This Week in Space 95 Transcript

Please be advised this transcript is AI-generated and may not be word for word. Time codes refer to the approximate times in the ad-supported version of the show.


Rod Pyle (00:00:00):
On this episode of this Weekend Space, we'll be talking about game-changing clean power from space with former NASA technologist and Space Solar Power guru John Mankins

TWiT (00:00:13):
Podcasts you love from people you trust.

This is

Rod Pyle (00:00:21):
This week in space, episode number 95, recorded on January 26th, 2024, clean Energy for Space with John Mankins.

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Rod Pyle (00:00:47):
Hello and welcome to this week in Space, the Clean Power from Space Edition. I'm Rod Pyle, editor Chief VA Astor Magazine, and it's my enduring pleasure to be joined as always by the indistinguishable Tarek Malik, editor in chief of And I mean that in the nicest possible way.

Tariq Malik (00:01:04):
Hello? Hello. I thought that just meant that I just blur in with the background there, but no, that can't be the

Rod Pyle (00:01:09):
Case. No, I just needed a subscriber that started with an eye and that's the one that came to mind. We'll be joined today in a few minutes by John Mankins, who is an expert in space solar power. John was the original architects of the current iteration of plans for clean power from space from the United States during his time in senior management positions at NASA and NASA Jet Propulsion Laboratory and has been working on this for decades, is a world-class expert on space solar power and there aren't many and continues to research and advocate for space solar power Today, he's also on the board of directors of the National Space Society and has a resume of achievements and affiliations that are, let's see, longer than these two arms. So they're big. But before we get to John, a couple of housekeeping memos. Just a reminder that TWIT needs your help.

We want to keep our show in the air and twit available at all, and you can help for just $7 a month by joining Club Twit and we'll talk more about that at the end of the episode. Easy to do and it's good for you, it's good for us, it's good for everybody. And it's survey time still. You've got just a few days left to do this. The annual twit survey helps us keep informed of audience wants and thoughts and desires and who you are and helps us make your listening experience better despite my lame dad space jokes. Now, when I say who you are, I don't mean that we keep individual information, but we do like to know what kind of audience we've got. So we know that you're all smart. We know that you're all dedicated to your communities. We know that you're technically savvy and that's the kind of thing that we like to keep abreast of. It only takes a few minutes, your data stays private. Very important in the last day to take it is January 31st end of the month. And don't forget to tell 'em that you're listening to this week in space because we want the love. Alright, it's time for my trademark Bad Dad Space joke.

I'm ready. One more from our increasingly good pal Tucker Drake from the Will Eisner book 101 Space jokes

Tariq Malik (00:03:07):

Rod Pyle (00:03:08):
This one's a bit of a head scratcher. Two astronauts, two astronauts were stranded on a deserted planet I guess at that point. Kind of wasn't deserted by definition, but you get the idea. Astronaut one, I'm so lonely I could cry. Astronaut two. What do you mean lonely? I'm here Astronaut one. That's what I mean. Sorry, that was the punchline in case nobody was wondering. That's like

Tariq Malik (00:03:36):
The worst case scenario is to be stuck on a planet with someone you absolutely can't stand.

Rod Pyle (00:03:43):
So are you just happen to be talking about me or are you just No,

Tariq Malik (00:03:47):
I'm not. I'm not. No Rod. Rod, I love you. I love you Rod.

Rod Pyle (00:03:50):
Think of the fun we'd have. And you'd only have to manage me instead of all of

Tariq Malik (00:03:57):
I don't have to outrun the space alien on that planet. Rod, I only have to outrun you. So that's right.

Rod Pyle (00:04:03):
Right. So this reminds me of my Arctic adventure. When we're up there, there's eight of us including Pascal, and we're about the same size and age and we're getting the polar bear lecture what to do. Somebody's got a shotgun, but you try not to use it and you try to get away and so forth. When they were talking about the running away part, everybody, there's seven people looking at me as if to say, well, we know who he'll get first. They took great comfort in that, which I did not. Alright, let's get some headlines banged out here.

Tariq Malik (00:04:37):
Yes, yes, yes. Let's do that.

Rod Pyle (00:04:39):
So the big one for me is the Ingenuity Mars Helicopter, which has been an amazing program. They wanted at least one flight for 30 seconds. They would've been happy with that. Yeah, the baseline they hoped for was five flights, which they passed eons ago, and now we're about 15 times that at 72 flights. But a last it's had its last flight. Tell us why.

Tariq Malik (00:05:08):
That's right. That's right. The Mars ingenuity helicopter will fly no more. Actually, just the day before you and I are recording this late in the afternoon, NASA announced that due to some rotor damage, this tiny little helicopter drone has these two rotor blades on it to keep it alt. It can't fly anymore. And sadly they learned about it this week, but a lot of this happened last week as we're recording this, when NASA lost contact with the helicopter during its 72nd flight, it disappeared. And what they think happened is something happened to the helicopter maybe on its way down or whatnot, but it has this kind of landmark based navigation system. It looks for things like rocks and stuff and say, okay, that's where I am. And apparently it was just flying over a really boring part of Mars and there was nothing bland. They called it featurelessness of it.

And because of that, it got confused and it went into an auto land sequence and either it experienced a power dropout on the way down and then crashed or after touching the ground, maybe it was a little bit bumpy or on a tilt, its rotors hit the ground or something. It had some kind of an impact and it damaged about half at least of one of the two foot along rotors. And that's really bad because the atmosphere on Mars is super, super thin. We've got for folks on the video, we've got a picture of the damaged rotor. Now they know this, they can see the damage in a shadow of the rover of the rotor on the ground. So they know that it's damaged. And because the atmosphere of Mars is so, so thin and the blades spin so fast, it messes up the balance and the helicopter can't fly anymore. So the upside is it's not dead. NASA can talk to it, but only

Rod Pyle (00:07:19):
As long as the rover is in

Tariq Malik (00:07:20):
Range, only as long as perseverance. Its Parent rover is in range. So they're going to study the systems on board, kind of use it again for the engineering science until perseverance has to pack up and leave the area and they eventually lose contact with ingenuity. But as you mentioned, rod, its first flight was in what April of after the landing in 2021. April, 2021 I think was the first flight they had until May to get those five flights in. They got 72 in three years. And in fact they kind of modified, this is just a technology demonstrator, they didn't know if it would ever work, and now they've proven that they can fly helicopters on other planets. They've greenlit the dragonfly mission to Titan based on the success that they saw here. That's a nuclear powered helicopter and two of these similar types of tiny drones for the central return mission. And although of course that budget's being, but they're

Rod Pyle (00:08:24):
Going to be bigger because those are actually retrieval drones.

Tariq Malik (00:08:28):
Yes, yes. But it's still like they were on the mission, but now they're at the budget and we don't know if they're going to make, but they all lead back to this one helicopter, which almost never got put on the rover in beginning. This

Rod Pyle (00:08:43):
Is the pathfinder of planetary helicopters.

Tariq Malik (00:08:46):
Right, exactly. And just like everything JPL builds, and I know that you're an alum, right from the folks that work there, they mighty with this one and they hit it out of the park. So RIP ingenuity, we will miss you, but I think we learned a lot from this. We got aerial pictures of a rover on Mars from this little drone and we got pictures of the first flying thing on another planet as well from the rover watching its little drone fly around. So just an awesome mission overall.

Rod Pyle (00:09:22):
Just a couple other points that came out of the press conference yesterday. I wasn't in the question queue, so I was glad they got asked of my stead. So one of them was of course, can it still fly with that damage? And as you point out, it can't. And the speed of the rotors is I believe something over 2,600 RPM, which is fast. So when you get something that's got an offset balance like that slinging around, it's going to be more like a slingshot than a helicopter. So that's not going to work. And as was pointed out, however, there are no science instruments on this thing. It was just an engineering study really. There's a camera and the altimeter and stuff, it needs to come back down. And a microprocessor, a retail microprocessor out of a cell phone, but there's not science instruments, so they're not going to be losing anything particularly noteworthy once they drive away because it's crippled. I mean, if it could still fly, obviously that's something you want to do, but because it's now ground bound, once they drive away in a matter of weeks or months, it's no harm, no foul. Yeah, I

Tariq Malik (00:10:24):
Hope they name it's it's final landing site, something fun like how

Rod Pyle (00:10:30):
Memorial Bluff or something

Tariq Malik (00:10:31):
Like that. Hey, that's got a nice ring to it. I got a couple of stats just really quick just so that we can close it out, but we talked about 72 flights over the last three years. That's a total flying time of 129 minutes for this little solar powered drone. It covered about 11 miles of ground as it flew around according to its flight log. And as you mentioned about the, and it weighed about four pounds if anyone is wondering a very, very small kind of a thing. And if it had tried to fly because it was so balanced and it has to spin its rotors so fast, it would most likely just rip itself apart. The rotors would fly apart coming off because they would be so off balance is what NASA said during the call last night.

Rod Pyle (00:11:17):
Okay, so let's get through these two stories so we can get to the meat of the episode here. Speaking of hard landings. That's right. The Japanese slim lander came down on the moon, successful soft landing but not necessarily a successful outcome.

Tariq Malik (00:11:33):
This is a really interesting one because Japan made history with the slim landing and to become the fifth country to do so and they kind of jettisoned out these tiny probes on the way down and one of the probes took a picture of the, and it landed on its nose basically. So it's almost upside down from this picture. And yet they're hailing it as a success. They're hopeful that eventually the solar panels which are pointed kind of away from the sun will get some sunlight and they can do some science on board. But one of the key takeaways from a press conference that JSA had this week was that they have proved, and I quote that you can land wherever you want on the moon with this technology that this one also another technology demonstrator for the moon was there. I just think it's adorable that these two little micro probes that it kind of just spit out on the way down took photos of it and they got photos from the lander itself of the terrain after it landed too. So it wasn't like it bounced and then turned off. They actually got data and science from the surface of the moon too. And they're committed JSA is to building newer and future probes to follow up on this technology. They can use it now to kind of land wherever they feel like they've proven that concept out, they feel.

Rod Pyle (00:13:10):
Alright. And finally, I know you did this just for me, I'll quote you. Hubble has found something hot and steamy in space.

Tariq Malik (00:13:19):
I don't know what you're talking about. Rock, I reserve

Rod Pyle (00:13:21):
Comment. Go for it.

Tariq Malik (00:13:23):
Yeah, so the Hubble Space telescope decades on, I know James Webb is the shiny new toy, but it's found a new exoplanet called GJ 98 70 2D. And the scientist described it as a hot and steamy world. It's a relatively small planet, about 97 light years from earth. And they're excited because it has a water vapor, what they can see of at least in the returning signals in its atmosphere. And of course wherever we have water on earth, we have some kind of life which has scientists are really, really excited, but it's not like the most perhaps comfortable place we'd want to visit. It gets up to 752 degrees there, which is kind of like Venus, the temperature of Venus, and it's hot enough to melt lead. So while it might be kind of like a steamy water vapory world, we would probably not call it a nice place to call home. But still very interesting because the smallest exoplanet that they found so far with what looks like water vapor, which is we're getting kind of closer and closer to that second earth, that earth counterpart that we can find in terms of size with this ingredient for life. So

Rod Pyle (00:14:49):
Sounds like our love lives many years ago. Well, all right, well thank you for that and we will be right back after this message with John Mankins to talk about clean power from space. Stay with us.

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Rod Pyle (00:15:17):
And we are back with John Mankins of Mankin Space Technology to talk about clean energy from space. It goes by many names, space-based solar power space, solar power. I've seen a few others, but basically the idea is it's a good thing and once it's deployed has no carbon footprint, which you can say about very few other types of power. So hello John, thanks for joining us. Really appreciate you coming by.

John Mankins (00:15:44):
Good morning from California, great to be with you.

Rod Pyle (00:15:46):
Not just California, but from the prettiest part of California,

John Mankins (00:15:50):
The California Central coast, which is gorgeous, right this time of year.

Rod Pyle (00:15:55):
Well, I wish I could say that about Los Angeles, but it's never the case. So John, if you could just give us a quick backgrounder about where you came from when you got into this, because you were there at nasa, as I understand at the very beginning of this conversation about power coming from space. Is that right?

John Mankins (00:16:13):
Luckily, no.

Rod Pyle (00:16:15):

John Mankins (00:16:18):
The first era of space, solar power back in the 1940s was just a couple of stories in science fiction magazines, no real concepts for how to do it. The second era was in the late 1960s when Peter Glaser of Arthur D. Little invented the solar power satellite and patented it. He got patented in 1973. He and a real wonderful man, a brilliant man, bill Brown at Raytheon who invented wireless power transmission were the initial champions of space solar power in the early 1970s when I was still in middle school, still in the eighth grade. So luckily I wasn't part of the very beginning in the late 1970s. There were studies on the concept and that's about the time when I went to work for JPL. I worked at JPL in flight projects and deep space network mission operations, advanced studies for about 10 years. And then I moved to NASA headquarters where I led the technology planning for the space exploration initiative and then did a variety of things relating to space technology programs.

In the mid nineties, I became the manager of advanced concept studies at NASA headquarters. I later was the chief technologist for human exploration. I ran the technology portfolio and a lot of the concept studies for the vision for space exploration before Dr. Griffin came in and reshaped it to be constellation. I created a number of new concepts for space solar power as a part of studies that NASA did at that time of the concept, I wrote the first detailed definitions of the technology readiness levels or TLS that many people are familiar with these days. They're an ISO standard and are globally used to monitor and measure and anticipate the development of new technologies. And about 2005 I left nasa and since then I've been an entrepreneur and a consultant and doing a lot of pro bono work with the National Space Society, with the International Academy of Astronautics, the International Astronomical Federation. I've probably published something like 200 plus papers and a couple of books. And I've tried to keep busy with innovation and one of the most interesting and controversial subjects that I got involved with some 30 years ago at NASA headquarters was space solar power. And so it's a great topic for today.

Rod Pyle (00:19:35):
Alright, so if you would just kind of give us a runup for people who may not have been exposed to this, what is space solar power and its key advantages?

John Mankins (00:19:47):
So in space near earth, the sun shines 24 7 and has about 30% more energy in a square foot or a square meter of sunlight than the brightest clearest summer day in Arizona here in the us. So about 1400 watts per square meter in terms of energy versus about a thousand watts per square meter at midday on a clear day in the desert near the equator here on earth space solar power is the idea of sending large systems, building them up in space, build them in space and use them to harvest the solar energy, which is more intense and constant there and send it by wireless means to markets here on earth. Very simple concept, and as I mentioned, it's been around since the late 1960s as an operational idea and for 80 plus years as a vision in science fiction.

Tariq Malik (00:21:06):
Can I ask, it is a simple concept. It seems you're thinking about renewable energy, you think about solar panels, you put them where the sun is always shining and then you beam that to earth. It seems so beneficial the way that you describe it, and yet here it is 2024 and we still don't have this stuff. I mean, I assume that there's either some sort of insurmountable technical hurdle or something for a reason that we haven't done it. Or is there even one overarching thing that we don't have it if it's been studied since the sixties?

John Mankins (00:21:41):
So fundamentally, the physics of a solar power satellite is extraordinarily well established. It's the same physics, the same component engineering that is used in every communication satellite that ever flew at star links to TDRs up in tracking and data relay satellites up in geostationary earth orbit. Same physics that makes GPSA success, which we use every day for everything to get to anywhere in our cars. The issue with space, solar power, with the concept of the solar power satellite, it's not the physics, it's not the basic technology. It's not like, for example, with fusion where after 70 years of research, they're still just inching up on breakeven after tens of billions of dollars. So the physics is not yet proven for magnetic confinement fusion. As an example, just the last year or so, laser detonation fusion was proven here in California at the uc system, but the problem is cost. Solar energy, thank God is fairly diffuse. Otherwise we would all fry. But that means that systems that are going to collect solar energy and deliver it in meaningful scale to the markets on the earth have to be huge. And the challenge when these things were looked at first in the 1970s was that even though they were technically feasible, no one's ever argued since 30 years ago that it wasn't technically feasible. The issue is always been economics, and as I'm sure we'll get into in a few moments, it's these barriers, the economic barriers that have started to fall in the last decade.

Tariq Malik (00:23:34):
And I guess I know you kind of touched on it, but the hardware that we're talking about is you've got a satellite, we've got that technology set, but is it the receiving end then the costs for that and setting that up and then I guess you have to get all of the permissions to build anything like that and work with people who maybe don't want power being beamed down from space in their backyard. Is that the cost that we're looking at right now? Or are there advances that we have to make to get that efficiency to where it's economically feasible?

John Mankins (00:24:12):
So you absolutely have to improve the efficiency of the key technologies. So vol take cells, wireless power, transmission, the cost of launch, all of those things, improvements are needed. However, the engineering of wireless power transmission was first demonstrated on the Walter Cronkite NewsHour in 1963. So it's got a long heritage. The problem is how to do it not on a kilowatt scale like a microwave oven kind of scale, but to do it on a thousand megawatt scale, which is sort of at the scale at which you're powering cities and those are remarkably large systems. And in those cases it's not. And I give you one example of how the technology has changed. So in the 1970s when this was looked at, photovoltaic cells were still relatively new. Nobody was using them on earth and for space the estimated efficiency was 10%. So 10% of the sunlight falling on a photovoltaic cell in a communication satellite, 10% of that sunlight was turned into electricity. Today, the efficiency for operational cells, PV cells for example, for satellites is up to 30%.

Tariq Malik (00:25:40):
Oh wow.

John Mankins (00:25:41):
Threefold improvement. And that directly reduces the amount of area of PV cells that are necessary for a given amount of power. And in the laboratory efficiencies, up to about 50% have been achieved. So there's huge improvement since the seventies room for more improvement. Similarly, do you mind if I just give you a couple more? Yes, yes,

Tariq Malik (00:26:06):
Please. Okay.

John Mankins (00:26:08):
So similarly in the cost of launch. So it has always been said, oh, space is hard. It's always going to be expensive to go to space. It costs $30,000 a kilogram or 20,000, 10 or $20,000 a pound for the space shuttle to launch anything to space. And that's just the way it's got to be. That's what people believed right up until 2015

When the first Falcon nine reusable launched that's, and before that it was an article of faith among good, solid, conservative, reliable systems engineers that in radically improving the cost of launch was a bridge too far. It was just not something we were going to be able to do. And now all of a sudden nine years ago, this thing is going up and coming down and going up and coming down. And it's not just that it's reusable, but the booster itself is cheap. And so today there's SpaceX is working aggressively on the Starship with its big booster and is anticipating costs will go from around $2,000 a kilogram where they are with the Falcon nine reusable down to around $200 a kilogram and that's down from $20,000 with the shuttle or 35 $40,000 a kilogram depending on how you rack and stack the costs. With the SLS launcher, reusability is key and suddenly everybody knows it can be done.

There's reusable launcher programs in China, in Europe, here in the US there's also Blue Origin. There are innovative ideas to go beyond rockets like space elevators and spin launch. And so all of a sudden in just the last dozen years, less than 10 years, the cost of launch as a barrier to big visions in space like space solar power has plummeted by one order of magnitude so far and the cost is projected to plummet by at least another order of magnitude or maybe only a factor of five during the next half dozen years. Wow. Lastly, the other big component in these very large systems is the cost of the hardware. So you got to be able to collect, convert, and transmit the energy efficiently. Talked about that. You got to be able to get these big systems into space at an affordable price. Talked about that.

The last one is how much does the platform itself cost because it's going to be huge. And in the last five years it has been proven by starlink, by one web, by Kier system, by all these programs that are commercial programs that are pursuing mass produced space hardware that you can make space systems super cheap for on the order of a thousand dollars a kilogram or less. Whereas traditionally, a large satellite and geostationary in Earth orbit was projected to cost on the order of a hundred thousand dollars a kilogram. So there again, this is one where it's already proven that if you can make your system like starlink or OneWeb or Kier, you can make your system out of lots of small pieces and you can mass produce those pieces even though they're complicated space systems, just like jet engines, just like the, in an Airbus three 50 or at Boeing 7, 7, 7 and do it at a very affordable price. So with those three barriers being broken shattered really over the last 10 years, it radically changes the doability and the economics that you can expect for space solar power.

Rod Pyle (00:30:26):
Alright, well we are going to come back. You've given me a perfect pivot point here. Thank you John. We'll be back after a quick break to talk about NASA and space solar power. Standby. So John, and you're going to have to excuse me because there's three or four fish hooks in this question, but you'll see the main one right away because we've been talking about it a lot between US space, solar power sort of really gained initial traction as idea as an idea in the United States. And then over the decades as things will do with the United States, it sort of seemed to lose some of its propulsive force. Japan got interested, Europe got interested. Now China's interested and as we've seen once China decides to do something that's a little easier for them to keep it going, they just have one administration, they don't change every four to eight years and they may never change again. So here we are in the US still thinking about, okay, are we going to do this? How are we going to do this? And NASA says, we'll do a study. So it takes a few more years and expected finally this study comes out and it's a specific office of nasa, so it's a NASA commission study I guess, and it wasn't quite what we expected, so I wonder if you could talk about that a bit.

John Mankins (00:31:44):
So the study which you can find online if anybody wants to take a look at it, it represents a really strong methodology, IE the analytical methodology. Looking at the economics is fine and looking at various scenarios and different sets of assumptions and then exploring how do those assumptions impact the final numbers. The findings and recommendations are not bad, they're pretty good and they recommend NASA should work with international partners and says that NASA technology is relevant to doing space, solar power, things like robotics and so on. And that's all perfectly true. Good component technologies. NASA has excellent researchers and funds, great research through programs like small business innovation research. The weird thing is that when they got down during the last, and this study was in preparation for two full years, more than two years, about a year ago, it went into a cycle of reediting and rewriting.

And the main body of the analytical part of the study shows as its baseline assumptions, a collection of numbers that are profoundly out of step with all the studies that have been done in the uk, in Europe, in Japan, everywhere. And which do not represent even the technology developments that are being pursued in the US or by NASA or by the Department of Defense. So they reached back and said, let's one, if you don't mind, I'll give you a couple of the assumptions, just the flavor of them. One, they said stay solar power can't possibly be developed until after 2050. So first thing is push the whole idea off by a quarter century because that's just what we're going to do. We're going to push it off by a quarter of a century. Now that's worse than Mars and it's even worse than Mars. Now in 2050 we are going to assume that there's going to be a Falcon nine replacer, there's going to be Starship, but the cost of launch for Starship is going to be a thousand dollars a kilogram rather than the 100 to $200 a kilogram that SpaceX has talked about.

And so right there, the cost of launch of the system by assumption, not based on any evidence, just by assumption is five to 10 times higher than what SpaceX is saying or what any none of these companies that are putting huge amounts of money into lower cost launch would do it if they didn't believe they could build a better mousetrap if they thought they weren't going to be any better than Falcon nine reusable. In addition, for reasons that I cannot understand, they have assumed that the only way to move large payloads space, solar power systems from a lower earth orbit to a higher orbit like geostationary Earth orbit 37,000 kilometers up as opposed to 500 kilometers up. The only way to move these pieces from low earth orbit to geostationary earth orbit is with chemical propulsion. And they're use a version of the Starship, which has to be refueled with like six or eight tanker trips for each flight from lower earth orbit to geostationary earth orbit. So you've got the first one to launch the payload six or eight more to refuel it, and then when this vehicle gets to geostationary earth orbit, you throw it away.

It's not reusable anymore somehow, even though of course that's not the SpaceX plan, SpaceX. Anyway, set that aside. So one, you don't do anything until 2052, whatever you do in 2050, it's not going to be economically any better than today. And it's the worst version of today because what you could assume is you use higher efficiency propulsion systems such as solar electric propulsion, which is now being used by basically all communication satellites. The starlink satellite system with it's 5,000 satellites, I think now it's, they're on the order of 5,000. All of those have electric thrusters on them. So mass production of low cost high efficiency electric propulsion has been demonstrated by the biggest satellite constellation in history.

Another assumption which is stupendous is, and I mean that facetiously is that given all of that, they have assumed that, well, they've assumed that the solar power satellite will require something which only the satellite itself only costs something like 10, 12 billion in their estimate. And that's not a bad number. They based their system concepts on a concept that I came up with SPS alpha and one that the Japanese have studied, which is a sandwich array, which we can talk about more if you want the definition. At any event, the cost of the satellite's not bad, it's like 10, 12 billion. However, then there are two really hammering assumptions. One that it's going to cost like 157 billion for the maintenance of the solar power satellite. Even though itself it only costs like 10 or 12, and I'm not trying to get the exact numbers, but in addition to that, the solar power satellite with its 157 billion worth of maintenance only lives for 10 years.

After 10 years, you have to throw the whole thing away and build a completely new one if you want to continue to have power. So at the end of the day, these studies that didn't find space solar power to be economically viable in the 1970s, their system concepts of technologies, they assumed the numbers they put together, they at the bottom line in 1970, NASA said it's going to be about 500 billion to a trillion dollars to deliver 300 gigawatts, 300,000 megawatts. Now that works out to be about a dollar 50 to $2 per watt. And that was expensive, far more expensive than gas or coal or oil. And so it wasn't viewed to be economically viable. The current study is it's 300 to 400 billion for 2000 megawatts or 150 to $200 per watt in 2050. So over the course of 70 years, the price of space, solar power in this report would go up from a dollar 50 a watt to $150 a watt as sort of a bottom line that gives you, I think could give you a feeling for how weird these assumptions are.

They took the worst of the possible assumptions and combined them to get their baseline number. Now the analysis goes through and it gives all the various trades and it says, oh, you could reduce this by this much and you could reduce this by this much. And buried in the middle of the report is a comment that if you actually took the reasonable assumptions that everybody else is making about Starship and Space hardware and Lifetime and so on, you get down to something like three to 5 cents a kilowatt hour. But the NASA number, even with all the things they did is still, they couldn't get it to be worse than 60 cents a kilowatt hour, but they tried

Tariq Malik (00:40:31):
A forever. Well John, I wanted to, you mentioned a lot of the mechanics involved and I'm very interested in how we could do it right. And I know that you have a great concept that I was hoping you can kind of walk us through because I've seen in the report that you mentioned that we were discussing from nasa, they've got the primary methods that they're talking about this heliostat with a swarm of satellites that are getting the power and then beaming it down, I believe through microwaves and then this planer array. And if James Bonds die another day is correct, you can always put a mirror up in space too and then reflect all of that down to a solar farm on earth.

We could talk about the sci-fi worries and fear mongering about solar power from space, but can you walk us through the mechanics then of how you see a great system? Because as you mentioned, we have these more affordable launch, some like blue origin are going to have huge payload fairings to fit giant platforms like this in. So what would you say was the optimized size for the platform? How is it going to get the energy to earth? How do you collect it and then distribute it that way? What's the perfect system right now that we could do?

John Mankins (00:41:55):
So the concept that I came up with, what is called SPS Alpha Solar Power satellite by means of arbitrarily large phased array. And what that means is it's a hyper modular and highly scalable approach where you could build out of the piece parts a solar powered satellite with 10 megawatts or a hundred megawatts or a thousand megawatts, all with the same piece part. So that's hyper modular means you've got the same kind of pieces and you just add more and more pieces to scale up more and more.

Tariq Malik (00:42:38):
You would build it together like a space station, you'd get a first module going up and then you'd add another one to double it, that kind of thing.

John Mankins (00:42:46):
More like Legos. More like Legos. So the space station has a number of unique systems which are quite large and required a lot of touch labor to put 'em together in space. The same's not true. Think more about as a metaphor, a colony of ants or a coral reef in which you have literally a million organisms all working together. Each one's relatively small, each one does its function. Now the reason why this is sensible is that this has been looked at in several different types of system concept space, solar power concept, and it's to try to reduce the in space power management and thermal management that you need for the satellite that all conventional satellites have these big solar arrays, all the power through come through a couple of rotating gimbals into a wiring harness that's in the box. And then it goes from the power management system to the payload, the radio transmitter for a DirecTV satellite or whatever it is.

That's exactly the way the original solar power satellite concepts looked in the 1970s, a huge version of a conventional satellite. Well in the 1990s, partially through the studies that I was doing, partially through at NASA and with the team there and partially through the work that was being done in Japan, especially the idea of a sandwich module emerged. And with the sandwich module, you basically, well, I've got incoming photo vol takes, I got incoming sunlight, there's going to hit on a photo, vol take cell, and then I've got to take that and process it with electronics and send it out of the satellite with an RF transmitter and an antenna. Well all of that to do that, that's like two kilograms, five kilograms, it's like 10 pounds worth of hardware.

But in the reference system concept of the 1970s, you had this huge solar array that was separate from the transmitter. You had thousands of megawatts of power in this huge power grid in space. You don't need any of that. You can simply have, if you think about it like the table in your kitchen or a card table, the top is the photo take array. The bottom is the RF transmitter rate, and in between is the electronics and some structure, it's like a pizza box, the lid of the box, the bottom of the box, and a pizza in the middle. But it doesn't need to be any bigger than a pizza box in principle as a module now. But there's a dilemma, and that is in these concepts, the RF transmitter always has to point at the earth, otherwise it can't send power down. But as these satellites go around the planet, sometimes the sun is above them, sometimes the sun is in front of them, sometimes the sun is off to the side. The only time it can really generate power efficiently is when the sun is at local noontime, IE, the satellite is between the sun and the earth. And what SPS Alpha did as a concept is it added one more element and that is a very modular array of heliostats. Of reflectors on a supporting structure. So that as this planer array PV structure and power electronics and RF transmitters and it goes around the earth, it is supported by a set of mirrors up above it so that it is constantly illuminated by the sunlight.

Tariq Malik (00:46:50):

John Mankins (00:46:51):
And that's how it works.

Tariq Malik (00:46:53):
So just really quick, I've got my pizza box array in space with mirrors sticking off from it. That can then make sure that the sunlight is hitting the top of the pizza box so that the bottom, which is always facing the earth, is beaming that power through radio. Radio waves. Is that kind of like the simple? The simple,

John Mankins (00:47:15):
Yes. But then of course, just to go back to the colony of ants or the coral reef, but it's a million pizza boxes.

Tariq Malik (00:47:25):

John Mankins (00:47:26):
I have a lot of sunlight to power cities and the physics of wireless power transmission is such that the optimum frequencies that go through the weather and through clouds and so on are in what's called the microwave regime, like a two to eight gigahertz. It's called, it's wavelengths that are about as long as your hand or in the visible. And of course the visible is like lasers and whatnot, but visible light, as you know from any cloudy day, doesn't pass very well through weather. And so if you want power 24 7 from a solar power satellite, you go with a version of microwaves. Microwaves. And that means that the system has to be large. So that's the million pizza boxes.

Rod Pyle (00:48:25):
Alright, well I have a burning question to ask, but we first have to take one more quick break and we will be right back. So John, we have this idea that's been growing for decades. We're at a point now where it seems more economically viable than ever where there don't seem to be any major technological breakthroughs that need to occur. There's incremental advances and so forth that would be beneficial for it. But as you've explained, the physics of it makes sense and we understand all the core engineering. We also have something that the US seems to really need often to get off the mark, which is international competition. And we have some very wealthy individuals who might be persuaded investing in something like this if they got good news about it. And in the midst of all this, and this is just my judgment, I'm not putting this on you, but in the midst of all this, my observation is NASA through this sub office comes out with this report that's a little lukewarm at its conclusions and could have a chilling effect, not just here but internationally. A, why would something like that happen unless it's really sound core thinking, which it doesn't sound like it necessarily is, and B, what do we have to do to move past this?

John Mankins (00:49:44):
Yeah, so it is absolutely true that there is more interest and more activity internationally than there ever has been before. And there had been a couple of opportunities to really move the ball forward, but the question was really not so much how much money was there or where did it come from, but what was done with it. So fabulous research was done with a huge grant, like a hundred million dollars from, as I understand it, Donald Bren, who is the founder of the Irvine Corporation, and he gave a grant to Caltech to work on space solar power. And they approached it from a research standpoint and several professors have done a fabulous job of research and matriculating students. And ultimately after five or seven years and a hundred million dollars, they flew an experiment that just finished up. It was really the first of its kind, the first technology experiment in space testing space, solar power technologies.

The dilemma of course is that they were doing research, weren't trying. This is like the difference between doing research on combustion and then doing a test of your theories in a scale rocket versus building the Falcon nine. It is not that they're not both rocket science, but the purposes are different. In the case, another almost $200 million that I know of that was invested by the US government went into the Department of Defense to the Air Force Research Lab and they continue to work on a project for space, solar power for military applications. And that radically, again, radically changes the economics of the prospective space, solar power system and its scale. I mean for a forward operating basis that need a hundred kilowatts, you don't build a system that would be consistent with delivering a thousand megawatts. So a fair amount of money has been spent in the us but internationally, the policies that have emerged in the past decade or two addressing global climate change and moving towards carbon net zero have strongly influenced how everybody internationally at least, and in some cases here domestically, are thinking about energy transportation in a wide variety of parts of the economy in Europe, in the uk, in Japan, in China, in Australia, in New Zealand, in these various places there is research and South Korea research and development going on.

In some cases there are nascent programs to do space demos, all targeting space, solar power for terrestrial and in-space applications. And not trying to do super long-term research, but really build something. And it is an opportunity or rather it's a prospect where there maybe the thing that the US needs is to see somebody else fly something another country. And if they speak mandarin, maybe that's the best way to get people in the US motivated. But I would just say just one last comment and that is that when you're talking about objects for these space systems that are on the order of kilograms and scales, like from a pizza box up to a kitchen table, that kind of scale, anybody can do them, anybody can build them. So if there is a multimillionaire or somebody who works for one who would like to develop a space solar power system and do it in a hurry, I'd be happy to talk to 'em.

Tariq Malik (00:54:40):
That's interesting because there is one billionaire I know who not only has a mass market satellite capability, but also an electric vehicle and a solar power company all at one time. You think that'd be right for him? That's Elon Musk. For the folks that are wondering, I probably have time for one last question, John, but I did want to ask about safety because we're talking about beaming energy or delivering energy from space to the earth. And you were talking about microwaves. I just found out that it's not the worst thing in the worst to be passing in front of my microwave when I'm cooking dinner, which I thought that I had to fear it like the plague, but there could be members of the public that would worry about having a microwave receiving station or recana. Is that right? Is that the right word for it on the ground? And I was just curious if you could touch on how safe that is compared to walking around with background radiation or whatever. And then also a layar fears, I mentioned die the other day with James Bond where you've got a supervi pirating, a space power concept and turning it into a weapon on earth. And in Ben BOA's power set, by the way, that's a very excellent sci-fi book that happens as well. How can we prevent that from happening too?

John Mankins (00:56:11):
So first things first. So as I mentioned, there are two different ways that you can contemplate wireless power transmission with good efficiency involving our planet. One is with microwaves about 12 centimeters, 10 to 12 centimeters in length in the wavelength approximately. And the other is with lasers, which are like nanometers. Well lasers are at approximately the same wavelength as sunlight. And as I mentioned, it won't pass through clouds conveniently much less rain or other kinds of precipitation or even a hazy day, it'll get attenuated significantly. Most of the economical concepts for terrestrial markets look at the use of microwaves or near microwave. Fortunately in that case, physics is on the side of safety because the intensity of sunlight in space, as I mentioned, is about 1400 watts per square meter. And if I take that and even if I concentrate it a little bit, which is what you do with SPS alpha, because you have these mirrors and you concentrate it just a little bit to improve the end-to-end efficiency of the energy conversion food chain, you still end up when the power reaches earth with something like one or 200, maybe up to 300 watts per square meter at the peak of the beam and at the edges of the beam.

And the beam is going to be several miles across because it's is a large object in space. It's a large object on the earth. The power at the edges is going to be down around like two, three watts. So if you think of going out into a hot summer day and getting a thousand watts per square meter, if you go out to do sunbathing, you're getting at about a thousand watts. And it includes ultraviolet, which is mutagenic IE. It breaks chemical bonds and causes skin cancer. Well, microwaves have been tested with insects and mammals and plants over the last 40 years, 40 plus years. And at these kinds of intensities has been shown to be perfectly safe. It will cause a little heating, which is why microwave ovens can heat up your cup of tea, but they don't break chemical bonds. They can't break chemical bonds. So they're not mutagenic, they can't, they can cause eye damage and you cannot concentrate it anymore based on what's called the physics of diffraction, limited optics. So it basically just means that it's going to stay diffuse and you won't have to worry about it if you inadvertently got into the beam. Now lasers are different. You will have to worry if somebody decides to build systems like a thousand megawatt laser over your country, then you have to worry about whether they're really doing it for reasons of the marketplace.

And I'll just also mention one other aspect of this in terms of the system. So the right way to think about a receiver of a solar power satellite transmission is, think of it like a lake. So it's a large area thing. It's got to be physically contiguous. It's an ellipse of some sort, depending on where it is on the earth. On the equator it would be a circle up near Chicago, it would be in ellipse. The area is going to be somewhere between 10 and 30 square kilometers for this antenna to receive like two megawatts, or sorry, 2000 megawatts, two gigawatts. I'll give you an example for comparison. The Lake mead, which is the lake that feeds Hoover Dam, is about 415 square kilometers in terms of its water surface area. The dam produces on order 500 megawatts. So 415 square kilometers to produce a half a gigawatt, 500 megawatts. In the case of SPS alpha, the mark three version, the receiver would be about 29 square kilometers and deliver 2000 megawatts. So four times more power for less than 8% of the area. But nobody's getting solar power, satellite power to their home. But outside of your town, you could have a lake over an electric lake, over farmland or desert or offshore on a lake or out of the ocean and you'd get power whenever you wanted it dispatched from space at 15 times more power per square meter than hydropower. I'm sold. I'm sold, rod,

Rod Pyle (01:01:41):
I'm sold. Yeah. So just to wrap it up, lemme just hit some points and correct me if I'm wrong on any of these, but we're talking about something that requires no major breakthroughs in technology or physics. It just needs willpower to be built. Deployed is zero carbon, carbon neutral once it's in space, can last for a third of my lifetime if I make it 90 and is global in nature. Am I missing any of the obvious things about why this is a good idea?

John Mankins (01:02:15):
So there's one thing that you missed or thing that you misstated. I don't know if you know the story about my grandfather's ax. No. So when he died, I inherited my grandfather's ax. Now since then, that was decades ago. I've had to replace the handle twice and I had to replace the head of the ax once, but I still have my grandfather's ax. So the point being that if you've got renewable systems, you can constantly recycle and replenish the pieces and you still have the functionality. So for a solar power satellite like SPS Alpha, the baseline modules would be designed to operate for about 30 years, but you're going to be constantly replenishing, renewing, recycling, rebuilding them. And all of that's built into the economic analysis that I've done over the years. So essentially the solar power satellite becomes like a new permanent source of energy. Like Hoover Dam, you have to repair, maintain, and replenish it. But unless you decide to decommission Hoover Dam, it's going to be with us for the rest of this century. Same thing with these solar power satellites. You put it up, it's going to deliver thousands of megawatts of green energy, carbon, zero energy within its field of view on earth for the remainder of everybody's lifetime. It's just not going to die a natural death if you have to dismantle it on purpose.

Rod Pyle (01:03:58):
Well, I want to thank you for both of us for coming in today. We really appreciate it. I know you've been doing a lot of podcasts the last couple of weeks, so we appreciate you getting us on your schedule. And John, where can we best track your ongoing activities in this important subject area?

John Mankins (01:04:16):
So I need to update my website. I will be doing that and I'll get you the information. To be honest, I thought this was an argument or a discussion that had already been worked through and with everybody now working on space, solar power outside the us I thought it was only a matter of time before the US moved forward in this field that it invented. But now I've, now I've got to dig back in again so soon, but not yet.

Rod Pyle (01:04:50):
Okay, Tarek, where can we keep track of your unbelievably cool life?

Tariq Malik (01:04:54):
Well, oh man. Man, don't oversell it. No, you can find as always. And this weekend I'll be looking forward to Northrop Robins first sickness launch on a SpaceX rocket, which seems like a Frankenstein of commercial space flights to the space station for nasa, which launches on Monday. So that'll be pretty exciting to see. And you can read all about it on and on Twitter, I'll be tweeting that live as it happens at lunchtime.

Rod Pyle (01:05:26):
Seems like a bit of oil and water there. And of course you can always find Please don't forget to drop us a line at twist twit tv. That's TWIs at twit tv. We always welcome your comments, suggestions, and ideas, I swear. And we answer all our emails. And don't forget to check out, the website's, the name and the National Space We're both good people and both are good places to satisfy your space. Flight cravings for information new episodes, this podcast publish every Friday on your favorite pod catcher. And please make sure to subscribe, tell your friends, and give us reviews. We'll take thumbs up or tongues out or whatever they offer on that particular venue. And don't forget, you can get all the great programming on the TWIT Network ad free on Club twit, as well as some extras that are only available there for just $7 per month. Less, less than a super mega soy vegan SG free frappuccino. And you've heard Leo talk about the tough times facing podcasters. It's real. It's true. So this is your chance to stand up and be counted. And don't forget if you have a chance to get in there and do that TWIT survey for us, you can also follow the Twit Tech podcast network at twit on Twitter and on Facebook and twit TV on Instagram. Thanks everybody, and we will see you next time.


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