see they 518 00:17:46,020 --> 00:17:48,329 are looking with an algorithm in a star 519 00:17:48,330 --> 00:17:50,189 catalog and trying to determine which 520 00:17:50,190 --> 00:17:52,019 starts. They have seen just by the 521 00:17:52,020 --> 00:17:54,089 brightness, the relative positions 522 00:17:54,090 --> 00:17:55,979 and so on. And from that, you really get 523 00:17:55,980 --> 00:17:56,980 a good 524 00:17:58,050 --> 00:17:59,329 knowledge about your attitude. 525 00:18:00,840 --> 00:18:03,299 So why why would we control attitude? 526 00:18:03,300 --> 00:18:05,369 So after deployment, due to the 527 00:18:05,370 --> 00:18:06,659 deployment mechanism, we have to push up 528 00:18:06,660 --> 00:18:08,999 plate. You usually have some tumbling. 529 00:18:09,000 --> 00:18:10,229 It's not perfect. 530 00:18:10,230 --> 00:18:12,329 So if you think you can just be 531 00:18:12,330 --> 00:18:13,739 still and then do nothing, of course you 532 00:18:13,740 --> 00:18:15,119 have to sell themselves. But you also get 533 00:18:15,120 --> 00:18:16,289 something from the start. 534 00:18:16,290 --> 00:18:17,699 Then of course you might have a payload 535 00:18:17,700 --> 00:18:19,499 which requires pointing your camera wants 536 00:18:19,500 --> 00:18:22,139 to look at Earth or things like that. 537 00:18:22,140 --> 00:18:23,309 Then you have antennas. 538 00:18:23,310 --> 00:18:25,259 If you have directional antennas, they 539 00:18:25,260 --> 00:18:27,209 want to be pointed to the ground station. 540 00:18:27,210 --> 00:18:29,489 And also if you have antennas which are 541 00:18:29,490 --> 00:18:31,859 really only directional but have some 542 00:18:31,860 --> 00:18:33,839 some zeros, some places where you don't 543 00:18:33,840 --> 00:18:35,939 really radiate anything to, then if 544 00:18:35,940 --> 00:18:38,219 you just tumble, you get just 545 00:18:38,220 --> 00:18:40,259 fading signal. So the signal goes down 546 00:18:40,260 --> 00:18:42,419 that you might not be able to send 547 00:18:42,420 --> 00:18:43,420 a complete packet. 548 00:18:44,280 --> 00:18:46,589 And of course, if it is too expensive, 549 00:18:46,590 --> 00:18:48,299 the antennas might actually bend and then 550 00:18:48,300 --> 00:18:49,859 they are behaving in completely different 551 00:18:49,860 --> 00:18:51,979 because our first black magic. 552 00:18:54,930 --> 00:18:57,249 So not a perfect fall collection. 553 00:18:57,250 --> 00:18:58,739 So if you especially if you have a 554 00:18:58,740 --> 00:19:00,749 deployable solar panel, you really want 555 00:19:00,750 --> 00:19:02,309 to use it, then you should, of course, 556 00:19:02,310 --> 00:19:04,499 try to orient yourself towards the sun. 557 00:19:04,500 --> 00:19:06,209 And then you also might want to have 558 00:19:06,210 --> 00:19:07,649 attitude control. 559 00:19:07,650 --> 00:19:08,999 And what problems do we encounter? 560 00:19:09,000 --> 00:19:11,519 I mean, if you think about normal motion, 561 00:19:11,520 --> 00:19:13,619 if I push something in the direction 562 00:19:13,620 --> 00:19:16,079 Newton says, it should start 563 00:19:16,080 --> 00:19:17,579 to move in this direction and continue to 564 00:19:17,580 --> 00:19:19,529 move in this direction. This nice 565 00:19:19,530 --> 00:19:21,669 invitation. If I just would give a talk 566 00:19:21,670 --> 00:19:23,669 around the Nexus, it would probably just 567 00:19:23,670 --> 00:19:24,670 such a tumble. 568 00:19:26,160 --> 00:19:27,479 The problem is that if you look into the 569 00:19:27,480 --> 00:19:30,299 physics, the motion around 570 00:19:30,300 --> 00:19:32,789 just arbitrary exercise usually coupled 571 00:19:32,790 --> 00:19:34,949 so is 572 00:19:34,950 --> 00:19:37,019 very matrix which come into play here. 573 00:19:37,020 --> 00:19:39,419 And there are only three defined 574 00:19:39,420 --> 00:19:41,039 distinguishable galaxies in each solid 575 00:19:41,040 --> 00:19:42,929 body where you don't have any coupling, 576 00:19:42,930 --> 00:19:44,639 the so-called principle axis, but only 577 00:19:44,640 --> 00:19:45,839 even two of them. 578 00:19:45,840 --> 00:19:47,009 The motion is stable. 579 00:19:47,010 --> 00:19:48,089 So if you have just have a small 580 00:19:48,090 --> 00:19:50,249 disturbance, one of 150 axis, 581 00:19:50,250 --> 00:19:52,739 we can start to make a tumble. 582 00:19:52,740 --> 00:19:54,839 So if you want to have a satellite 583 00:19:54,840 --> 00:19:57,069 which moves around a certain axis, maybe 584 00:19:57,070 --> 00:19:58,859 because you want to have a measurement or 585 00:19:58,860 --> 00:20:00,389 something like that, then you should 586 00:20:00,390 --> 00:20:02,489 think about distributing the mass in such 587 00:20:02,490 --> 00:20:04,709 a satellite. So that is easy 588 00:20:04,710 --> 00:20:06,449 for the control algorithm to control it. 589 00:20:06,450 --> 00:20:08,669 So maybe choose a principle axis 590 00:20:08,670 --> 00:20:09,670 for that which is stable. 591 00:20:10,910 --> 00:20:13,169 A couple of methods, how to stabilize 592 00:20:13,170 --> 00:20:15,339 the satellite, especially a CubeSat. 593 00:20:15,340 --> 00:20:17,519 The easiest way would be passive magnetic 594 00:20:17,520 --> 00:20:18,960 stabilization you. 595 00:20:20,410 --> 00:20:22,839 By choice put a satellite 596 00:20:22,840 --> 00:20:25,119 which is fixed to the frame and 597 00:20:25,120 --> 00:20:27,279 it, of course tries to orient itself like 598 00:20:27,280 --> 00:20:29,019 a compass needle to the Earth's magnetic 599 00:20:29,020 --> 00:20:29,499 field. 600 00:20:29,500 --> 00:20:31,749 The problem is, of course, if it starts 601 00:20:31,750 --> 00:20:33,729 turned itself against kinetic energy and 602 00:20:33,730 --> 00:20:36,519 then goes into a pendulum oscillation. 603 00:20:36,520 --> 00:20:37,929 So you also want to have something which 604 00:20:37,930 --> 00:20:40,029 dissipates this movement 605 00:20:40,030 --> 00:20:40,309 away. 606 00:20:40,310 --> 00:20:42,729 So you also have, uh, 607 00:20:42,730 --> 00:20:45,009 hysteresis watts here or out 608 00:20:45,010 --> 00:20:47,109 of heartful magnetic material 609 00:20:47,110 --> 00:20:50,259 in each direction and inside the 610 00:20:50,260 --> 00:20:52,689 movement is then dissipated. 611 00:20:52,690 --> 00:20:53,829 Of course, there are limits because, I 612 00:20:53,830 --> 00:20:55,689 mean, it's easy. So it has to be, uh, 613 00:20:55,690 --> 00:20:56,690 somehow flawed. 614 00:20:58,750 --> 00:21:00,159 So you have interference with your 615 00:21:00,160 --> 00:21:01,659 attitude, determination. I mean, if you 616 00:21:01,660 --> 00:21:03,729 build a huge magnet inside your 617 00:21:03,730 --> 00:21:06,099 compass, then it will not work anymore. 618 00:21:06,100 --> 00:21:08,769 Um, it's not easily changed 619 00:21:08,770 --> 00:21:10,449 for a fixed position over the Earth 620 00:21:10,450 --> 00:21:12,159 because, I mean, if you really built this 621 00:21:12,160 --> 00:21:13,160 heart 622 00:21:14,330 --> 00:21:16,299 into your satellite, then maybe you can 623 00:21:16,300 --> 00:21:17,979 use it to point you satellite to your 624 00:21:17,980 --> 00:21:19,729 ground stations directly above. 625 00:21:19,730 --> 00:21:22,179 But in any other 626 00:21:22,180 --> 00:21:24,039 position above Earth, you don't really 627 00:21:24,040 --> 00:21:26,199 have any wiggle room to readjust 628 00:21:26,200 --> 00:21:28,809 your position that this is not a 629 00:21:28,810 --> 00:21:29,469 good enough force. 630 00:21:29,470 --> 00:21:31,119 You still have a degree of freedom which 631 00:21:31,120 --> 00:21:32,829 just rotates around the magnetic field 632 00:21:32,830 --> 00:21:35,049 line because, uh, then 633 00:21:35,050 --> 00:21:36,549 there is no talking point. 634 00:21:36,550 --> 00:21:38,079 And you might have deployment problems 635 00:21:38,080 --> 00:21:39,819 because let's say we have two of these in 636 00:21:39,820 --> 00:21:42,009 one deployment, but they are 637 00:21:42,010 --> 00:21:43,689 pushed out and then they are just 638 00:21:43,690 --> 00:21:44,690 attracted, just 639 00:21:46,060 --> 00:21:47,060 not good. 640 00:21:48,700 --> 00:21:50,949 So the next step up, let's say, is 641 00:21:50,950 --> 00:21:52,839 active magnetic control. 642 00:21:52,840 --> 00:21:54,729 We have electro magnetic inside the 643 00:21:54,730 --> 00:21:56,469 satellite. So, for example, our coils 644 00:21:56,470 --> 00:21:59,209 integrated into the CubeSat penalty 645 00:21:59,210 --> 00:22:01,299 or maybe also to awards, 646 00:22:01,300 --> 00:22:03,519 which are just slender, uh, 647 00:22:03,520 --> 00:22:05,709 slender electromagnets inside a 648 00:22:05,710 --> 00:22:06,710 satellite structure. 649 00:22:07,870 --> 00:22:10,419 And yeah, just by controlling 650 00:22:10,420 --> 00:22:11,889 the current going forward, we produce our 651 00:22:11,890 --> 00:22:13,599 own variable magnetic field. 652 00:22:13,600 --> 00:22:15,459 So we have a lot more degrees of freedom 653 00:22:15,460 --> 00:22:17,559 to control it and move to satellite 654 00:22:17,560 --> 00:22:19,689 around. So, for example, in combination 655 00:22:19,690 --> 00:22:20,679 with the magnetic attitude, 656 00:22:20,680 --> 00:22:22,839 determination, we can use, 657 00:22:22,840 --> 00:22:25,119 uh, something called the algorithm 658 00:22:25,120 --> 00:22:26,409 to adjust the tumble to satellite. 659 00:22:26,410 --> 00:22:28,029 So then afterwards it's just spinning 660 00:22:28,030 --> 00:22:29,409 around one axis. 661 00:22:29,410 --> 00:22:31,539 That's nice. But of course, this, as 662 00:22:31,540 --> 00:22:33,489 opposed to the other one, uses power. 663 00:22:33,490 --> 00:22:34,749 Power is scarce. 664 00:22:34,750 --> 00:22:36,279 And again, you have one degree of 665 00:22:36,280 --> 00:22:38,049 freedom. So if you're, let's say, 666 00:22:38,050 --> 00:22:40,209 spinning around the magnetic 667 00:22:40,210 --> 00:22:41,709 field line and you want to stop that, 668 00:22:41,710 --> 00:22:43,000 there's not much you can do. 669 00:22:45,070 --> 00:22:47,259 So even more 670 00:22:47,260 --> 00:22:49,539 accurate, are we actually basically 671 00:22:49,540 --> 00:22:51,909 flywheels with an electric motor 672 00:22:51,910 --> 00:22:53,679 and as no excuse me, actually. 673 00:22:53,680 --> 00:22:56,289 So if we put a talk on the flywheel, 674 00:22:56,290 --> 00:22:58,059 the motor itself and the whole satellite, 675 00:22:58,060 --> 00:23:00,489 it's mounted, you will 676 00:23:00,490 --> 00:23:03,009 get to talk in the other direction. 677 00:23:03,010 --> 00:23:05,949 So with this, you can get very high 678 00:23:05,950 --> 00:23:06,849 pointing accuracy. 679 00:23:06,850 --> 00:23:08,559 The problem is that, for example, if you 680 00:23:08,560 --> 00:23:11,169 have a disturbance torque, which always 681 00:23:11,170 --> 00:23:13,299 has a bias that always tends to push you, 682 00:23:13,300 --> 00:23:15,369 let's say clockwise, then you always 683 00:23:15,370 --> 00:23:17,439 have to apply a counter torque in 684 00:23:17,440 --> 00:23:18,939 the same direction C02. 685 00:23:18,940 --> 00:23:21,219 So you add spin to the wheel and spin 686 00:23:21,220 --> 00:23:22,899 to the wheels and maybe the bearings 687 00:23:22,900 --> 00:23:24,099 fail. 688 00:23:24,100 --> 00:23:25,719 Of course, you don't want that to have 689 00:23:25,720 --> 00:23:28,089 the way to have another 690 00:23:28,090 --> 00:23:30,159 type of attitude control 691 00:23:30,160 --> 00:23:33,129 to desaturate your 692 00:23:33,130 --> 00:23:34,869 wheels. And of course, this needs all the 693 00:23:34,870 --> 00:23:36,399 power and its continuous power because we 694 00:23:36,400 --> 00:23:38,649 would just stop power to the 695 00:23:38,650 --> 00:23:40,719 flywheels, then they would slow down due 696 00:23:40,720 --> 00:23:43,089 to friction and this would give the 697 00:23:43,090 --> 00:23:44,949 talk you put into them back into your 698 00:23:44,950 --> 00:23:46,659 satellite. So the whole thing starts to 699 00:23:46,660 --> 00:23:48,729 spin and tumble again because you don't 700 00:23:48,730 --> 00:23:49,629 want that. 701 00:23:49,630 --> 00:23:51,939 So again, it's more 702 00:23:51,940 --> 00:23:52,940 power. 703 00:23:53,770 --> 00:23:55,269 A few words about communication. 704 00:23:56,620 --> 00:23:58,809 So to telemetry, if you can't get 705 00:23:58,810 --> 00:24:01,539 data to your satellite, if your satellite 706 00:24:01,540 --> 00:24:03,429 doesn't respond and the satellite is 707 00:24:03,430 --> 00:24:05,619 passed, so you really want to have this 708 00:24:05,620 --> 00:24:06,819 thing nailed down 709 00:24:08,470 --> 00:24:10,239 first measured usually after you 710 00:24:10,240 --> 00:24:11,889 deploying a satellite or if there was any 711 00:24:11,890 --> 00:24:13,569 fault in the satellite goes into a safe 712 00:24:13,570 --> 00:24:15,729 state, it starts to transmit 713 00:24:15,730 --> 00:24:17,829 a beacon, which is just 714 00:24:17,830 --> 00:24:19,929 a short package, which 715 00:24:19,930 --> 00:24:22,569 includes the most important telemetry 716 00:24:22,570 --> 00:24:24,699 of the satellite. This helps you 717 00:24:24,700 --> 00:24:25,809 to locate your satellites. 718 00:24:25,810 --> 00:24:28,119 So, for example, after launch, you have 719 00:24:28,120 --> 00:24:30,219 just a flock of satellite shots were 720 00:24:30,220 --> 00:24:32,889 released. You don't know which of these 721 00:24:32,890 --> 00:24:35,019 is yours. So you just try to 722 00:24:35,020 --> 00:24:37,119 ping each one and whichever sense 723 00:24:37,120 --> 00:24:38,500 of it might be the right one. 724 00:24:40,630 --> 00:24:41,630 So. 725 00:24:42,150 --> 00:24:44,189 Yeah, and today, in case of failure, just 726 00:24:44,190 --> 00:24:46,289 get the most important values you 727 00:24:46,290 --> 00:24:48,929 need to debunk the problem or at least 728 00:24:48,930 --> 00:24:50,040 find out what's going on. 729 00:24:51,270 --> 00:24:53,279 So a different types of antenna's the 730 00:24:53,280 --> 00:24:55,499 easiest type of just 731 00:24:55,500 --> 00:24:57,629 this kind of extending Youlus. 732 00:24:57,630 --> 00:24:59,769 You bend over the edge and hold 733 00:24:59,770 --> 00:25:02,439 down. So if you burn this wire, 734 00:25:02,440 --> 00:25:04,919 it's flips up and 735 00:25:04,920 --> 00:25:06,269 you have a working antenna. 736 00:25:06,270 --> 00:25:07,589 If you did anything right. 737 00:25:07,590 --> 00:25:08,590 Uh. 738 00:25:09,170 --> 00:25:10,879 You have to distinguish between DirecTV 739 00:25:10,880 --> 00:25:12,949 and omnidirectional antenna, 740 00:25:12,950 --> 00:25:15,229 so these types of antennas are usually, 741 00:25:15,230 --> 00:25:17,629 uh, near omnidirectional. 742 00:25:17,630 --> 00:25:20,329 So they have multiple 743 00:25:20,330 --> 00:25:22,459 configurations and they are very good 744 00:25:22,460 --> 00:25:24,229 for, let's say, lower frequencies. 745 00:25:24,230 --> 00:25:26,089 If you want to have DirecTV, DirecTV 746 00:25:26,090 --> 00:25:28,189 antenna usually go to higher frequencies 747 00:25:28,190 --> 00:25:29,479 because they're it's feasible to 748 00:25:29,480 --> 00:25:31,639 construct such an antenna because 749 00:25:31,640 --> 00:25:33,139 the same structure used, for example, 750 00:25:33,140 --> 00:25:35,269 here for this antenna, uh, would 751 00:25:35,270 --> 00:25:37,609 be much, much larger if you go 752 00:25:37,610 --> 00:25:39,409 to these frequencies. 753 00:25:39,410 --> 00:25:41,479 And yeah, basically you have a patch on 754 00:25:41,480 --> 00:25:43,819 time, which really just is a patch 755 00:25:43,820 --> 00:25:45,409 helical. And of course, you here you 756 00:25:45,410 --> 00:25:46,669 would have another point of failure 757 00:25:46,670 --> 00:25:48,739 because you have to deploy this in orbit. 758 00:25:48,740 --> 00:25:50,959 Uh, yeah, but these are the 759 00:25:50,960 --> 00:25:52,339 most common forms of intensity. 760 00:25:52,340 --> 00:25:53,340 And CubeSat. 761 00:25:54,300 --> 00:25:57,149 So just a few words about frequencies, 762 00:25:57,150 --> 00:25:59,339 common frequencies, if you come 763 00:25:59,340 --> 00:26:01,979 from the amateur radio 764 00:26:01,980 --> 00:26:04,109 edge of the spectrum, are 70 765 00:26:04,110 --> 00:26:05,849 centimeters and two meter frequency, so 766 00:26:05,850 --> 00:26:08,549 about 430, 144 megahertz, 767 00:26:08,550 --> 00:26:10,799 very common, a long time useful 768 00:26:10,800 --> 00:26:12,239 amateur radio purpose. 769 00:26:12,240 --> 00:26:14,159 And the nice thing is, because if we 770 00:26:14,160 --> 00:26:15,989 could say relatively low, you have pretty 771 00:26:15,990 --> 00:26:18,239 efficient components from this because 772 00:26:18,240 --> 00:26:19,919 the frequencies are so low, the available 773 00:26:19,920 --> 00:26:21,629 bandwidth or the bandwidth you're allowed 774 00:26:21,630 --> 00:26:23,819 to use is relatively 775 00:26:23,820 --> 00:26:25,919 small. So you get only about nine point 776 00:26:25,920 --> 00:26:27,719 six kilobits per second while the 777 00:26:27,720 --> 00:26:28,989 satellite is in reach of your 778 00:26:28,990 --> 00:26:30,899 organization. This is only just a 779 00:26:30,900 --> 00:26:33,119 fraction of its orbit. So, uh, 780 00:26:33,120 --> 00:26:34,529 you need a lot of orbits to get, let's 781 00:26:34,530 --> 00:26:36,689 say, a picture and 782 00:26:36,690 --> 00:26:39,149 of course, get a test for these, uh, 783 00:26:39,150 --> 00:26:41,309 wavelengths will get pretty 784 00:26:41,310 --> 00:26:42,899 big. And you can put us on your, uh, 785 00:26:42,900 --> 00:26:44,459 CubeSat probably. 786 00:26:44,460 --> 00:26:45,929 So you might want to go to higher 787 00:26:45,930 --> 00:26:48,269 frequencies, uh, especially 788 00:26:48,270 --> 00:26:50,519 popular with commercial, uh, 789 00:26:50,520 --> 00:26:52,199 chipsets, which get different kind of 790 00:26:52,200 --> 00:26:54,029 licenses, are usually not operated under 791 00:26:54,030 --> 00:26:56,309 amateur radio, uh, regulations. 792 00:26:56,310 --> 00:26:58,409 And those get signal rates up 793 00:26:58,410 --> 00:26:59,999 into the megabits per second rate. 794 00:27:00,000 --> 00:27:02,219 So that's, uh, much nicer because 795 00:27:02,220 --> 00:27:03,689 they have more bandwidth available. 796 00:27:03,690 --> 00:27:05,939 And if you don't need your higher 797 00:27:05,940 --> 00:27:08,129 data rate, you want to use less 798 00:27:08,130 --> 00:27:10,199 power, then you can also use the higher 799 00:27:10,200 --> 00:27:11,579 bandwidth to increase your linked budget. 800 00:27:11,580 --> 00:27:13,679 So the, uh, the transmission is 801 00:27:13,680 --> 00:27:14,680 more reliable. 802 00:27:17,660 --> 00:27:18,859 So just a few 803 00:27:20,000 --> 00:27:22,069 words about protocol and, 804 00:27:22,070 --> 00:27:24,499 uh, really just a few, 805 00:27:24,500 --> 00:27:26,599 um, common protocols, you might 806 00:27:26,600 --> 00:27:28,339 want to look into a few interesting 807 00:27:28,340 --> 00:27:30,469 things that that would be x 25, which is, 808 00:27:30,470 --> 00:27:31,669 uh, amateur radio. 809 00:27:31,670 --> 00:27:33,799 A packet radio protocol, which 810 00:27:33,800 --> 00:27:35,959 is used has been used for lots of 811 00:27:35,960 --> 00:27:38,329 CubeSat, especially in the old days. 812 00:27:38,330 --> 00:27:40,639 If you want to take a look at a as 813 00:27:40,640 --> 00:27:42,859 a satellite communication protocol, 814 00:27:42,860 --> 00:27:44,269 which is a bit more advanced, which is 815 00:27:44,270 --> 00:27:46,249 also used for big missions and big 816 00:27:46,250 --> 00:27:48,409 satellites, one can take a look at the 817 00:27:48,410 --> 00:27:50,629 available documentation on access 818 00:27:50,630 --> 00:27:53,029 which is used for its emissions. 819 00:27:53,030 --> 00:27:55,249 And, uh, yeah, please note that 820 00:27:55,250 --> 00:27:57,559 especially if you need a good connection. 821 00:27:57,560 --> 00:27:58,789 For example, if the satellite just 822 00:27:58,790 --> 00:28:00,889 started tumbling, you want to recover it. 823 00:28:00,890 --> 00:28:03,259 And it's important that you can, uh, 824 00:28:03,260 --> 00:28:05,359 that your protocol is able to 825 00:28:05,360 --> 00:28:06,889 work with a weak signal. 826 00:28:06,890 --> 00:28:09,169 Uh, I heard of people trying 827 00:28:09,170 --> 00:28:10,339 to log on with S.H. 828 00:28:10,340 --> 00:28:11,340 on the satellite. 829 00:28:13,200 --> 00:28:16,429 Not a good idea, at least handshaking. 830 00:28:16,430 --> 00:28:19,519 So, uh, yeah. 831 00:28:19,520 --> 00:28:20,749 Uh, more on regulation. 832 00:28:20,750 --> 00:28:22,099 So, of course, if you want to use, uh, 833 00:28:22,100 --> 00:28:24,439 amateur radio frequencies, you 834 00:28:24,440 --> 00:28:26,629 are, as an amateur radio use, are usually 835 00:28:26,630 --> 00:28:29,089 allowed to do not use them. 836 00:28:29,090 --> 00:28:30,889 But you should go through a frequency 837 00:28:30,890 --> 00:28:32,959 coordination step, which just make sure 838 00:28:32,960 --> 00:28:34,519 that there is no other satellite in 839 00:28:34,520 --> 00:28:36,529 similar orbit sending on the same 840 00:28:36,530 --> 00:28:37,439 frequency. 841 00:28:37,440 --> 00:28:39,409 And then you get a lot of restrictions 842 00:28:39,410 --> 00:28:41,959 based which vary between the jurisdiction 843 00:28:41,960 --> 00:28:44,089 based on, for example, 844 00:28:44,090 --> 00:28:46,369 who are you allowed to 845 00:28:46,370 --> 00:28:48,709 use amateur radio if you get a government 846 00:28:48,710 --> 00:28:51,139 grant or is your ground station 847 00:28:51,140 --> 00:28:53,299 operator allowed to be paid for 848 00:28:53,300 --> 00:28:55,069 operating grants and things like that? 849 00:28:55,070 --> 00:28:57,139 But in general, uh, there is a at least 850 00:28:57,140 --> 00:28:59,149 an exception for commands being sent to 851 00:28:59,150 --> 00:29:00,679 the satellite because they are allowed to 852 00:29:00,680 --> 00:29:01,789 be encrypted. 853 00:29:01,790 --> 00:29:04,489 Everything else under amateur radio, uh, 854 00:29:04,490 --> 00:29:06,609 uh, regulations has to be clear checks. 855 00:29:06,610 --> 00:29:08,149 So it has to be readable, might be 856 00:29:08,150 --> 00:29:09,589 compressed. That's OK as long as it's 857 00:29:09,590 --> 00:29:11,659 documented. But, uh, commands to 858 00:29:11,660 --> 00:29:12,919 satellite is the only thing that is 859 00:29:12,920 --> 00:29:14,960 allowed to be encrypted in amateur radio. 860 00:29:15,980 --> 00:29:17,449 And what's also important is that you 861 00:29:17,450 --> 00:29:19,279 have a fast and permanent transmission 862 00:29:19,280 --> 00:29:21,019 killswitch. So if your satellite goes 863 00:29:21,020 --> 00:29:23,599 haywire and, uh, just sends 864 00:29:23,600 --> 00:29:26,239 a carrier on your, uh, frequency, 865 00:29:26,240 --> 00:29:27,859 you have to be able to shut it down. 866 00:29:27,860 --> 00:29:29,959 And fast could even mean that you 867 00:29:29,960 --> 00:29:32,329 need multiple ground stations in middle 868 00:29:32,330 --> 00:29:34,969 latitudes. So we get it the 869 00:29:34,970 --> 00:29:37,189 let's say half a day or so, and 870 00:29:37,190 --> 00:29:38,429 Poland really means Poland. 871 00:29:38,430 --> 00:29:40,669 So there has been a satellite which has 872 00:29:40,670 --> 00:29:42,199 been shut down, but then there was a 873 00:29:42,200 --> 00:29:43,939 reset and start to transmit again. 874 00:29:43,940 --> 00:29:45,079 That is not good. 875 00:29:45,080 --> 00:29:46,839 So please really make it permanent. 876 00:29:48,290 --> 00:29:50,359 So if you not 877 00:29:50,360 --> 00:29:51,739 if you're not in Russia where you 878 00:29:51,740 --> 00:29:53,919 license, you have to talk 879 00:29:53,920 --> 00:29:55,999 to your National Frequency 880 00:29:56,000 --> 00:29:58,159 Coordination Agency, then you can 881 00:29:58,160 --> 00:30:00,259 something like experimental permits 882 00:30:00,260 --> 00:30:02,509 or things like that which allow you 883 00:30:02,510 --> 00:30:04,819 to use similar frequencies, maybe 884 00:30:04,820 --> 00:30:06,119 even in the same range. 885 00:30:06,120 --> 00:30:08,479 Uh, and yeah. 886 00:30:08,480 --> 00:30:10,579 Get a little bit more freedom. 887 00:30:10,580 --> 00:30:12,959 And what kind of, uh, uh, 888 00:30:12,960 --> 00:30:15,079 uh, applications you use here. 889 00:30:15,080 --> 00:30:16,759 So, uh, but please note that frequency 890 00:30:16,760 --> 00:30:18,349 coordination and allocation takes a lot 891 00:30:18,350 --> 00:30:20,449 of time. So, uh, it would be best 892 00:30:20,450 --> 00:30:21,949 if your satellite is built ready to 893 00:30:21,950 --> 00:30:23,269 launch, but you don't have your location 894 00:30:23,270 --> 00:30:25,549 yet. So please look into it early 895 00:30:25,550 --> 00:30:26,550 in the project. 896 00:30:27,540 --> 00:30:29,130 So electrical power systems. 897 00:30:30,150 --> 00:30:31,150 It's all about power, 898 00:30:32,670 --> 00:30:35,099 so you leave for power collection, 899 00:30:35,100 --> 00:30:36,589 junction solar cells are used. 900 00:30:36,590 --> 00:30:37,590 They're pretty efficient. 901 00:30:39,000 --> 00:30:41,279 If you have a maximum peak efficiency 902 00:30:41,280 --> 00:30:43,679 of usually 27 to 30 percent, if they're 903 00:30:43,680 --> 00:30:44,699 lit directly 904 00:30:45,750 --> 00:30:47,099 and afterwards, you usually have a 905 00:30:47,100 --> 00:30:49,619 maximum optimum power point tracker 906 00:30:49,620 --> 00:30:51,899 which adjusts the load the 907 00:30:51,900 --> 00:30:54,029 solar cell needs so that the power 908 00:30:54,030 --> 00:30:56,459 which is sucked out of it is 909 00:30:56,460 --> 00:30:58,859 optimized because otherwise you might, 910 00:30:58,860 --> 00:31:00,959 especially with the low voltage 911 00:31:00,960 --> 00:31:03,539 you have on just a few cells on a cell 912 00:31:03,540 --> 00:31:04,540 on the CubeSat side, 913 00:31:06,300 --> 00:31:08,549 you don't really get 914 00:31:08,550 --> 00:31:09,989 the maximum power, but of course you lose 915 00:31:09,990 --> 00:31:11,589 some power also due to these thing. 916 00:31:11,590 --> 00:31:13,709 So as every real circuit, it's not 917 00:31:13,710 --> 00:31:15,349 really 100 percent efficient. 918 00:31:16,440 --> 00:31:18,569 But let's say near the 919 00:31:18,570 --> 00:31:20,789 Earth, uh, you get about 920 00:31:20,790 --> 00:31:23,519 two point three watts per CubeSat panel 921 00:31:23,520 --> 00:31:25,829 when they are illuminated perpendicular. 922 00:31:25,830 --> 00:31:28,469 So if you have a cell which is rotating, 923 00:31:28,470 --> 00:31:31,139 then you would get a slightly varying 924 00:31:31,140 --> 00:31:32,969 power power and take. 925 00:31:34,170 --> 00:31:36,569 And you have a collection, 926 00:31:36,570 --> 00:31:36,779 please. 927 00:31:36,780 --> 00:31:38,699 We wanted to include a charging connector 928 00:31:38,700 --> 00:31:40,919 for testing and also for 929 00:31:40,920 --> 00:31:42,989 storage because it 930 00:31:42,990 --> 00:31:45,149 is not very nice if you would have to 931 00:31:45,150 --> 00:31:47,279 put your satellite under a lamp 932 00:31:47,280 --> 00:31:48,569 every time you want to charge it during 933 00:31:48,570 --> 00:31:49,570 testing. 934 00:31:50,920 --> 00:31:52,809 So how could we increase this population? 935 00:31:52,810 --> 00:31:55,299 Obviously, we could try to increase our 936 00:31:55,300 --> 00:31:56,629 social area. 937 00:31:56,630 --> 00:31:59,349 So you have your common 938 00:31:59,350 --> 00:32:00,489 things, you can only see. 939 00:32:00,490 --> 00:32:02,559 So, for example, just winds pulling out 940 00:32:02,560 --> 00:32:04,029 or flaps going up. 941 00:32:04,030 --> 00:32:05,469 Of course, if you look at this 942 00:32:05,470 --> 00:32:07,029 configuration when it started, looks like 943 00:32:07,030 --> 00:32:09,289 this would this might not be a nice 944 00:32:09,290 --> 00:32:10,719 thing if you have to become a satellite. 945 00:32:10,720 --> 00:32:12,129 Something went wrong, an early face 946 00:32:12,130 --> 00:32:14,169 because the battery trains. 947 00:32:14,170 --> 00:32:16,059 So we might also want to include a few 948 00:32:16,060 --> 00:32:17,709 solar cells here on the outside. 949 00:32:17,710 --> 00:32:19,419 But then after they deployed, they are 950 00:32:19,420 --> 00:32:22,419 shadowed and shadow solar cells tend to 951 00:32:22,420 --> 00:32:24,579 become loads if you don't include extra 952 00:32:24,580 --> 00:32:26,420 protection circuits or keys. 953 00:32:27,460 --> 00:32:28,489 Yeah, look into it. 954 00:32:28,490 --> 00:32:30,609 So this doesn't 955 00:32:30,610 --> 00:32:32,799 eat up all your power and gets 956 00:32:32,800 --> 00:32:33,800 hot. 957 00:32:37,060 --> 00:32:39,639 So if you have collected your bet, 958 00:32:39,640 --> 00:32:42,189 your power, you want to start usually so 959 00:32:42,190 --> 00:32:45,249 often, uh, lithium batteries are used, 960 00:32:45,250 --> 00:32:47,979 which are for 961 00:32:47,980 --> 00:32:49,719 just a satellite, but usually the most 962 00:32:49,720 --> 00:32:51,759 temperature sensitive components. 963 00:32:51,760 --> 00:32:53,529 So you want to keep this happy? 964 00:32:53,530 --> 00:32:55,719 Usually they are coming pretty integrated 965 00:32:55,720 --> 00:32:57,369 with a heater. So at least you don't 966 00:32:57,370 --> 00:32:58,370 freeze them. 967 00:32:59,240 --> 00:33:01,459 But what kind of capacity you need, 968 00:33:01,460 --> 00:33:03,529 so you have to supply your satellite 969 00:33:03,530 --> 00:33:05,269 with power throughout the eclipse period, 970 00:33:05,270 --> 00:33:06,520 so the period in the shadow, 971 00:33:07,550 --> 00:33:09,709 but also if you have short bursts of 972 00:33:09,710 --> 00:33:11,719 activity, so, for example, transmission, 973 00:33:11,720 --> 00:33:13,009 if you have a payload, you have to 974 00:33:13,010 --> 00:33:15,229 operate, then you need just short bursts 975 00:33:15,230 --> 00:33:16,789 of power. And this is also. 976 00:33:18,510 --> 00:33:20,759 Cared for by the buffer of the 977 00:33:20,760 --> 00:33:21,659 battery here. 978 00:33:21,660 --> 00:33:23,099 The problem is if you just look at the 979 00:33:23,100 --> 00:33:25,469 advertising and see what our batteries 980 00:33:25,470 --> 00:33:27,569 and you can get should be enough, you 981 00:33:27,570 --> 00:33:29,669 usually are only allowed to 982 00:33:29,670 --> 00:33:32,039 discharge 20 percent of that. 983 00:33:32,040 --> 00:33:33,629 The reason is that if you think about 984 00:33:33,630 --> 00:33:35,969 your phone, I mean, it maybe lasts 985 00:33:35,970 --> 00:33:38,879 the battery last a year without that much 986 00:33:38,880 --> 00:33:40,259 drop in capacity. 987 00:33:40,260 --> 00:33:42,059 But in the satellite, you have a charge 988 00:33:42,060 --> 00:33:44,249 just like discharge cycle, maybe every 989 00:33:44,250 --> 00:33:45,449 90 minutes. 990 00:33:45,450 --> 00:33:47,639 So you really want to limit your depth 991 00:33:47,640 --> 00:33:48,599 of discharge. 992 00:33:48,600 --> 00:33:51,269 So you get maybe two years 993 00:33:51,270 --> 00:33:52,270 of battery. 994 00:33:53,790 --> 00:33:56,469 So what about verification? 995 00:33:56,470 --> 00:33:58,529 It's important that you really test 996 00:33:58,530 --> 00:34:00,869 the whole power chain as one, so 997 00:34:00,870 --> 00:34:03,179 maybe get some kind of language, 998 00:34:03,180 --> 00:34:05,549 simulate solar spectrum and then 999 00:34:05,550 --> 00:34:07,829 see if really your battery gets charged, 1000 00:34:07,830 --> 00:34:10,499 if your consumers can get 1001 00:34:10,500 --> 00:34:12,479 charged with battery and so on, and also 1002 00:34:12,480 --> 00:34:15,029 make sure that the efficiency values 1003 00:34:15,030 --> 00:34:16,769 are according to your calculations, 1004 00:34:16,770 --> 00:34:18,899 because often in the data sheets, even 1005 00:34:18,900 --> 00:34:20,939 if you are buying a satellite electrical 1006 00:34:20,940 --> 00:34:21,940 power supply, 1007 00:34:23,280 --> 00:34:25,379 you only get one efficiency value, which 1008 00:34:25,380 --> 00:34:26,669 is really not enough. 1009 00:34:26,670 --> 00:34:28,769 So please make sure that 1010 00:34:28,770 --> 00:34:31,109 the efficiencies that occur under 1011 00:34:31,110 --> 00:34:33,629 your operational profile are 1012 00:34:33,630 --> 00:34:36,178 such that you don't run out of 1013 00:34:36,179 --> 00:34:37,179 power. 1014 00:34:38,830 --> 00:34:41,049 On the computer, so really, 1015 00:34:41,050 --> 00:34:42,849 if you look at flown on board computer 1016 00:34:42,850 --> 00:34:44,559 systems, you see everything from really, 1017 00:34:44,560 --> 00:34:46,749 really small microcontrollers 1018 00:34:46,750 --> 00:34:48,939 to embedded. Suppose you can find 1019 00:34:48,940 --> 00:34:50,948 an iPhone, something on the computers, 1020 00:34:50,949 --> 00:34:53,049 our phones, but is 1021 00:34:53,050 --> 00:34:54,658 not so often. 1022 00:34:54,659 --> 00:34:56,619 You can also see some FPGA which have 1023 00:34:56,620 --> 00:34:58,150 been flown in chipsets. 1024 00:34:59,260 --> 00:35:01,359 And of course, in space you have to 1025 00:35:01,360 --> 00:35:02,469 deal with a different radiation 1026 00:35:02,470 --> 00:35:04,239 environment than you find on Earth. 1027 00:35:04,240 --> 00:35:06,429 And you have two types of effects. 1028 00:35:06,430 --> 00:35:08,619 One single event effects, for example, 1029 00:35:08,620 --> 00:35:10,739 lets up on this shortly and 1030 00:35:10,740 --> 00:35:13,719 bit flaps and corruption, uh, 1031 00:35:13,720 --> 00:35:16,359 later just messes with your program. 1032 00:35:16,360 --> 00:35:19,659 This can damage your software 1033 00:35:19,660 --> 00:35:21,729 hardware if you don't account for it. 1034 00:35:21,730 --> 00:35:23,679 And then you get total dose effect, which 1035 00:35:23,680 --> 00:35:25,779 don't happen instantly, 1036 00:35:25,780 --> 00:35:28,029 but, uh, accumulate 1037 00:35:28,030 --> 00:35:29,709 over the life of your satellite and 1038 00:35:29,710 --> 00:35:31,989 usually lead, for example, to increase 1039 00:35:31,990 --> 00:35:34,419 in power consumption of your, uh, 1040 00:35:34,420 --> 00:35:35,229 of your electronics. 1041 00:35:35,230 --> 00:35:37,959 So it should size your power system, 1042 00:35:37,960 --> 00:35:40,389 take this into account that you have some 1043 00:35:40,390 --> 00:35:42,519 Headspaces for later on your satellite's 1044 00:35:42,520 --> 00:35:43,599 life. 1045 00:35:43,600 --> 00:35:44,979 So, uh, what are laptops 1046 00:35:46,360 --> 00:35:47,360 typically a cure 1047 00:35:48,530 --> 00:35:51,429 for heavy iron or proton 1048 00:35:51,430 --> 00:35:53,559 hits a similar device and 1049 00:35:53,560 --> 00:35:55,689 then activates a parasitic transistor. 1050 00:35:55,690 --> 00:35:57,909 If you look at the typical Simos 1051 00:35:57,910 --> 00:36:00,249 device structure here, there are 1052 00:36:00,250 --> 00:36:02,799 these two transistor structures 1053 00:36:02,800 --> 00:36:04,959 here which are not really intended 1054 00:36:04,960 --> 00:36:06,849 to be there. But just because of the 1055 00:36:06,850 --> 00:36:08,349 structure, they can be there. 1056 00:36:08,350 --> 00:36:10,519 And now we have a particle going 1057 00:36:10,520 --> 00:36:12,639 in here creating charges and those 1058 00:36:12,640 --> 00:36:14,439 two are activated, basically short 1059 00:36:14,440 --> 00:36:15,939 circuiting your supply. 1060 00:36:15,940 --> 00:36:18,099 And this is, of course, not good because 1061 00:36:18,100 --> 00:36:19,749 it heats the damages the device. 1062 00:36:19,750 --> 00:36:21,849 So if you are seeing a 1063 00:36:21,850 --> 00:36:23,919 sharp increase in power 1064 00:36:23,920 --> 00:36:26,019 consumption, then it's a good idea 1065 00:36:26,020 --> 00:36:28,119 to just reset the circuit because 1066 00:36:28,120 --> 00:36:31,119 this will not turn off until the power is 1067 00:36:31,120 --> 00:36:33,209 taken off and put them back. 1068 00:36:33,210 --> 00:36:35,349 Again, this is for, uh, just 1069 00:36:35,350 --> 00:36:36,939 a commercial off the shelf circuits. 1070 00:36:36,940 --> 00:36:39,519 If you have a, uh, let's say, better 1071 00:36:39,520 --> 00:36:41,619 hardened integrated circuit, 1072 00:36:41,620 --> 00:36:43,869 then you sometimes get insulated 1073 00:36:43,870 --> 00:36:46,539 substrates. So maybe it's on a sapphire 1074 00:36:46,540 --> 00:36:48,069 or something like that. 1075 00:36:48,070 --> 00:36:50,349 And they're, uh, this kind of 1076 00:36:50,350 --> 00:36:51,789 problem is prevented. 1077 00:36:51,790 --> 00:36:53,829 But this is one of the main reasons you 1078 00:36:53,830 --> 00:36:56,139 often get resets on your satellite just 1079 00:36:56,140 --> 00:36:57,849 because the power supply detects the 1080 00:36:57,850 --> 00:37:01,089 latch up and we sell the whole system. 1081 00:37:01,090 --> 00:37:03,219 So the of protection here 1082 00:37:03,220 --> 00:37:04,929 is often integrated into the electrical 1083 00:37:04,930 --> 00:37:06,639 power supply if you're looking at the 1084 00:37:06,640 --> 00:37:08,709 commercially available CubeSat power. 1085 00:37:10,060 --> 00:37:12,369 A few other effects on electronics, which 1086 00:37:12,370 --> 00:37:13,959 you might not have heard of, soaring 1087 00:37:13,960 --> 00:37:16,179 whiskers are small, really 1088 00:37:16,180 --> 00:37:18,579 small tendrils which are forming 1089 00:37:18,580 --> 00:37:20,469 from solid waypoints, but they are big 1090 00:37:20,470 --> 00:37:21,969 enough that they might switch 1091 00:37:23,530 --> 00:37:25,959 to another voltage potential 1092 00:37:25,960 --> 00:37:27,549 and then create a short circuit. 1093 00:37:27,550 --> 00:37:29,559 And this is especially problematic if you 1094 00:37:29,560 --> 00:37:32,019 use the lead-free 1095 00:37:32,020 --> 00:37:34,179 shoulder. So that's the reason 1096 00:37:34,180 --> 00:37:36,459 why space applications are usually exempt 1097 00:37:36,460 --> 00:37:39,069 from using lead-free 1098 00:37:39,070 --> 00:37:40,070 Letteri soldiery. 1099 00:37:41,480 --> 00:37:43,309 Another thing, especially for launch 1100 00:37:43,310 --> 00:37:44,439 vibration, it's always good to have 1101 00:37:44,440 --> 00:37:45,339 strained relief. 1102 00:37:45,340 --> 00:37:47,079 So if you want to solve a cable to your 1103 00:37:47,080 --> 00:37:49,239 PCB, think about just putting it 1104 00:37:49,240 --> 00:37:51,429 once and then up so you can expect 1105 00:37:51,430 --> 00:37:53,319 it from the top and have some kind of 1106 00:37:53,320 --> 00:37:55,029 strange relief here so that when the 1107 00:37:55,030 --> 00:37:57,399 vibrations kick in, you are not damaging 1108 00:37:57,400 --> 00:37:58,869 your soloing point. 1109 00:37:58,870 --> 00:38:00,789 And also, of course, and remember, you 1110 00:38:00,790 --> 00:38:02,259 don't have any convection. 1111 00:38:02,260 --> 00:38:04,589 So if you find if you find 1112 00:38:04,590 --> 00:38:06,669 the formula describing how to size 1113 00:38:06,670 --> 00:38:09,129 your lines on your PCB 1114 00:38:09,130 --> 00:38:10,989 to withstand a certain amount of current, 1115 00:38:10,990 --> 00:38:13,449 think about if it's also 1116 00:38:13,450 --> 00:38:15,459 the same under vacuum conditions without 1117 00:38:15,460 --> 00:38:17,109 this cooling effects, because now you 1118 00:38:17,110 --> 00:38:19,179 have to dissipate all your heat 1119 00:38:19,180 --> 00:38:20,180 through your PCB. 1120 00:38:22,230 --> 00:38:24,479 Few things about programing, 1121 00:38:24,480 --> 00:38:26,549 unscheduled results, resets 1122 00:38:26,550 --> 00:38:28,769 are to be expected, so if your program 1123 00:38:28,770 --> 00:38:30,179 has any problems of that, then you should 1124 00:38:30,180 --> 00:38:31,180 rewrite it. 1125 00:38:32,280 --> 00:38:33,959 For example, if you have some state which 1126 00:38:33,960 --> 00:38:36,129 must not be lost, you have to save it in 1127 00:38:36,130 --> 00:38:38,309 nonvolatile memory, obviously, 1128 00:38:38,310 --> 00:38:40,019 and which also sometimes creates 1129 00:38:40,020 --> 00:38:41,619 problems, timing, synchronization. 1130 00:38:41,620 --> 00:38:43,709 So after a reset, if you set that has no 1131 00:38:43,710 --> 00:38:45,509 idea which time it is, it might not be 1132 00:38:45,510 --> 00:38:48,179 able to perform important work 1133 00:38:48,180 --> 00:38:50,369 sent when it's over a ground station, 1134 00:38:50,370 --> 00:38:51,299 things like that. 1135 00:38:51,300 --> 00:38:52,649 So, for example, there was on satellite 1136 00:38:52,650 --> 00:38:53,849 which couldn't complete the mission 1137 00:38:53,850 --> 00:38:56,369 because its time. We said at one point 1138 00:38:56,370 --> 00:38:58,739 and it just the 1139 00:38:58,740 --> 00:39:00,899 sequence just didn't get food. 1140 00:39:00,900 --> 00:39:03,159 And then also, as I talked about earlier, 1141 00:39:03,160 --> 00:39:04,169 the a bit flips. 1142 00:39:04,170 --> 00:39:06,269 So just your program could 1143 00:39:06,270 --> 00:39:07,979 not get corrupted. So it's a good idea if 1144 00:39:07,980 --> 00:39:09,509 you have a bootloader, if it's not 1145 00:39:09,510 --> 00:39:11,609 integrated into the silicon of 1146 00:39:11,610 --> 00:39:14,129 your processor, then just have a small, 1147 00:39:14,130 --> 00:39:16,199 very compact bootloader which is unlikely 1148 00:39:16,200 --> 00:39:18,359 you get hurt and which maybe checks 1149 00:39:18,360 --> 00:39:20,609 itself and also the other software 1150 00:39:20,610 --> 00:39:22,319 program prior to execution. 1151 00:39:22,320 --> 00:39:23,759 And then if you have the space, maybe 1152 00:39:23,760 --> 00:39:25,889 have several copies so you can 1153 00:39:25,890 --> 00:39:27,779 at least reconstruct your program code 1154 00:39:27,780 --> 00:39:28,780 afterwards. 1155 00:39:29,730 --> 00:39:31,769 And if you want to update your software 1156 00:39:31,770 --> 00:39:32,770 in space 1157 00:39:34,610 --> 00:39:36,839 that there was always a risk 1158 00:39:36,840 --> 00:39:37,739 associated with it. 1159 00:39:37,740 --> 00:39:39,989 If you have really long term mission, you 1160 00:39:39,990 --> 00:39:41,099 might want to do it. 1161 00:39:41,100 --> 00:39:43,269 So then maybe space is 1162 00:39:43,270 --> 00:39:44,699 limited apart. If you have different 1163 00:39:44,700 --> 00:39:46,949 software, different code blocks 1164 00:39:46,950 --> 00:39:49,019 which fall out of your compiler prior to 1165 00:39:49,020 --> 00:39:50,999 linking, maybe have a link or file which 1166 00:39:51,000 --> 00:39:53,099 spaces them apart in your memory because 1167 00:39:53,100 --> 00:39:54,599 then you can override parts of your 1168 00:39:54,600 --> 00:39:56,909 memory without having to 1169 00:39:56,910 --> 00:39:58,769 shift back all the things that come after 1170 00:39:58,770 --> 00:40:01,049 it. So this would make it easier to 1171 00:40:01,050 --> 00:40:02,309 update the software in space because you 1172 00:40:02,310 --> 00:40:04,499 just have to make 1173 00:40:04,500 --> 00:40:07,199 Delta dates instead of reprograming 1174 00:40:07,200 --> 00:40:09,269 the whole nonvolatile 1175 00:40:09,270 --> 00:40:10,270 memory. 1176 00:40:10,900 --> 00:40:13,419 Just some miscellaneous things about 1177 00:40:13,420 --> 00:40:15,699 orbit's so available all the time, mostly 1178 00:40:15,700 --> 00:40:17,349 dictated, but what kinds of launches are 1179 00:40:17,350 --> 00:40:19,959 available because are only secondary 1180 00:40:19,960 --> 00:40:21,999 satellites, there are some started to try 1181 00:40:22,000 --> 00:40:24,369 to build the rockets just 1182 00:40:24,370 --> 00:40:26,409 for CubeSat launches, but they haven't 1183 00:40:26,410 --> 00:40:28,509 materialized yet. So just 1184 00:40:28,510 --> 00:40:30,639 a few common orbits, 1185 00:40:30,640 --> 00:40:32,889 low Earth orbit from ISIS 1186 00:40:32,890 --> 00:40:35,079 deployment there. We don't have such 1187 00:40:35,080 --> 00:40:37,149 a long life, maybe a month depending on 1188 00:40:37,150 --> 00:40:39,279 your size, but they are well 1189 00:40:39,280 --> 00:40:40,929 and expensive. So for 1190 00:40:42,180 --> 00:40:44,139 I've seen it starting at, let's say, 1191 00:40:44,140 --> 00:40:46,929 sixty thousand dollars for this launch 1192 00:40:46,930 --> 00:40:49,269 and then 1193 00:40:50,350 --> 00:40:51,599 we get a little bit more expensive. 1194 00:40:51,600 --> 00:40:53,669 You want to go in something transorbital 1195 00:40:53,670 --> 00:40:56,109 that later you start 1196 00:40:56,110 --> 00:40:58,359 at, let's say, 100000 US 1197 00:40:58,360 --> 00:41:00,069 dollars, but here you get more 1198 00:41:00,070 --> 00:41:01,689 interesting illumination properties. 1199 00:41:01,690 --> 00:41:03,849 If you want to do Earth observation or 1200 00:41:03,850 --> 00:41:06,189 if you want to optimize geothermal 1201 00:41:06,190 --> 00:41:08,559 or power, the budget. 1202 00:41:08,560 --> 00:41:10,959 And then we have not so common 1203 00:41:10,960 --> 00:41:13,299 geo transfer orbits, which are the orbits 1204 00:41:13,300 --> 00:41:15,819 that rockets inject into. 1205 00:41:15,820 --> 00:41:17,349 If you want to put a satellite on the 1206 00:41:17,350 --> 00:41:19,449 geostationary orbit, which is pretty 1207 00:41:19,450 --> 00:41:21,609 eccentric, gets you pretty far out if 1208 00:41:21,610 --> 00:41:22,610 you need it. 1209 00:41:23,380 --> 00:41:25,659 But, uh, yeah, it's much 1210 00:41:25,660 --> 00:41:28,089 less common than the previous two. 1211 00:41:28,090 --> 00:41:30,289 So what is the drivers on your orbit 1212 00:41:30,290 --> 00:41:32,529 selection if you can select 1213 00:41:32,530 --> 00:41:34,119 so the distance to have service, for 1214 00:41:34,120 --> 00:41:35,349 example? 1215 00:41:35,350 --> 00:41:37,149 It's important if you consider the power 1216 00:41:37,150 --> 00:41:39,399 you need to transmit your data or get, 1217 00:41:39,400 --> 00:41:42,019 uh, commands back to the satellite. 1218 00:41:42,020 --> 00:41:43,509 The illumination is important because 1219 00:41:43,510 --> 00:41:44,799 different all of the planes have 1220 00:41:44,800 --> 00:41:46,959 different, uh, vectors to 1221 00:41:46,960 --> 00:41:49,149 the sun. So you have different times 1222 00:41:49,150 --> 00:41:50,769 in the shadow of the earth, different 1223 00:41:50,770 --> 00:41:51,849 times and sunlight. 1224 00:41:51,850 --> 00:41:54,039 This not only messes with your power 1225 00:41:54,040 --> 00:41:55,389 collection, but also with your thermal 1226 00:41:56,500 --> 00:41:57,909 behavior. A. 1227 00:41:57,910 --> 00:42:00,489 Also variations of the year because 1228 00:42:00,490 --> 00:42:02,219 the earth moves around the sun. 1229 00:42:02,220 --> 00:42:03,669 That's that's not good. 1230 00:42:03,670 --> 00:42:05,889 So, uh, then the next 1231 00:42:05,890 --> 00:42:06,529 is radiation. 1232 00:42:06,530 --> 00:42:08,589 So if you don't want to study the Van 1233 00:42:08,590 --> 00:42:10,659 Allen belts, keep out of the Van Allen 1234 00:42:10,660 --> 00:42:11,660 belts. 1235 00:42:12,460 --> 00:42:14,529 These are in the medium earth orbit 1236 00:42:14,530 --> 00:42:16,779 range. And if you stay there for long, 1237 00:42:16,780 --> 00:42:18,519 then you probably get just reset all the 1238 00:42:18,520 --> 00:42:20,559 time. And something something which just 1239 00:42:20,560 --> 00:42:22,689 might not be as obvious is 1240 00:42:22,690 --> 00:42:24,789 there is an implicit lifetime 1241 00:42:24,790 --> 00:42:27,759 limit. So this is not yet legislation, 1242 00:42:27,760 --> 00:42:30,189 but, uh, in general, 1243 00:42:30,190 --> 00:42:32,379 it will be probably pretty soon that 1244 00:42:32,380 --> 00:42:34,539 every CubeSat put into space 1245 00:42:34,540 --> 00:42:36,849 must be we entered before 20 1246 00:42:36,850 --> 00:42:39,099 years of its lifetime just 1247 00:42:39,100 --> 00:42:41,019 to reduce the amount of space debris. 1248 00:42:41,020 --> 00:42:43,479 Not every CubeSat launched 1249 00:42:43,480 --> 00:42:44,739 last year has 1250 00:42:45,850 --> 00:42:48,129 kept its limits. So we'll probably to 1251 00:42:48,130 --> 00:42:50,199 have a much longer lifetime in 1252 00:42:50,200 --> 00:42:52,449 orbit. But, uh, many, 1253 00:42:52,450 --> 00:42:53,919 many CubeSat launch providers now 1254 00:42:53,920 --> 00:42:55,989 required to show that the 1255 00:42:55,990 --> 00:42:58,239 orbit you launch and, uh, 1256 00:42:58,240 --> 00:43:00,189 is compliant with this also is, of 1257 00:43:00,190 --> 00:43:01,989 course, dependent on the type of CubeSat 1258 00:43:01,990 --> 00:43:04,059 you have and are currently things 1259 00:43:04,060 --> 00:43:07,299 development which reduces 1260 00:43:07,300 --> 00:43:09,699 your lifetime. So, for example, balloons 1261 00:43:09,700 --> 00:43:11,309 which inflate or things like that. 1262 00:43:13,570 --> 00:43:15,909 So about the sun synchronous orbit, 1263 00:43:15,910 --> 00:43:17,409 because I found this interesting. 1264 00:43:17,410 --> 00:43:19,089 So if you would just have a normal 1265 00:43:19,090 --> 00:43:21,399 undisturbed orbit and you would move 1266 00:43:21,400 --> 00:43:23,559 along and orbital plane, then as 1267 00:43:23,560 --> 00:43:25,689 the year progresses, the plane wouldn't 1268 00:43:25,690 --> 00:43:27,249 change because it's static in the 1269 00:43:27,250 --> 00:43:28,419 inertial frame. 1270 00:43:28,420 --> 00:43:30,729 So you see the illumination conditions 1271 00:43:30,730 --> 00:43:32,949 here. You have a midnight lunar 1272 00:43:32,950 --> 00:43:35,529 orbit named after the time zones 1273 00:43:35,530 --> 00:43:36,819 that it's flying over. 1274 00:43:36,820 --> 00:43:39,009 And then it changes to a dusk dawn orbit 1275 00:43:39,010 --> 00:43:41,079 here because it moves along the 1276 00:43:41,080 --> 00:43:43,299 so-called Terminator line between light 1277 00:43:43,300 --> 00:43:45,009 and shadow here. 1278 00:43:45,010 --> 00:43:47,259 If you have a sun synchronous orbit, you 1279 00:43:47,260 --> 00:43:49,479 are using the, uh, 1280 00:43:49,480 --> 00:43:51,189 the fact that the Earth is not a perfect 1281 00:43:51,190 --> 00:43:53,209 sphere. It's slightly ablated. 1282 00:43:53,210 --> 00:43:55,449 So, uh, this, uh, 1283 00:43:55,450 --> 00:43:57,519 distribution of Marzia exerts a 1284 00:43:57,520 --> 00:44:00,159 force and tends to, uh, 1285 00:44:00,160 --> 00:44:02,049 rotate your orbital plane. 1286 00:44:02,050 --> 00:44:03,879 And if you're going into the just the 1287 00:44:03,880 --> 00:44:06,909 right inclination. So just about, uh, 1288 00:44:06,910 --> 00:44:09,369 just the right angle between the equator 1289 00:44:09,370 --> 00:44:11,259 and your with the plane, then this will 1290 00:44:11,260 --> 00:44:13,719 rotate at such that as 1291 00:44:13,720 --> 00:44:15,819 the earth moves around the sun to 1292 00:44:15,820 --> 00:44:17,979 orbit, the plane rotates with it. 1293 00:44:17,980 --> 00:44:20,199 So you can see that approximately 1294 00:44:20,200 --> 00:44:22,329 at each time of the year the orbit is 1295 00:44:22,330 --> 00:44:24,819 stable and then you just need to choose 1296 00:44:24,820 --> 00:44:27,279 which which 1297 00:44:27,280 --> 00:44:29,529 basically local time you have here 1298 00:44:29,530 --> 00:44:31,059 on your satellite. So here, for example, 1299 00:44:31,060 --> 00:44:33,219 you would always have a midnight moon 1300 00:44:33,220 --> 00:44:35,689 orbit, but you could also always choose, 1301 00:44:35,690 --> 00:44:37,719 uh, uh, dust storm. 1302 00:44:37,720 --> 00:44:39,969 But so this does not mean 1303 00:44:39,970 --> 00:44:42,609 that nearly always you are completely 1304 00:44:42,610 --> 00:44:43,839 with one side and sunlight. 1305 00:44:43,840 --> 00:44:45,669 This is good for power, maybe not so good 1306 00:44:45,670 --> 00:44:48,009 for thermal, but that's a tradeoff 1307 00:44:48,010 --> 00:44:49,010 you have to do. 1308 00:44:51,740 --> 00:44:53,599 So something about ships, the transports. 1309 00:44:53,600 --> 00:44:55,759 Of course, you don't only want to build 1310 00:44:55,760 --> 00:44:57,409 your CubeSat, you want to maybe keep it 1311 00:44:57,410 --> 00:44:59,569 starts at your university 1312 00:44:59,570 --> 00:45:02,089 or heck hackerspace location, 1313 00:45:02,090 --> 00:45:03,169 but then at some point, you have to 1314 00:45:03,170 --> 00:45:05,059 transport it to your ships, a launch 1315 00:45:05,060 --> 00:45:07,129 provider. And then, 1316 00:45:07,130 --> 00:45:08,659 of course, it's obvious you want to 1317 00:45:08,660 --> 00:45:10,729 prevent excess humidity, particle 1318 00:45:10,730 --> 00:45:12,589 combination particle contamination and 1319 00:45:12,590 --> 00:45:13,799 electrical distress. 1320 00:45:13,800 --> 00:45:15,469 And so a mechanical shock. 1321 00:45:15,470 --> 00:45:17,239 But you also really have to think through 1322 00:45:17,240 --> 00:45:18,229 your whole transport chain. 1323 00:45:18,230 --> 00:45:20,059 So, for example, if you want to transport 1324 00:45:20,060 --> 00:45:22,369 your satellite and your hand luggage 1325 00:45:22,370 --> 00:45:24,829 at the airport, at the airport, you might 1326 00:45:24,830 --> 00:45:26,229 be asked to open it. 1327 00:45:27,770 --> 00:45:29,419 And this is especially bad if you have 1328 00:45:29,420 --> 00:45:31,669 taken extensive measures to keep 1329 00:45:31,670 --> 00:45:33,559 humidity and particles away from the 1330 00:45:33,560 --> 00:45:35,629 satellite. So I also heard stories 1331 00:45:35,630 --> 00:45:38,089 about experiments headed to Mars 1332 00:45:38,090 --> 00:45:39,739 which were asked to be opened at the 1333 00:45:39,740 --> 00:45:41,929 airport. So please make 1334 00:45:41,930 --> 00:45:43,459 sure in advance that you don't get into 1335 00:45:43,460 --> 00:45:44,959 any problems like that. 1336 00:45:44,960 --> 00:45:46,699 And of course, then also after the 1337 00:45:46,700 --> 00:45:47,839 transport, you want to check for 1338 00:45:47,840 --> 00:45:48,829 transport damage. 1339 00:45:48,830 --> 00:45:50,599 And if you can't look into your satellite 1340 00:45:50,600 --> 00:45:52,399 anymore, maybe think about that. 1341 00:45:52,400 --> 00:45:54,409 How do you can verify that there really 1342 00:45:54,410 --> 00:45:57,529 was no damage? Just have a basic check. 1343 00:45:57,530 --> 00:45:59,569 So, yeah, I hope I could give you a small 1344 00:45:59,570 --> 00:46:00,780 glimpse into the 1345 00:46:02,660 --> 00:46:04,219 development and what kind of 1346 00:46:04,220 --> 00:46:06,419 peculiarities there is and satellite and 1347 00:46:06,420 --> 00:46:07,309 CubeSat design. 1348 00:46:07,310 --> 00:46:08,809 If you're interested in things like that. 1349 00:46:09,910 --> 00:46:11,539 I think it would be best if you look at 1350 00:46:11,540 --> 00:46:13,109 other CubeSat projects reports during the 1351 00:46:13,110 --> 00:46:15,109 day, especially if the university 1352 00:46:15,110 --> 00:46:17,569 projects to write papers about 1353 00:46:17,570 --> 00:46:18,769 operation and so on. 1354 00:46:18,770 --> 00:46:20,479 And there are lots of interesting things 1355 00:46:20,480 --> 00:46:22,489 to found you. And I just want to remind 1356 00:46:22,490 --> 00:46:23,989 you that verification is key. 1357 00:46:23,990 --> 00:46:26,209 So if you have a thing that must 1358 00:46:26,210 --> 00:46:27,799 work, then you have to test it. 1359 00:46:27,800 --> 00:46:30,079 Otherwise you can just think it 1360 00:46:30,080 --> 00:46:31,099 probably won't work. 1361 00:46:31,100 --> 00:46:33,169 And if there is something 1362 00:46:33,170 --> 00:46:35,299 a risk you take, then think about a plan 1363 00:46:35,300 --> 00:46:37,879 B.. So if the fault occurs, 1364 00:46:37,880 --> 00:46:38,929 what do you do? 1365 00:46:38,930 --> 00:46:40,009 Is there any mitigation? 1366 00:46:40,010 --> 00:46:42,139 At least you can do maybe a reduced set 1367 00:46:42,140 --> 00:46:43,969 of science measurements of things like 1368 00:46:43,970 --> 00:46:45,119 that. So, yeah. 1369 00:46:45,120 --> 00:46:47,239 And does the end of my talk and what 1370 00:46:47,240 --> 00:46:49,189 was interesting for you and I think we 1371 00:46:49,190 --> 00:46:50,289 can do Cunetio. 1372 00:46:52,770 --> 00:46:54,630 Yes, so thank you very much. 1373 00:47:03,260 --> 00:47:05,389 So for now, the usual police line 1374 00:47:05,390 --> 00:47:07,759 up behind the microphones while we see 1375 00:47:07,760 --> 00:47:10,009 if we have questions from the Internet, I 1376 00:47:10,010 --> 00:47:12,439 don't see our signal angels standing. 1377 00:47:12,440 --> 00:47:13,879 So, uh, just line up. 1378 00:47:16,110 --> 00:47:18,229 It wasn't really interesting talk, 1379 00:47:18,230 --> 00:47:19,250 by the way, so. 1380 00:47:20,690 --> 00:47:22,849 Oh, yeah. Please leave the room 1381 00:47:22,850 --> 00:47:24,439 quietly because 1382 00:47:26,270 --> 00:47:28,429 we are still wanting to hear 1383 00:47:28,430 --> 00:47:30,079 the questions that might occur. 1384 00:47:30,080 --> 00:47:32,329 And as or we can see there are 1385 00:47:32,330 --> 00:47:34,300 many, many questions. 1386 00:47:35,930 --> 00:47:37,329 That's interesting. 1387 00:47:37,330 --> 00:47:40,319 OK, we'll just start over there. 1388 00:47:40,320 --> 00:47:41,320 Right. 1389 00:47:41,660 --> 00:47:42,660 Hello. 1390 00:47:48,690 --> 00:47:50,809 Hello, thanks for the talk. 1391 00:47:50,810 --> 00:47:53,069 Um, I've heard about, 1392 00:47:53,070 --> 00:47:55,799 um, Intel, Edison 1393 00:47:55,800 --> 00:47:57,989 reports, Hecate, BCB, something like 1394 00:47:57,990 --> 00:48:00,579 that used for concert. 1395 00:48:00,580 --> 00:48:03,629 Uh, do you know about any 1396 00:48:03,630 --> 00:48:05,879 Hecate Bisbee's like Raspberry Pi 1397 00:48:05,880 --> 00:48:08,189 or Arduino clones, which 1398 00:48:08,190 --> 00:48:10,289 are, um, which 1399 00:48:10,290 --> 00:48:11,929 can work at the space? 1400 00:48:11,930 --> 00:48:14,219 Fine. Well, 1401 00:48:14,220 --> 00:48:16,859 depending on how you build it, it's more 1402 00:48:16,860 --> 00:48:18,929 the question of how well it will work. 1403 00:48:18,930 --> 00:48:21,149 So as I showed you about variation, 1404 00:48:21,150 --> 00:48:23,519 there are some things you have to design 1405 00:48:23,520 --> 00:48:24,869 around for and so on. 1406 00:48:24,870 --> 00:48:27,149 So there was at least 1407 00:48:27,150 --> 00:48:28,919 Adreno. I know for certain that there was 1408 00:48:28,920 --> 00:48:31,019 a mission which used, uh, Adreno 1409 00:48:31,020 --> 00:48:33,509 at least compatible hardware as 1410 00:48:33,510 --> 00:48:36,059 a computer. But this was also, 1411 00:48:36,060 --> 00:48:38,369 as if I remember correctly, mostly done 1412 00:48:38,370 --> 00:48:40,559 so that other people can program 1413 00:48:40,560 --> 00:48:41,789 for the satellite. 1414 00:48:41,790 --> 00:48:44,759 So it was more used as a compatibility 1415 00:48:44,760 --> 00:48:46,859 thing and not for any other 1416 00:48:46,860 --> 00:48:48,659 obvious advantage in hardware, 1417 00:48:48,660 --> 00:48:49,680 architecture or programing. 1418 00:48:51,340 --> 00:48:53,409 But it, uh, this Bisbee's 1419 00:48:53,410 --> 00:48:56,709 are not specified for such circumstances, 1420 00:48:56,710 --> 00:48:58,419 such conditions. 1421 00:48:58,420 --> 00:49:00,099 Well, the problems you might get with 1422 00:49:00,100 --> 00:49:01,809 just commercial off the shelf 1423 00:49:03,040 --> 00:49:05,169 PCP's for Raspberry Pi also 1424 00:49:05,170 --> 00:49:07,569 are, for example, as I showed you this 1425 00:49:07,570 --> 00:49:09,579 sold to investors Whiskas because they 1426 00:49:09,580 --> 00:49:11,829 are certainly produced without that 1427 00:49:11,830 --> 00:49:12,830 in their shoulder. 1428 00:49:14,020 --> 00:49:16,119 And they have been even full 1429 00:49:16,120 --> 00:49:17,769 commercial satellites which failed due to 1430 00:49:17,770 --> 00:49:19,539 solar, because at least that's what I 1431 00:49:19,540 --> 00:49:20,439 think it was. 1432 00:49:20,440 --> 00:49:22,389 So this might be a problem. 1433 00:49:22,390 --> 00:49:24,879 And then, of course, yeah, just 1434 00:49:24,880 --> 00:49:26,589 the whole way structures might not be 1435 00:49:26,590 --> 00:49:28,189 ideal to mount inside a satellite, but 1436 00:49:28,190 --> 00:49:30,369 that has to really depend on the 1437 00:49:30,370 --> 00:49:32,079 on the PCB. I can't give you a general 1438 00:49:32,080 --> 00:49:32,889 answer for that. 1439 00:49:32,890 --> 00:49:33,890 Thank you. 1440 00:49:34,360 --> 00:49:36,369 OK, then you have two questions from the 1441 00:49:36,370 --> 00:49:37,299 signal Angel. 1442 00:49:37,300 --> 00:49:39,379 So, um, yes. 1443 00:49:39,380 --> 00:49:41,889 Or Niazi. They're asking 1444 00:49:41,890 --> 00:49:43,719 for Turness asking if there are any 1445 00:49:43,720 --> 00:49:45,699 satellites up there that can be used 1446 00:49:45,700 --> 00:49:48,819 freely and legally by hobbyists. 1447 00:49:48,820 --> 00:49:51,459 Well, if you're a licensed amateur radio 1448 00:49:51,460 --> 00:49:53,889 user, then there are some amateur radio 1449 00:49:53,890 --> 00:49:55,029 satellites up there. 1450 00:49:55,030 --> 00:49:57,159 So then you get most of 1451 00:49:57,160 --> 00:49:59,049 them with a satellites. 1452 00:49:59,050 --> 00:50:01,389 So you send an analog 1453 00:50:01,390 --> 00:50:03,969 signal, usually sound after, 1454 00:50:03,970 --> 00:50:06,039 and then it just gets repeated on a 1455 00:50:06,040 --> 00:50:08,199 different frequency down a day. 1456 00:50:08,200 --> 00:50:10,449 Also, I'm not sure if there's any one 1457 00:50:10,450 --> 00:50:12,369 active right now, but there was also some 1458 00:50:12,370 --> 00:50:14,529 actual radio satellites in the past which 1459 00:50:14,530 --> 00:50:16,419 used some kind of message, boxing 1460 00:50:16,420 --> 00:50:18,489 technique to transmit 1461 00:50:18,490 --> 00:50:20,889 messages. But, uh, as I said, getting 1462 00:50:20,890 --> 00:50:23,169 you have to need an amateur radio 1463 00:50:23,170 --> 00:50:25,210 license to use these satellite. 1464 00:50:27,570 --> 00:50:29,789 And the other question is 1465 00:50:29,790 --> 00:50:32,009 from handsome pirate. 1466 00:50:32,010 --> 00:50:34,649 I'm asking if you would recommend 1467 00:50:34,650 --> 00:50:37,229 to use a red hardened CPU 1468 00:50:37,230 --> 00:50:38,230 and memory. 1469 00:50:39,600 --> 00:50:41,999 Well, the problem with this, 1470 00:50:42,000 --> 00:50:44,099 if it's really red heart, 1471 00:50:44,100 --> 00:50:46,079 then they cost usually a lot of money 1472 00:50:46,080 --> 00:50:48,149 because they have small lots and so on, 1473 00:50:48,150 --> 00:50:50,219 and they are usually 1474 00:50:50,220 --> 00:50:52,589 at least that I know of not many cubists 1475 00:50:52,590 --> 00:50:54,779 which use this kind of technology. 1476 00:50:54,780 --> 00:50:57,299 So at least the 1477 00:50:57,300 --> 00:50:59,549 consensus among the design seems 1478 00:50:59,550 --> 00:51:01,769 to be that you should rather design 1479 00:51:01,770 --> 00:51:04,559 around the radiation problem than to 1480 00:51:04,560 --> 00:51:07,199 just select hardened components, because 1481 00:51:07,200 --> 00:51:09,569 especially if you are using the CubeSat 1482 00:51:09,570 --> 00:51:11,579 form factor because it's cheap, maybe you 1483 00:51:11,580 --> 00:51:13,739 can accommodate for certain 1484 00:51:13,740 --> 00:51:15,869 failure rate then you don't want 1485 00:51:15,870 --> 00:51:17,849 to get into this. 1486 00:51:17,850 --> 00:51:19,979 Yeah, just expenses with 1487 00:51:19,980 --> 00:51:20,980 red hot components. 1488 00:51:23,390 --> 00:51:25,609 OK, then we have questions here on the 1489 00:51:25,610 --> 00:51:27,419 four you left side. 1490 00:51:27,420 --> 00:51:29,659 Yes, I have 1491 00:51:29,660 --> 00:51:31,129 one comment and one question, actually. 1492 00:51:31,130 --> 00:51:32,779 And the comment is, if you think about 1493 00:51:32,780 --> 00:51:35,029 orbit, I think latency, especially 1494 00:51:35,030 --> 00:51:37,549 if you do communication, because 1495 00:51:38,840 --> 00:51:41,509 at certain altitudes, the light 1496 00:51:41,510 --> 00:51:43,789 speed of light actually is your limit for 1497 00:51:43,790 --> 00:51:45,799 communications. And it takes a while to 1498 00:51:45,800 --> 00:51:47,239 get there. And if you especially go in 1499 00:51:47,240 --> 00:51:49,909 high orbits like geostationary orbits, 1500 00:51:49,910 --> 00:51:52,549 you have significant 1501 00:51:52,550 --> 00:51:53,839 delays. 1502 00:51:53,840 --> 00:51:55,399 So that from my experience with 1503 00:51:55,400 --> 00:51:58,309 geostationary satellites. 1504 00:51:58,310 --> 00:52:00,619 But my question is also 1505 00:52:00,620 --> 00:52:01,620 regarding orbits 1506 00:52:03,830 --> 00:52:06,289 to what orbit do you know 1507 00:52:06,290 --> 00:52:08,719 if GPS available or 1508 00:52:08,720 --> 00:52:10,879 is it available at all? 1509 00:52:10,880 --> 00:52:12,649 Well, there are lots of tricks. 1510 00:52:12,650 --> 00:52:14,719 I mean, I use on CubeSat. 1511 00:52:14,720 --> 00:52:17,159 The problem is that if you just buy 1512 00:52:17,160 --> 00:52:19,519 a GPS receiver off the shelf, 1513 00:52:19,520 --> 00:52:20,520 there are these 1514 00:52:21,860 --> 00:52:23,959 limits built into it usually so 1515 00:52:23,960 --> 00:52:26,119 that you don't use it to build 1516 00:52:26,120 --> 00:52:28,309 intercontinental ballistic missiles. 1517 00:52:28,310 --> 00:52:31,009 So they have a 1518 00:52:31,010 --> 00:52:33,169 speed limit and an altitude limit. 1519 00:52:33,170 --> 00:52:35,239 And while on high altitude balloons, you 1520 00:52:35,240 --> 00:52:36,859 usually get away. If you find something 1521 00:52:36,860 --> 00:52:38,989 which needs both of them violated to shut 1522 00:52:38,990 --> 00:52:40,999 down on a satellite, you violate both of 1523 00:52:41,000 --> 00:52:43,069 them. So either you need some 1524 00:52:43,070 --> 00:52:45,379 special firmware for that or. 1525 00:52:46,400 --> 00:52:48,649 Yeah, or use a component 1526 00:52:48,650 --> 00:52:50,629 which is built to meet these 1527 00:52:50,630 --> 00:52:52,339 requirements. But of course, those get 1528 00:52:52,340 --> 00:52:53,469 pretty expensive. 1529 00:52:53,470 --> 00:52:56,089 So it's it's, 1530 00:52:56,090 --> 00:52:57,889 uh, it's it's definitely 1531 00:52:58,940 --> 00:53:00,709 possible to use GPS, especially on the 1532 00:53:00,710 --> 00:53:02,869 low Earth orbit, because GPS is more like 1533 00:53:02,870 --> 00:53:04,519 a medium Earth orbit. 1534 00:53:04,520 --> 00:53:06,439 But even if you are above the satellite, 1535 00:53:06,440 --> 00:53:08,599 uh, uh, the GPS 1536 00:53:08,600 --> 00:53:10,759 satellite orbits, they are 1537 00:53:10,760 --> 00:53:12,619 uh, I'm not sure. 1538 00:53:12,620 --> 00:53:14,899 I think it has been used already, 1539 00:53:14,900 --> 00:53:17,329 but the the antennas 1540 00:53:17,330 --> 00:53:19,399 of the GPS satellite try to 1541 00:53:19,400 --> 00:53:21,559 illuminate basically the whole earth, 1542 00:53:21,560 --> 00:53:23,209 but they have some overspill. 1543 00:53:23,210 --> 00:53:25,309 So if you look at the Earth, then, 1544 00:53:25,310 --> 00:53:27,079 uh, Cheapside Light coming from the other 1545 00:53:27,080 --> 00:53:29,119 side might send you a signal. 1546 00:53:29,120 --> 00:53:31,519 And by a tricks like that, you get also 1547 00:53:31,520 --> 00:53:33,619 some GPS reception on higher 1548 00:53:33,620 --> 00:53:34,609 orbit. 1549 00:53:34,610 --> 00:53:36,709 So it is possible it 1550 00:53:36,710 --> 00:53:38,839 has been done, but I don't know if 1551 00:53:38,840 --> 00:53:40,969 any just component you 1552 00:53:40,970 --> 00:53:41,970 can grab for that. 1553 00:53:43,480 --> 00:53:44,949 Interesting and one more thing. 1554 00:53:44,950 --> 00:53:46,689 Are you familiar with the alternate 1555 00:53:46,690 --> 00:53:48,969 project, the alternate, 1556 00:53:48,970 --> 00:53:51,219 which is actually an attempt 1557 00:53:51,220 --> 00:53:53,019 to build the global Internet with 1558 00:53:53,020 --> 00:53:54,020 CubeSat? 1559 00:53:54,940 --> 00:53:57,489 But they are not very far yet, I guess, 1560 00:53:57,490 --> 00:53:59,829 but have you ever heard of that? 1561 00:53:59,830 --> 00:54:01,299 I'm not completely sure. 1562 00:54:01,300 --> 00:54:03,469 I heard of one project, which I think 1563 00:54:03,470 --> 00:54:04,470 wanted to use. 1564 00:54:05,380 --> 00:54:06,939 I'm not sure because I think they use 1565 00:54:06,940 --> 00:54:09,099 just regular communication satellites to 1566 00:54:09,100 --> 00:54:11,329 distribute information, 1567 00:54:11,330 --> 00:54:12,819 but I'm not sure if this is the same. 1568 00:54:12,820 --> 00:54:14,529 I think it is that currently they're 1569 00:54:14,530 --> 00:54:16,569 using the existing satellites to just 1570 00:54:16,570 --> 00:54:18,399 broadcast things like Wikipedia and 1571 00:54:18,400 --> 00:54:18,669 stuff. 1572 00:54:18,670 --> 00:54:21,279 But as I said, if you just use, 1573 00:54:21,280 --> 00:54:22,569 let's say, amateur radio frequencies, 1574 00:54:22,570 --> 00:54:24,099 then your bandwidth is pretty, pretty 1575 00:54:24,100 --> 00:54:26,229 small. The problem is also north of it, 1576 00:54:26,230 --> 00:54:28,419 of course. So that just pushes 1577 00:54:28,420 --> 00:54:30,609 by. So you maybe have a 10 minute 1578 00:54:30,610 --> 00:54:32,679 contact window and you don't get 1579 00:54:32,680 --> 00:54:34,789 a lot of data down this time. 1580 00:54:34,790 --> 00:54:37,119 And yeah, 1581 00:54:37,120 --> 00:54:39,219 so if you will really want to dispute 1582 00:54:39,220 --> 00:54:41,589 a lot of information, then 1583 00:54:41,590 --> 00:54:43,989 you might have to think about how to time 1584 00:54:43,990 --> 00:54:45,579 it and how to maybe use multiple 1585 00:54:45,580 --> 00:54:47,319 satellites. You know, of course, 1586 00:54:47,320 --> 00:54:49,389 transmission on the satellite as often 1587 00:54:49,390 --> 00:54:51,969 some of the more power hungry things. 1588 00:54:51,970 --> 00:54:53,289 So if you're looking at your overall 1589 00:54:53,290 --> 00:54:55,359 power budget, this might also limit the 1590 00:54:55,360 --> 00:54:57,519 time you can transmit at all. 1591 00:54:57,520 --> 00:54:59,319 And you need multiple tracking 1592 00:54:59,320 --> 00:55:00,489 attendance, which is also 1593 00:55:01,900 --> 00:55:02,589 a problem. 1594 00:55:02,590 --> 00:55:04,059 I mean, this, of course, depends on what 1595 00:55:04,060 --> 00:55:06,309 kind of signal that send 1596 00:55:06,310 --> 00:55:08,949 if it's a very robust signal which can 1597 00:55:08,950 --> 00:55:11,019 penetrate even noise or something like 1598 00:55:11,020 --> 00:55:14,049 that, then maybe you get away with less, 1599 00:55:14,050 --> 00:55:16,179 uh, less directive on the underground 1600 00:55:16,180 --> 00:55:17,049 station. 1601 00:55:17,050 --> 00:55:18,609 But yeah, it's of course, a trade off 1602 00:55:18,610 --> 00:55:19,779 and. 1603 00:55:19,780 --> 00:55:20,949 Yeah, thanks. 1604 00:55:22,610 --> 00:55:24,709 OK, we don't have an endless 1605 00:55:24,710 --> 00:55:27,079 amount of time left, so, um, 1606 00:55:27,080 --> 00:55:29,479 maybe if you have longer questions, 1607 00:55:29,480 --> 00:55:31,009 it would be nice if you could ask them 1608 00:55:31,010 --> 00:55:33,109 afterwards and from now 1609 00:55:33,110 --> 00:55:35,359 on the side, there might be another 1610 00:55:35,360 --> 00:55:35,549 one. 1611 00:55:35,550 --> 00:55:38,649 Just wanted to ask if you have, uh, 1612 00:55:38,650 --> 00:55:40,819 a tip or something where 1613 00:55:40,820 --> 00:55:43,789 we can get some of the 1614 00:55:43,790 --> 00:55:46,069 already computer data or something, 1615 00:55:46,070 --> 00:55:48,559 something cool. A cool project 1616 00:55:48,560 --> 00:55:49,650 that you can recommend. 1617 00:55:50,870 --> 00:55:52,909 Well, if you are just interested in, 1618 00:55:52,910 --> 00:55:55,099 let's say, CubeSat housekeeping data, 1619 00:55:55,100 --> 00:55:57,649 then I already mentioned to fund your 1620 00:55:57,650 --> 00:55:59,779 project once they upload 1621 00:55:59,780 --> 00:56:01,639 all the housekeeping data they have on 1622 00:56:01,640 --> 00:56:02,809 the satellite. So if you just want to 1623 00:56:02,810 --> 00:56:04,729 know how just the environment is 1624 00:56:04,730 --> 00:56:06,829 approximately on your satellite 1625 00:56:06,830 --> 00:56:09,019 in orbit, then you might take a look at 1626 00:56:09,020 --> 00:56:10,020 their website. 1627 00:56:12,170 --> 00:56:14,389 Yeah, there is a slight 1628 00:56:14,390 --> 00:56:15,889 problem with the data we're going to 1629 00:56:15,890 --> 00:56:18,169 scrape it is that if they don't have data 1630 00:56:18,170 --> 00:56:19,819 for a certain time period, they still 1631 00:56:19,820 --> 00:56:21,379 give you data, but it's just repeated 1632 00:56:21,380 --> 00:56:23,239 over and over again with a new timestamp. 1633 00:56:23,240 --> 00:56:24,649 So if you want to scrape the data, you 1634 00:56:24,650 --> 00:56:27,109 might have to filter it out afterwards. 1635 00:56:27,110 --> 00:56:29,299 But at least that's why I got some, 1636 00:56:29,300 --> 00:56:31,040 uh, just data on housekeeping. 1637 00:56:33,360 --> 00:56:36,269 OK, again, we're here the uvo, 1638 00:56:36,270 --> 00:56:38,429 so you told that battery 1639 00:56:38,430 --> 00:56:40,559 discharge is limited to 20, 20 1640 00:56:40,560 --> 00:56:41,909 percent of the capacity 1641 00:56:43,470 --> 00:56:45,869 can it can be used 1642 00:56:45,870 --> 00:56:48,239 on other types of batteries, 1643 00:56:48,240 --> 00:56:50,309 which is more designed 1644 00:56:50,310 --> 00:56:52,799 for such kind of temperature 1645 00:56:52,800 --> 00:56:56,439 swings? Or I know Ernestas. 1646 00:56:56,440 --> 00:56:58,499 I mean, of course, you can look 1647 00:56:58,500 --> 00:56:59,669 at the whole range of available 1648 00:56:59,670 --> 00:57:02,069 batteries. The problem is that 1649 00:57:02,070 --> 00:57:05,129 while chipsets often are more volume 1650 00:57:05,130 --> 00:57:06,869 limited than really mass limited. 1651 00:57:06,870 --> 00:57:08,189 I mean, often in space you hear about 1652 00:57:08,190 --> 00:57:10,439 mass and how much it costs to put a a 1653 00:57:10,440 --> 00:57:12,329 kilogram into orbit or something, but it 1654 00:57:12,330 --> 00:57:14,429 keeps us from putting 1655 00:57:14,430 --> 00:57:16,139 everything into your small space. 1656 00:57:16,140 --> 00:57:17,969 So you basically have a similar problem 1657 00:57:17,970 --> 00:57:19,379 as you have in your smartphone. 1658 00:57:19,380 --> 00:57:21,299 And that's why they both converge maybe 1659 00:57:21,300 --> 00:57:23,279 to the same type of technology, because 1660 00:57:23,280 --> 00:57:25,589 it's so far above the 1661 00:57:25,590 --> 00:57:27,959 energy densities of other alternative 1662 00:57:27,960 --> 00:57:29,009 methods. 1663 00:57:29,010 --> 00:57:30,010 Thank you. 1664 00:57:31,590 --> 00:57:33,839 Um, before you can ask the next 1665 00:57:33,840 --> 00:57:35,909 question, everyone that's leaving now, it 1666 00:57:35,910 --> 00:57:37,769 would be great if you could leave through 1667 00:57:37,770 --> 00:57:40,019 the door near the stage because there's 1668 00:57:40,020 --> 00:57:42,389 already a queue outside and 1669 00:57:42,390 --> 00:57:43,769 then it's not getting up. 1670 00:57:43,770 --> 00:57:45,959 Ringold And, you 1671 00:57:45,960 --> 00:57:48,239 know, many people and stuff 1672 00:57:49,260 --> 00:57:50,269 this microphone. 1673 00:57:50,270 --> 00:57:52,269 Hey, thanks for this amazing talk. 1674 00:57:52,270 --> 00:57:54,359 My question is, how do you maneuver your 1675 00:57:54,360 --> 00:57:56,429 satellite in a specific orbit once 1676 00:57:56,430 --> 00:57:58,439 launched? And then there's a question, 1677 00:57:58,440 --> 00:58:00,709 how does the electronics react on the 1678 00:58:00,710 --> 00:58:03,119 vacuum condition, such as, um, 1679 00:58:03,120 --> 00:58:05,520 uh, capacitor putting it evaporate? 1680 00:58:07,030 --> 00:58:08,140 Yeah, well, of course, you can 1681 00:58:09,190 --> 00:58:11,439 sometimes see the same ground based 1682 00:58:12,910 --> 00:58:15,619 vacuum applications that I just go to 1683 00:58:15,620 --> 00:58:17,769 the electrolytic capacitors, so 1684 00:58:17,770 --> 00:58:18,820 it's somehow 1685 00:58:19,990 --> 00:58:21,769 encapsulated. 1686 00:58:21,770 --> 00:58:23,019 But of course if you have a space 1687 00:58:23,020 --> 00:58:25,269 application, you might try to get just 1688 00:58:25,270 --> 00:58:27,849 away from these kind of capacitors. 1689 00:58:29,380 --> 00:58:32,259 The other thing about in orbit 1690 00:58:32,260 --> 00:58:33,999 manoeuvers, the problem with that is that 1691 00:58:35,140 --> 00:58:36,969 you get into, let's say, rocket 1692 00:58:36,970 --> 00:58:39,189 propulsion territory, and that 1693 00:58:39,190 --> 00:58:41,269 means you need mass to 1694 00:58:41,270 --> 00:58:43,389 get the energy to make any kind 1695 00:58:43,390 --> 00:58:45,789 of maneuver. And as I said, 1696 00:58:45,790 --> 00:58:47,799 usually, if you would just need a small 1697 00:58:47,800 --> 00:58:49,869 engine, let's say a chemical engine 1698 00:58:49,870 --> 00:58:51,969 might be the way to go, 1699 00:58:51,970 --> 00:58:54,069 but you are not allowed to have dangerous 1700 00:58:54,070 --> 00:58:56,379 substances or high energy 1701 00:58:56,380 --> 00:58:57,699 content in your satellite. 1702 00:58:57,700 --> 00:59:00,249 So these kinds of engines 1703 00:59:00,250 --> 00:59:01,449 can be used. 1704 00:59:01,450 --> 00:59:03,519 There are some projects at the moment 1705 00:59:03,520 --> 00:59:05,589 which try to develop, let's 1706 00:59:05,590 --> 00:59:07,689 say, ion engines, which use 1707 00:59:07,690 --> 00:59:10,179 the power collected by the satellite 1708 00:59:10,180 --> 00:59:12,279 to propel a medium 1709 00:59:12,280 --> 00:59:14,049 and thereby generate some thrust. 1710 00:59:14,050 --> 00:59:16,689 But even if you would think 1711 00:59:16,690 --> 00:59:19,509 if you are brought to applications 1712 00:59:19,510 --> 00:59:21,609 and used, the amount of thrust 1713 00:59:21,610 --> 00:59:23,679 they give you is not that the amount 1714 00:59:23,680 --> 00:59:25,479 of total change in velocity, so-called 1715 00:59:25,480 --> 00:59:27,829 Delta V is not that much. 1716 00:59:27,830 --> 00:59:29,619 So you might be able to extend, let's 1717 00:59:29,620 --> 00:59:30,909 say, your lifetime if you're on a low 1718 00:59:30,910 --> 00:59:31,839 Earth orbit. 1719 00:59:31,840 --> 00:59:34,119 But it's difficult to, 1720 00:59:34,120 --> 00:59:36,339 let's say, ways to orbit significantly 1721 00:59:36,340 --> 00:59:37,939 or you can change the orbital plane. 1722 00:59:37,940 --> 00:59:40,389 That's that's very expensive. 1723 00:59:40,390 --> 00:59:42,519 So, yeah, 1724 00:59:42,520 --> 00:59:44,739 it's currently not that feasible 1725 00:59:44,740 --> 00:59:46,509 in a CubeSat to make big changes. 1726 00:59:46,510 --> 00:59:49,029 I mean, there are lots of projects 1727 00:59:49,030 --> 00:59:50,059 going on. 1728 00:59:50,060 --> 00:59:51,849 Let's see what they get at. 1729 00:59:51,850 --> 00:59:54,519 But at the moment, it's 1730 00:59:54,520 --> 00:59:55,630 there's no component 1731 00:59:56,640 --> 00:59:57,789 you can use for that. 1732 00:59:57,790 --> 00:59:59,799 So you basically stick with the big 1733 00:59:59,800 --> 01:00:00,579 satellite. 1734 01:00:00,580 --> 01:00:02,899 Yeah, you do stay on the same orbit. 1735 01:00:02,900 --> 01:00:04,929 The upper stage left you on. 1736 01:00:04,930 --> 01:00:06,279 And of course, then you have all this 1737 01:00:06,280 --> 01:00:08,109 disturbance influences which changes your 1738 01:00:08,110 --> 01:00:09,819 orbit. But in general, you stay on the 1739 01:00:09,820 --> 01:00:10,599 same orbit. 1740 01:00:10,600 --> 01:00:13,179 Thank you. OK, we are out of time. 1741 01:00:13,180 --> 01:00:14,559 Thank you very much again.