Governing the Satellites that Orbit Earth, with Akhil Rao

Notable Quotes

• The number of objects in Earth’s lowest layer of orbit will keep increasing: “Since about 2015, there’s been a lot more discussion of large systems in low Earth orbit, or large collections of satellites … These megaconstellations that have been proposed are on the order of hundreds, thousands, or sometimes even tens of thousands of satellites per system. There are currently on the order of 10 systems that are proposed at varying levels of realization.” (9:49)
• Debris in orbit poses challenges for placements and paths of satellites: “An active satellite can be controlled, or at least there’s someone to talk to who is in charge of it—but debris doesn’t really have an operator. It’s not something that you can maneuver around yourself … That complicates things further.” (13:40)
• No market for property in Earth’s orbit: “The Outer Space Treaty explicitly prohibits the allocation of property rights over space … No nation can claim sovereignty over outer space or anything therein. And if you can’t claim sovereignty, then how are you going to allocate resources from there? It’s widely understood to prevent explicit property rights, and so, without the explicit property rights, you don’t really have the market.” (19:18)

Top of the Stack

• The Earth Transformed: An Untold History by Peter Frankopan
• Building a Ruin: The Cold War Politics of Soviet Economic Reform by Yakov Feygin

The Full Transcript

Daniel Raimi: Hello, and welcome to Resources Radio, a weekly podcast from Resources for the Future. I'm your host, Daniel Raimi. Today, we talk with Akhil Rao, an assistant professor of economics at Middlebury College. Akhil is an expert on space. In particular, he studies the economics and governance of objects that orbit the Earth.

Today, I'll ask Akhil to give us a little bit of Earth orbit 101. He'll help us understand how many satellites are up there, how many more will be launched in the coming years, and whether Earth's orbit is getting crowded. We'll also talk about whether Earth's orbit is a “renewable” resource, what that means for countries and international bodies that seek to govern the resource, and a whole lot more. Stay with us.

Akhil Rao from Middlebury College, welcome to Resources Radio.

Akhil Rao: Thanks for having me.

Daniel Raimi: It's a pleasure to have you. We're going to talk about space today, a topic that we really haven't talked about much on the show before, and I'm really excited about it. Before we talk about space, we always ask our guests how they got interested in their line of work. So, how did you get into space economics?

Akhil Rao: I actually started off not interested in space economics at all. I was very interested in water issues. I grew up in California, and when I was a child, we moved to South India, to a town called Mysore. South India, broadly, but Mysore, as well, has some pretty interesting water-governance challenges. The resource is scarce. The flows are very seasonal. It depends a lot on the monsoons, and there's a lot of difficulties, I'll say, in figuring out how to allocate water between states that are upriver of dams and states that are downriver of dams. All this to say that, by the time I got to college, I was thinking a lot about water. My undergraduate degree was actually in business and finance, though, so I didn't really know what economics was beyond a class that I did okay in.

At some point, I started thinking more seriously about economics. I had a really good labor economics professor. By the time I was going to grad school, which was a couple of years later, I worked in Los Angeles doing, I'll say, miscellaneous jobs. By the time I was going to grad school, I was thinking a lot about water in California and how these resources could be managed better, and the Australian experience with water markets was pretty neat, to my mind. The Bureau of Meteorology there has a great data set on water trading that I was hoping to use for my job market paper, but this was in 2014, 2015. They were in the process of changing out their data set and adding a whole bunch more fields that would've made it perfect for what I wanted to do, so I corresponded with them and asked them about their timelines. They said, "Yeah. It'll be maybe another two or three years."

I thought, "Well, I can't wait that long to start doing my research." And so, I went to grad school at the University of Colorado Boulder. There's a lot of space stuff going on there. I was walking around thinking, "What else do I like that I could do that is in the same vein of managing common-pool resources?" And I think I read a short story, or maybe I saw a talk, but something got me thinking about orbital space. The more I looked into it, the more I thought, "Maybe I could do one or two papers here while I wait for the water data set to get uploaded," and I think now this is almost 10 years later. I have not gone back to water.

Daniel Raimi: That's cool. I was going to ask you if you ever got the data set and you ever did the water paper, but it sounds like no.

Akhil Rao: Nope.

Daniel Raimi: Interesting. Well, let's talk a little bit about orbit. Because this is a relatively new topic to me and to our audience, it'd be great if we could just understand some basics. When objects are launched from Earth and go into orbit, what are the range of orbits that they might enter into? What does that look like, and can you help us visualize it?

Akhil Rao: Yeah. This can get very complicated as you get into the details, so let's start at the simplest level. When we talk about Earth’s orbit, we can loosely think about this in three domains.

Picture the Earth as an orange ball, and imagine that it's got a bunch of skin on top. It's got a bunch of layers on top of it. The lowest layer, from about 100 kilometers above mean sea level to about 2,000 kilometers above mean sea level—that circular shell is what we call low Earth orbit, or LEO. From about 2,000 kilometers up to—I'm going to get the exact numbers wrong here—let's say, about 34,000, 35,000 kilometers, is what is broadly referred to as medium Earth orbit, or MEO.

35,500 kilometers above the Earth's surface is the geostationary belt. This is called GEO. There's some subtleties there involving parameters of drift and so forth, but at a high level, you can think about GEO as a place where, if you put a satellite there, it will stay over the exact same latitude and longitude on the Earth. It moves around the Earth. It orbits with the same period as the Earth rotates. Anywhere below, from GEO down to LEO, the satellite orbits with a period faster than the Earth rotates. The closer you get to the Earth, the faster the satellite orbits. And so, by the time you get down to LEO, we're talking about satellites that are going around the Earth maybe 16 times a day; they're not exactly staying over the same band on the Earth. If you think about the orbit as a circle, it's not like it's frozen over the Earth. It's kind of precessing all around.

These are the first level of orbits you might think about. There are some more exotic orbits. If you're thinking about orbits circularly, this is all you need. If you're thinking about orbits elliptically, because they don't just have to be circles, you can construct all kinds of orbits that move through all three of the domains that we just talked about.

Daniel Raimi: That's really interesting. I didn't know that you could do elliptical orbits. I think we're going to talk mostly about low Earth orbit, or LEO, today. Folks might've read about this a little bit, and I know I have, but could you give us a little bit of a sense of how crowded it is in low Earth orbit, and how much more crowded do we think it might get in the next, let's say, 10 or 20 years?

Akhil Rao: This is a really great question, because the definition of the term “crowded” here is currently very contested. Before saying “crowded,” I'll just say how many objects are going up and how many objects we think are going to go up, and then we can talk about why “crowded” is a point of contention today as a term.

From the dawn of the Space Age to about the year 2015, LEO had seen something like 1,000 objects at any given time. Currently, they're operating and active. Maybe another 1,000 or so objects [in LEO] were derelict. They were left behind spacecrafts, debris from a mission up there; maybe some astronaut lost a glove or left a tool behind.

Daniel Raimi: I hope not a glove …

Akhil Rao: So, think on the order of low thousands for most of the time that humans have been operating in low Earth orbit. Now, that's active objects. The inactive objects and debris objects have been accumulating over time, and some of that has been due to unexpected explosions or missile tests.

Around 2008 or late 2007, there was a Chinese missile test at about 800 kilometers that left a whole bunch of fragments. They blew up one of their own satellites to demonstrate the capability to do this. The United States has also done several missile tests. Russia and India are the two other countries that have done anti-satellite missile tests. These have left debris in some orbits, but the lower they are, the faster they go down. The Chinese missile test in 2007 is notable here, because it added a lot of objects to low Earth orbit, but because of conservation mass, it didn't add much mass. This is pre-2015.

We're still thinking on the order of low, single-digit thousands. Since about 2015, there's been a lot more discussion of large systems in low Earth orbit, or large collections of satellites—what we call “constellations,” or in some cases, if they're very large, “megaconstellations.” These megaconstellations that have been proposed are on the order of hundreds, thousands, or sometimes even tens of thousands of satellites per system. There are currently on the order of 10 systems that are proposed at varying levels of realization. The best known of these is SpaceX's Starlink system. Starlink, I believe, currently has on the order of 6,500 satellites active in orbit now. This gives you a sense of the rate of growth. For decades, we've been in the 1,000–2,000 regime. Now, we have a single system that is layered on top of that, that is about 6,500, that is going to be growing at least to the low tens of thousands, possibly as high as 40,000 in the not-too-distant future; maybe in the next 10 years.

Daniel Raimi: That's great. That gives us a sense of really rapid growth.

So, let's talk now about this idea of what is crowded. Can you give us a sense of how we should think about Earth’s orbit being crowded, and how we should think about risk? How should we think about, as more active objects go up and maybe even more debris, as well, what the probabilities and risks of collisions are? What are the implications of some of those risks? I know that's a big question, but can you give us a flavor for it?

Akhil Rao: Crowding gets weird in orbit, because space is quite big, and there's a lot of space. In principle, it is possible to imagine a way to organize all of the objects that are currently in LEO, plan to be in LEO, or conceived to be in LEO, such that we never run into crowding issues. But that's kind of a misleading statement. It's like saying, "Well, if you were to take all of the US population, you could organize it around the American West in such a way that nobody ever experienced traffic congestion." Yes, that is a true statement, but that is not really how people live, and that is not really a useful thought experiment. I like to say, “the West is big, but Los Angeles still has traffic.” So, there are certain regions of LEO that are very in demand and see a lot of activity, and there are certain regions that are just not really used at all.

The shell from about 500–550 kilometers above mean sea level is a pretty popular shell. There's a lot going on there. 550–600 is another pretty popular shell, but there's not really anybody using or talking about using, say, 1,900–1,950 kilometers. It's a much bigger shell, if you think about the math of radii and spheres, but nobody really wants to use that shell. In some of these high-demand shells, people are starting to talk about crowding, in the sense that if I wanted to put my satellite there, I would need to be coordinating with either a lot of people or with a lot of satellites, and that coordination problem gets quite challenging. Once you add in debris, it gets even more challenging, because you can't control where debris goes. That's one of the things that defines it. An active satellite can be controlled, or at least there's someone to talk to who is in charge of it—but debris doesn't really have an operator. It's not something that you can maneuver around yourself. You can move your satellite around the debris. That complicates things further.

The last layer of complication here is that our ability to observe where things are and what is where is limited. Objects in Earth’s orbit are subject to a lot of perturbations from irregularities in the Earth's surface, and so they don't move exactly circularly. You may be able to predict where something is going to be a day out with good accuracy, but by the time you get to three days out, there's big uncertainties in where it might be, depending on all kinds of factors. The Moon is going to influence things.

This adds to a sense of crowding, because you're not really sure what you might be running into or the likelihood that you might run into something. And, of course, there's small things that you can't really track well. So, all of this to say that in the more "crowded” orbits, it is less that you can't fit more stuff in there and more that the probability of getting to this other point, the probability that you're going to run into something, is rising rapidly, and people feel less than comfortable with that.

Daniel Raimi: Really interesting.

One really quick question before we start talking about the economics and the kind of governance of this whole topic. Does debris stay in orbit forever, or does it eventually fall to Earth? Is there a lot of variation in the way that debris behaves?

Akhil Rao: That's a great question. There's a ton of variation. Some of it is well understood. Some of it is less well characterized. Taking one step back, for this audience: We often think about resources as being renewable or nonrenewable, right? Orbit in general, but low Earth orbit, in particular, is both. At lower altitudes, there are self-cleaning mechanisms. The Earth's atmosphere exerts drag force on objects in orbit, and so they will tend to fall down without active maintenance.

That drag force drops off exponentially as you increase the altitude that you're operating in, so that at about 300 kilometers, something that is left there will fall down in a year or less. At about 550, maybe 600 kilometers, a thing that is left there will fall down on the order of 5 to 20 years. By the time you get up to 2,000 kilometers, we're into the hundreds of years for the time it will take for the object to fall down. As you go higher, these times increase. So, things do fall down, but you can think about renewability here in terms of the removal of objects that are in the volume on a continuum.

Daniel Raimi: That's great. I sometimes think about coal as a renewable resource. It's just the time period in which it’s renewable is very, very long.

Akhil Rao: Exactly.

Daniel Raimi: Two interrelated questions now. The first one came into my head as you were talking about different levels of orbit being in demand. Is there a market for Earth orbit? Do you have to pay to put your satellite in a certain spot? If there's not a market, what other types of governance structures are in place to manage the resource that's up there. Or is it the Wild West?

Akhil Rao: It's a very good question, because it's a bit of both. I shouldn't say that it is the Wild West, because there are governance structures that are in place. These are structures that exist sometimes at the international level and sometimes, increasingly more commonly, at the national level. But to answer your other question, there is no market where you go and buy a path in LEO. That is not a thing that exists. To understand why, and to see why the governance structures are weird, we have to go back to 1957, when a treaty called the Outer Space Treaty was put together and signed. The Outer Space Treaty is the foundation of space law and space governance today. In 1957, of course, the uses anticipated or realized of space were quite different than they are now. Now, we think about companies like SpaceX operating in orbit, we have space stations, and we are thinking about going to the Moon again.

There are lots of things that we're doing now that we weren't really doing in 1957, or that in 1957 seemed less plausible. At the time, though, it was the United States and the Union of Soviet Socialist Republics that were the main users of space. It's a Cold War context. They're thinking about this from a more geostrategic perspective than a perspective of, "How do we allocate this resource efficiently?".

And so, the Outer Space Treaty explicitly prohibits the allocation of property rights over space. It's not phrased as such. The way that it comes through is that no nation can claim sovereignty over outer space or anything therein. And if you can't claim sovereignty, then how are you going to allocate resources from there? So, it's widely understood to prevent explicit property rights, and without the explicit property rights, you don't really have the market. It also limits the ability of nations to prevent anyone from going to space on the grounds that they are just not allowed to use that resource. What it does do, however, is give nations the right to license and to supervise—“continuing supervision” is the specific term—space actors that are under their jurisdiction.

While the Federal Aviation Administration cannot tell you that you are not allowed to go to space, they can tell you that you do not meet the criteria for a launch license, so they will simply not give you a permit to launch from the United States. You can, if you choose, go to another jurisdiction that will give you a launch permit. However, there are many barriers in the way. For example, rockets and space technologies often fall under some type of export control. You may just legally not be allowed to take the technology you were planning to launch outside the United States, or if you're in a different country, you may face a similar issue. The other country you're going to may not have launch facilities in the same way. You may not have the same type of workforce there. So, this is not quite the Wild West with leakage and race to the bottom dynamics, but the governance structures are very patchy. Because of the existing international law, we're in a setting where explicit markets are not really a thing.

Now, I say that, but I want to note that the geostationary belt may be an exception to this. In the geostationary belt, the International Telecommunications Union (ITU) has set up a regime around spectrum licensing. If you want to be in the geostationary belt, more likely than not, you are doing telecommunications of some type, and you need spectrum rights to communicate. The ITU has a pretty good, well-developed system for spectrum management; when they ported over to GEO in the 1970s, they were able to say, "We are going to tie the spectrum licenses to specific geostationary slots that are above latitude-longitude points on the Earth." And so, while the ITU cannot stop you from going to a particular location, they can deny you a spectrum license, or they can deny your country a spectrum license, and then your country can deny you the spectrum license to operate from that spot.

So, while there's no property rights for the GEO slots that you can trade, there are property rights, of a type, for the spectrum resources that people can and do make deals around.

Daniel Raimi: Right. That makes sense. Then, I presume, if you can't get the spectrum you want, there's no point in putting your satellite in that particular spot. Is that right?

Akhil Rao: More or less. I mean, you could, of course, say, "Well, I have my spectrum for Spot A. I'll move my satellite over to Spot B. I don't have spectrum rights there. I'll take some pictures, and my satellite will be automated, and I'll move back to Spot A." Or you could say, "Look, I'm just going to break the law and see what you do."

Daniel Raimi: That's really interesting.

Another question just popped into my head. Are there secret satellites? We talked about the United States and Russia and the Cold War. You can imagine intelligence agencies wanting to have information, and they don't want to disclose the methods and sources of that information. Is that a thing? Do we know anything about that?

Akhil Rao: The short answer is yes, there are satellites that we have limited information about. It's not quite as straightforward as it would be, though, to have secret satellites, as it would be to have … I don't know, it's a bit weird now, right? Because your satellites can take pictures of the ground, so can you actually have a secret base these days? It’s unclear. Maybe a secret airplane is the middle ground. I don't know, but you can't stop anyone from looking up with a telescope, and if your orbit passes their telescope, or they happen to bounce a radar signal off you, they could detect your satellite.

The reason why I think it's still useful to call these secret satellites, like you did, is that many of these satellites are not entered into the databases that people like you or I might be able to use to characterize what objects are in orbit and where they are. The main database is maintained by the US Space Force, and so you can understand that the Space Force is not going to be including data on classified satellites that they do not want the world to be able to easily find out about.

Daniel Raimi: Right, right. One of the things that I know you've been doing the last year is you've been on leave from Middlebury, working at NASA in the Office of Technology Policy and Strategy. Can you tell us a little bit about what you've been working on?

Akhil Rao: Most of my academic research has been about orbit use, what we now call “space sustainability.” At the Office of Technology Policy and Strategy, I am still working on space sustainability, but it's a bit different than my academic work. Academic economists tend to focus on things like economic policy. What would a Pigouvian tax look like? What would a cap-and-trade scheme look like to manage this resource? NASA is not a regulator, and NASA does not really do those types of things, but NASA does do a lot of science and technology investment.

Going from the academic world to the Office of Technology Policy and Strategy, I've been doing a lot more assessment of space sustainability technologies. How would we combine, for example, better shielding and tracking systems to reduce the collision-risk externalities or the collision risk overall, even, to better manage the resource? You might think of this as going from doing carbon tax research to doing solar supply chain or solar technology research.

Daniel Raimi: That's great.

One last question before we go to our Top of the Stack segment, which is near and dear to many of us at Resources for the Future (RFF). As some listeners probably know, RFF had a really amazing scholar whose name was Molly Macauley, who worked on space economics until she was killed, tragically, in 2016. For people who don't know Molly or don't know about her work, can you say a little bit about her and the contribution that she made to the field?

Akhil Rao: I should note that I never met Molly, so I didn't know her personally. By all accounts, she was an incredible person. I would've very much liked to have met her. Her work, I think, is really incredible. There's a huge range of topics. When I have spoken to people in the space-policy community, I am always amazed by the range of people who knew her or her work, and I've only ever heard favorable things.

On the space stuff, her work was genuinely an inspiration to me when I was a graduate student, looking into this stuff. When I was trying to find what the literature looked like, her analysis was basically the only thing that came up.

It's also worth noting that it's hard to see a topic about satellites that she did not do something about. I think this is pretty interesting. She's worked on space solar power, which is not a thing that most people have worked on. This is pretty interesting, though, because when we think about space today, we often think about going to the Moon, going to Mars. We think about settlement and expansion.

Molly's work, to me, is super cool, because she was thinking in very detailed, granular terms about satellites, a thing that exists today, and how they can help people who are on Earth today. To me, I found that, as a graduate student, super inspirational.

Daniel Raimi: Yeah. Thank you for sharing that. I did not know Molly well. I got to know her a little bit when I started at RFF, but I started in 2016, and she died shortly after I started. My brief experiences with her were very much in line with what you say, which is that she was a wonderful, kind, and pretty amazing person, so it's too bad we can't have Molly around still and be working on these topics.

Well, Akhil, thank you so much for this conversation. I've learned a ton. I'm sure our listeners have, too. I'd love to ask you, now, the same question that we ask all of our guests at the end of each episode, which is to recommend something. It can be something that you've read or you've watched or you've heard. It could be related to space or the environment or not. We're not very picky, so Akhil, what's at the top of your literal or your metaphorical reading stack?

Akhil Rao: I will mention two things, one environment related, one not. On the environment, I recently finished reading Peter Frankopan's The Earth Transformed, and if you haven't read it, I think it's an incredible book. I don't know if one of your other guests has mentioned this before, because it goes through the very long scope of the Earth's history and talks about the relationship, as we best understand it, between the environment and human civilization. There's discussions of hundred-year cycles in broadly construed civilization related to volcanic eruptions and the changes in insulation and agriculture that follow from it.

If you're thinking about how to think better about long-term environmental change, this is a great book, because the climate has changed in the past, and there is a lot of interesting insight there. The non-environmental book is Yakov Feygin's Building a Ruin: The Cold War Politics of Soviet Economic Reform. It's fascinating. It's about the use and the sociology of economics in the USSR, particularly in the post-1958 period. Lots of great insights there and lots of fascinating stories there about how these economists of various stripes and flavors were trying to get their ideas to the top in a very different kind of society.

Daniel Raimi: Those both sound so interesting. Great recommendations, Akhil. We'll have links to both of them in the show notes so people can check them out for themselves and get a hold of and read them. One more time, thank you so much for coming onto Resources Radio, helping us learn a little bit about space economics and what's going on out there. We really appreciate it.

Akhil Rao: Thanks for having me.

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