Daniel and Jorge Explain the UniverseDaniel and Kelly talk about how to keep solar panels bright and powerful when they far away on a dusty planet.
See omnystudio.com/listener for privacy information.
If you love iPhone, you'll love Apple Card. It's the credit card designed for iPhone. It gives you unlimited daily cash back that can earn four point four zero percent annual percentage yield. When you open a high Yield savings account through Apple Card, apply for Applecard in the wallet app subject to credit approval. Savings is available to Apple Card owners subject to eligibility. Apple Card and Savings by Goldman Sachs Bank USA, Salt Lake City Branch, Member FDIC terms and more at applecard dot Com. When you pop a piece of cheese into your mouth, you're probably not thinking about the environmental impact. But the people in the dairy industry are. That's why they're working hard every day to find new ways to reduce waste, conserve natural resources, and drive down greenhouse gas emissions. How is US Dairy tackling greenhouse gases? Many farms use anaerobic digesters to turn the methane from manure into renewable energy that can power farms, towns, and electric cars. Visit us dairy dot COM's Last Sustainability to learn more.
Everyone loves getting good at advice and staying in the know. There's nothing like getting a heads up on something before you've even had time to think about whether you need or want it. Well, thankfully, AT and T provides personalized recommendations and solutions so you get what's right for you. Whether right for you means a plan that's better suited for you and your family or a product that makes sense for you and your lifestyle. So relax and let AT and T provide proactive recommendations to help empower your best connected life.
There are children, friends, and families walking, riding on paths and roads every day. Remember they're real people with loved ones who need them to get home safely. Protect our cyclists and pedestrians because they're people too.
Go safely.
California from the California Office of Traffic Safety and Caltrans.
Hey, Keilly, how are things running on the science Farm?
Pretty well?
But our house is like over one hundred years old, so there's the usual number of issues that you'd expect from a house.
Of that age.
And so who's the like fixer upper in your family? Is it the biologist or the cartoonist?
Oh, it is absolutely the biologist.
I have a series of Twitter posts actually where I secretly record Zac trying to use tools and.
Each video is better than the last.
Every time a contractor comes through and is like, ma'am, where is your husband? Should we discuss this with him? I laugh out loud because because Zach, he's just not interested in this stuff at all. So all right, how about in your family?
Is it?
So let's see, you're an experimentalist. So does that make you the one who's handy with tools?
Ooh, I wish. Technically I'm an experimentalist, but in practice I do more computer stuff, so that means I fix like the broken laptops and the iPhones MI like in your family, my wife is much more hands on than I am, and so is.
She the one who usually is doing the fixing.
She's actually too busy fixing stuff in her lab to fix stuff around the house. So we don't really have anybody fixing stuff.
So what do you do when the stuff breaks?
Stuff doesn't just not break because there's no one available to fix it.
I've learned that our strategy is to live with it as long as possible. The house is pretty new when we moved in, and so we're just going to see how long that works.
This is all horrible, playing Daniel.
Houses are not disposable you think you can't just break.
It down and then move out.
We'll see good luck. Hi. I'm Daniel. I'm a physicist and a professor at UC Irvine, and I'm not good at fixing broken stuff.
Hi. I'm Kelly Weener Smith. I'm adjunct at Bryce Universe, and if I didn't fix things, the house would fall down around us.
It sounds like you're going to be actually useful when the end times.
Come, I hope.
So you know Zach Garden, so he might be useful when the end times come. We joke about the apocalypse a lot, but we're pretty sure that when it comes to self defense more donors.
I pretty much have no useful skills. I mean, I can write programs, I can record podcasts, I can think deeply about the nature of the universe, but you know, none of that's going to translate into like whiskey or gold in the end times.
Yeah.
No, so, you like probably wouldn't make it to the second season of The Walking Dead. I like to think that I'd still be around on The Walking Dead, but I'm not sure I'd have to get good with the sword or something.
You know, The Walking Dead actually does teach people to survive. There is this incredible story about a young woman in Irvine who's attacked in a parking garage in real life by huge ex marine and she managed to wrestle the blade away from him and kill her attacker. And when they asked her how she managed to do that, she said, I watch The Walking Dead. I know it's kill or be killed.
Oh my gosh, I mean she.
Must have like she must work out or have had some prior martial art training or so there's got to be more to it than I watched The Walking Dead because I've seen it.
Turns out there's a lot more grit in Orange County than you might expect.
I guess, so I believe it. That's incredible.
But speaking about grit and survival, humanity needs to have a sustainable way to live here on Earth and out in the Solar System. And on this podcast, we like to think about the future, but what science and technology hold for our future exploration of our neighborhood. So welcome to the podcast Daniel and Jorge explain the Universe, in which we talk about exactly those things, how the universe works, how it all comes together, and how we can take advantage of our knowledge of physical laws to build ourselves a sustainable life here on Earth and perhaps also on neighboring planets. Thanks very much Kelly for being a guest host on today's episode.
Thanks for having me back. I always love being on the show.
And I always love talking to you about fancy technology in space because you bring that bracing dash of skepticism.
Yes, everybody loves to have the wet blanket around. I'm glad I'm appreciated somewhere.
Well, you know, it's fun to blue sky think about what might be possible. But if we're actually gonna make it out into the Solar System, if we're going to send our probes and one day our children out into deep space, we better have stuff that actually works, that somebody has actually thought through and maybe even tested.
Well, you know, you need the wet blankets to put out the fires, and so that I offer a service I like to think.
And fire turns out to be quite essential. We use it to hear on Earth, to keep ourselves warm, and also to transform various kinds of energy into electricity. We have mammoth amounts of coal and gas still being burnt to turn steam turbines to convert it into electricity, as well as huge amounts of the planet covered in solar panels to generate electricity for our lifestyle. But when we send our robots into outer space, they don't necessarily have access to coal fired power plants, so they need to think about other ways to stay warm and keep running.
And the environment of space is a tough one.
As we've talked about several times on the podcast. So on today's episode, we're going to think through some of the details of how our little robots can keep chugging away on the surface of alien planets. More specifically, on today's episode, we'll answer the question how can we keep solar panels clean on Mars? But maybe we should start closer to home. How do you keep your solar panels clean? Kelly A.
I don't.
You can't just let these things break and then move on.
Oh, I you know it's possible. I'm a bit of a hypocrite.
Sometime now, I actually well, I was thinking about today's episode. I realized that I have never cleaned the solar panels that are up on top of one of our barns. I just don't know how I'd reach them. But we do live in a dusty. You know, we've got Virginia dusty clay. So I guess I just hope it rains a lot.
And it does.
Don't you have small children? They're good at climbing, and their little fingers are great at cleaning tiny little electronics that yes.
No, absolutely, And I haven't read the child labor laws to know if I'm allowed to do this or not, but probably it's fine, and so maybe that's what they'll do this weekend.
Well, I hear they're loosening labor laws all across the South, so maybe soon your children can legally work for you.
Yay, thank you politics.
So if Kelly can't even keep her solar panels clean on Earth, how it could be possible for NASA to keep solar panels clean on Mars, a famously dusty and very distant environment where there aren't even child laborers available to clean those little robots.
Gosh, I hope we can fix that one day.
That's why we have to send people to Mars, starting with children.
Yes, absolutely, But.
We reached out to our audience to ask them if they had thoughts about how to keep solar panels clean when there are thousands and millions of miles away and also essential to the operation of remote robots. If you would like to answer questions for this segment of the podcast, please don't be shy. We would love to have your voice on the podcast. Just send me an email to questions at Danielandjorge dot com and I will set you up. So think about for a moment, do you have clever ideas for how to keep solar panels clean on Mars. Here's what people had to say. You know what, that's a good question. The rover has got a lot of batteries.
It's not solar powered.
It's not solar powered.
That's why I would say that. The reason why they don't have wipers is because we would have to probably have fluid to spray on the solar panels to wipe and clean, and that's probably just too much to do with the rover.
I've never really thought about that.
My guess is that, you know, using a regular wiper would scrape the lens. So I'm guessing they blow the dust off with some type of compressed air system.
I don't know.
That's a really good point.
Maybe the solar panels have a self cleaning technology, like self cleaning glasses.
That are available in civil construction.
Hm.
I don't know.
If it's a dry maybe that would just scratch the lenses. Maybe you need like the film that just keeps replacing itself.
I thought these were really great answers. The listeners identified a lot of the actual big problems and had some good ideas.
And to be honest, I hadn't heard of self cleaning window technology. Do you know about this, Daniel? Do you know how it works?
I'm not an expert in self cleaning windows, but later in the episode we're going to talk about self cleaning solar panels. This is actually technology people at MIT are working on.
Ooh, very cool.
So you're right, our listeners are on point. These are some smart people we have listening to the podcast, and good looking too.
Yes, that's called the halo effect, I think. Yeah.
I bet they're also good at video games and probably very fast.
Didn't correlation applies causation? Like the more episodes of the podcast you listen to, the better looking you are. Yeah.
No, And I hope that if I co host enough that I'll be even more good looking than just listening.
So that's what I'm banking on. I'm not here just because you're fun to talk to. Daniel.
I'm not sure it might go the other way. You know, if we have faces that are good for podcasting, it might just bean that they get better and better for podcasting.
Daniel, I'm sorry, I have to go. It's been fun, but I'm doing something else with my time.
All right, But we do want to keep our little robots powered on alien planets. I mean, we send these devices off to Mars to measure earthquakes, to gather samples, just to drive around and see the geology and understand what used to be on Mars, maybe even discovering water, evidence of life or potentially even existent life on Mars. The questions are still open. And well beyond Mars, we send things to other planets. We'd like to drive them around and even fly them around those planets. And for all these things, they need power. None of this stuff comes for free.
And we need to get really good at this stuff if we're ever going to have humans living in space, because you really can't have your power ever break down.
If you're living in space.
That's right in space. You can't just wait till your space station breaks down and then move out into another one. Space stations are not disposable.
Well, I mean, we've burned a lot of them up in the atmosphere, but you better have another plan before that happens.
Yeah, we like to do some repairs before we recycle. But solar power actually isn't the only way to power some of these distant devices.
How else do we do it? Daniel?
Well, another option is really fascinating are nuclear batteries. I mean, if you want to power something for a long long time, you need a steady source of energy, then you definitely don't want to bring gasoline along. You want a very, very dense source of power. You want some kind of fuel that releases a lot of energy and doesn't have a lot of kilograms. And so, in the same way that we power like our aircraft carriers and our summary, we turn to atomic physics to produce that energy. You know that aircraft carriers can go for like decades without refueling because they have nuclear power plants on board, like fully functioning fission reactors on board turning uranium into electricity. Same with submarines sliding around the Earth's ocean. It's really pretty amazing.
Hang would take me a little while to get used to knowing that I was living that close to a nuclear reactor. On the other hand, it would be good to know that you have a reliable power source.
But these things are delicate and dangerous, and you can't put a whole nuclear power plant on a satellite or on a little rover and it's going to be driving around the surface of Mars. Instead, they have a different way to extract energy from radioactive elements. These things are called RTGs radio isotope thermoelectric generators. Basically, it's a big block of material which decays radioactively and turns the heat from that decay into electricity. So that's one the ways that we can power things in space. Kelly, you're something of an expert in the history of nuclear power and space. Have humans ever launched an actual working fission reactor into space?
Oh?
Man, we've done it more times than you're probably comfortable knowing.
More than zero is more times than uncomfortable knowing.
Yeah, exactly, And so in nineteen sixty five the US did it for a satellite. It was like a test, and it didn't go great, but then we boosted it into a graveyard orbit. So we actually have one of these reactors still orbiting the Earth. But the USSR loved these. They did it a bunch of times. I think they sent up thirty three or maybe even more of them. And so yeah, there have been a lot of little nuclear reactors that have been sent to space to power our satellites. I don't think any of them have gone to like Mars or the Moon to power rovers, but we do have some experience with using these as satellites. Also fun fact, if your definition of fun is raining nuclear waste over the Earth. One of the u USSR's satellites that was powered by a nuclear reactor. This one's called Cosmos nine fifty four accidentally re entered when it wasn't meant to re entered and it sprayed nuclear material all over Canada. The US and Canada had to clean it up.
That sounds bad, It was bad.
Russia agreed to pay for half of it. I think it's the only time in which the Liability Convention through the United Nations has been invoked as a like, dude, this is kind of your responsibility. And I think the Soviet Union tried to be like, well, it's hard. Maybe not, but eventually they went have.
These with us well, sending working fission reactors into space doesn't seem like a great idea. But fortunately these other devices, the radioisotope thermoelectric generators, are simpler solid state devices. They don't have any moving parts, they can't like melt down. Basically, just have like a block of radioactive material which is decaying and releasing energy as those decays happen, which heats up the block, and then you just got to turn that heat to electricity.
Yeah, and most of the time you don't end up with for example, one of the lunicods breaking up over the Soviet Union and sending colonium all over the place when they're radioactive.
What is it?
This was a thermoelectric generator that broke up and you know, dropped waste over the USSR.
You're right, this is definitely a danger if you are launching radioactive materials, whether it's for an RTG or a working reactor, you're risking blowing that over the surface of the Earth at launch, because launches are still violent and risky events. No matter how good we get at it, sometimes these things still blow up, and if your payload is dangerous, then that presents a danger to the population on Earth.
There are ways to make it safer.
You know, there's like new cladding that you can get, and you can send up smaller and smaller amounts on different rocket launches and then put them all together when you get to space. But certainly our history is littered with radioactive accidents.
So these things are dangerous. They're also super duper expensive. I mean often they use like plutonium two thirty eight, for which we have a very limited supply because until recently we stopped making plutonium, and so it's not easy to get this stuff. If it blows up on launch, it's very dangerous. On the flip side, it lasts for a long time, Like you can build one of these things and it will steadily produce power for ten to fifteen years just pumping out electricity. Doesn't require the Sun, there's no moving parts, it's very very stable. So these things are sort of the gold standard for NASA if it wants to power something that goes to like the outer Solar System, where even solar panels are not going to be effective because you're so far away from the Sun.
Well, not going to say, if I was moving to Mars, I would really like to have a tiny nuclear power plant on Mars rather than relying on anything else. And there are engineers working on it, and they all really like the Simpsons and they name all of their designs after Simpson stuff.
Oh no, so what let's see.
In twenty eighteen they tested the Kilo power reactor using Sterling technology and by like the right letters out of those various words, they come up with crusty.
And like the clown.
I think they also had one called Duff, like after Duff beer. And anyway, one of the engineers has been at this for like decades. But anyway, it is a nice reliable power source if you could get it to work safely.
It is very cool and it uses an interesting effect where you turn heat into electricity by having two different kinds of metal. One is hotter and one is cooler, and that generates an electromotive force across them. Basically like the electrons and the hotter side are moving more and the electrons and the cooler side are not, and that creates a flow of current across the threshold. And so you can turn this heat into electricity again with no moving parts. You don't need like a steam engine or a turbine or anything. It just produces electricity, and yeah, if I was living on the surface of Mars, I would like a backup source of energy, especially if it didn't come with me to Mars, if you're like landed separately, so I didn't have to worry about radiation firmative.
It broke down, Yeah, no doubt well.
And also there's lots of reasons in space why you'd like to have heat, And these reactors also produce heat, so you could, you know, I don't know, maybe heat up your ice and turn it into water.
But because these things are expensive and they are dangerous, and they're also in limited supply, NASA tends to be pretty stingy with these things. They reserve them for like the deepest, longest, high priority, lowest risk missions. And so when people started talking about putting a rover on Mars, the Mars program wasn't really in great shape. That had a bunch of losses. It seemed very high risk. They were thinking these rovers were only going to cruise around for like a few weeks at most, so they didn't have the option of using one of these nuclear batteries, and they had to go for solar panels.
And after the break, we'll tell you about how those were.
With big wireless providers, what you see is never what you get. Somewhere between the store and your first month's bill, the price, your thoughts you were paying magically skyrockets. With Mintmobile, You'll never have to worry about gotcha's ever again. When mint Mobile says fifteen dollar a month for a three month plan, they really mean it. I've used mint Mobile and the call quality is always so crisp and so clear. I can recommend it to you, So say bye bye to your overpriced wireless plans, jaw dropping monthly bills and unexpected overages. You can use your own phone with any mint Mobile plan and bring your phone number along with your existing contacts. So dit your overpriced wireless with mint Mobiles deal and get three months a premium wireless service for fifteen bucks a month. To get this new customer offer and your new three month premium wireless plan for just fifteen bucks a month, go to mintmobile dot com slash universe. That's mintmobile dot com slash universe. Cut your wireless bill to fifteen bucks a month. At mintmobile dot com slash universe. Forty five dollars upfront payment required equivalent to fifteen dollars per month new customers on first three month plan only speeds slower about forty gigabytes on unlimited plan. Additional taxi spees and restrictions apply. See mint Mobile for details.
AI might be the most important new computer technology ever. It's storming every industry and literally billions of dollars are being invested, so buckle up. The problem is that AI needs a lot of speed and processing power, So how do you compete without cost spiraling out of control. It's time to upgrade to the next generation of the cloud. Oracle Cloud Infrastructure or OCI. OCI is a single platform for your infrastructure, database, application development, and AI needs. OCI has four to eight times the bandwidth of other clouds, offers one consistent price instead of variable regional pricing, and of course nobody does data better than Oracle. So now you can train your AI models at twice the speed and less than half the cost of other clouds. If you want to do more and spend less, like Uber eight by eight and Data Bricks Mosaic, take a free test drive of OCI at Oracle dot com slash strategic that's Oracle dot com. Slash Strategic Oracle dot Com Slash Strategic.
If you love iPhone, you'll love Apple Card. It's the credit card designed for iPhone. It gives you unlimited daily cash back that can earn four point four zero percent annual percentage yield. When you open a high e yield savings account through Apple Card, apply for Apple Card in the wallet app subject to credit approval. Savings is available to Apple Card owners subject to eligibility. Apple Card and Savings by Goldman Sachs Bank USA, Salt Lake City Branch Member FDIC terms and more at applecard dot com. When you pop a piece of cheese into your mouth or enjoy a rich spoonful of Greek yogurt, you're probably not thinking about the environmental impact of each and every bite, But the people in the dairy industry are US. Dairy has set themselves some ambitious sustainability goals, including being greenhouse gas neutral by twenty to fifty. That's why they're working hard every day to find new ways to reduce waste, conserve natural resources, and drive down greenhouse gas emissions. Take water, for example, most dairy farms reuse water up to four times the same water cools the milk, cleans equipment, washes the barn and irrigates the crops. How is US dairy tackling greenhouse gases? Many farms use anaerobic digestors that turn the methane from maneuver into renewable energy that can power farms, towns, and electric cars. So the next time you grab a slice of pizza or lick an ice cream cone, know that dairy farmers and processors around the country are using the latest practices and innovations to provide the nutrient dense dairy products we love with less of an impact. Visit us dairy dot com slash sustainability to learn more.
Okay, so we've decided that nuclear power is reliable, but it's expensive and sometimes things go wrong and one way or another. Solar panels are really popular on space voyages. So how about you tell us a bit how solar panels in space work.
Yeah, solar panels in space work the same way the solar panels do here on Earth, which is essentially transforming the energy of the photons into current and photons interacting with electrons is of course very famous in physics. It's the basis of the photoelectric effect, for which Einstein won the Nobel Prize. More than one hundred years ago. When photons hit a piece of metal, they don't just interact with the whole metal, and they're not classical electromagnetic waves where they deposit their energy broadly, or they come in terms of photons, which means that a single photon hits a single electron and deposits its energy. The photoelectric effect is when there's so much energy in that photon that electrons boil off the surface. Like you can knock electrons off of a piece of metal by shining high energy light at it. So that's the photoelectric effect. The photovoltaic effect is the principle underlying solar panels, and it's the sort of like lower energy cousin of the photoelectric effect. If you dial down the energy to photons so that they don't have enough energy to kick the electrons out of the metal and not boiling electrons off the surface. Instead, you're just exciting the electrons. You're giving them more energy so they can flow around.
And then how do you get energy out of them flowing around?
Yeah, so you need to build a special kind of material. So here we use silicon diodes and silicon, remember is a semiconductor so it's not quite an insulator where all the electrons are like trapped in the lattice of the crystal. It's not quite a conductor where there's no gap between where the electrons live in the crystal and where the electrons flow freely. So electrons are just zooming everywhere. A semiconductor has like a little bit of a gap there, so it's like hard for the electrons to flow, but not impossible. And if you put the right kind of materials into the silicon, and if you dope it with other kinds of elements, then you can subtly tune the size of that gap. So a diode has two different kinds of silicon in it. They call it end doped and P doped. Endoped silicon has like extra electrons in it. It's endoped, it's more negative. P doped silicon has more positive charges, basically has holes for the electron. So you have these two kinds of silicon next to each other, and you apply an electric field to keep the electrons from flowing from the endside to the P side, So it's sort of like having a bunch of water behind a dam. Then when the photons come in, they push some of those electrons basically over that ridge, and they flow across the material, and that creates a current, and that's what you want. The current is your electrical energy. So he turns those photons into motion of electrons across the silicon, which then adds to the voltage on your battery.
I did not know that.
And I'll also note that I've never heard the word dope using a scientific context, and it's great. I actually feel like I should write a song, maybe like a rap song, about how diodes work.
Maybe not, Maybe let's pull that out.
Doping is for smarty pants.
It turns out that's right, that's right.
I always thought of it doping more in the Land's armstrong sense than in the like you're a dope sort of sense.
Well, no, I so you're a dope is like negative, But I was thinking of it as like, that's dope, man, like that, and when I said it sounded incredibly uncool.
So anyway, this is where I am in the universe.
The silicon is definitely dope material.
Yeah right, okay, so now we know how you get energy from it, Is this like a good way to do it?
Yeah, it's a pretty good way to get energy out of the photons. It's frustratingly not one hundred percent efficient. Some of the energy is lost just a diffusion and just a heat is not all directly converted from the energy of the photon to the energy of the electron. They have like research systems where they try to optimize all the conditions and they can get it up to like maybe forty five to fifty percent. That's like the record in research. In terms of the photovoltaic panels like on your house or on big power plants, they're typically like twenty percent efficient, which means like eighty percent of the energy is just lost. You know, stuff gets heated up or it's not ending up in your battery.
That's interesting, And of course as a biologist, what I'm wondering is how far behind are we lagging nature? So, you know, photosynthesis is all about capturing the Sun's energy.
How efficient is photosynthesis?
Weirdly, photosynthesis is a lot less efficient. It's something like three percent efficient. Yeah, compared to the photovoltaic method.
Come on, evolution, you're letting me down.
But photosynthesis is pretty awesome because you know, it builds itself right like my solar panels aren't making more solar panels. And in addition, as you know, like it turns the energy of the photons into like complex chemicals that store energy. It's much much better than a battery, right, It's like it's literally creating fuel out of sunlight, whereas all we can do is like convert it into electricity, which then stays in a battery, and that's hard to transmit across long distances, et cetera, et cetera. So plants are doing something that we're definitely not doing.
All right, evolution, I'm sorry about what I said about you, Let's be friends again.
On the other hand, photobo take cells can use like infra red light and V light. They can use a broader spectrum, whereas plants mostly get their energy from the visible spectrum. So there's pluses and minuses. But yeah, I would like free solar panels that grow themselves and maintain themselves. That would be pretty awesome.
That would be solid And if you were starting a settlement on Mars, that would really give you a leg up.
But we don't know how to do that yet.
But speaking of Mars, so you know, on Earth were closer to the Sun than Mars, which probably helps with gathering energy. What is the situation like on Mars, it's further out, so how much less sunlight does it get?
Yeah, Mars is much further out than Earth, so the solar energy is like a quarter of what lands on Earth. But you know, it's closer than a lot of other planets. You want to send something to Urinus or Neptune. By the time you get out there, the Sun is a distant dot in the sky and it's really very little solar energy. So Mars is in a pretty good spot for solar panels because it's close enough to really be able to gather some energy. And when they were building the first rover, that's what they went with. Sojourner in nineteen ninety seven was only supposed to last for like seven days or seven souls actually, so they didn't even ask for like a nuclear power plant that would last for ten to fifteen years. They thought that would be a waste, and this is a very experimental technology. So they put a little solar panel on top, and that little guy well outperformed its mission. Instead of only going for seven it worked for eighty three and it traveled up to one hundred meters. This is like the first time people are really driven around on an alien planet. It was pretty awesome.
That's totally incredible. And so since then, how many of our rovers have used solar.
Spirit in two thousand and three also used solar panels, and it went like eight kilometers before getting trapped in the sand. Opportunity in two thousand and three was amazing. It lasted for fifty three hundred souls and drove forty five kilometers until dust storms blocked its solar panels.
I gotta be honest, I'm not like a very sentimental person. I don't cry very often, but when I read about some of these rovers, I get like kind of choked up. Like when Curiosity landed. I remember watching the landing and like shedding the single tear. I feel like some of this stuff is just like the best humans have to offer. The fact that we've managed to land a rover and then operate it for fifty three hundred souls is just like amazing.
So sorry, okay, opportunity.
Yeah, opportunity great. And by then the Mars rover program had really sort of earned its strife. People believed that it could work and that it could last for a while, that you weren't sending something up there that was just going to drive around for a week. So Curiosity actually has a nuclear power plant, and that's one reason why it's still going like it doesn't matter how dusty it is or what the weather is like on Mars. Curiosity gets its power from its nuclear battery.
Nice and I think some of the ones that have solar also have radioactive heaters. They're not like thermocoupled to generate electricity, but you still got to it gets pretty cold up there exactly.
And inside Lander, which doesn't have a roverb but it's operating on Mars and doing a bunch of science, it also has solar panels and they have to worry about keeping them clean. Perseverance, which landed in twenty twenty, which is the one with the helicopter on top, that one also has a nuclear plant. So these days we still see some with solar panels, but it's sort of transitioning to the nuclear power plants because these are longer lasting, lower risk missions.
Probably being too picky.
Are those power plants or are those thermoelectric generator couplers.
No, you're right, these are not fission plants. These are like nuclear batteries. These are RTGs.
So when we were writing our book about space settlements, I was super surprised because I don't think I had really absorbed the magnitude of the dust storm problem on Mars, which of course is going to be majorly bad for solar panels. Can you tell us a bit about the dust problem on Mars.
So dust is really a big problem on Mars and a big problem for solar panels in general. Even here on Earth, dust storms are a big issue. Like there are big power plants in the deserts, like in the UAE that produce like ten megawatts, but they estimate that dust storms in the desert have reduced production at those facilities by like forty percent. In order to clean them, they need water because you've got to spray them clean. You can't scrape them clean or you'll scratch them. So it takes a huge amount of water to clean these desert solar panels. They're currently estimating it costs like ten billion gallons of water per year just to keep those solar panels clean.
Oh my gosh, and that's got to get pumped in from somewhere.
It's crazy. And you know, for a really big solar installation, even like a one or two percent reduction results in a huge loss in annual revenue over the life cycle of these plants. It can be like billions of dollars. And so for most of these facilities here on Earth, the cost of keeping it clean and just keeping the dust off of the panels is about ten percent of the operating cost of these facilities.
So it's interesting what we were writing our book. An argument we came across often was like, well, we'll figure out how to do this stuff when the stakes are high, so you know, like we'll figure out how to clean the solar panels on Mars.
But apparently the.
Stakes are already super high on Earth. Like, this is tons of money that's being lost. If it was just like finding a slightly better like rags you could buff off the dust, presumably somebody would have like spent the money on that already. But anyway, Okay, wow, I didn't realize the scope of the problem.
Yeah, Well, ironically it's kind of good news for space exploration. That's also a problem here on Earth because it means that like big money players are going to try to solve this problem. You know, it's just like in particle physics, when we need to invent something fancy and new, we always look around to see, like, hmm, is some other huge industry invented this already for other reasons, you know, like we use GPUs in our machine learning at the large Sha drunk collider. GPUs that were invented for like making Call of Duty a better video game, right, not for unraveling the secrets of the universe. But turns out they're awesome for inverting matrices and solving machine learning problems. And so you know, this is a well worn path in science. Remember, like the NSF's entire budget is a tiny fraction of the amount of money people spend on like cell phones every year. So if you can get like the military or some huge commercial industry involved in your physics problem, then probably they're going to solve it for you in about ten minutes and come up with a cheap solution. And so fortunately, there are a lot of people working on ways to keep solar panels clean, especially here on Earth, and we hope that some of those might translate to Mars.
It sounds like at the moment we don't have a great solution, but on the other hand, Mars does have plenty of water. It's not easy to get It's gonna be a bit of a pain, but you know, you'd be in a lot more trouble if you were on the Moon for example.
Yeah, that's true. But Mars also has a whole lot of dust. I mean, there are these huge dust storms that can like choke up Mars for weeks at a time. Anyway, solar panels on Mars face a very similar problem to solar panels on Earth. The wind is gonna blow, dust is going to block it. And as the dust blocks the solar panels, the energy output drops. And if you're driving your rover across the surface, you got to keep those panels clean. People might remember in the movie The Martian he spent a good fraction of his day washing his solar panels to keep his energy production up.
Stressful, you went through and you talked about a bunch of rovers that sort of extended their stay life longer than we thought that they would.
In the end for a lot of them was dust. The thing that killed.
Them in the end. It was Yeah, now spirit got trapped in the sand unfortunately. So it wasn't the solar panel issue, but like Opportunity. It was a dust storm that blocked its panels and basically killed it. It couldn't stay warm, and it couldn't keep moving. The same thing for the inside lander.
Mars is far enough way that you can't just sort of like send someone out there to brush something off if you get a dust storm that you didn't expect.
If you're not willing to send your kids to climb up on your barn, you're definitely not sending them to Mars with a brush.
Probably not.
So let's take a break and then talk about methods that we've come up with so far for trying to keep our solar panels clean on Mars.
When you pop a piece of cheese into your mouth or enjoy a rich spoonful of Greek yogurt, you're probably not thinking about the environmental impact of each and every bite. But the people in the dairy industry are US. Dairy has set themselves vicious sustainability goals, including being greenhouse gas neutral by twenty to fifty. That's why they're working hard every day to find new ways to reduce waste, conserve natural resources, and drive down greenhouse gas emissions. Take water, for example, most dairy farms reuse water up to four times. The same water cools the milk, cleans equipment, washes the barn, and irrigates the crops. How is US dairy tackling greenhouse gases? Many farms use anaerobic digestors that turn the methane from maneuver into renewable energy that can power farms, towns, and electric cars. So the next time you grab a slice of pizza or lick an ice cream cone, know that dairy farmers and processors around the country are using the latest practices and innovations to provide the nutrient dense dairy products we love with less of an impact. Visit us dairy dot com slash sustainability to learn more.
There are children, friends, and families walking, riding on passing the roads every day. Remember they're real people with loved ones who need them to get home safely. Protect our cyclists and pedestrians because they're people too, Go safely California from the California Office of Traffic Safety in caltrans Hey.
Their fellow globetrotters and destination dreamers. If you're anything like us, you know that life's too short for boring toasters and towels. That's why we decided to ditch the traditional wedding registry and went with honeyfund dot Com. Imagine your friends and family chipping in to send you on a dreamy, exotic honeymoon. Practical check, meaningful, double check. Plus, it's fee free and so fun for wedding guests to shop. So why get more stuff when you can have unforgettable experiences. Join the revolution at honey fund dot com and start your adventure today.
I've been struggling with my gut health for years and years. I tried everything, I mean everything without luck. But then I stumbled upon the solution. I've been looking for coffee enemas. Yep, coffee animas from Happy bumco. And you know what the best part is, It's all natural and I can do it at home. When my friends started to notice something was different, they were shocked. When I told them I was literally glowing from the inside out. I had tons of energy, my skin cleared, and my gut issues were gone. Now they are all all hooked. Coffee inemas are my new wellness tool. Thank goodness, Happy Bum has made it so easy. After my naturopathic doctor recommended them, I wasn't sure where to start. Happy bomb has everything you need to begin your coffee inema detox journey. Their products are safe, organic and all natural. Trust me, it's a game changer. If you are ready to transform your health. Visit happybumcode dot com and use code glow for fifteen percent off your first bundle. Trust me, you'll feel the difference. That's happybumcode dot com. I promise you won't regret it.
Okay, So we have some experience with trying to keep solar panels clean on Mars. You know, we've sent up enough rovers that we've probably learned a thing or two. So Daniel, what do we do now? And we just hope that there's no dust storms that take out our rovers or can we be proactive?
Yeah? Thoughts and prayers don't really work very well when it comes to keeping your mission going on an alien planet. You know, I come back to what the listeners were mentioning. You might imagine, like, let's just put a rag on the thing, or like put a mechanical arm with a brush to wipe stuff off. But as people mentioned, like it could scrape it. These solar panels have a delicate surface, and if you scrape it, it's going to reduce the absorption and then also be a way for dust to gather right creating little valleys that are gonna like grab the dust out of the air. And you really don't want anything like mechanical on your rover as much as possible. You want to keep it simple because you know, things that turn and grind, they're gonna break, They're prone to failure. And dust on Mars is particularly tricky because it's really really small, Like there's sand and grit, but the actual dust it's sort of like particles of smoke. It's hyper fine, and so in order to brush that off, you need a brush that had really really really fine bristles, otherwise you're just gonna slide right over it. So it's really a tricky problem.
So if you send your kids out there, they should have a really good ventilator. That's the lesson.
I think one of the listeners suggested, like an air compressor. Could you send the rover with like an air compressor and like blow it off.
You might be able to. I mean people have talked about like helicopter blades blowing things off the solar panels, and we do have one helicopter on Mars. Remember, the atmosphere is very very thin, and so helicopter blades don't produce a whole lot of wind, and so that sort of seems very dangerous in terms of air compression. You know, you're either gonna have to bring compressed air or you're gonna have to compress it, which takes a lot of energy, and so you're probably not going to in the end win by compressing your own air.
So we've struck out a few times. Now, what are some other options?
But you know, these little guys on Mars have lasted for a long time, so you might wonder, like, how is it possible to keep going for fifty four hundred days. There are a couple of tricks. One of them basically is thoughts and prayers, which means waiting for wind, because you know there are storms on Mars, and sometimes those Martian storms will like deposit a bunch of dust on your solar panels, and sometimes they will blow it clean.
It's got to be amazing to have spent like a decade of your life planning a project and then hoping a breeze comes by so that you can keep collecting data. A breeze comes by.
On Mars. But okay, so breezes work sometimes.
Yeah, and Spirit and Opportunity, both of these relied on breezes for years to keep things clean. The Mars Pathfinder mission unfortunately didn't benefit from such winds, and its solar panels got blocked and never recovered. You know, that's the tough thing about it. Is like if you go down to zero and get too cold, things just stop working. So you really can't like stay cold for veri and long. You need like a consistent source of energy. But you know, NASA has clever engineers and they've come up with some like really counterintuitive solutions to this problem. One of them is poor dirt on the solar panels.
What no, no, no, no, no, that's that's gonna make it worse, all right, How does that help?
It's sort of amazing. It's because the soil, the dirt on Mars has some dust in it, but mostly it's sand, and that sand actually works as a cleansing agent. So you pour like a bunch of the sand on top and it'll grab those little hyperfine pieces of dust and pull them along with it. And so you pour dirt on top of it, and the sand will pull that dust off of your solar panels, and.
That's less likely to scratch it than like using a rag.
That's less likely to scratch it. Here, you're also relying on wind, and this is something they discovered accidentally. They have this seismometer on Mars which is separated from the inside lander, and there's a tether that connects the seismometer to inside itself that like sends along power and information. And they were trying to keep the tether in place, so they dumped a bunch of soil on top of it, and they noticed that when wind came along, it would blow off the soil and leave it shiny, sparklingly clean. So then they thought, all right, let's try this on the solar panels, and so they on purpose dumped sand on top of their own solar panels, and like that must have been terrifying, right, Like, you make this mistake, there's no going back. But it worked and it boosted the energy production by like five percent.
Can you imagine telling the funders for this project, like, no, hear me out, We're gonna dump dirt on the solar panels.
It's gonna be great.
They try to time it for like the windiest part of the day. So basically it's like you're building a little thing to catch the wind, which is gonna push the sand along, which is gonna grab the dust with it and clean off the solar panels. So it like makes better use of the wind than just waiting for the wind to blow this hyperfying dust away.
Fat is incredible and super smart, But.
So if I was going to be living in a settlement on Mars, I would hope we'd have a better option than dumping dirt on top of the solar panels.
Are there any more.
Like futuristic options that we're hoping we'll be able to test out in the future.
There are people working on ways to clean solar panels here on Earth for all the reasons that we talked about, and billions of dollars in research, not just because we want to have our rulers drive around on Mars, but because we want to have efficient energy production here on Earth without spending lots of time, money, and especially water on cleaning them. What they're looking into our solid state solutions, things with no mechanical moving parts, And one of the most promising technologies is called electrostatic cleaning, and it takes advantage of the fact that these dust particles are not neutral. They tend to have positive or negative charges. You know, it's not that hard to make something ionized. Like the reason you get static electricity when you walk across the floor or when you rub a balloon against your head is that you're like stripping electrons off the surface of the material. So you know, these electrons in some cases are kind of loosely held, and so dust is like flying around the atmosphere in Mars and ends up losing some of its charges. So these dust particles are charged, which means you can push them with electric fields.
So you would like start from the center and sort of move the electric charge outward to move things off the edges of the panels.
Is that the idea, Yeah, so you actually build oscillating electric fields. You have electric fields that go one way and then another way, and in one configuration they will push off like positively charged particles, and then you flip it to push off negatively charged particles. And the idea is just to like loosen them so then they drift off. So you like loosen the negatively charged particles and then they drift away. You flip it and you loosen the positively charged particles and they drift away. And this process of oscillating the charges is actually a little bit violent for the uncharged particles, and they can end up stripping them of their electrons charging them so that they can also then get pushed away.
Is that good or bad?
That's good? Right? So you want to push away the negatives and the positives and the neutrals, So you flip the electric field so you get the positives and then the negatives, and then the process you convert the neutrals to either positive or negative so they can get flipped off in the next cycle.
Nice. Got it? Awesome? And how have we been able to try something like this on Earth yet?
So this technology is under development in research settings, and what they're working on is like minimizing the amount of electrical current that's needed. Just like with the air compressor example, you don't want to develop a system to boost your energy which costs more energy than it saves, right, And so in the case here, they're focusing on using a very small electrical current and one that only needs to be applied for like a couple of minutes every day in order to boost the overall electrical generation power of your system.
Nice. I like it.
This is clever, all right, Maybe you can get me to move to Mars. What else do we have?
This involves also like treating the solar panels with like a few nanometers of special material to cover the glass, and then applying a voltage across that. These other system to have like a little metal bar that passes over the panel, though that's mechanical, so it's less attractive. Otherwise people are working on systems like vibration, Like instead of blowing something on it or brushing something across it, these are tiny, a little hyperfine particle. What if you just like shook them a little bit, you know, very very gently shook them, could the dust just like fall off?
I feel like I would worry that over time the panels would hold up less well if they're constantly being slightly vibrated. But I'm I'm sure someone's thought of that.
No, you're right, that definitely is an issue. I mean, anytime you're like shaking your system, you're going to be like loosening connections and something that you don't want to shake off might shake off one day. But in test, this works pretty well for like the bigger pieces, the very very fine particles don't tend to get shaken off as well using the vibration system. But you know, people are working on this, and people are working in lots of other different directions. It's definitely a big area that people are exploring because we want to be powering our devices. We want them to last as long as possible. You spend like hundreds of millions of dollars developing this thing, and people's entire careers are focused on the questions that might be answered. You don't want it to go up there and then get blocked by a dust storm in like week two and then it's over right. You want to definitely want something beyond thoughts and prayers, well more long term.
You've got humans living on Mars. You don't want them to have.
To spend all their day cleaning the like many football fields worth of solar panels that you're going to need to run your settlement.
Although you know, children have to have something that they complain about or does it really count as a childhood Oh, you know, they can.
Be maintaining the cricket ranch for the protein, they'll have plenty to complain about.
If they're living on Mars.
Yeah, that's true. Children are creative. They'll always find something to drive about. Mommy, these crickets are too spicy.
You're lucky you've got any protein.
That's right, exactly. So, as humans think about how to explore the solar system and how to power our little robotic devices that are going to lead the way and tell us where the most promising places are for our humans to maybe one day build colonies, we want them to keep their power, and we want those solar panels crystal clean as well as down here on Earth. If we're converting ourselves into sustainable sources of energy, we want our solar panels to stay clean and dry without requiring a bazillion gallons of water.
Absolutely, this is definitely an area where if the space scientists figure out a solution, it would help the rest of us.
Too, exactly. And maybe that means that our solar panels will eventually be self cleaning and neither me nor Kelly will have to get up on the roof and do some squeegeing.
You mean my kids. It'll be good that they don't have to go.
On exactly, all right, thanks for joining us in this tour. Of solar panels around the solar system. We hope they all stay sparkling clean. Thanks very much Kelly for joining us today, and thanks everybody for listening.
Thanks for having me have a good time.
Everyone, Thanks for listening, and remember that Daniel and Jorge Explain the Universe is a production of iHeartRadio. For more podcasts from iHeartRadio, visit the iHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows. When you pop a piece of cheese into your mouth, you're probably not thinking about the environmental impact. But the people in the dairy industry are. That's why they're working hard every day to find new ways to reduce waste, conserve natural resources, and drive down greenhouse gas emissions. House US dairy tackling greenhouse gases. Many farms use anaerobic digestors to turn the methane from manure into renewable energy that can power farms, towns, and electric cars. Visit you as dairy dot COM's Last Sustainability to learn more.
There are children, friends, and families walking, riding on passing the roads every day. Remember they're real people with loved ones who need them to get home safely, protect our cyclists and pedestrians because they're people too. Go Safely California from the California Office of Traffic Safety and Caltrans.
Hey, their fellow globetrotters and destination dreamers. If you're anything like us, you'd note that life's too short for boring toasters and towels. That's why we decided to ditch the traditional wedding registry and went with honeyfund dot com. Imagine your friends and family chipping in to send you on a dreamy, exotic honeymoon. Practical check, meaningful double check. Plus it's fee free and so fun for wedding.
Guests to shop. So why get more stuff when you.
Can have unforgettable experiences. Join the revolution at honey fund dot com and start your adventure today
