Speaker 1: Brought to you by Toyota. Let's go places. Welcome to
Speaker 1: Forward Thinking. Hey there, and welcome to Forward Thinking, the
Speaker 1: podcast that looks at the future and says, I'm sailing away.
Speaker 1: I'm Jonathan Strickland, I'm Lauren Bocan, and I'm Joe McCormick.
Speaker 1: And guys, I thought today we could talk about solar sales.
Speaker 1: We've mentioned them a few times in past episodes, and
Speaker 1: I will probably talk about them in future episodes too.
Speaker 1: But the reason why I specifically wanted to bring it
Speaker 1: up is because, not too long ago, in the news
Speaker 1: we're recording this in June, there was a story about
Speaker 1: a crowd funded solar sale projects. So we're gonna talk
Speaker 1: about that a little bit later in the episode. But
Speaker 1: in order for that conversation to even make sense, we
Speaker 1: need to just kind of talk about what these things
Speaker 1: are in general and what their purpose is. Now we're
Speaker 1: solar sales, the vessels that Sailor Moon and the other
Speaker 1: sailor scouts sail I don't know, because Lauren had not
Speaker 1: gotten that far into the explanation of what Sailor Moon
Speaker 1: is all about for us. Can you help us out here, Lauren,
Speaker 1: um I believe they are not, although I'm sure the
Speaker 1: magical cats Luna and Artemis are very fine sailors. We
Speaker 1: we honestly were having Lauren explained to us what sailor
Speaker 1: Moon is all about earlier. So so, yeah, that's just
Speaker 1: a peak in the inner working, so forward thinking. But
Speaker 1: of course solar sales are not a component of a cartoon.
Speaker 1: They are a reality. Yeah. Yeah, it's a propulsion system
Speaker 1: that doesn't require fuel. Now, we just recently on this podcast,
Speaker 1: talked about a supposed propulsion system that doesn't require fuel
Speaker 1: in our podcast on the M drive and the microwave
Speaker 1: oven that makes rockets go, well, yes, supposedly, no, no,
Speaker 1: makes a vessel go without the need for rockets, and
Speaker 1: the appeal of the M drive as it is supposed
Speaker 1: to work. Now, we ended that podcast with a lot
Speaker 1: of hesitation about whether something like this could actually work.
Speaker 1: But if you take the M drive proponents at their word,
Speaker 1: what they're saying happens is they've got a method for
Speaker 1: making a spaceship go through space without a chemical reaction,
Speaker 1: shooting stuff out the back of it without any kind
Speaker 1: of propellent. Yeah yeah. And and the reason why that's important,
Speaker 1: obviously is that you can't carry an infinite amount of
Speaker 1: fuel on your spacecraft, right you. You are limited by
Speaker 1: the volume of whatever vessel you have, and the reality
Speaker 1: that fuel is a three dimensional thing that you have
Speaker 1: to lug around, right yeah, And that it adds weight
Speaker 1: to the spacecraft, which means the more weight you add,
Speaker 1: the more fuel you need in order to escape the
Speaker 1: gravitational poll of the Earth I mean. And then once
Speaker 1: you're out into space, then you need more fuel to
Speaker 1: get to where you're going to accelerate to whatever the
Speaker 1: top speed is. You can only accelerate so much with fuel.
Speaker 1: Of course, if you had some sort of system that
Speaker 1: could gather fuel while you are sailing through space, then
Speaker 1: that would help solve it. And there are ideas like
Speaker 1: that you can travel along through space picking up tiny
Speaker 1: particles and ions and and heaving those out the back
Speaker 1: of a spacecraft. There's not much mass in those, so
Speaker 1: you don't get a lot of acceleration, but slowly over
Speaker 1: time you can build up speed with the method like that.
Speaker 1: And another method similar is solar sales, and that it's
Speaker 1: again one something that has a steady but but low acceleration,
Speaker 1: so you're you're consistently accelerating at least until you get
Speaker 1: to really kind of the top speed of whatever mass
Speaker 1: you are you are using. Uh, but you are accelerating
Speaker 1: steadily up to that point. It's just that it's a
Speaker 1: low level of acceleration. And the reason why we call
Speaker 1: them solar sales is that they're very similar, at least
Speaker 1: in concept, to the sales that we use here on
Speaker 1: Earth to propel things like oats and ships, right, which
Speaker 1: are I suppose technically fueled by the sun because the
Speaker 1: Sun heats the Earth which makes the wind blow. That's true. Yeah,
Speaker 1: if we go far enough back, it is. It is
Speaker 1: kind of a solar powered means of propulsion. But surely
Speaker 1: you're not suggesting that there is wind in space. Well,
Speaker 1: it's similar into wind in space. We're specifically talking about
Speaker 1: photons in the case of solar sales. But before I
Speaker 1: get too far, I do want to make one distinction
Speaker 1: clear for any of our sailing friends out there. It's
Speaker 1: more a solar sales more like a an Earth sail
Speaker 1: if you were sailing directly downwind. Uh. This is an
Speaker 1: important distinction because sales can actually be used to sail
Speaker 1: sort of into the wind, which seems counterintuitive. But it's
Speaker 1: because the construction of sales is such that they act
Speaker 1: kind of like a airplane wing does, so you can
Speaker 1: actually yeah, yeah, Otherwise you could only go in the
Speaker 1: same direction that the wind is blowing, which would not
Speaker 1: be terribly that would be inconvenient. I've actually always wondered
Speaker 1: about that. I have no idea how that works. It's
Speaker 1: very much like a like an airplane wing. It's designed
Speaker 1: so that the airflow is different across one surface than
Speaker 1: the other, and it's it's similar to generating left except
Speaker 1: you're generating thrust essentially, So solar sales are more like
Speaker 1: if you're sailing directly down wind, you're catching the wind
Speaker 1: to push you forward. In this case, a solar sale
Speaker 1: is capturing or or is acting as kind of a
Speaker 1: surface for photons to bounce off of. And photons, as
Speaker 1: we have talked about many times on this show, are
Speaker 1: particles of light. Sure, A photon is a a quantum
Speaker 1: of light. It's the smallest indivisible unit of light energy
Speaker 1: that transfers the electromagnetic force throughout the universe. So yeah,
Speaker 1: the Sun is of course putting out lots of photons
Speaker 1: all the time, shining them out into the universe. That
Speaker 1: shining is of course electromagnetic radiation, and it turns out
Speaker 1: you can use that shine, meaning the sunshine, the electromagnetic
Speaker 1: radiation coming off of the Sun to push a sail
Speaker 1: in the same way the wind would push a sail
Speaker 1: on Earth. But that's kind of weird because the wind
Speaker 1: that pushes a sail on Earth is made up of
Speaker 1: particles of air. It's gas, it's massive particles, and it's
Speaker 1: very easy to see how that imparts a force, how
Speaker 1: that gives momentum to the craft that's attached to the sail, right,
Speaker 1: because yet again the air that we are breathing is
Speaker 1: not open empty space. It's soup. Right. But if you
Speaker 1: remember from like a high school physics class, what is momentum,
Speaker 1: There's that equation P equals m v, so that will
Speaker 1: tell you that momentum is mass times velocity. So you
Speaker 1: take the you know, the mass of the wind hitting
Speaker 1: the sail and how fast it's hitting the sail on
Speaker 1: that vector. That's important. And I was about I was
Speaker 1: about to throw in the direction, but you you covered
Speaker 1: it exactly. Velocity is is a is a vector, and
Speaker 1: that you need both a magnitude in a direction for
Speaker 1: that particular measurement. But yes, exactly. You take that mass,
Speaker 1: you take the velocity, you multiply them together, you get
Speaker 1: the momentum. This is sort of a way of describing
Speaker 1: the movement energy of UH an object in motion and
Speaker 1: with massive objects. That makes it pretty simple to understand.
Speaker 1: You know. You think, oh, if I'm running at a
Speaker 1: speed of eight miles per hour, I have a certain
Speaker 1: amount of momentum. It's going to take a certain amount
Speaker 1: of energy to stop me because of the the energy
Speaker 1: that I that that represents. If a semitruck is traveling
Speaker 1: at eight miles per hour, it's going to need more
Speaker 1: energy to stop it because it is a much more
Speaker 1: massive object, all right, And in the stopping of it,
Speaker 1: it's going to transfer some of that momentum to the
Speaker 1: object of stopping. Yeah. So if you if you have
Speaker 1: something that is has less uh potential force there, then
Speaker 1: you probably aren't going to stop this in my truck,
Speaker 1: but you will definitely alter the stopping whatever it was,
Speaker 1: like a wall or fence. Yeah. But photons, the makeup
Speaker 1: of the sunshine don't have any mass. They don't have
Speaker 1: a rest mass or variant mass, right, Yeah, so this
Speaker 1: makes it a little tricky because you would think, well,
Speaker 1: we just talked about how that that equation is mass
Speaker 1: times velocity, So how could a photon that has no
Speaker 1: mass transfer momentum, I mean, momentum depends on mass, right, Yeah,
Speaker 1: But one way I've seen of explaining this is to
Speaker 1: say that momentum isn't really fundamentally mass times velocity. That's
Speaker 1: just sort of the Newtonian level shortcut for describing how
Speaker 1: things work, and and it makes sense because for most
Speaker 1: of us that's i mean, that's the world we live in,
Speaker 1: I'm sure in the macro level, or at the macro level.
Speaker 1: Rather if we're going to use prepositions correctly, which we are, Uh,
Speaker 1: that's completely valid. But photons are are in that strange
Speaker 1: little little less than big. Yeah, we're talking quantum level
Speaker 1: on there. Yeah. So you could look at this in
Speaker 1: terms of quantum mechanics or in terms of relativity. But
Speaker 1: either way, what this works out too is that the
Speaker 1: energy of a photon sort of plays the role of
Speaker 1: mass that we would usually think about in this equation.
Speaker 1: And Einstein pointed this out right, there's the famous equation
Speaker 1: E equals mc squared. This tells you the relationship between
Speaker 1: energy and mass. So a small amount of mass is
Speaker 1: equivalent to an enormous amount of energy because you're multiplying
Speaker 1: at times the constant of the speed of light squared. Well,
Speaker 1: that also means that mass is equal to energy divided
Speaker 1: by c squared. You know, you just change around the
Speaker 1: the equation there. So that photon, that representation of a
Speaker 1: of an amount of energy of light is equivalent to
Speaker 1: a certain amount of mass. It's just a very small
Speaker 1: amount of mass. But that small amount of mass doesn't
Speaker 1: think you know, the fact that it's small doesn't really
Speaker 1: matter because of two big things. Really. One is that
Speaker 1: in space you don't have gravity to work against. So, uh,
Speaker 1: any amount of momentum transferred to the solar sale is
Speaker 1: going to have some effect the the solar sale is
Speaker 1: going to end. Whatever is attached to it is going
Speaker 1: to move in the opposite or or is going to
Speaker 1: move in the same direction as the impact. Secondly, it's
Speaker 1: not like it's a single photon that's saying the solar sale.
Speaker 1: There are lots of photons hitting the solar sale. They're
Speaker 1: doing so at the speed of light. Uh, So you
Speaker 1: are getting a transfer of momentum in that way. Light
Speaker 1: itself can have momentum, as can other types of electromagnetic radiation,
Speaker 1: so that's kind of exciting. So each individual photon imparts
Speaker 1: only a very slight amount of momentum, but there's enough
Speaker 1: of them that you can build up a traveling force
Speaker 1: over time, right. And the amount of moment to possessed
Speaker 1: by any individual photon is dependent upon that photons wavelength
Speaker 1: and frequency. So if you were to take a photons
Speaker 1: frequency and its wavelength and multiply them together, the product
Speaker 1: would be the speed of light, all right. So in
Speaker 1: other words, if you have a longer wavelength of light,
Speaker 1: it's going to have a lower frequency. Though those two
Speaker 1: have to change, right, because the end product has to
Speaker 1: be the speed of light with a photon. If you
Speaker 1: know one of these variables, you know the other one, right.
Speaker 1: So higher frequencies have shorter wavelengths, and they also have
Speaker 1: higher energy levels. So a high frequency, short wavelength photon
Speaker 1: has more energy than one that has a lower frequency
Speaker 1: but longer wavelength. Uh, that's important as well. And Uh,
Speaker 1: there's an astrophysicist that actually, Joe you had had clued
Speaker 1: me in on that. I had read some of his
Speaker 1: work before, but didn't know him by name and his
Speaker 1: explanations of this sort of stuff really made it a
Speaker 1: lot easier to understand. Yeah, his name is Ethan Siegel.
Speaker 1: He's one of my favorite science bloggers on the internet.
Speaker 1: He's on Twitter as at starts with the Bang. He's
Speaker 1: really worth reading. And he also, for me, has made
Speaker 1: a lot of sort of astrophysics concepts much easier to grasp. Yeah,
Speaker 1: and he's also he's also kind of an eccentric guy,
Speaker 1: and I dig that. It's pretty awes Yes, he does. Yeah,
Speaker 1: like his Twitter handle, he's got horns coming out of
Speaker 1: his head and stuff. It's pretty pretty cool. Cool. Yeah,
Speaker 1: So now we've we've got up the the physics behind
Speaker 1: why solar sales could work as a means of propelling
Speaker 1: a spacecraft without using any actual fuel. Uh. Now, to
Speaker 1: actually take advantage of it, you have to build your
Speaker 1: spacecraft in a very strategic way. You want to minimize
Speaker 1: the amount of mass you're using so that the propulsion
Speaker 1: from the solar energy is max smized, because the more
Speaker 1: massive it is, the more solar energy you're going to
Speaker 1: need to you know, it's going to it's going to
Speaker 1: accelerate slower and slower, or as the mass increases, the
Speaker 1: rate of acceleration is lower, so it takes longer to
Speaker 1: accelerate to those incredible speeds. Alright, same principle is if
Speaker 1: you have a heavier car, it takes more gas to
Speaker 1: move it, right yeah, yeah, very similar to that. But
Speaker 1: you also want the largest possible surface on which the
Speaker 1: sun can push right yeah. Yeah. It doesn't do you
Speaker 1: much good if your solar sale is you know, a
Speaker 1: couple of square inches, then it's not going to capture
Speaker 1: enough photons for that to really be worthwhile. So you
Speaker 1: want a lot of surface area, uh, and not a
Speaker 1: lot of mass. So that also means that whatever material
Speaker 1: you're using, you want it to be super thin. Uh.
Speaker 1: Tends to be reflective, so the photons hit it, they
Speaker 1: bounce off, and the momentum is transferred to the solar sale,
Speaker 1: which in turn transfers that momentum to the spacecraft itself. Uh. Now,
Speaker 1: this acceleration, like we said, is small, but and it
Speaker 1: is continuous. So the longer the spacecraft is capturing the
Speaker 1: solar energy, the faster it is moving. It's accelerating slowly
Speaker 1: over time, but it keeps going until you've reached the
Speaker 1: maximum speed that spacecraft can go according to its uh mass,
Speaker 1: or you are no longer able to capture a significant
Speaker 1: amount of photons to continue accelerating. But either way, at
Speaker 1: that point, you're traveling at an incredible, incredible speed and
Speaker 1: you're not going to slow down unless you encounter something
Speaker 1: that makes you slow down, like an asteroid, yeah, or
Speaker 1: a planet or a moon or something that has a
Speaker 1: gravitational effect on your spacecraft. Right, or you know those
Speaker 1: jerk aliens. I hate the jerk aliens, always clinging onto
Speaker 1: stuff much before rotisserie. Oh nice, Okay, so moving on.
Speaker 1: Typically this super thin solar sale is only a few
Speaker 1: microns thick. So to get an idea of how thin
Speaker 1: we're talking about, I you get a plastic bag from
Speaker 1: grocery store, you know, your typical thin plastic bag. Those
Speaker 1: tend to be twice as thick or more than twice
Speaker 1: as thick as the solar sale material. So this is
Speaker 1: really thin, delicate stuff. Yeah. That material is typically a
Speaker 1: polymer film that's capable of withstanding the high temperature fluctuations
Speaker 1: of space because it can be pretty chilly and it
Speaker 1: can also be pretty warm, depending on how much radiation
Speaker 1: is hitting you at the time. Some researchers have also
Speaker 1: investigated using carbon fiber woven to be you know, hundreds
Speaker 1: of times thicker than these films would be, but just
Speaker 1: as a light due to their structure, their holy holy structure. Ye,
Speaker 1: holy as in lots of holes in it. Yes, yes,
Speaker 1: you really can't say holy twice without saying it thrice,
Speaker 1: holy holy holy, Right, let's hear it again, holy holy
Speaker 1: holy structure. Um, that's my high Church of technology talking.
Speaker 1: That's fair, thank you, thank you. So if you're wondering
Speaker 1: what kind of fantastic speeds were actually talking about, well,
Speaker 1: Planetary Society co founder Lou Friedman once told the UK's
Speaker 1: Royal Society of Chemistry, and by once, I mean back
Speaker 1: in two thousand nine that the contemporary technology should allow
Speaker 1: acceleration rates of about point zero zero zero five meters
Speaker 1: per second. Well, all right, so what's the miles per hour?
Speaker 1: That's point zero one miles per hour. This is the
Speaker 1: acceleration rate. Yes, yes, um, I mean, of course, given
Speaker 1: a probable size of sail and weight of vehicle that
Speaker 1: you would expect to be launching like the kind of
Speaker 1: things that they were thinking about in two thousand nine,
Speaker 1: which we will get into a little bit later here,
Speaker 1: um to to get that up to a sort of
Speaker 1: range that's a little bit more understandable. Over the course
Speaker 1: of the of a day, that's about a hundred and
Speaker 1: sixty kilometers per hour a k A about a hundred
Speaker 1: miles per hour, and that means that in a year
Speaker 1: it could hit thing like fifty eight thousand kilometers per
Speaker 1: hour or thirty six thousand miles per hour, which is
Speaker 1: something like three times the speed of our current interplanetary missions.
Speaker 1: That's that's now, that's incredible because again, just through the
Speaker 1: fact that it is continuously accelerating, it's able to hit
Speaker 1: these speeds. And sure it takes a long time to
Speaker 1: hit those amazing speeds, but it can and it doesn't
Speaker 1: require the use of fuel. That's why it's so attractive. Now,
Speaker 1: what would you actually be using these solar sales for,
Speaker 1: I mean, what would it be propelling? Obviously, uh, we're
Speaker 1: not necessarily talking about manned missions here, where we'd have
Speaker 1: people aboard a uh some form of transport and using
Speaker 1: solar sales to move. That's a possibility, but it's not
Speaker 1: necessarily what they'd be used for. Well, they have very
Speaker 1: few moving parts because you really just need to be
Speaker 1: able to deploy the solar sale right, unfurl the sail,
Speaker 1: and and then you end up there. There needs to
Speaker 1: be some means of controlling the the attitude, the the
Speaker 1: the position. Yeah, the position of the spacecraft in relation
Speaker 1: to whatever source of photons you're talking about. You need
Speaker 1: that as well. But apart from that, you're you're pretty
Speaker 1: much set. So they're great candidates for reuse. So instead
Speaker 1: of having to build a spacecraft for every single mission,
Speaker 1: you could have a solar sale craft that could potentially
Speaker 1: be used multiple times before ever needing to be replaced.
Speaker 1: So they'd make really great delivery or cargo vehicles in
Speaker 1: this way, I've seen one of the big ones. One
Speaker 1: of the big use cases that has been put forward
Speaker 1: is it could be used to deliver cargo and supplies
Speaker 1: to Mars. Now, you wouldn't have a solar sales spacecraft
Speaker 1: land on Mars. That would not be good for anybody there.
Speaker 1: But what you could do is have it fly by
Speaker 1: Mars and do essentially a controlled drop of cargo. Or
Speaker 1: it could rendezvous with other spacecraft like a space station
Speaker 1: that's in orbit around on Mars. You could have a
Speaker 1: rendezvous where cargo gets transferred and then the solar sale
Speaker 1: is redirected and sent back to Earth. It can be
Speaker 1: kind of a taxi vehicle, another another interplanetary uber. It
Speaker 1: could be. Yeah, I wouldn't be surprised if we see
Speaker 1: an app for that in the next five years. But
Speaker 1: the next application would be possibly to create an early
Speaker 1: warning system for space weather. Uh. This would be really
Speaker 1: useful solar weather happens. I mean you probably are at
Speaker 1: least familiar with solar flares. They have the potential to
Speaker 1: disrupt electronics here on Earth. If it's a large enough
Speaker 1: solar flare, it can cause some surges in things like
Speaker 1: power grids, and in fact, it can even cause an
Speaker 1: entire blackout of a region if it's powerful enough. There's
Speaker 1: also coronal mass ejections, which sometimes but not always a
Speaker 1: company solar flares that can cause some problems, uh, and
Speaker 1: we're not always aware of them until it's pretty late
Speaker 1: in the game. So if we were able to put
Speaker 1: spacecraft into different orbits, then we can usually uh achieve
Speaker 1: on our own. Then with our other satellites and other probes,
Speaker 1: then we could have uh more of a a complete
Speaker 1: look at what's going on with the Sun at any
Speaker 1: given time, and then if we spot warning signs, we
Speaker 1: might be able to prepare ourselves in the event of
Speaker 1: a solar flare coronal mass ejection that could potentially cause
Speaker 1: havoc here on Earth. It might mean being able to
Speaker 1: balance loads or reduce loads on our electrical grids to
Speaker 1: reduce the potential damage that could happen. It's really important,
Speaker 1: and it's something that a lot of people have been
Speaker 1: pushing for for a while, saying, you know, it's just
Speaker 1: a matter of time before there's a big solar flare
Speaker 1: up that could at least temporarily cause real problems for
Speaker 1: us here on Earth or yeah, yeah, I mean the
Speaker 1: and these weather patterns happen in cycles. Now, just because
Speaker 1: they happened in cycles doesn't mean that every eleven years
Speaker 1: we're going to get a massive solar flare that's gonna
Speaker 1: wipe out you know, Detroit or something. It's that's not
Speaker 1: what it means. But it does mean that they there
Speaker 1: are periods of increased activity and then there are periods
Speaker 1: of a lull of activity. But this sort of spacecraft,
Speaker 1: a solar sales spacecraft that could go into these eccentric
Speaker 1: orbits that normally we wouldn't be able to achieve, could
Speaker 1: at least give us a heads up when that sort
Speaker 1: of thing might happen. You know, what could be even
Speaker 1: better is if we made one that was really big,
Speaker 1: just big enough to completely block the Sun from the Earth,
Speaker 1: and then we'd never have to worry about So you're
Speaker 1: taking the Mr. Burns approach. I see, I always liked
Speaker 1: something about him. Excellent. So it could also be used
Speaker 1: to propel spacecraft through interstellar space, not necessarily carrying humans,
Speaker 1: but maybe who knows, by the time we get to
Speaker 1: the point where we were seriously talking about in interstellar travel,
Speaker 1: it might be one of the more approved of ways
Speaker 1: of doing that. UM. But what you would typically do
Speaker 1: would you would have your spacecraft do a run near
Speaker 1: the Sun so it could get a good boost of
Speaker 1: energy and then uh accelerate as it moves outward to
Speaker 1: escape the solar system. Uh. Eventually you would get to
Speaker 1: a point where you would have fewer photons hit the
Speaker 1: solar sale, so you wouldn't really receive the acceleration that
Speaker 1: you had when you first passed by the Sun. But
Speaker 1: by that point you're already traveling at this insane speed,
Speaker 1: so it would be probably one of the more viable
Speaker 1: means of propelling a spacecraft outside the Solar System. Uh,
Speaker 1: in a you know, reasonable time frame. By reasonable, I'm
Speaker 1: still talking a long long time, you know, not necessarily
Speaker 1: something like oh, within within a year and a half
Speaker 1: will be on the Solar System. That yeah, but but
Speaker 1: more reasonable than the generations upon generations that it would
Speaker 1: currently take. You get out right doing like little slingshots
Speaker 1: around various planets and stuff. Um So, also it might
Speaker 1: be used to help protect us against collisions from space rocks,
Speaker 1: like like giant asteroids. I've actually read about this method. Yeah.
Speaker 1: So the idea is, if you have an asteroid on
Speaker 1: a collision course with Earth, you don't necessarily have to
Speaker 1: destroy the asteroid to protect the Earth. You just have
Speaker 1: to divert its path. Yeah. In fact, destroying the asteroid
Speaker 1: might be not as productive in the sense that now
Speaker 1: you've got a whole bunch of little asteroids aiming at
Speaker 1: Earth instead of a big one. In the words of
Speaker 1: some random guy from the movie Independence Day, you risk
Speaker 1: turning one dangerous falling rock into many. Yeah. I think
Speaker 1: phil Plate has referred to it as as you turn
Speaker 1: you turn a slug into a blast of shotgun pellets um,
Speaker 1: and and so the idea would be you attach a
Speaker 1: solar sale to this, like, well, first you have to
Speaker 1: detect it, right, you detect that there is an a
Speaker 1: body that is on a potential collision course with Earth,
Speaker 1: although hey, having erratic satellites up there might help with
Speaker 1: detect and having having the enormous solar sale satellites to
Speaker 1: kind of detect that sort of stuff. Plus we've got
Speaker 1: really sophisticated uh telescopes these days that can detect stuff
Speaker 1: from much further away than we did before. Then what
Speaker 1: you would want to do is send up a spacecraft
Speaker 1: that could attach itself to the asteroid and deploy a
Speaker 1: solar sale and use that that momentum from the photons
Speaker 1: to help pull the asteroid off course. And it doesn't
Speaker 1: have to be that far, assuming you catch it far
Speaker 1: enough away from the Earth, right, Yeah, So the idea
Speaker 1: is you'd essentially make the sun word facing side of
Speaker 1: the asteroid a huge mirror, and then you'd hope that
Speaker 1: over time it gathers enough acceleration away from the Sun
Speaker 1: via that huge mirror, the same principle as a solar
Speaker 1: sale to make it miss the Earth. But like you
Speaker 1: were saying, Jonathan, this would only work if you had
Speaker 1: a very long lead time because that acceleration based on
Speaker 1: the photon reflection is going to be pretty slow. Right, Yeah,
Speaker 1: you need to make sure that you know. The earlier
Speaker 1: you are able to deploy this, the better your chances
Speaker 1: are of of diverting the pathway so that you no
Speaker 1: longer have to worry about a collision. But again, it's
Speaker 1: when you think about it, it really does make sense.
Speaker 1: Like if I'm standing two feet away from you, uh,
Speaker 1: and I have a water a water pistol in my hand,
Speaker 1: and then I move my my hand just a little
Speaker 1: bit to the left or right, I'm still gonna hit
Speaker 1: you because I'm two feet away from you. But let's
Speaker 1: say that this water pistol can shoot water across the
Speaker 1: football field. First of all, you're not gonna want me
Speaker 1: to shoot you from two feet away. But let's say
Speaker 1: I'm I'm across the football field from you and I
Speaker 1: move my hand that same distance. Because of the distances involved,
Speaker 1: obviously the the trajectory, it's gonna totally miss you, you know,
Speaker 1: not taking wind into account, which I never do anyway.
Speaker 1: So uh yeah, that's the same basic idea from this
Speaker 1: potential use case. So let's talk about some solar sale projects,
Speaker 1: because this is not science fiction. This is actual technology
Speaker 1: that has already been used. Well it's yeah, it's not
Speaker 1: even science. Maybe one day it's it's science. A few
Speaker 1: years ago. Yeah, yeah, the first one Okay, well the
Speaker 1: first one was not supposed to be the first one
Speaker 1: if things had worked out properly. But what ended up
Speaker 1: being the first solar sale spacecraft that actually worked was
Speaker 1: the Chorus Space Probe, which was not choros I K
Speaker 1: A R O s uh. So this was in June
Speaker 1: of so this was just a few months before another
Speaker 1: solar sale test craft was launched by NASA. Uh it
Speaker 1: was launched by the Japan Aerospace Exploration Agency or Jackson
Speaker 1: and ACARUS is actually an acronym. It's not all capitalized.
Speaker 1: It's like some other acronyms that are no longer completely capitalized,
Speaker 1: but stands for interplanetary kite craft accelerated by radiation of
Speaker 1: the Sun. I wonder how many people had to think
Speaker 1: of the like the acronym. Yeah, but it was all
Speaker 1: meant to just demonstrate whether or not solar sales could
Speaker 1: could really work. Why is the acronym in English as
Speaker 1: another excellent question to which I do not have an answer.
Speaker 1: I can give you a few more details about the craft,
Speaker 1: but I can't tell you what you know why it's
Speaker 1: called that? Uh not interested? Sorry, Well for everyone who's
Speaker 1: not Joe, tell me about the craft, all right. Uh So,
Speaker 1: the sale itself was forty six ft wide, which is
Speaker 1: fourteen meters, and uh Acorus had l c D p
Speaker 1: annals on the edges of the sail. And you might
Speaker 1: wonder why why would a solar sale have l c
Speaker 1: D panels. And it was all to control their reflectivity
Speaker 1: of the sales because that was how the spacecraft could
Speaker 1: adjust its attitude in space. Not like it had a
Speaker 1: bad attitude. I don't. I don't mean attitude in that
Speaker 1: sense like mood. I'm talking about its position relative to
Speaker 1: the sun. Oh okay, so this should be kind of
Speaker 1: like the boom on a sail on a sailboat, where
Speaker 1: you can sort of like adjust its attitude towards the wind. Right.
Speaker 1: So in this case, you're adjusting the reflectivity of the sale,
Speaker 1: or at least the edges of the sail, and that
Speaker 1: is what would cause the photons to either transfer more
Speaker 1: or less momentum to those edges, and that would adjust
Speaker 1: the attitude of the spacecraft, which I thought was a
Speaker 1: very elegant means of a of of creating a control system.
Speaker 1: Um so that was pretty cool. Now. The second one
Speaker 1: was the Nano Sale D two, and that too is important.
Speaker 1: Uh So this was one that was launched by NASA.
Speaker 1: You see, they had planned on launching the Nano Sale
Speaker 1: D cube sat. CubeSats are tiny little satellites. They're usually
Speaker 1: um carried along with the payload of other larger satellites. Yeah,
Speaker 1: they're they're only ten centimeters square, and so they're really
Speaker 1: handy for doing stuff cheaply in space. Yeah, usually it's all.
Speaker 1: They're often uses test craft for platforms for for testing technology,
Speaker 1: or they're used in various ways. A lot of crowdfunded
Speaker 1: science uses these sort of cube satellites for various means.
Speaker 1: They're really cool. Um Now, in this case, there was
Speaker 1: going to be a launch in two thousand eight, so
Speaker 1: this that would have been the first solar sale launched,
Speaker 1: uh and so NASA would have been the first to
Speaker 1: ever do it. But the satellite was lost during the launch,
Speaker 1: so they were unable like, like, where did we put
Speaker 1: the satellite. It was right here next to my key
Speaker 1: ease like that, but more explosively. So Nano scale D
Speaker 1: two was but that one was a success. So that
Speaker 1: one happened in two thousand and ten. But it did
Speaker 1: happen just a few months after uh, the Koros solar
Speaker 1: sale satellite went up. This one was a one square
Speaker 1: foot or nine point three square meter solar sale and
Speaker 1: it was attached to a small satellite, also meant as
Speaker 1: a proof of concept, and it orbited the Earth for
Speaker 1: two hundred forty days and then re entered the Earth's
Speaker 1: atmosphere and uh and burned up on It was not
Speaker 1: was not designed to come back in one piece, but
Speaker 1: was meant to just be sort of a proof of
Speaker 1: concept to prove that the technology to deploy the sale
Speaker 1: would work, that the sale would operate as expected, that
Speaker 1: sort of thing. Sure. Yeah, um, but I had heard
Speaker 1: a while back that there was supposed to be uh
Speaker 1: something launching from NASA this year. Yeah, that was the
Speaker 1: sun Jammer. Uh. It was supposed to launch this year.
Speaker 1: It was supposed to be this enormous solar sale. This
Speaker 1: was gonna be the next big step, the one saying
Speaker 1: here's going this is going to be a propulsion technology
Speaker 1: for the future, and this is our serious show of
Speaker 1: what it can do. It was to have a nearly
Speaker 1: thirteen thousand square foot sale that's twelve hundred square meters,
Speaker 1: so much bigger than the previous ones, but it was
Speaker 1: actually scrapped last year. In two thousand fourteen, NASA said
Speaker 1: that they had quote a lack of confidence in its
Speaker 1: contractors ability to deliver end quote. That's a quote from
Speaker 1: Space News, not from NASA itself. So in other words,
Speaker 1: they had partnered with a contractor to design the solar
Speaker 1: sale and over the course of the partnership realized that
Speaker 1: things were not coming together on schedule or on budget
Speaker 1: or both, and so in fourteen they said, we're not
Speaker 1: doing this anymore. And that pretty much ended the quest
Speaker 1: to use solar sales for the near future in NASA,
Speaker 1: But not as it turns out, for everybody. And that
Speaker 1: brings us to the light sale project and our buddy, uh,
Speaker 1: the science guy, Bill Nill. Yeah, Bill Knight, the science guy.
Speaker 1: He built a solar sale. Well, he heads the group
Speaker 1: that built the solar sale, or that oversaw the building
Speaker 1: of the solar fine. Uh. It was on one of
Speaker 1: those long lost episodes of Bill Night the sides guy. No,
Speaker 1: so he built it, then he put it in a catapult,
Speaker 1: shouted across the room, and then showed us a replay
Speaker 1: and slow motion four or five times. Slight misinformation from Joe,
Speaker 1: But here's what actually happened. So Bill Ny is the
Speaker 1: CEO of a group called the Planetary Society, which is
Speaker 1: a citizen funded, uh group that's dedicated to really promoting
Speaker 1: science and to performing science experiments by involving citizens in
Speaker 1: various means. Right. It was co founded by Carl Sagan
Speaker 1: and Lou Friedman, who I mentioned earlier and one other
Speaker 1: human person who I am forgetting right now, But at
Speaker 1: any rate, it was it was again like great science communicators,
Speaker 1: and so you know Carl Sagan an amazing science communicator, right,
Speaker 1: Bill Night also a great science communicator. So it's it's
Speaker 1: the continuation of that, and it's getting people involved on
Speaker 1: various levels, including through crowdfunding. Um. So there are a
Speaker 1: couple of companies involved in this, right Uh. Yeah, that's
Speaker 1: Stellar Exploration Incorporated and Ecliptic Enterprises, as well as a
Speaker 1: couple of universities California Polytechnic State University and also Georgia Tech. Yeah. Yeah,
Speaker 1: In fact, Georgia Tech designed the satellite that was used
Speaker 1: as sort of the casing for this particular solar sale.
Speaker 1: So the light sale itself is three d and forty
Speaker 1: four square feet or thirty two square meters, and that
Speaker 1: sale is composed of four triangles of aluminum reinforced milar
Speaker 1: that are just four point five microns thick. Yeah, that's
Speaker 1: even thinner than the ones I was mentioning earlier, where
Speaker 1: like before I had seen five microns, Like that was
Speaker 1: when solar sales were first being talked about, and now
Speaker 1: we're even developing material that's thinner than that. The whole
Speaker 1: thing is packaged in a a three cube SAT configuration,
Speaker 1: which which we just mentioned earlier, and so it's only
Speaker 1: a couple of feet tall all things considered, right, And
Speaker 1: so this was actually launched this year. Light sale went up. Uh,
Speaker 1: it was part of a payload. There were some issues
Speaker 1: when it was you know, detached from the rest of
Speaker 1: the payload. Um. Yeah, there was this lovely glitch wherein Okay,
Speaker 1: So the team wanted to see whether or not the
Speaker 1: sale had properly unfurled. So they a light sale take
Speaker 1: a couple of selfies, and the first one came back fine,
Speaker 1: the sale looked great. Everything was really cool. From the
Speaker 1: other side, the data that it sent back did not
Speaker 1: actually compile into an image. It compiled into nothing. It
Speaker 1: was gibberish. And then then the light Sale started transmitting
Speaker 1: this continuous stream of gibberish and simultaneously stopped responding to commands.
Speaker 1: I would like to think that was the moment that
Speaker 1: the Light Sale wanted to learn how to love. I
Speaker 1: just thought about event Horizon. I was like, oh, oh,
Speaker 1: it unfurled into another dimension. This is bad um. But no, no,
Speaker 1: that that is not as far as we can currently tell,
Speaker 1: what happened. Right, They did manage eventually to reconnect with
Speaker 1: the lights Sale. There were a lot of issues, but
Speaker 1: they ended up calling the entire mission that success because
Speaker 1: its purpose was simply to test the deployment of the
Speaker 1: light Sale. It wasn't meant to actually use the light
Speaker 1: Sale for propulsion. It was just to make sure that
Speaker 1: what they had designed would work. And so this sets
Speaker 1: us up for the next project. Now, if you're wondering
Speaker 1: what happened to the Light Sale, it actually re entered
Speaker 1: the Earth's atmosphere on June fifteen, two fifteen and approximately
Speaker 1: one pm and burned up, and some child saw a
Speaker 1: shooting star made a wish that was not a shooting
Speaker 1: star child wish that will never be granted. You don't
Speaker 1: know that that child might end up becoming the first
Speaker 1: person to set foot on Mars, which would be very poetic.
Speaker 1: But at any rate, the this this mission was all
Speaker 1: about setting a platform upon which further missions will be built,
Speaker 1: and the Planetary Society already has that in mind. They're
Speaker 1: going to launch another light sale in late uh and
Speaker 1: this one is actually going to go at an altitude
Speaker 1: high enough to deploy the sales and use it for propulsion.
Speaker 1: So this will go beyond just the employment phase to
Speaker 1: actually zipping around a little bit out in space, which
Speaker 1: is pretty exciting that that's part of why the first
Speaker 1: light sale did not move anywhere, because it was in
Speaker 1: a low enough orbit that enough of the Earth's atmosphere
Speaker 1: was still in the way for it to really uh
Speaker 1: moving again, going yeah, it was it was that would
Speaker 1: block whatever moment timate would have picked up. This one
Speaker 1: is the one that actually is going to be inside
Speaker 1: the satellite designed by Georgia Tech, that it's going to
Speaker 1: be a prox one satellite. Ah. Yeah, they're gonna launch
Speaker 1: it on a Falcon heavy rocket from SpaceX are old friends,
Speaker 1: and um, the prox One is going to deploy the
Speaker 1: light Sale and then kind of follow along its path,
Speaker 1: providing data on its performance and taking some pictures and
Speaker 1: stuff like that. And it's possible that I'm just not
Speaker 1: properly understanding the press releases, but I think it's going
Speaker 1: to be able to like automatically nudge the light Sale
Speaker 1: around to keep it on its proper flight path. Yeah,
Speaker 1: so it's going to have some adjusting ability to make
Speaker 1: sure that it is. Yeah, yeah, yeah, that makes sense.
Speaker 1: And if you happen to be listening to this podcast
Speaker 1: before Friday June, which is my birthday, oh hey, happy
Speaker 1: early birthday. Thank you. Um you can fund light Sale
Speaker 1: on Kickstarter. We'll try to remember to link it on
Speaker 1: social but I have complete faith in all of you
Speaker 1: to google light Sale Kickstarter and figure it out. Yeah.
Speaker 1: So really exciting. Potentially one of the new methods of
Speaker 1: zipping around outer space without having to worry about all
Speaker 1: that fuel, which you know is a is an amazing possibility.
Speaker 1: I don't know that light sales are going to be
Speaker 1: used for everything, And of course they're very similar to
Speaker 1: what we've what would be called a beam sailor. Beam
Speaker 1: sailors would be based on almost identical principle, except instead
Speaker 1: of capturing photons from the sun, you would aim a
Speaker 1: beam of energy at the sale to move it along.
Speaker 1: So that's something that people have talked about possibly using.
Speaker 1: You could equip like a laser on one of these
Speaker 1: vehicles and use it to blow air in its own
Speaker 1: sales essentially kind of yeah yeah, Or you could use
Speaker 1: one from directed from the ground, or from a satellite,
Speaker 1: or from a space station. There are a lot of
Speaker 1: different potential uses of this. Uh. So I'm really excited
Speaker 1: that we're seeing what could be the dawn of a
Speaker 1: new era of space exploration. Um, you know, it's it's
Speaker 1: really exciting. And also to know that we could get
Speaker 1: directly involved by and by funding it or by joining
Speaker 1: organizations like the Planetary Society and uh and and putting
Speaker 1: our stamp on that era of space exploration, that's really cool.
Speaker 1: So I'm glad that we had chance to talk about this.
Speaker 1: It's it's one of those things that captures the imagination,
Speaker 1: especially like I'm a huge fan of sailing, here on Earth.
Speaker 1: So the thought, oh yeah, yeah, I actually uh was
Speaker 1: helmsman for the oldest sailing vessel in the Southeast a
Speaker 1: few years ago. The Governor Stone. Uh yeah, I'll tell
Speaker 1: you guys about it later anyway. Um yeah, So this
Speaker 1: was a lot of fun to cover. If you guys
Speaker 1: have any suggestions for future topics, maybe it's another space
Speaker 1: related topic, or you know one of our other favorite
Speaker 1: topics like three D printing or robots, you can let
Speaker 1: us know, send us a message, or you just have
Speaker 1: a question or comment about the show. You can send
Speaker 1: us an email that addresses f W Thinking at how
Speaker 1: Stuff Works dot com, or drop us a line on Twitter,
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