1
00:00:08,480 --> 00:00:10,719
Speaker 1: Hey, Kelly, how are things running on the science farm?

2
00:00:10,960 --> 00:00:14,040
Speaker 2: Pretty well? But our house is like over one hundred

3
00:00:14,160 --> 00:00:16,640
Speaker 2: years old, so there's the usual number of issues that

4
00:00:16,680 --> 00:00:18,320
Speaker 2: you'd expect from a house of that age.

5
00:00:18,640 --> 00:00:21,400
Speaker 1: And so who's the like fixer upper in your family?

6
00:00:21,600 --> 00:00:23,400
Speaker 1: Is it the biologist or the cartoonist?

7
00:00:23,600 --> 00:00:25,520
Speaker 3: Oh, it is absolutely the biologist.

8
00:00:25,600 --> 00:00:27,920
Speaker 2: I have a series of Twitter posts actually where I

9
00:00:28,080 --> 00:00:34,120
Speaker 2: secretly record Zach trying to use tools, and each video

10
00:00:34,320 --> 00:00:37,360
Speaker 2: is better than the last. Every time a contractor comes

11
00:00:37,400 --> 00:00:40,400
Speaker 2: through and is like, ma'am, where is your husband? Should

12
00:00:40,440 --> 00:00:43,680
Speaker 2: we discuss this with him? I laugh out loud because

13
00:00:44,080 --> 00:00:47,520
Speaker 2: because Zach, he's just not interested in this stuff at all.

14
00:00:47,560 --> 00:00:49,159
Speaker 2: So all right, how about in your family?

15
00:00:49,440 --> 00:00:49,720
Speaker 3: Is it?

16
00:00:49,960 --> 00:00:53,720
Speaker 2: So let's see, you're an experimentalist. So does that make

17
00:00:53,800 --> 00:00:55,720
Speaker 2: you the one who's handy with tools?

18
00:00:56,040 --> 00:00:59,960
Speaker 1: Ooh, I wish. Technically I'm an experimentalist, but in practice

19
00:01:00,080 --> 00:01:03,040
Speaker 1: I do more computer stuff, so that means I fix

20
00:01:03,120 --> 00:01:05,679
Speaker 1: like the brooken laptops and the iPhones. Like in your family.

21
00:01:05,800 --> 00:01:08,560
Speaker 1: My wife is much more hands on than I am,

22
00:01:08,760 --> 00:01:09,600
Speaker 1: and so is she.

23
00:01:09,520 --> 00:01:11,120
Speaker 2: The one who usually is doing the fixing.

24
00:01:11,360 --> 00:01:14,240
Speaker 1: She's actually too busy fixing stuff in her lab to

25
00:01:14,280 --> 00:01:17,399
Speaker 1: fix stuff around the house. So we don't really have

26
00:01:17,520 --> 00:01:18,800
Speaker 1: anybody fixing stuff.

27
00:01:19,400 --> 00:01:23,560
Speaker 2: So what do you do when the stuff breaks? Stuff

28
00:01:23,600 --> 00:01:25,720
Speaker 2: doesn't just not break because there's no one available to

29
00:01:25,760 --> 00:01:26,160
Speaker 2: fix it.

30
00:01:26,240 --> 00:01:29,039
Speaker 1: I've learned that our strategy is to live with it

31
00:01:29,080 --> 00:01:31,840
Speaker 1: as long as possible. The house is pretty new when

32
00:01:31,840 --> 00:01:33,880
Speaker 1: we moved in, and so we're just going to see

33
00:01:33,920 --> 00:01:35,160
Speaker 1: how long that works.

34
00:01:36,680 --> 00:01:40,680
Speaker 2: This is all horrible plan, Daniel, Houses are not disposable.

35
00:01:40,760 --> 00:01:42,840
Speaker 3: You think you can't just break it down and then

36
00:01:42,920 --> 00:01:43,520
Speaker 3: move out.

37
00:01:44,680 --> 00:01:45,480
Speaker 1: We'll see.

38
00:01:46,120 --> 00:01:46,640
Speaker 3: Good luck.

39
00:02:02,000 --> 00:02:04,680
Speaker 1: Hi, I'm Daniel. I'm a physicist and a professor at

40
00:02:04,760 --> 00:02:08,080
Speaker 1: UC Irvine, and I'm not good at fixing broken stuff.

41
00:02:08,400 --> 00:02:12,279
Speaker 2: Hi. I'm Kelly Weener Smith. I'm adjunct at Rice University.

42
00:02:12,320 --> 00:02:14,600
Speaker 2: And if I didn't fix things, the house would fall

43
00:02:14,639 --> 00:02:15,359
Speaker 2: down around us.

44
00:02:15,560 --> 00:02:17,720
Speaker 1: It sounds like you're going to be actually useful when

45
00:02:17,760 --> 00:02:18,840
Speaker 1: the end times come.

46
00:02:19,160 --> 00:02:21,760
Speaker 2: I hope. So you know Zach Garden, so he might

47
00:02:21,800 --> 00:02:24,120
Speaker 2: be useful when the end times come. We joke about

48
00:02:24,120 --> 00:02:26,160
Speaker 2: the apocalypse a lot, but we're pretty sure that when

49
00:02:26,200 --> 00:02:27,720
Speaker 2: it comes to self defense more donners.

50
00:02:30,480 --> 00:02:33,120
Speaker 1: I pretty much have no useful skills. I mean, I

51
00:02:33,120 --> 00:02:36,560
Speaker 1: can write programs, I can record podcasts, I can think

52
00:02:36,600 --> 00:02:39,360
Speaker 1: deeply about the nature of the universe, but you know,

53
00:02:39,440 --> 00:02:41,640
Speaker 1: none of that's going to translate into like whiskey or

54
00:02:41,680 --> 00:02:42,960
Speaker 1: gold in the end times.

55
00:02:43,240 --> 00:02:45,280
Speaker 2: Yeah no, so you like probably wouldn't make it to

56
00:02:45,320 --> 00:02:48,840
Speaker 2: the second season of The Walking Dead. I like to

57
00:02:48,840 --> 00:02:50,919
Speaker 2: think that I'd still be around on The Walking Dead,

58
00:02:50,919 --> 00:02:52,800
Speaker 2: but I'm not sure I'd have to get good with

59
00:02:52,840 --> 00:02:53,760
Speaker 2: the sword or something.

60
00:02:53,960 --> 00:02:56,799
Speaker 1: You know, The Walking Dead actually does teach people to survive.

61
00:02:57,160 --> 00:02:59,480
Speaker 1: There is this incredible story about a young woman in

62
00:02:59,600 --> 00:03:03,120
Speaker 1: Irvine who's attacked in a parking garage in real life

63
00:03:03,320 --> 00:03:06,720
Speaker 1: by huge ex marine and she managed to wrestle the

64
00:03:06,720 --> 00:03:09,880
Speaker 1: blade away from him and kill her attacker. And when

65
00:03:09,880 --> 00:03:11,960
Speaker 1: they asked her how she managed to do that, she said,

66
00:03:12,200 --> 00:03:14,600
Speaker 1: I watch The Walking Dead. I know it's kill or

67
00:03:14,639 --> 00:03:15,240
Speaker 1: be killed.

68
00:03:15,400 --> 00:03:16,320
Speaker 3: Oh my gosh.

69
00:03:16,840 --> 00:03:21,840
Speaker 2: I mean she must have like she must work out

70
00:03:22,000 --> 00:03:24,080
Speaker 2: or have had some prior martial art training or so.

71
00:03:24,080 --> 00:03:25,960
Speaker 2: There's got to be more to it than I watched

72
00:03:26,000 --> 00:03:28,440
Speaker 2: The Walking Dead, because I've seen it all.

73
00:03:28,960 --> 00:03:31,000
Speaker 1: Turns out there's a lot more grit in Orange County

74
00:03:31,000 --> 00:03:31,880
Speaker 1: than you might expect.

75
00:03:32,160 --> 00:03:34,280
Speaker 2: I guess, so I believe it. That's incredible.

76
00:03:34,560 --> 00:03:38,200
Speaker 1: But speaking about grit and survival. Humanity needs to have

77
00:03:38,240 --> 00:03:41,160
Speaker 1: a sustainable way to live here on Earth and out

78
00:03:41,200 --> 00:03:44,120
Speaker 1: in the Solar System. And on this podcast we like

79
00:03:44,200 --> 00:03:46,960
Speaker 1: to think about the future, but what science and technology

80
00:03:47,000 --> 00:03:50,600
Speaker 1: hold for our future exploration of our neighborhood. So welcome

81
00:03:50,640 --> 00:03:53,480
Speaker 1: to the podcast Daniel and Jorge explain the Universe, in

82
00:03:53,520 --> 00:03:56,880
Speaker 1: which we talk about exactly those things, how the universe works,

83
00:03:56,920 --> 00:03:58,960
Speaker 1: how it all comes together, and how we can take

84
00:03:59,000 --> 00:04:02,280
Speaker 1: advantage of our knowledge of physical laws to build ourselves

85
00:04:02,400 --> 00:04:05,400
Speaker 1: a sustainable life here on Earth and perhaps also on

86
00:04:05,480 --> 00:04:08,280
Speaker 1: neighboring planets. Thanks very much Kelly for being a guest

87
00:04:08,320 --> 00:04:09,680
Speaker 1: host on today's episode.

88
00:04:09,800 --> 00:04:12,000
Speaker 2: Thanks for having me back. I always love being on

89
00:04:12,040 --> 00:04:12,680
Speaker 2: the show, and.

90
00:04:12,640 --> 00:04:15,280
Speaker 1: I always love talking to you about fancy technology in

91
00:04:15,360 --> 00:04:19,159
Speaker 1: space because you bring that bracing dash of skepticism.

92
00:04:20,400 --> 00:04:27,320
Speaker 2: Yes, everybody loves to have the wet blanket around. I'm

93
00:04:27,320 --> 00:04:28,880
Speaker 2: glad I'm appreciated somewhere.

94
00:04:29,120 --> 00:04:29,280
Speaker 3: Well.

95
00:04:29,279 --> 00:04:31,080
Speaker 1: You know, it's fun to blue sky think about what

96
00:04:31,160 --> 00:04:33,320
Speaker 1: might be possible. But if we're actually going to make

97
00:04:33,360 --> 00:04:35,160
Speaker 1: it out into the Solar System, if we're going to

98
00:04:35,240 --> 00:04:38,200
Speaker 1: send our probes and one day our children out into

99
00:04:38,240 --> 00:04:40,839
Speaker 1: deep space, we better have stuff that actually works, that

100
00:04:40,920 --> 00:04:43,599
Speaker 1: somebody has actually thought through and maybe even tested.

101
00:04:43,839 --> 00:04:46,120
Speaker 2: Well, you know, you need the wet blankets to put

102
00:04:46,160 --> 00:04:49,360
Speaker 2: out the fires, and so that I offer a service

103
00:04:49,400 --> 00:04:50,200
Speaker 2: I like to think.

104
00:04:52,080 --> 00:04:54,960
Speaker 1: And fire turns out to be quite essential. We use

105
00:04:55,000 --> 00:04:56,960
Speaker 1: it to hear on Earth, to keep ourselves warm, and

106
00:04:57,040 --> 00:05:01,320
Speaker 1: also to transform various kinds of energy in to electricity.

107
00:05:01,400 --> 00:05:03,800
Speaker 1: We have mammoth amounts of coal and gas still being

108
00:05:03,839 --> 00:05:07,240
Speaker 1: burnt to turn steam turbines to convert it into electricity,

109
00:05:07,360 --> 00:05:09,599
Speaker 1: as well as huge amounts of the planet covered in

110
00:05:09,640 --> 00:05:13,160
Speaker 1: solar panels to generate electricity for our lifestyle. But when

111
00:05:13,200 --> 00:05:16,640
Speaker 1: we send our robots into outer space, they don't necessarily

112
00:05:16,680 --> 00:05:20,560
Speaker 1: have access to coal fired power plants, so they need

113
00:05:20,600 --> 00:05:23,480
Speaker 1: to think about other ways to stay warm and keep running.

114
00:05:23,720 --> 00:05:25,880
Speaker 3: And the environment of space is a tough.

115
00:05:25,640 --> 00:05:29,480
Speaker 1: One, as we've talked about several times on the podcast.

116
00:05:29,640 --> 00:05:31,640
Speaker 1: So on today's episode, we're going to think through some

117
00:05:31,720 --> 00:05:34,479
Speaker 1: of the details of how our little robots can keep

118
00:05:34,560 --> 00:05:38,200
Speaker 1: chugging away on the surface of alien planets. More specifically,

119
00:05:38,440 --> 00:05:46,080
Speaker 1: on today's episode, we'll answer the question how can we

120
00:05:46,200 --> 00:05:50,200
Speaker 1: keep solar panels clean on Mars? But maybe we should

121
00:05:50,200 --> 00:05:52,279
Speaker 1: start closer to home. How do you keep your solar

122
00:05:52,279 --> 00:05:57,640
Speaker 1: panels cleaning, Kelly, HAA, I don't. You can't just let

123
00:05:57,720 --> 00:05:59,080
Speaker 1: these things break and then move on.

124
00:06:00,240 --> 00:06:03,120
Speaker 2: Oh, I you know it's possible.

125
00:06:03,160 --> 00:06:04,240
Speaker 3: I'm a bit of a hypocrite.

126
00:06:04,440 --> 00:06:08,120
Speaker 2: Sometime now, I actually, well, I was thinking about today's episode.

127
00:06:08,120 --> 00:06:10,839
Speaker 2: I realized that I have never cleaned the solar panels

128
00:06:10,880 --> 00:06:12,640
Speaker 2: that are up on top of one of our barns.

129
00:06:13,080 --> 00:06:15,320
Speaker 2: I just don't know how i'd reach them. But we

130
00:06:15,400 --> 00:06:17,720
Speaker 2: do live in a dusty you know, we've got Virginia

131
00:06:17,839 --> 00:06:20,320
Speaker 2: dusty clay. So I guess I just hope it rains

132
00:06:20,320 --> 00:06:21,240
Speaker 2: a lot. And it does.

133
00:06:22,320 --> 00:06:24,840
Speaker 1: Don't You have small children. They're good at climbing, and

134
00:06:24,880 --> 00:06:28,200
Speaker 1: their little fingers are great at cleaning tiny little electronics

135
00:06:28,360 --> 00:06:29,120
Speaker 1: that yes.

136
00:06:29,000 --> 00:06:32,200
Speaker 2: No, absolutely, And I haven't read the child labor laws

137
00:06:32,240 --> 00:06:33,880
Speaker 2: to know if I'm allowed to do this or not,

138
00:06:34,720 --> 00:06:37,560
Speaker 2: but probably it's fine, And so maybe that's what they'll

139
00:06:37,600 --> 00:06:38,240
Speaker 2: do this weekend.

140
00:06:38,400 --> 00:06:41,080
Speaker 1: Well, I hear they're loosening labor laws all across the South,

141
00:06:41,120 --> 00:06:43,520
Speaker 1: So maybe soon your children can legally work for you.

142
00:06:43,760 --> 00:06:45,279
Speaker 2: Yay, thank you politics.

143
00:06:45,520 --> 00:06:48,119
Speaker 1: So if Kelly can't even keep her solar panels clean

144
00:06:48,200 --> 00:06:51,240
Speaker 1: on Earth, how it could be possible for NASA to

145
00:06:51,320 --> 00:06:55,479
Speaker 1: keep solar panels clean on Mars, a famously dusty and

146
00:06:55,760 --> 00:06:59,680
Speaker 1: very distant environment where there aren't even child laborers available

147
00:06:59,800 --> 00:07:01,279
Speaker 1: to clean those little robots.

148
00:07:01,480 --> 00:07:03,000
Speaker 3: Gosh, I hope we can fix that one day.

149
00:07:04,560 --> 00:07:06,800
Speaker 1: That's why we have to send people to Mars, starting

150
00:07:06,839 --> 00:07:09,880
Speaker 1: with children. Yes, absolutely, but we reached out to our

151
00:07:09,920 --> 00:07:12,800
Speaker 1: audience to ask them if they had thoughts about how

152
00:07:12,840 --> 00:07:15,480
Speaker 1: to keep solar panels clean when there are thousands and

153
00:07:15,560 --> 00:07:19,240
Speaker 1: millions of miles away and also essential to the operation

154
00:07:19,520 --> 00:07:22,360
Speaker 1: of remote robots. If you would like to answer questions

155
00:07:22,360 --> 00:07:24,520
Speaker 1: for this segment of the podcast, please don't be shy.

156
00:07:24,560 --> 00:07:26,960
Speaker 1: We would love to have your voice on the podcast.

157
00:07:27,200 --> 00:07:30,240
Speaker 1: Just send me an email to Questions at Danielandjorge dot

158
00:07:30,280 --> 00:07:33,040
Speaker 1: com and I will set you up. So think about

159
00:07:33,120 --> 00:07:35,360
Speaker 1: for a moment, do you have clever ideas for how

160
00:07:35,400 --> 00:07:39,160
Speaker 1: to keep solar panels clean on Mars. Here's what people

161
00:07:39,280 --> 00:07:41,360
Speaker 1: had to say. You know what, that's a good question.

162
00:07:41,600 --> 00:07:42,960
Speaker 2: The rover has got a lot of batteries.

163
00:07:42,960 --> 00:07:46,080
Speaker 1: It's not solar powered. It's not solar powered.

164
00:07:46,080 --> 00:07:48,840
Speaker 4: That's why I would say that the reason why they

165
00:07:48,840 --> 00:07:52,920
Speaker 4: don't have wipers is because we would have to probably

166
00:07:53,000 --> 00:07:56,720
Speaker 4: have fluid to spray on the solar panels to wipe

167
00:07:56,760 --> 00:08:00,360
Speaker 4: and clean, and that's probably just too much to do

168
00:08:01,080 --> 00:08:01,600
Speaker 4: with the rover.

169
00:08:02,040 --> 00:08:03,440
Speaker 1: I've never really thought about that.

170
00:08:04,160 --> 00:08:07,000
Speaker 4: My guess is that, you know, using a regular wiperd

171
00:08:07,000 --> 00:08:07,920
Speaker 4: would scrape the lens.

172
00:08:08,200 --> 00:08:10,360
Speaker 1: So I'm guessing they blow the dust off with some

173
00:08:10,520 --> 00:08:13,120
Speaker 1: type of compressed air system. I don't know. That's a

174
00:08:13,200 --> 00:08:16,200
Speaker 1: really good point. Maybe the solar panels have.

175
00:08:16,320 --> 00:08:20,160
Speaker 2: A self cleaning technology, like self cleaning glasses that are

176
00:08:20,160 --> 00:08:22,360
Speaker 2: available in civil construction.

177
00:08:22,680 --> 00:08:22,960
Speaker 4: Hm.

178
00:08:22,960 --> 00:08:26,160
Speaker 1: I don't know. If it's a dry maybe that would

179
00:08:26,160 --> 00:08:30,440
Speaker 1: just scratch the lenses. Maybe you need like the film

180
00:08:30,520 --> 00:08:33,120
Speaker 1: that just keeps replacing itself.

181
00:08:33,520 --> 00:08:35,040
Speaker 3: I thought these were really great answers.

182
00:08:35,080 --> 00:08:38,479
Speaker 2: The listeners identified a lot of the actual big problems

183
00:08:38,520 --> 00:08:39,680
Speaker 2: and had some good ideas.

184
00:08:39,679 --> 00:08:41,920
Speaker 3: And to be honest, I hadn't.

185
00:08:41,640 --> 00:08:46,520
Speaker 2: Heard of self cleaning window technology. Do you know about this, Daniel,

186
00:08:46,520 --> 00:08:47,360
Speaker 2: Do you know how it works?

187
00:08:47,679 --> 00:08:50,520
Speaker 1: I'm not an expert in self cleaning windows. But later

188
00:08:50,600 --> 00:08:53,120
Speaker 1: in the episode we're going to talk about self cleaning

189
00:08:53,160 --> 00:08:57,120
Speaker 1: solar panels. This is actually technology people at MIT are

190
00:08:57,280 --> 00:08:57,800
Speaker 1: working on.

191
00:08:58,360 --> 00:08:59,520
Speaker 3: Ooh, very cool.

192
00:08:59,559 --> 00:09:02,480
Speaker 1: So you're right, our listeners are on point. These are

193
00:09:02,480 --> 00:09:04,760
Speaker 1: some smart people we have listening to the podcast, and

194
00:09:04,920 --> 00:09:05,720
Speaker 1: good looking too.

195
00:09:06,600 --> 00:09:09,840
Speaker 3: Yes, that's called the halo effect, I think. Yeah.

196
00:09:09,840 --> 00:09:13,200
Speaker 2: I bet they're also good at video games and probably

197
00:09:13,320 --> 00:09:13,880
Speaker 2: very fast.

198
00:09:14,080 --> 00:09:16,840
Speaker 1: Did think correlation applies causation, Like the more episodes of

199
00:09:16,840 --> 00:09:19,040
Speaker 1: the podcast you listen to, the better looking you are.

200
00:09:19,360 --> 00:09:21,959
Speaker 2: Yeah. No, And I hope that if I co host

201
00:09:22,040 --> 00:09:25,120
Speaker 2: enough that I'll be even more good looking than just listening.

202
00:09:25,280 --> 00:09:27,880
Speaker 2: So that's what I'm banking on. I'm not here just

203
00:09:27,920 --> 00:09:29,360
Speaker 2: because you're fun to talk to, Daniel.

204
00:09:30,400 --> 00:09:32,079
Speaker 1: I'm not sure it might go the other way.

205
00:09:32,240 --> 00:09:32,480
Speaker 4: You know.

206
00:09:32,600 --> 00:09:35,200
Speaker 1: If we have faces that are good for podcasting, it

207
00:09:35,280 --> 00:09:37,920
Speaker 1: might just mean that they get better and better for podcasting.

208
00:09:39,320 --> 00:09:39,640
Speaker 3: Daniel.

209
00:09:39,679 --> 00:09:45,000
Speaker 2: I'm sorry I have to go. It's been fun, but

210
00:09:45,040 --> 00:09:46,839
Speaker 2: I'm doing something else with my time, all right.

211
00:09:46,880 --> 00:09:49,880
Speaker 1: But we do want to keep our little robots powered

212
00:09:49,920 --> 00:09:52,880
Speaker 1: on alien planets. I mean, we send these devices off

213
00:09:52,920 --> 00:09:56,360
Speaker 1: to Mars to measure earthquakes, to gather samples, just to

214
00:09:56,480 --> 00:09:59,400
Speaker 1: drive around and see the geology and understand what used

215
00:09:59,440 --> 00:10:02,800
Speaker 1: to be on Mars, maybe even discovering water, evidence of

216
00:10:02,880 --> 00:10:07,200
Speaker 1: life or potentially even existent life on Mars. The questions

217
00:10:07,240 --> 00:10:09,880
Speaker 1: are still open, and well beyond Mars, we send things

218
00:10:09,960 --> 00:10:12,400
Speaker 1: to other planets. We'd like to drive them around and

219
00:10:12,440 --> 00:10:15,800
Speaker 1: even fly them around those planets. And for all these things,

220
00:10:15,880 --> 00:10:19,000
Speaker 1: they need power. None of this stuff comes for free, and.

221
00:10:19,000 --> 00:10:20,600
Speaker 2: We need to get really good at this stuff if

222
00:10:20,600 --> 00:10:22,760
Speaker 2: we're ever going to have humans living in space, because

223
00:10:22,800 --> 00:10:25,320
Speaker 2: you really can't have your power ever break down if

224
00:10:25,320 --> 00:10:26,160
Speaker 2: you're living in space.

225
00:10:26,240 --> 00:10:28,160
Speaker 1: That's right in space. You can't just wait till your

226
00:10:28,160 --> 00:10:30,920
Speaker 1: space station breaks down and then move out into another one.

227
00:10:31,240 --> 00:10:33,120
Speaker 1: Space stations are not disposable.

228
00:10:33,320 --> 00:10:35,840
Speaker 2: Well, I mean, we've burned a lot of them up

229
00:10:35,840 --> 00:10:38,760
Speaker 2: in the atmosphere, but you better have another plan before

230
00:10:38,800 --> 00:10:39,400
Speaker 2: that happens.

231
00:10:39,600 --> 00:10:42,240
Speaker 1: Yeah, we like to do some repairs before we recycle.

232
00:10:42,440 --> 00:10:45,600
Speaker 1: But solar power actually isn't the only way to power

233
00:10:45,720 --> 00:10:47,520
Speaker 1: some of these distant devices.

234
00:10:47,800 --> 00:10:48,640
Speaker 3: How else do we do it?

235
00:10:48,760 --> 00:10:52,840
Speaker 1: Daniel, Well, another option that's really fascinating are at nuclear batteries.

236
00:10:53,200 --> 00:10:54,960
Speaker 1: I mean, if you want to power something for a

237
00:10:55,000 --> 00:10:58,160
Speaker 1: long long time, you need a steady source of energy,

238
00:10:58,480 --> 00:11:01,040
Speaker 1: then you definitely don't want to bring gas along. You

239
00:11:01,080 --> 00:11:03,360
Speaker 1: want a very very dense source of power. You want

240
00:11:03,440 --> 00:11:05,880
Speaker 1: some kind of fuel that releases a lot of energy

241
00:11:05,880 --> 00:11:08,440
Speaker 1: and doesn't have a lot of kilograms and so in

242
00:11:08,480 --> 00:11:11,160
Speaker 1: the same way that we power like our aircraft carriers

243
00:11:11,200 --> 00:11:14,800
Speaker 1: and our submarines. We turn to atomic physics to produce

244
00:11:14,880 --> 00:11:17,400
Speaker 1: that energy. You know that aircraft carriers can go for

245
00:11:17,440 --> 00:11:21,199
Speaker 1: like decades without refueling because they have nuclear power plants

246
00:11:21,240 --> 00:11:25,600
Speaker 1: on board, like fully functioning fission reactors on board, turning

247
00:11:25,720 --> 00:11:30,960
Speaker 1: uranium into electricity. Same with submarines sliding around the Earth's ocean.

248
00:11:31,600 --> 00:11:32,800
Speaker 1: It's really pretty amazing.

249
00:11:32,960 --> 00:11:35,000
Speaker 2: Hang would take me a little while to get used

250
00:11:35,040 --> 00:11:37,280
Speaker 2: to knowing that I was living that close to a

251
00:11:37,360 --> 00:11:40,160
Speaker 2: nuclear reactor. On the other hand, it would be good

252
00:11:40,160 --> 00:11:42,280
Speaker 2: to know that you have a reliable power source.

253
00:11:42,480 --> 00:11:45,520
Speaker 1: But these things are delicate and dangerous, and you can't

254
00:11:45,520 --> 00:11:48,880
Speaker 1: put a whole nuclear power plant on a satellite or

255
00:11:48,920 --> 00:11:50,679
Speaker 1: on a little rover and it's going to be driving

256
00:11:50,720 --> 00:11:53,760
Speaker 1: around the surface of Mars. Instead, they have a different

257
00:11:53,840 --> 00:11:58,640
Speaker 1: way to extract energy from radioactive elements. These things are

258
00:11:58,679 --> 00:12:04,360
Speaker 1: called RTGs radio isotope thermoelectric generators. Basically, it's a big

259
00:12:04,480 --> 00:12:08,800
Speaker 1: block of material which decays radioactively and turns the heat

260
00:12:08,880 --> 00:12:12,040
Speaker 1: from that decay into electricity. So that's one of the

261
00:12:12,040 --> 00:12:15,040
Speaker 1: ways that we can power things in space. Kelly, here's

262
00:12:15,040 --> 00:12:17,920
Speaker 1: something of an expert in the history of nuclear power

263
00:12:17,920 --> 00:12:20,920
Speaker 1: and space. Have humans ever launched an actual working fission

264
00:12:20,960 --> 00:12:21,960
Speaker 1: reactor into space?

265
00:12:22,120 --> 00:12:22,320
Speaker 4: Oh?

266
00:12:22,360 --> 00:12:25,520
Speaker 2: Man, we've done it more times than you're probably comfortable knowing.

267
00:12:26,760 --> 00:12:29,439
Speaker 1: More than zero is more times than uncomfortable knowing.

268
00:12:29,679 --> 00:12:32,800
Speaker 2: Yeah, exactly. And so in nineteen sixty five, the US

269
00:12:32,840 --> 00:12:35,640
Speaker 2: did it for a satellite. It was like a test

270
00:12:35,920 --> 00:12:38,280
Speaker 2: and it didn't go great, but then we boosted it

271
00:12:38,320 --> 00:12:40,600
Speaker 2: into a graveyard orbit. So we actually have one of

272
00:12:40,600 --> 00:12:44,720
Speaker 2: these reactors still orbiting the Earth. But the USSR loved these.

273
00:12:44,960 --> 00:12:45,760
Speaker 2: They did it a.

274
00:12:45,800 --> 00:12:46,680
Speaker 3: Bunch of times.

275
00:12:46,800 --> 00:12:50,080
Speaker 2: I think they sent up thirty three or maybe even

276
00:12:50,800 --> 00:12:53,240
Speaker 2: more of them. And so, yeah, there have been a

277
00:12:53,240 --> 00:12:55,160
Speaker 2: lot of little nuclear reactors that have been sent to

278
00:12:55,200 --> 00:12:57,560
Speaker 2: space to power our satellites. I don't think any of

279
00:12:57,600 --> 00:13:00,800
Speaker 2: them have gone to like Mars or the Moon Tower rovers,

280
00:13:00,840 --> 00:13:03,439
Speaker 2: but we do have some experience with using these as satellites.

281
00:13:03,920 --> 00:13:04,280
Speaker 3: Also.

282
00:13:04,880 --> 00:13:08,920
Speaker 2: Fun fact, if your definition of fun is raining nuclear

283
00:13:08,960 --> 00:13:13,760
Speaker 2: waste over the Earth. One of the USSR's satellites that

284
00:13:13,840 --> 00:13:17,040
Speaker 2: was powered by a nuclear reactor. This one's called Cosmos

285
00:13:17,120 --> 00:13:20,720
Speaker 2: nine fifty four accidentally re entered when it wasn't meant

286
00:13:20,720 --> 00:13:25,400
Speaker 2: to re entered and it sprayed nuclear material all over Canada.

287
00:13:25,559 --> 00:13:27,480
Speaker 2: The US and Canada had to clean it up.

288
00:13:27,800 --> 00:13:28,720
Speaker 1: That sounds bad.

289
00:13:29,160 --> 00:13:31,400
Speaker 2: It was bad. Russia agreed to pay for half of it.

290
00:13:31,679 --> 00:13:34,239
Speaker 2: I think it's the only time in which the Liability

291
00:13:34,280 --> 00:13:39,040
Speaker 2: Convention through the United Nations has been invoked as a like, dude,

292
00:13:39,040 --> 00:13:42,320
Speaker 2: this is kind of your responsibility. And I think the

293
00:13:42,360 --> 00:13:46,120
Speaker 2: Soviet Union tried to be like, well, it's hard.

294
00:13:46,360 --> 00:13:49,040
Speaker 3: Maybe not, but eventually they went have these with US.

295
00:13:49,240 --> 00:13:52,400
Speaker 1: Well, sending working fission reactors into space doesn't seem like

296
00:13:52,440 --> 00:13:55,800
Speaker 1: a great idea, but fortunately these other devices, the radioisotope

297
00:13:55,840 --> 00:13:59,760
Speaker 1: thermoelectric generators, are simpler solid state devices. They don't have

298
00:13:59,800 --> 00:14:02,800
Speaker 1: any moving parts, they can't like melt down. Basically, you

299
00:14:02,880 --> 00:14:05,679
Speaker 1: just have like a block of radioactive material which is

300
00:14:05,679 --> 00:14:09,360
Speaker 1: decaying and releasing energy as those decays happen, which heats

301
00:14:09,440 --> 00:14:11,200
Speaker 1: up the block, and then you just got to turn

302
00:14:11,240 --> 00:14:13,000
Speaker 1: that heat into electricity.

303
00:14:13,240 --> 00:14:16,200
Speaker 2: Yeah, and most of the time you don't end up with,

304
00:14:16,400 --> 00:14:19,560
Speaker 2: for example, one of the lunicons breaking up over the

305
00:14:19,560 --> 00:14:22,320
Speaker 2: Soviet Union and sending colonium all over the place when

306
00:14:22,320 --> 00:14:23,640
Speaker 2: they're radioactive.

307
00:14:24,040 --> 00:14:24,440
Speaker 3: What is it?

308
00:14:24,520 --> 00:14:28,960
Speaker 2: This was a thermoelectric generator. That broke up and you know,

309
00:14:29,080 --> 00:14:30,480
Speaker 2: dropped waste over the USSR.

310
00:14:30,560 --> 00:14:32,640
Speaker 1: You're right, this is definitely a danger if you're launching

311
00:14:32,720 --> 00:14:36,320
Speaker 1: radioactive materials, whether it's for an RTG or a working reactor,

312
00:14:36,520 --> 00:14:38,800
Speaker 1: you're risking blowing that over the surface of the Earth

313
00:14:38,840 --> 00:14:41,920
Speaker 1: at launch, because launches are still violent and risky events.

314
00:14:41,960 --> 00:14:43,960
Speaker 1: No matter how good we get at it, sometimes these

315
00:14:43,960 --> 00:14:47,560
Speaker 1: things still blow up, and if your payload is dangerous,

316
00:14:47,720 --> 00:14:50,480
Speaker 1: then that presents a danger to the population on Earth.

317
00:14:50,560 --> 00:14:52,720
Speaker 2: There are ways to make it safer, you know, there's

318
00:14:52,800 --> 00:14:54,600
Speaker 2: like new cladding that you can get, and you can

319
00:14:54,600 --> 00:14:57,720
Speaker 2: send up smaller and smaller amounts on different rocket launches

320
00:14:57,720 --> 00:14:59,800
Speaker 2: and then put them all together when you get to space.

321
00:15:00,000 --> 00:15:05,040
Speaker 2: But certainly our history is littered with radioactive accidents.

322
00:15:05,360 --> 00:15:08,840
Speaker 1: So these things are dangerous. They're also super duper expensive.

323
00:15:09,040 --> 00:15:11,720
Speaker 1: I mean often they use like plutonium two thirty eight,

324
00:15:11,880 --> 00:15:14,200
Speaker 1: for which we have a very limited supply because until

325
00:15:14,240 --> 00:15:17,840
Speaker 1: recently we stopped making plutonium, and so it's not easy

326
00:15:17,880 --> 00:15:20,080
Speaker 1: to get this stuff. If it blows up on launch,

327
00:15:20,160 --> 00:15:22,960
Speaker 1: it's very dangerous. On the flip side, it lasts for

328
00:15:23,000 --> 00:15:24,760
Speaker 1: a long time. Like you can build one of these

329
00:15:24,760 --> 00:15:27,880
Speaker 1: things and it will steadily produce power for ten to

330
00:15:27,920 --> 00:15:32,480
Speaker 1: fifteen years just pumping out electricity, doesn't require the sun,

331
00:15:32,760 --> 00:15:36,200
Speaker 1: there's no moving parts, it's very very stable. So these

332
00:15:36,200 --> 00:15:39,320
Speaker 1: things are sort of the gold standard for NASA if

333
00:15:39,320 --> 00:15:41,080
Speaker 1: it wants to power something that goes to like the

334
00:15:41,120 --> 00:15:44,440
Speaker 1: outer Solar system, where even solar panels are not going

335
00:15:44,480 --> 00:15:46,880
Speaker 1: to be effective because you're so far away from the Sun.

336
00:15:47,120 --> 00:15:48,800
Speaker 2: Well, not going to say, if I was moving to Mars,

337
00:15:48,880 --> 00:15:51,680
Speaker 2: I would really like to have a tiny nuclear power

338
00:15:51,680 --> 00:15:55,120
Speaker 2: plant on Mars rather than relying on anything else. And

339
00:15:56,040 --> 00:15:58,600
Speaker 2: there are engineers working on it, and they all really

340
00:15:58,680 --> 00:16:01,280
Speaker 2: like the Simpsons, and they name all of their designs

341
00:16:01,800 --> 00:16:03,040
Speaker 2: after Simpson stuff.

342
00:16:03,080 --> 00:16:04,840
Speaker 3: Oh no, so what let's see.

343
00:16:04,840 --> 00:16:09,040
Speaker 2: In twenty eighteen they tested the Kilo power reactor using

344
00:16:09,160 --> 00:16:13,600
Speaker 2: sterling technology, and by like picking the right letters out

345
00:16:13,640 --> 00:16:17,520
Speaker 2: of those various words, they come up with crusty and

346
00:16:18,040 --> 00:16:20,560
Speaker 2: like the clown. I think they also had one called Duff,

347
00:16:21,200 --> 00:16:24,040
Speaker 2: like after Duff beer. And anyway, one of the engineers

348
00:16:24,080 --> 00:16:26,040
Speaker 2: has been at this for like decades. But anyway, it

349
00:16:26,120 --> 00:16:28,280
Speaker 2: is a nice reliable power source if you could get

350
00:16:28,280 --> 00:16:29,480
Speaker 2: it to work safely, it is.

351
00:16:29,520 --> 00:16:31,840
Speaker 1: Very cool and it uses an interesting effect where you

352
00:16:31,880 --> 00:16:36,480
Speaker 1: turn heat into electricity by having two different kinds of metal,

353
00:16:36,880 --> 00:16:39,360
Speaker 1: one is hotter and one is cooler, and that generates

354
00:16:39,360 --> 00:16:42,960
Speaker 1: an electromotive force across them. Basically like the electrons and

355
00:16:43,080 --> 00:16:46,000
Speaker 1: hotter side are moving more and electrons and the cooler

356
00:16:46,000 --> 00:16:48,680
Speaker 1: side are not, and that creates a flow of current

357
00:16:48,800 --> 00:16:51,600
Speaker 1: across the threshold. And so you can turn this heat

358
00:16:51,680 --> 00:16:54,320
Speaker 1: into electricity again with no moving parts. You don't need

359
00:16:54,400 --> 00:16:57,280
Speaker 1: like a steam engine or a turbine or anything. It

360
00:16:57,440 --> 00:16:59,840
Speaker 1: just produces electricity. And yeah, if I was living on

361
00:16:59,880 --> 00:17:02,280
Speaker 1: this surface of Mars, I would like a backup source

362
00:17:02,320 --> 00:17:05,560
Speaker 1: of energy, especially if it didn't come with me to Mars.

363
00:17:05,560 --> 00:17:07,520
Speaker 1: If you're like landed separately, so I didn't have to

364
00:17:07,520 --> 00:17:10,200
Speaker 1: worry about radiation firmative it broke.

365
00:17:10,080 --> 00:17:11,439
Speaker 3: Down, Yeah, no doubt well.

366
00:17:11,480 --> 00:17:14,040
Speaker 2: And also there's lots of reasons in space why you'd

367
00:17:14,080 --> 00:17:16,960
Speaker 2: like to have heat, And these reactors also produce heat,

368
00:17:17,040 --> 00:17:18,680
Speaker 2: so you could, you know, I don't know, maybe heat

369
00:17:18,720 --> 00:17:20,120
Speaker 2: up your ice and turn it into water.

370
00:17:20,320 --> 00:17:23,040
Speaker 1: But because these things are expensive and they are dangerous,

371
00:17:23,080 --> 00:17:26,080
Speaker 1: and they're also in limited supply, NASA tends to be

372
00:17:26,160 --> 00:17:29,040
Speaker 1: pretty stingy with these things. They reserve them for like

373
00:17:29,119 --> 00:17:33,280
Speaker 1: the deepest, longest, high priority, lowest risk missions. And so

374
00:17:33,320 --> 00:17:36,120
Speaker 1: when people started talking about putting a rover on Mars,

375
00:17:36,400 --> 00:17:38,919
Speaker 1: the Mars program wasn't really in great shape, that had

376
00:17:38,920 --> 00:17:41,520
Speaker 1: a bunch of losses. It seemed very high risk. They

377
00:17:41,520 --> 00:17:44,000
Speaker 1: were thinking these rovers were only going to cruise around

378
00:17:44,040 --> 00:17:46,240
Speaker 1: for like a few weeks at most, so they didn't

379
00:17:46,280 --> 00:17:49,240
Speaker 1: have the option of using one of these nuclear batteries,

380
00:17:49,280 --> 00:17:51,080
Speaker 1: and they had to go for solar panels.

381
00:17:51,280 --> 00:18:06,680
Speaker 2: And after the break, we'll tell you about how those were. Okay,

382
00:18:06,680 --> 00:18:10,400
Speaker 2: so we've decided that nuclear power is reliable, but it's

383
00:18:10,480 --> 00:18:14,120
Speaker 2: expensive and sometimes things go wrong, and one way or another,

384
00:18:14,200 --> 00:18:18,280
Speaker 2: solar panels are really popular on space voyages. So how

385
00:18:18,320 --> 00:18:20,520
Speaker 2: about you tell us a bit how solar panels in

386
00:18:20,560 --> 00:18:21,080
Speaker 2: space work.

387
00:18:21,280 --> 00:18:23,520
Speaker 1: Yeah, solar panels in space work the same way the

388
00:18:23,560 --> 00:18:27,840
Speaker 1: solar panels do here on Earth, which is essentially transforming

389
00:18:27,920 --> 00:18:32,160
Speaker 1: the energy of the photons into current. And photons interacting

390
00:18:32,200 --> 00:18:35,080
Speaker 1: with electrons is of course very famous in physics. It's

391
00:18:35,080 --> 00:18:38,760
Speaker 1: the basis of the photoelectric effect for which Einstein won

392
00:18:38,760 --> 00:18:41,600
Speaker 1: the Nobel Prize more than one hundred years ago. When

393
00:18:41,640 --> 00:18:44,200
Speaker 1: photons hit a piece of metal, they don't just interact

394
00:18:44,240 --> 00:18:47,240
Speaker 1: with the whole metal, and they're not classical electromagnetic waves

395
00:18:47,240 --> 00:18:50,320
Speaker 1: where they deposit their energy broadly. Where they come in

396
00:18:50,400 --> 00:18:53,040
Speaker 1: terms of photons, which means that a single photon hits

397
00:18:53,040 --> 00:18:57,200
Speaker 1: a single electron and deposits its energy. The photoelectric effect

398
00:18:57,560 --> 00:19:00,119
Speaker 1: is when there's so much energy in that photon that

399
00:19:00,160 --> 00:19:04,080
Speaker 1: electrons boil off the surface. Like you can knock electrons

400
00:19:04,240 --> 00:19:07,200
Speaker 1: off of a piece of metal by shining high energy

401
00:19:07,280 --> 00:19:11,040
Speaker 1: light at it. So that's the photoelectric effect. The photovoltaic

402
00:19:11,160 --> 00:19:14,480
Speaker 1: effect is the principle underlying solar panels, and it's the

403
00:19:14,480 --> 00:19:17,840
Speaker 1: sort of like lower energy cousin of the photoelectric effect.

404
00:19:18,080 --> 00:19:21,080
Speaker 1: If you dial down the energy to photons so that

405
00:19:21,119 --> 00:19:24,040
Speaker 1: they don't have enough energy to kick the electrons out

406
00:19:24,080 --> 00:19:27,719
Speaker 1: of the metal, you know, boiling electrons off the surface. Instead,

407
00:19:27,720 --> 00:19:30,639
Speaker 1: you're just exciting the electrons. You're giving them more energy

408
00:19:30,840 --> 00:19:32,120
Speaker 1: so they can flow around.

409
00:19:32,440 --> 00:19:34,720
Speaker 3: And then how do you get energy out of them

410
00:19:34,760 --> 00:19:35,520
Speaker 3: flowing around?

411
00:19:35,760 --> 00:19:38,320
Speaker 1: Yeah, so you need to build a special kind of material.

412
00:19:38,440 --> 00:19:41,280
Speaker 1: So here we use silicon diodes. And silicon, remember is

413
00:19:41,320 --> 00:19:44,760
Speaker 1: a semiconductor, so it's not quite an insulator where all

414
00:19:44,800 --> 00:19:47,680
Speaker 1: the electrons are like trapped in the lattice of the crystal,

415
00:19:47,760 --> 00:19:50,719
Speaker 1: and it's not quite a conductor where there's no gap

416
00:19:50,760 --> 00:19:53,040
Speaker 1: between where the electrons live in the crystal and where

417
00:19:53,040 --> 00:19:56,320
Speaker 1: the electrons flow freely, So electrons are just zooming everywhere.

418
00:19:56,520 --> 00:19:59,240
Speaker 1: A semiconductor has like a little bit of a gap there,

419
00:19:59,280 --> 00:20:02,040
Speaker 1: so it's like hard for the electrons to flow, but

420
00:20:02,280 --> 00:20:04,720
Speaker 1: not impossible. And if you put the right kind of

421
00:20:04,720 --> 00:20:07,280
Speaker 1: materials into the silicon, and if you dope it with

422
00:20:07,400 --> 00:20:10,480
Speaker 1: other kinds of elements, then you can subtly tune the

423
00:20:10,520 --> 00:20:14,440
Speaker 1: size of that gap. So a diode has two different

424
00:20:14,560 --> 00:20:17,360
Speaker 1: kinds of silicon in it. They call it end doped

425
00:20:17,600 --> 00:20:21,879
Speaker 1: and P doped. Endoped silicon has like extra electrons in it.

426
00:20:21,880 --> 00:20:25,720
Speaker 1: It's endoped, it's more negative. P doped silicon has more

427
00:20:25,760 --> 00:20:29,280
Speaker 1: positive charges, basically has holes for the electron. So you

428
00:20:29,359 --> 00:20:31,880
Speaker 1: have these two kinds of silicon next to each other,

429
00:20:32,160 --> 00:20:34,679
Speaker 1: and you apply an electric field to keep the electrons

430
00:20:34,720 --> 00:20:37,200
Speaker 1: from flowing from the end side to the P side,

431
00:20:37,240 --> 00:20:38,720
Speaker 1: So it's sort of like having a bunch of water

432
00:20:38,800 --> 00:20:41,560
Speaker 1: behind a dam. Then when the photons come in, they

433
00:20:41,640 --> 00:20:44,439
Speaker 1: push some of those electrons basically over that ridge and

434
00:20:44,440 --> 00:20:47,520
Speaker 1: they flow across the material, and that creates a current,

435
00:20:47,560 --> 00:20:50,879
Speaker 1: and that's what you want. The current is your electrical energy,

436
00:20:51,320 --> 00:20:55,360
Speaker 1: so it turns those photons into motion of electrons across

437
00:20:55,359 --> 00:20:58,640
Speaker 1: the silicon, which then adds to the voltage on your battery.

438
00:20:58,880 --> 00:21:00,160
Speaker 3: I did not know that.

439
00:21:00,840 --> 00:21:03,240
Speaker 2: And I'll also note that I've never heard the word

440
00:21:03,680 --> 00:21:08,359
Speaker 2: dope using a scientific context, and it's great. I actually

441
00:21:08,440 --> 00:21:11,080
Speaker 2: feel like I should write a song, maybe like a

442
00:21:11,160 --> 00:21:13,160
Speaker 2: rap song about how diodes work.

443
00:21:13,440 --> 00:21:14,880
Speaker 3: Maybe not, maybe let's pull that out.

444
00:21:15,080 --> 00:21:16,359
Speaker 1: Doping is for smarty pants.

445
00:21:16,400 --> 00:21:18,000
Speaker 3: It turns out that's right, that's right.

446
00:21:18,080 --> 00:21:19,760
Speaker 1: I always thought of it doping more in the lance

447
00:21:19,840 --> 00:21:22,360
Speaker 1: armstrong sense than in the like you're a dope sort

448
00:21:22,359 --> 00:21:22,800
Speaker 1: of sense.

449
00:21:23,040 --> 00:21:25,200
Speaker 2: Well, no, I so you're a dope is like negative,

450
00:21:25,280 --> 00:21:28,480
Speaker 2: But I I was thinking of it as like, that's dope, man,

451
00:21:28,680 --> 00:21:34,480
Speaker 2: Like that's and when I said it sounded incredibly uncool.

452
00:21:34,640 --> 00:21:37,879
Speaker 3: So anyway, this is where I am in the universe.

453
00:21:37,920 --> 00:21:39,800
Speaker 1: The silicon is definitely dope material.

454
00:21:39,880 --> 00:21:42,360
Speaker 2: Yeah, right, okay, so now we know how you get

455
00:21:42,480 --> 00:21:44,840
Speaker 2: energy from it, Is this like a good way to

456
00:21:44,920 --> 00:21:45,240
Speaker 2: do it?

457
00:21:45,320 --> 00:21:47,240
Speaker 1: Yeah, it's a pretty good way to get energy out

458
00:21:47,240 --> 00:21:50,560
Speaker 1: of the photons. It's frustratingly not one hundred percent efficient.

459
00:21:50,680 --> 00:21:52,840
Speaker 1: Some of the energy is lost just a diffusion and

460
00:21:52,920 --> 00:21:56,000
Speaker 1: just a heat is not all directly converted from the

461
00:21:56,080 --> 00:21:58,680
Speaker 1: energy of the photon to the energy of the electron.

462
00:21:58,840 --> 00:22:01,800
Speaker 1: They have like researchystems where they try to optimize all

463
00:22:01,800 --> 00:22:03,560
Speaker 1: the conditions and they can get it up to like

464
00:22:03,920 --> 00:22:06,879
Speaker 1: maybe forty five to fifty percent. That's like the record

465
00:22:06,960 --> 00:22:10,080
Speaker 1: in research. In terms of the photovoltaic panels like on

466
00:22:10,240 --> 00:22:14,199
Speaker 1: your house or on big power plants, they're typically like

467
00:22:14,280 --> 00:22:17,840
Speaker 1: twenty percent efficient, which means like eighty percent of the

468
00:22:17,960 --> 00:22:20,359
Speaker 1: energy is just lost. You know, stuff gets heated up

469
00:22:20,480 --> 00:22:22,640
Speaker 1: or it's not ending up in your battery.

470
00:22:22,720 --> 00:22:24,960
Speaker 2: That's interesting, And of course as a biologist, what I'm

471
00:22:25,000 --> 00:22:29,399
Speaker 2: wondering is how far behind are we lagging nature? So,

472
00:22:29,480 --> 00:22:33,159
Speaker 2: you know, photosynthesis is all about capturing the Sun's energy.

473
00:22:33,320 --> 00:22:34,960
Speaker 3: How efficient is photosynthesis?

474
00:22:35,200 --> 00:22:38,879
Speaker 1: Weirdly, photosynthesis is a lot less efficient. It's something like

475
00:22:39,200 --> 00:22:42,920
Speaker 1: three percent efficient. Yeah, compared to the photovoltaic method.

476
00:22:43,160 --> 00:22:45,320
Speaker 2: Come on, evolution, you're letting me down.

477
00:22:46,000 --> 00:22:50,200
Speaker 1: But photosynthesis is pretty awesome because you know, it builds itself, right,

478
00:22:50,400 --> 00:22:53,399
Speaker 1: like my solar panels aren't making more solar panels. And

479
00:22:53,520 --> 00:22:56,080
Speaker 1: in addition, as you know, like it turns the energy

480
00:22:56,119 --> 00:23:00,320
Speaker 1: the photons into like complex chemicals that store energy. It's

481
00:23:00,440 --> 00:23:03,120
Speaker 1: much much better than a battery, right, It's like it's

482
00:23:03,160 --> 00:23:07,080
Speaker 1: literally creating fuel out of sunlight, whereas all we can

483
00:23:07,119 --> 00:23:09,680
Speaker 1: do is like convert it into electricity, which then stays

484
00:23:09,680 --> 00:23:13,000
Speaker 1: in a battery, and that's hard to transmit across long distances,

485
00:23:13,240 --> 00:23:15,480
Speaker 1: et cetera, et cetera. So plants are doing something that

486
00:23:15,520 --> 00:23:16,640
Speaker 1: we're definitely not doing.

487
00:23:17,000 --> 00:23:19,560
Speaker 2: All right, evolution, I'm sorry about what I said about you,

488
00:23:20,119 --> 00:23:21,040
Speaker 2: Let's be friends again.

489
00:23:21,119 --> 00:23:23,439
Speaker 1: On the other hand, photobo take cells can use like

490
00:23:23,480 --> 00:23:26,080
Speaker 1: infrared light and u V light. They can use a

491
00:23:26,119 --> 00:23:29,440
Speaker 1: broader spectrum, whereas plants mostly get their energy from the

492
00:23:29,520 --> 00:23:32,800
Speaker 1: visible spectrum. So there's pluses and minuses. But yeah, I

493
00:23:32,800 --> 00:23:36,160
Speaker 1: would like free solar panels that grow themselves and maintain themselves.

494
00:23:36,160 --> 00:23:37,119
Speaker 1: That would be pretty awesome.

495
00:23:37,200 --> 00:23:39,320
Speaker 2: That would be solid and if you were starting a

496
00:23:39,400 --> 00:23:42,040
Speaker 2: settlement on Mars, that would really give you a leg up.

497
00:23:42,480 --> 00:23:44,880
Speaker 3: But we don't know how to do that yet.

498
00:23:44,920 --> 00:23:47,960
Speaker 2: But speaking of Mars, so you know on Earth we're

499
00:23:48,440 --> 00:23:51,280
Speaker 2: closer to the Sun than Mars, which probably helps with

500
00:23:51,720 --> 00:23:54,159
Speaker 2: gathering energy. What is the situation like on Mars it's

501
00:23:54,200 --> 00:23:56,440
Speaker 2: farther out so how much less sunlight does it get.

502
00:23:56,560 --> 00:23:58,800
Speaker 1: Yeah, Mars is much further out than Earth, so the

503
00:23:58,800 --> 00:24:01,600
Speaker 1: solar energy is like a order of what lands on Earth,

504
00:24:02,040 --> 00:24:04,199
Speaker 1: but you know, it's closer than a lot of other planets.

505
00:24:04,280 --> 00:24:07,240
Speaker 1: You want to send something to Urinus or Neptune. By

506
00:24:07,240 --> 00:24:08,840
Speaker 1: the time you get out there, the Sun is a

507
00:24:08,960 --> 00:24:12,040
Speaker 1: distant dot in the sky and it's really very little

508
00:24:12,040 --> 00:24:14,879
Speaker 1: solar energy. So Mars is in a pretty good spot

509
00:24:14,960 --> 00:24:18,159
Speaker 1: for solar panels because it's close enough to really be

510
00:24:18,200 --> 00:24:20,800
Speaker 1: able to gather some energy. And when they were building

511
00:24:20,840 --> 00:24:23,399
Speaker 1: the first rover, that's what they went with. Sojourner in

512
00:24:23,480 --> 00:24:26,560
Speaker 1: nineteen ninety seven was only supposed to last for like

513
00:24:26,800 --> 00:24:30,000
Speaker 1: seven days or seven souls actually, so they didn't even

514
00:24:30,040 --> 00:24:32,400
Speaker 1: ask for like a nuclear power plant that would last

515
00:24:32,400 --> 00:24:33,960
Speaker 1: for ten to fifteen years. They thought that would be

516
00:24:34,000 --> 00:24:36,919
Speaker 1: a waste, and this is a very experimental technology. So

517
00:24:36,960 --> 00:24:38,879
Speaker 1: they put a little solar panel on top, and that

518
00:24:38,880 --> 00:24:42,240
Speaker 1: little guy well outperformed its mission. Instead of only going

519
00:24:42,240 --> 00:24:45,639
Speaker 1: for seven souls, it worked for eighty three and it

520
00:24:45,720 --> 00:24:48,359
Speaker 1: traveled up to one hundred meters. This is like the

521
00:24:48,400 --> 00:24:51,520
Speaker 1: first time people are really driven around on an alien planet.

522
00:24:51,520 --> 00:24:52,399
Speaker 1: It was pretty awesome.

523
00:24:52,720 --> 00:24:56,000
Speaker 2: That's totally incredible, And so since then, how many of

524
00:24:56,040 --> 00:24:58,480
Speaker 2: our rovers have used solar.

525
00:24:58,359 --> 00:25:01,439
Speaker 1: Spirit in two thousand and three also used solar panels,

526
00:25:01,480 --> 00:25:04,080
Speaker 1: and it went like eight kilometers before getting trapped in

527
00:25:04,119 --> 00:25:06,600
Speaker 1: the sand. Opportunity in two thousand and three was amazing.

528
00:25:06,920 --> 00:25:10,560
Speaker 1: It lasted for fifty three hundred souls and drove forty

529
00:25:10,640 --> 00:25:15,720
Speaker 1: five kilometers until dust storms blocked its solar panels.

530
00:25:15,960 --> 00:25:18,040
Speaker 2: I gotta be honest, I'm not like a very uh

531
00:25:18,080 --> 00:25:20,840
Speaker 2: sentimental person. I don't cry very often, but when I

532
00:25:21,080 --> 00:25:24,000
Speaker 2: when I read about some of these rovers, I get

533
00:25:24,000 --> 00:25:26,520
Speaker 2: like kind of choked up, Like when Curiosity landed. I

534
00:25:26,560 --> 00:25:29,160
Speaker 2: remember watching the landing and like shedding the single tear.

535
00:25:30,359 --> 00:25:32,199
Speaker 2: I feel like some of this stuff is just like

536
00:25:32,280 --> 00:25:34,280
Speaker 2: the best humans have to offer. The fact that we've

537
00:25:34,280 --> 00:25:36,760
Speaker 2: managed to land a rover and then operate it for

538
00:25:37,040 --> 00:25:40,320
Speaker 2: fifty three hundred souls is just like amazing.

539
00:25:40,359 --> 00:25:42,320
Speaker 3: So sorry, okay, Opportunity.

540
00:25:41,800 --> 00:25:44,480
Speaker 1: Yeah, Opportunity was great. And by then the Mars rover

541
00:25:44,600 --> 00:25:47,560
Speaker 1: program had really sort of earned its strife. People believed

542
00:25:47,840 --> 00:25:49,919
Speaker 1: that it could work and that it could last for

543
00:25:49,960 --> 00:25:51,720
Speaker 1: a while, that you weren't sending something up there that

544
00:25:51,840 --> 00:25:54,400
Speaker 1: was just gonna drive around for a week. So Curiosity

545
00:25:54,480 --> 00:25:57,320
Speaker 1: actually has a nuclear power plant, and that's one reason

546
00:25:57,359 --> 00:26:00,399
Speaker 1: why it's still going like it doesn't matter how dusty

547
00:26:00,440 --> 00:26:02,679
Speaker 1: it is or what the weather is like on Mars.

548
00:26:02,960 --> 00:26:05,960
Speaker 1: Curiosity gets its power from its nuclear battery.

549
00:26:06,240 --> 00:26:07,959
Speaker 2: Nice and I think some of the ones that have

550
00:26:08,000 --> 00:26:12,720
Speaker 2: solar also have radioactive heaters. They're not like Thermo coupled

551
00:26:12,760 --> 00:26:15,000
Speaker 2: to generate electricity, but you still got to it gets

552
00:26:15,000 --> 00:26:15,720
Speaker 2: pretty cold up.

553
00:26:15,680 --> 00:26:19,359
Speaker 1: There, exactly. And Insight Lander, which doesn't have a roverb

554
00:26:19,400 --> 00:26:21,600
Speaker 1: but is operating on Mars and doing a bunch of science,

555
00:26:21,640 --> 00:26:23,960
Speaker 1: it also has solar panels and they have to worry

556
00:26:24,040 --> 00:26:27,639
Speaker 1: about keeping them clean. Perseverance, which land in twenty twenty,

557
00:26:27,680 --> 00:26:30,000
Speaker 1: which is the one with the helicopter on top. That

558
00:26:30,080 --> 00:26:33,199
Speaker 1: one also has a nuclear plant. So these days we

559
00:26:33,240 --> 00:26:35,560
Speaker 1: still see some with solar panels, but it's sort of

560
00:26:35,560 --> 00:26:39,760
Speaker 1: transitioning to the nuclear power plants because these are longer lasting,

561
00:26:40,160 --> 00:26:41,560
Speaker 1: lower risk missions.

562
00:26:42,240 --> 00:26:44,080
Speaker 3: I'm probably being too picky.

563
00:26:44,200 --> 00:26:48,520
Speaker 2: Are those power plants or are those thermoelectric generator couplers.

564
00:26:48,760 --> 00:26:51,000
Speaker 1: No, you're right, these are not fission plants. These are

565
00:26:51,000 --> 00:26:51,919
Speaker 1: like nuclear batteries.

566
00:26:51,960 --> 00:26:55,280
Speaker 2: These are RTGs, So when we were writing our book

567
00:26:55,320 --> 00:26:58,560
Speaker 2: about space settlements, I was super surprised because I don't

568
00:26:58,560 --> 00:27:01,119
Speaker 2: think I had really absorbed it's a magnitude of the

569
00:27:01,200 --> 00:27:04,240
Speaker 2: dust storm problem on Mars, which of course is going

570
00:27:04,280 --> 00:27:07,720
Speaker 2: to be majorly bad for solar panels. Can you tell

571
00:27:07,800 --> 00:27:10,199
Speaker 2: us a bit about the dust problem on Mars.

572
00:27:10,440 --> 00:27:13,080
Speaker 1: So dust is really a big problem on Mars and

573
00:27:13,119 --> 00:27:16,120
Speaker 1: a big problem for solar panels in general. Even here

574
00:27:16,280 --> 00:27:19,680
Speaker 1: on Earth, dust storms are a big issue. Like there

575
00:27:19,680 --> 00:27:22,760
Speaker 1: are big power plants in the deserts, like in the

576
00:27:22,880 --> 00:27:26,800
Speaker 1: UAE that produce like ten megawatts, but they estimate that

577
00:27:26,920 --> 00:27:29,920
Speaker 1: dust storms in the desert have reduced production at those

578
00:27:29,960 --> 00:27:32,800
Speaker 1: facilities by like forty percent. In order to clean them,

579
00:27:32,840 --> 00:27:35,320
Speaker 1: they need water because you've gotta spray them clean. You

580
00:27:35,359 --> 00:27:37,639
Speaker 1: can't scrape them clean or you'll scratch them. So it

581
00:27:37,680 --> 00:27:41,520
Speaker 1: takes a huge amount of water to clean these desert

582
00:27:41,600 --> 00:27:45,920
Speaker 1: solar panels. They're currently estimating it costs like ten billion

583
00:27:46,119 --> 00:27:49,359
Speaker 1: gallons of water per year just to keep those solar

584
00:27:49,359 --> 00:27:50,000
Speaker 1: panels clean.

585
00:27:50,200 --> 00:27:51,919
Speaker 3: Oh my gosh, and that's got to get pumped in

586
00:27:51,960 --> 00:27:52,520
Speaker 3: from somewhere.

587
00:27:52,640 --> 00:27:55,800
Speaker 1: It's crazy. And you know, for a really big solar installation,

588
00:27:56,080 --> 00:27:59,000
Speaker 1: even like a one or two percent reduction results in

589
00:27:59,040 --> 00:28:02,320
Speaker 1: a huge loss annual revenue over the life cycle of

590
00:28:02,359 --> 00:28:05,680
Speaker 1: these plants. It can be like billions of dollars. And

591
00:28:05,800 --> 00:28:08,800
Speaker 1: so for most of these facilities here on Earth, the

592
00:28:08,840 --> 00:28:11,879
Speaker 1: cost of keeping it clean and just keeping the dust

593
00:28:12,000 --> 00:28:14,560
Speaker 1: off of the panels is about ten percent of the

594
00:28:14,600 --> 00:28:16,560
Speaker 1: operating cost of these facilities.

595
00:28:16,560 --> 00:28:18,760
Speaker 2: So it's interesting what we were writing our book. An

596
00:28:18,840 --> 00:28:21,320
Speaker 2: argument we came across often was like, well, we'll figure

597
00:28:21,320 --> 00:28:23,320
Speaker 2: out how to do this stuff when the stakes are high,

598
00:28:23,359 --> 00:28:25,120
Speaker 2: so you know, like we'll figure out how to clean

599
00:28:25,160 --> 00:28:28,040
Speaker 2: the solar panels on Mars. But apparently the stakes are

600
00:28:28,080 --> 00:28:31,000
Speaker 2: already super high on Earth. Like, this is tons of

601
00:28:31,080 --> 00:28:33,639
Speaker 2: money that's being lost. If it was just like finding

602
00:28:33,720 --> 00:28:37,280
Speaker 2: a slightly better like rags you could buff off the dust,

603
00:28:37,840 --> 00:28:41,680
Speaker 2: presumably somebody would have like spent the money on that already.

604
00:28:41,760 --> 00:28:45,000
Speaker 2: But anyway, Okay, wow, I didn't realize the scope of

605
00:28:45,000 --> 00:28:45,440
Speaker 2: the problem.

606
00:28:45,560 --> 00:28:48,280
Speaker 1: Yeah. Well, ironically it's kind of good news for space

607
00:28:48,320 --> 00:28:51,400
Speaker 1: exploration that is also a problem here on Earth because

608
00:28:51,440 --> 00:28:54,120
Speaker 1: it means that like big money players are going to

609
00:28:54,120 --> 00:28:55,960
Speaker 1: try to solve this problem. You know. It's just like

610
00:28:56,000 --> 00:28:58,680
Speaker 1: in particle physics when we need to invent something fancy

611
00:28:58,720 --> 00:29:01,800
Speaker 1: and new. Look around to see, like, hmm, is some

612
00:29:01,960 --> 00:29:06,480
Speaker 1: other huge industry invented this already for other reasons, you know,

613
00:29:06,600 --> 00:29:09,160
Speaker 1: like we use GPUs in our machine learning at the

614
00:29:09,240 --> 00:29:12,040
Speaker 1: large shad drunk collider. GPUs that were invented for like

615
00:29:12,200 --> 00:29:15,280
Speaker 1: making Call of Duty a better video game, right, not

616
00:29:15,360 --> 00:29:18,320
Speaker 1: for unraveling the secrets of the universe. But turns out

617
00:29:18,360 --> 00:29:22,320
Speaker 1: they're awesome for inverting matrices and solving machine learning problems.

618
00:29:22,920 --> 00:29:24,840
Speaker 1: And so you know, this is a well worn path

619
00:29:24,840 --> 00:29:28,400
Speaker 1: in science. Remember, like the NSF's entire budget is a

620
00:29:28,440 --> 00:29:31,200
Speaker 1: tiny fraction of the amount of money people spend on

621
00:29:31,360 --> 00:29:34,160
Speaker 1: like cell phones every year. So if you can get

622
00:29:34,160 --> 00:29:37,680
Speaker 1: like the military or some huge commercial industry involved in

623
00:29:37,720 --> 00:29:40,480
Speaker 1: your physics problem, then probably they're going to solve it

624
00:29:40,520 --> 00:29:42,440
Speaker 1: for you in about ten minutes and come up with

625
00:29:42,520 --> 00:29:45,400
Speaker 1: a really cheap solution. And so fortunately, there are a

626
00:29:45,400 --> 00:29:48,360
Speaker 1: lot of people working on ways to keep solar panels clean,

627
00:29:48,760 --> 00:29:50,960
Speaker 1: especially here on Earth, and we hope that some of

628
00:29:50,960 --> 00:29:52,800
Speaker 1: those might translate to Mars.

629
00:29:53,080 --> 00:29:54,560
Speaker 2: It sounds like at the moment we don't have a

630
00:29:54,600 --> 00:29:57,640
Speaker 2: great solution, but on the other hand, Mars does have

631
00:29:57,680 --> 00:30:00,360
Speaker 2: plenty of water it's not easy to get it's going

632
00:30:00,400 --> 00:30:02,880
Speaker 2: to be a bit of a pain, but you know

633
00:30:03,160 --> 00:30:04,600
Speaker 2: you'd be in a lot more trouble if you were

634
00:30:04,640 --> 00:30:05,560
Speaker 2: on the Moon for example.

635
00:30:05,720 --> 00:30:08,440
Speaker 1: Yeah, that's true. But Mars also has a whole lot

636
00:30:08,480 --> 00:30:11,240
Speaker 1: of dust. I mean, there are these huge dust storms

637
00:30:11,240 --> 00:30:14,440
Speaker 1: that can like choke up Mars for weeks at a time. Anyway,

638
00:30:14,520 --> 00:30:17,200
Speaker 1: solar panels on Mars face a very similar problem to

639
00:30:17,240 --> 00:30:19,680
Speaker 1: solar panels on Earth. The wind is going to blow,

640
00:30:19,920 --> 00:30:22,200
Speaker 1: dust is going to block it. And as the dust

641
00:30:22,200 --> 00:30:25,200
Speaker 1: blocks the solar panels, the energy output drops. And if

642
00:30:25,240 --> 00:30:27,840
Speaker 1: you're driving your rover across the surface, you got to

643
00:30:27,920 --> 00:30:30,440
Speaker 1: keep those panels clean. People might remember in the movie

644
00:30:30,480 --> 00:30:32,960
Speaker 1: The Martian he spent a good fraction of his day

645
00:30:33,280 --> 00:30:36,200
Speaker 1: washing his solar panels to keep his energy production up.

646
00:30:36,320 --> 00:30:39,760
Speaker 2: Stressful, you went through and you talked about a bunch

647
00:30:39,760 --> 00:30:43,160
Speaker 2: of rovers that sort of extended their stay longer than

648
00:30:43,200 --> 00:30:45,240
Speaker 2: we thought that they would. In the end, for a

649
00:30:45,280 --> 00:30:48,320
Speaker 2: lot of them was dust. The thing that killed them.

650
00:30:48,280 --> 00:30:51,320
Speaker 1: In the end. It was Yeah, now spirit got trapped

651
00:30:51,320 --> 00:30:54,480
Speaker 1: in the sand unfortunately, So it wasn't a solar panel issue,

652
00:30:54,640 --> 00:30:58,000
Speaker 1: but like Opportunity, it was a dust storm that blocked

653
00:30:58,040 --> 00:31:01,080
Speaker 1: its panels and basically killed it. It couldn't stay warm

654
00:31:01,120 --> 00:31:03,280
Speaker 1: and it couldn't keep moving. The same thing for the

655
00:31:03,320 --> 00:31:04,080
Speaker 1: inside lander.

656
00:31:04,360 --> 00:31:06,600
Speaker 2: Mars is far enough way that you can't just sort

657
00:31:06,600 --> 00:31:09,520
Speaker 2: of like send someone out there to brush something off

658
00:31:09,320 --> 00:31:11,600
Speaker 2: if you get a dust storm that you didn't expect.

659
00:31:12,440 --> 00:31:14,160
Speaker 1: If you're not willing to send your kids to climb

660
00:31:14,200 --> 00:31:16,280
Speaker 1: up on your barn, you're definitely not sending them to

661
00:31:16,360 --> 00:31:17,400
Speaker 1: Mars with a brush.

662
00:31:17,480 --> 00:31:18,200
Speaker 3: Probably not.

663
00:31:18,960 --> 00:31:21,440
Speaker 2: So let's take a break and then talk about methods

664
00:31:21,440 --> 00:31:23,280
Speaker 2: that we've come up with so far for trying to

665
00:31:23,320 --> 00:31:38,680
Speaker 2: keep our solar panels clean on Mars. Okay, so we

666
00:31:38,760 --> 00:31:42,360
Speaker 2: have some experience with trying to keep solar panels clean

667
00:31:42,400 --> 00:31:44,440
Speaker 2: on Mars. You know, we've sent up enough rovers that

668
00:31:44,480 --> 00:31:47,360
Speaker 2: we've probably learned a thing or two. So Daniel, what

669
00:31:47,480 --> 00:31:49,400
Speaker 2: do we do now? And we just hope that there's

670
00:31:49,480 --> 00:31:52,120
Speaker 2: no dust storms that take out our rovers or can

671
00:31:52,160 --> 00:31:52,960
Speaker 2: we be proactive?

672
00:31:53,480 --> 00:31:55,720
Speaker 1: Yeah, Thoughts and prayers don't really work very well when

673
00:31:55,720 --> 00:31:59,400
Speaker 1: it comes to keeping your mission going on an alien planet.

674
00:32:00,120 --> 00:32:03,000
Speaker 1: Back to what the listeners were mentioning, you might imagine,

675
00:32:03,040 --> 00:32:04,840
Speaker 1: like let's just put a rag on the thing, or

676
00:32:04,880 --> 00:32:07,280
Speaker 1: like put a mechanical arm with a brush to wipe

677
00:32:07,280 --> 00:32:10,880
Speaker 1: stuff off, but as people mentioned, like it could scrape it.

678
00:32:10,920 --> 00:32:13,960
Speaker 1: These solar panels have a delicate surface, and if you

679
00:32:14,080 --> 00:32:16,360
Speaker 1: scrape it, it's going to reduce the absorption and then

680
00:32:16,440 --> 00:32:19,800
Speaker 1: also be a way for dust to gather, right, creating

681
00:32:19,800 --> 00:32:22,280
Speaker 1: little valleys that are gonna like grab the dust out

682
00:32:22,280 --> 00:32:24,320
Speaker 1: of the air. And you really don't want anything like

683
00:32:24,480 --> 00:32:27,800
Speaker 1: mechanical on your rover as much as possible. You want

684
00:32:27,800 --> 00:32:30,200
Speaker 1: to keep it simple because you know, things that turn

685
00:32:30,400 --> 00:32:33,600
Speaker 1: and grind, they're gonna break, they're prone to failure. And

686
00:32:33,680 --> 00:32:38,000
Speaker 1: dust on Mars is particularly tricky because it's really really small,

687
00:32:38,120 --> 00:32:41,120
Speaker 1: Like there's sand and grit, but the actual dust it's

688
00:32:41,160 --> 00:32:44,960
Speaker 1: sort of like particles of smoke. It's hyper fine, and

689
00:32:45,000 --> 00:32:46,840
Speaker 1: so in order to brush that off you need a

690
00:32:46,880 --> 00:32:51,000
Speaker 1: brush that had really really really fine bristles, otherwise you're

691
00:32:51,040 --> 00:32:53,880
Speaker 1: just gonna slide right over it. So it's really a

692
00:32:53,920 --> 00:32:54,840
Speaker 1: tricky problem.

693
00:32:55,040 --> 00:32:56,960
Speaker 2: So if you send your kids out there, they should

694
00:32:56,960 --> 00:32:59,280
Speaker 2: have a really good ventilators.

695
00:32:59,560 --> 00:33:00,400
Speaker 3: That's the lesson.

696
00:33:00,480 --> 00:33:04,320
Speaker 2: I think one of the listeners suggested, like an air compressor.

697
00:33:04,760 --> 00:33:07,400
Speaker 2: Could you send the rover with like an air compressor

698
00:33:07,440 --> 00:33:09,120
Speaker 2: and like blow it off.

699
00:33:09,120 --> 00:33:10,800
Speaker 1: You might be able to. I mean people have talked

700
00:33:10,840 --> 00:33:13,880
Speaker 1: about like helicopter blades blowing things off the solar panels,

701
00:33:13,920 --> 00:33:17,040
Speaker 1: and we do have one helicopter on Mars. Remember, the

702
00:33:17,080 --> 00:33:20,240
Speaker 1: atmosphere is very very thin, and so helicopter blades don't

703
00:33:20,280 --> 00:33:22,720
Speaker 1: produce a whole lot of wind, and so that sort

704
00:33:22,760 --> 00:33:25,840
Speaker 1: of seems very dangerous. In terms of air compression, you know,

705
00:33:25,840 --> 00:33:28,880
Speaker 1: you're either gonna have to bring compressed air or you're

706
00:33:28,920 --> 00:33:31,800
Speaker 1: gonna have to compress it, which takes a lot of energy,

707
00:33:31,960 --> 00:33:33,560
Speaker 1: and so you're probably not going to in the end

708
00:33:33,680 --> 00:33:35,760
Speaker 1: win by compressing your own air.

709
00:33:36,280 --> 00:33:40,080
Speaker 2: So we've struck out a few times. Now, what are

710
00:33:40,080 --> 00:33:40,960
Speaker 2: some other options?

711
00:33:41,200 --> 00:33:43,840
Speaker 1: But you know, these little guys on Mars have lasted

712
00:33:43,880 --> 00:33:46,360
Speaker 1: for a long time, so you might wonder, like, how

713
00:33:46,520 --> 00:33:49,520
Speaker 1: is it possible to keep going for fifty four hundred days.

714
00:33:49,640 --> 00:33:52,000
Speaker 1: There are a couple of tricks. One of them basically

715
00:33:52,040 --> 00:33:56,440
Speaker 1: is thoughts and prayers, which means waiting for wind, because

716
00:33:56,440 --> 00:33:59,160
Speaker 1: you know there are storms on Mars, and sometimes those

717
00:33:59,200 --> 00:34:01,640
Speaker 1: Martian storms will like deposit a bunch of dust on

718
00:34:01,680 --> 00:34:04,320
Speaker 1: your solar panels, and sometimes they will blow it clean.

719
00:34:04,840 --> 00:34:07,160
Speaker 2: It's got to be amazing to have spent like a

720
00:34:07,200 --> 00:34:09,440
Speaker 2: decade of your life planning a project and then hoping

721
00:34:09,440 --> 00:34:12,240
Speaker 2: a breeze comes by so that you can keep collecting data.

722
00:34:12,680 --> 00:34:16,120
Speaker 2: A breeze comes by on Mars. But okay, so breezes

723
00:34:16,160 --> 00:34:16,920
Speaker 2: work sometimes.

724
00:34:17,000 --> 00:34:20,080
Speaker 1: Yeah, and spirit and opportunity, both of these relied on

725
00:34:20,239 --> 00:34:23,920
Speaker 1: breezes for years to keep things clean. The Mars Pathfinder

726
00:34:23,920 --> 00:34:27,040
Speaker 1: mission unfortunately didn't benefit from such winds, and its solar

727
00:34:27,040 --> 00:34:30,279
Speaker 1: panels got blocked and never recovered. You know, that's the

728
00:34:30,360 --> 00:34:31,920
Speaker 1: tough thing about it. Is like if you go down

729
00:34:31,920 --> 00:34:34,600
Speaker 1: to zero and get too cold, things just stop working.

730
00:34:35,080 --> 00:34:37,719
Speaker 1: So you really can't like stay cold for very and long.

731
00:34:37,800 --> 00:34:40,600
Speaker 1: You need like a consistent source of energy. But you know,

732
00:34:40,760 --> 00:34:43,239
Speaker 1: NASA has clever engineers and they've come up with some

733
00:34:43,360 --> 00:34:47,399
Speaker 1: like really counterintuitive solutions to this problem. One of them

734
00:34:47,640 --> 00:34:50,280
Speaker 1: is poor dirt on the solar panels.

735
00:34:50,719 --> 00:34:54,319
Speaker 2: What no, no, no, no, no, that's that's gonna make

736
00:34:54,360 --> 00:34:54,680
Speaker 2: it worse.

737
00:34:54,680 --> 00:34:55,719
Speaker 3: All right, How does that help?

738
00:34:56,200 --> 00:34:58,680
Speaker 1: It's sort of amazing. It's because the soil, the dirt

739
00:34:58,760 --> 00:35:01,960
Speaker 1: on Mars has some dust in it, but mostly it's sand,

740
00:35:02,400 --> 00:35:05,960
Speaker 1: and that sand actually works as a cleansing agent. So

741
00:35:06,000 --> 00:35:08,480
Speaker 1: you pour like a bunch of the sand on top,

742
00:35:08,760 --> 00:35:12,080
Speaker 1: and it'll grab those little hyperfine pieces of dust and

743
00:35:12,200 --> 00:35:15,440
Speaker 1: pull them along with it. And so you pour dirt

744
00:35:15,480 --> 00:35:17,480
Speaker 1: on top of it, and the sand will pull that

745
00:35:17,600 --> 00:35:19,360
Speaker 1: dust off of your solar panels.

746
00:35:19,640 --> 00:35:23,120
Speaker 2: And that's less likely to scratch it than like using

747
00:35:23,120 --> 00:35:23,840
Speaker 2: a rag.

748
00:35:23,800 --> 00:35:26,320
Speaker 1: That's less likely to scratch it. Here you're also relying

749
00:35:26,440 --> 00:35:29,879
Speaker 1: on wind, and this is something they discovered accidentally. They

750
00:35:29,920 --> 00:35:32,600
Speaker 1: have this seismometer on Mars, which is separated from the

751
00:35:32,600 --> 00:35:36,239
Speaker 1: inside lander, and there's a tether that connects the seismometer

752
00:35:36,680 --> 00:35:39,920
Speaker 1: to inside itself, so that like sends along power and information.

753
00:35:40,040 --> 00:35:41,880
Speaker 1: And they were trying to keep the teather in place,

754
00:35:42,120 --> 00:35:44,239
Speaker 1: so they dumped a bunch of soil on top of it,

755
00:35:44,280 --> 00:35:46,680
Speaker 1: and they noticed that when wind came along, it would

756
00:35:46,719 --> 00:35:50,360
Speaker 1: blow off the soil and leave it shiny, sparklingly clean.

757
00:35:51,000 --> 00:35:52,920
Speaker 1: So then they thought, all right, let's try this on

758
00:35:52,960 --> 00:35:56,960
Speaker 1: the solar panels, and so they on purpose dumped sand

759
00:35:57,080 --> 00:35:59,520
Speaker 1: on top of their own solar panels. And like that

760
00:35:59,640 --> 00:36:02,759
Speaker 1: must be terrifying, right, Like, you make this mistake, there's

761
00:36:02,760 --> 00:36:05,600
Speaker 1: no going back. But it worked, and it boosted the

762
00:36:05,680 --> 00:36:07,560
Speaker 1: energy production by like five percent.

763
00:36:07,680 --> 00:36:10,080
Speaker 2: Can you imagine telling the funders for this project like, no,

764
00:36:10,360 --> 00:36:15,080
Speaker 2: hear me out, We're gonna dump dirt on the solar panels.

765
00:36:15,120 --> 00:36:15,920
Speaker 3: It's gonna be great.

766
00:36:16,120 --> 00:36:18,160
Speaker 1: They try to time it for like the windiest part

767
00:36:18,239 --> 00:36:20,840
Speaker 1: of the day, So basically it's like you're building a

768
00:36:20,880 --> 00:36:23,239
Speaker 1: little thing to catch the wind, which is gonna push

769
00:36:23,280 --> 00:36:25,799
Speaker 1: the sand along, which is gonna grab the dust with

770
00:36:25,840 --> 00:36:29,080
Speaker 1: it and clean off the solar panels. So it makes

771
00:36:29,200 --> 00:36:32,319
Speaker 1: better use of the wind than just waiting for the

772
00:36:32,360 --> 00:36:34,440
Speaker 1: wind to blow this hyperfine dust away.

773
00:36:34,880 --> 00:36:39,560
Speaker 2: Fat is incredible and super smart, But so if I

774
00:36:39,800 --> 00:36:42,520
Speaker 2: was going to be living in a settlement on Mars,

775
00:36:43,360 --> 00:36:46,560
Speaker 2: I would hope we'd have a better option than dumping

776
00:36:46,600 --> 00:36:48,440
Speaker 2: dirt on top of the solar panels.

777
00:36:48,880 --> 00:36:50,040
Speaker 3: Are there any more.

778
00:36:50,000 --> 00:36:53,920
Speaker 2: Like futuristic options that we're hoping we'll be able to

779
00:36:54,000 --> 00:36:54,880
Speaker 2: test out in the future.

780
00:36:55,000 --> 00:36:58,040
Speaker 1: There are people working on ways to clean solar panels

781
00:36:58,040 --> 00:36:59,920
Speaker 1: here on Earth for all the reasons that we talked to,

782
00:37:00,280 --> 00:37:03,480
Speaker 1: and billions of dollars in research, not just because we

783
00:37:03,520 --> 00:37:05,360
Speaker 1: want to have our rowers drive around on Mars, but

784
00:37:05,400 --> 00:37:07,880
Speaker 1: because we want to have efficient energy production here on

785
00:37:07,920 --> 00:37:11,120
Speaker 1: Earth without spending lots of time, money, and especially water

786
00:37:11,239 --> 00:37:14,520
Speaker 1: on cleaning them. What they're looking into our solid state solutions,

787
00:37:14,560 --> 00:37:17,040
Speaker 1: things with no mechanical moving parts. And one of the

788
00:37:17,120 --> 00:37:21,560
Speaker 1: most promising technologies is called electrostatic cleaning, and it takes

789
00:37:21,600 --> 00:37:25,320
Speaker 1: advantage of the fact that these dust particles are not neutral.

790
00:37:25,680 --> 00:37:28,640
Speaker 1: They tend to have positive or negative charges. You know,

791
00:37:28,680 --> 00:37:31,400
Speaker 1: it's not that hard to make something ionized. Like the

792
00:37:31,440 --> 00:37:34,279
Speaker 1: reason you get static electricity when you walk across the

793
00:37:34,320 --> 00:37:36,800
Speaker 1: floor or when you rub a balloon against your head

794
00:37:37,040 --> 00:37:40,160
Speaker 1: is that you're like stripping electrons off the surface of

795
00:37:40,239 --> 00:37:42,920
Speaker 1: the material. So you know, these electrons in some cases

796
00:37:42,960 --> 00:37:45,560
Speaker 1: are kind of loosely held, and so dust is like

797
00:37:45,600 --> 00:37:48,560
Speaker 1: flying around the atmosphere in Mars and ends up losing

798
00:37:48,600 --> 00:37:51,400
Speaker 1: some of its charges. So these dust particles are charged,

799
00:37:51,440 --> 00:37:54,719
Speaker 1: which means you can push them with electric fields.

800
00:37:55,239 --> 00:37:58,200
Speaker 2: So you would like start from the center and sort

801
00:37:58,200 --> 00:38:01,160
Speaker 2: of move the electric charge outward to move things off

802
00:38:01,719 --> 00:38:03,080
Speaker 2: the edges of the panels.

803
00:38:03,160 --> 00:38:03,719
Speaker 3: Is that the idea?

804
00:38:03,920 --> 00:38:07,480
Speaker 1: Yeah, so you actually build oscillating electric fields. You have

805
00:38:07,480 --> 00:38:10,040
Speaker 1: the electric fields that go one way and then another way,

806
00:38:10,239 --> 00:38:13,040
Speaker 1: and in one configuration they will push off like positively

807
00:38:13,080 --> 00:38:15,680
Speaker 1: charged particles, and then you flip it to push off

808
00:38:15,760 --> 00:38:18,400
Speaker 1: negatively charged particles and the idea is just to like

809
00:38:18,480 --> 00:38:21,200
Speaker 1: loosen them so then they drift off. So you like

810
00:38:21,280 --> 00:38:23,880
Speaker 1: loosen the negatively charged particles and then they drift away.

811
00:38:24,160 --> 00:38:26,960
Speaker 1: You flip it and you loosen the positively charged particles

812
00:38:26,960 --> 00:38:30,000
Speaker 1: and they drift away. And this process of oscillating the

813
00:38:30,120 --> 00:38:33,840
Speaker 1: charges is actually a little bit violent for the uncharged particles,

814
00:38:33,880 --> 00:38:36,719
Speaker 1: and they can end up stripping them of their electrons

815
00:38:36,880 --> 00:38:39,680
Speaker 1: charging them so that they can also then get pushed away.

816
00:38:39,920 --> 00:38:41,440
Speaker 3: Is that good or bad?

817
00:38:41,680 --> 00:38:43,319
Speaker 1: That's good? Right? So you want to push away the

818
00:38:43,360 --> 00:38:46,720
Speaker 1: negatives and the positives and the neutrals, So you flip

819
00:38:46,760 --> 00:38:49,040
Speaker 1: the electric field so you get the positives and then

820
00:38:49,040 --> 00:38:51,720
Speaker 1: the negatives, and then the process you convert the neutrals

821
00:38:51,719 --> 00:38:54,320
Speaker 1: to either positive or negative so they can get flipped

822
00:38:54,320 --> 00:38:55,280
Speaker 1: off in the next cycle.

823
00:38:55,760 --> 00:38:57,240
Speaker 3: Nice, got it? Awesome?

824
00:38:57,360 --> 00:39:00,280
Speaker 2: Hey? And how have we been able to try something

825
00:39:00,360 --> 00:39:01,200
Speaker 2: like this on Earth yet?

826
00:39:01,239 --> 00:39:04,759
Speaker 1: So this technology is under development in research settings, and

827
00:39:04,880 --> 00:39:07,480
Speaker 1: what they're working on is like minimizing the amount of

828
00:39:07,520 --> 00:39:10,960
Speaker 1: electrical current that's needed, just like with the air compressor example,

829
00:39:11,000 --> 00:39:12,960
Speaker 1: you don't want to develop a system to boost your

830
00:39:13,000 --> 00:39:16,480
Speaker 1: energy which costs more energy than it saves, right, And

831
00:39:16,560 --> 00:39:18,719
Speaker 1: so in the case here, they're focusing on using a

832
00:39:18,840 --> 00:39:21,960
Speaker 1: very small electrical current and one that only needs to

833
00:39:22,000 --> 00:39:24,479
Speaker 1: be applied for like a couple of minutes every day

834
00:39:24,719 --> 00:39:28,160
Speaker 1: in order to boost the overall electrical generation power of

835
00:39:28,200 --> 00:39:28,720
Speaker 1: your system.

836
00:39:29,080 --> 00:39:29,799
Speaker 3: Nice, I like it.

837
00:39:29,840 --> 00:39:32,520
Speaker 2: This is clever, all right, babe? You can get me

838
00:39:32,560 --> 00:39:34,239
Speaker 2: to move to Mars. What else do we have?

839
00:39:34,440 --> 00:39:36,920
Speaker 1: This involves also like treating the solar panels with like

840
00:39:36,960 --> 00:39:40,560
Speaker 1: a few nanometers of special material to cover the glass

841
00:39:41,000 --> 00:39:44,040
Speaker 1: and then applying a voltage across that. There's other system

842
00:39:44,080 --> 00:39:46,399
Speaker 1: to have, like a little metal bar that passes over

843
00:39:46,440 --> 00:39:50,040
Speaker 1: the panel, though that's mechanical, so it's less attractive. Otherwise,

844
00:39:50,040 --> 00:39:53,480
Speaker 1: people are working on systems like vibration, like instead of

845
00:39:53,520 --> 00:39:56,200
Speaker 1: blowing something on it or brushing something across it, these

846
00:39:56,239 --> 00:39:59,120
Speaker 1: are tiny, little hyperfine particles. What if you just like

847
00:39:59,239 --> 00:40:01,840
Speaker 1: shook them a little bit, you know, very very gently

848
00:40:01,840 --> 00:40:04,200
Speaker 1: shook them. Could the dust just like fall off?

849
00:40:04,600 --> 00:40:07,279
Speaker 2: I feel like I would worry that over time the

850
00:40:07,280 --> 00:40:09,680
Speaker 2: panels would hold up less well if they're constantly being

851
00:40:09,719 --> 00:40:12,319
Speaker 2: slightly vibrated. But I'm I'm sure someone's thought of that.

852
00:40:12,760 --> 00:40:14,640
Speaker 1: No, You're right, that definitely is an issue. I mean,

853
00:40:14,640 --> 00:40:17,120
Speaker 1: anytime you're like shaking your system. You're going to be

854
00:40:17,120 --> 00:40:20,120
Speaker 1: like loosening connections and something that you don't want to

855
00:40:20,120 --> 00:40:23,439
Speaker 1: shake off might shake off one day. But in test

856
00:40:23,480 --> 00:40:26,360
Speaker 1: this works pretty well for like the bigger pieces, the

857
00:40:26,520 --> 00:40:29,239
Speaker 1: very very fine particles don't tend to get shaken off

858
00:40:29,280 --> 00:40:31,959
Speaker 1: as well using the vibration system. But you know, people

859
00:40:32,000 --> 00:40:33,640
Speaker 1: are working on this, and people are working in lots

860
00:40:33,640 --> 00:40:36,640
Speaker 1: of other different directions. It's definitely a big area that

861
00:40:36,680 --> 00:40:39,760
Speaker 1: people are exploring because we want to be powering our devices.

862
00:40:39,800 --> 00:40:41,920
Speaker 1: We want them to last as long as possible. You

863
00:40:41,960 --> 00:40:45,200
Speaker 1: spend like hundreds of millions of dollars developing this thing,

864
00:40:45,320 --> 00:40:49,080
Speaker 1: and people's entire careers are focused on the questions that

865
00:40:49,160 --> 00:40:50,839
Speaker 1: might be answered. You don't want it to go up

866
00:40:50,840 --> 00:40:52,560
Speaker 1: there and then get blocked by a dust storm on

867
00:40:52,680 --> 00:40:55,160
Speaker 1: like week two and then it's over right. You want

868
00:40:55,200 --> 00:40:57,360
Speaker 1: to definitely want something beyond thoughts and prayers.

869
00:40:57,800 --> 00:40:58,560
Speaker 3: Absolutely well.

870
00:40:58,560 --> 00:41:00,840
Speaker 2: In more long term, you've got human living on Mars.

871
00:41:00,840 --> 00:41:01,680
Speaker 3: You don't want them to have to.

872
00:41:01,600 --> 00:41:04,800
Speaker 2: Spend all their day cleaning the like many football fields

873
00:41:04,840 --> 00:41:06,520
Speaker 2: worth of solar panels that you're going to need to

874
00:41:06,600 --> 00:41:07,360
Speaker 2: run your settlement.

875
00:41:07,600 --> 00:41:09,440
Speaker 1: Although you know children have to have something that they

876
00:41:09,520 --> 00:41:11,799
Speaker 1: complain about, or does it really count as a childhood?

877
00:41:12,120 --> 00:41:14,640
Speaker 2: You know, they can be maintaining the cricket ranch for

878
00:41:14,680 --> 00:41:18,759
Speaker 2: the protein. They'll have plenty to complain about if they're

879
00:41:18,800 --> 00:41:19,560
Speaker 2: living on Mars.

880
00:41:19,880 --> 00:41:22,640
Speaker 1: Yeah, that's true. Children are creative. They'll always find something

881
00:41:22,680 --> 00:41:25,520
Speaker 1: to drive about. Mommy, these crickets are too spicy.

882
00:41:26,280 --> 00:41:28,040
Speaker 2: You're lucky you've got any protein.

883
00:41:28,280 --> 00:41:31,359
Speaker 1: That's right, exactly. So, as humans think about how to

884
00:41:31,400 --> 00:41:33,880
Speaker 1: explore the solar system and how to power our little

885
00:41:33,960 --> 00:41:36,520
Speaker 1: robotic devices that are going to lead the way and

886
00:41:36,560 --> 00:41:39,200
Speaker 1: tell us where the most promising places are for our

887
00:41:39,280 --> 00:41:42,399
Speaker 1: humans to maybe one day build colonies, we want them

888
00:41:42,440 --> 00:41:44,960
Speaker 1: to keep their power, and we want those solar panels

889
00:41:45,040 --> 00:41:48,279
Speaker 1: crystal clean as well as down here on Earth. If

890
00:41:48,320 --> 00:41:51,759
Speaker 1: we're converting ourselves into sustainable sources of energy, we want

891
00:41:51,760 --> 00:41:54,920
Speaker 1: our solar panels to stay clean and dry without requiring

892
00:41:55,120 --> 00:41:56,880
Speaker 1: a bazillion gallons of water.

893
00:41:57,480 --> 00:42:00,520
Speaker 2: Absolutely, this is definitely an area where if the space

894
00:42:00,760 --> 00:42:02,920
Speaker 2: scientists figure out a solution, it would help the.

895
00:42:02,840 --> 00:42:05,400
Speaker 1: Rest of us too, exactly, And maybe that means that

896
00:42:05,480 --> 00:42:08,200
Speaker 1: our solar panels will eventually be self cleaning and neither

897
00:42:08,280 --> 00:42:09,920
Speaker 1: me nor Kelly will have to get up on the

898
00:42:10,000 --> 00:42:11,520
Speaker 1: roof and do some squeegeing.

899
00:42:11,920 --> 00:42:14,479
Speaker 3: You mean my kids. It'll be good that they don't

900
00:42:14,480 --> 00:42:15,000
Speaker 3: have to go on.

901
00:42:15,040 --> 00:42:19,000
Speaker 1: The exactly all right. Thanks for joining us in this

902
00:42:19,239 --> 00:42:22,439
Speaker 1: tour of solar panels around the Solar system. We hope

903
00:42:22,440 --> 00:42:25,200
Speaker 1: they all stay sparkling clean. Thanks very much Kelly for

904
00:42:25,239 --> 00:42:27,200
Speaker 1: joining us today, and thanks everybody for listening.

905
00:42:27,320 --> 00:42:29,120
Speaker 3: Thanks for having me have a good time.

906
00:42:28,920 --> 00:42:39,720
Speaker 1: Everyone, Thanks for listening, and remember that Daniel and Jorge

907
00:42:39,800 --> 00:42:43,480
Speaker 1: explain the Universe is a production of iHeartRadio. For more

908
00:42:43,520 --> 00:42:48,360
Speaker 1: podcasts from iHeartRadio, visit the iHeartRadio app, Apple Podcasts, or

909
00:42:48,400 --> 00:42:50,640
Speaker 1: wherever you listen to your favorite shows.