and welcome to the first panel of CMRC. This is challenges to security and space. So, I am Nicholas Martin. I'll be the moderator today. And before I introduce our panelists, we will, I'll kind of go over the general format for this panel. So, each panelist here will give a short 15 minute presentation on that they've prepared beforehand. And then after that, we will open things up to a Q&A for the audience. So, for audience members, if you look at the bottom, middle bottom of your screen, there's a Q&A section that we can use after all panelists have finished their presentations. So, yeah, our first panel will cover the barriers the U.S. faces with maintaining and expanding current space operations and the importance of securing space-based services. We will also discuss foreign threats to American space operations and their impact on military, commercial, and civil sectors. Our first speaker joining us today is Dr. David Burbach, associate professor of national security affairs at the U.S. Naval War College. Dr. Burbach's scholarly interests include civil military relations, defense planning, and the relationship between international security and technology, particularly with regards to space and nuclear policy. We are also joined by Dr. Damon Colletta, associate director at U.S. AFA's Eisenhower Center for Space and Defense Studies. Dr. Colletta also edits the Eisenhower peer-reviewed journal Space and Defense and recently completed a book on technology and international security. And our final speaker is Dr. Everett Doleman, professor of comparative military studies at the U.S. Air Force's Air Command and Staff College. Dr. Doleman began his career at the National Security Agency as an intelligence analyst and also has experience at the United States Space Command. So, without further ado, we can go to our first speaker, Dr. Burbach. Okay, we should be on a screen share now. Good morning, everyone, and thank you very much for your interest and for joining the conference today. I'd like to talk a little bit about, and I did watch Mr. Samansky's presentation just before, so I'll try not to cover any of the same ground as him, but I'd like to in some way step back a little bit and just ask what is really new in space security? Why have concerns gone up so much? What's some of the reasons behind creating Space Force? And if you look at some of the U.S. strategic statements, whether from the Obama administration or from the Trump administration, there's been a concern expressed that as our space strategy about just under 10 years ago put it, that space is becoming increasingly congested, contested, and competitive. The Trump administration phrased that as competitors are turning space into a war fighting domain. And what do we mean by that? And what are the implications? Because in some ways, space really isn't all that new. Space is space, we have been operating in space longer than I've been alive, certainly longer than any of you students have been alive. It's been now more than 60 years since the first satellite. In fact, SpaceX just put another, sorry, the United Launch Alliance just put another U.S. military satellite in space yesterday. So there's really nothing new. And even if you go back to the early Cold War, within just a few years after Sputnik, we had spy satellites, we had military navigational satellites, we had anti-satellite weapons operating within just five years after Sputnik was launched. We even tested nuclear weapons in space. So what you see there is not a romantic shot of the moon, but is actually about a one megaton nuclear warhead a few hundred miles away from Hawaii lighting up the skies over Honolulu. So space has been militarized in a sense for a long time, but there are a few things that are causing us to have new concerns and raising the stakes. I would summarize that the two biggest changes from those early Cold War days is that space is now in everything, civil and military. It's in all sorts of civilian and military technologies such that we're dependent upon space in a much deeper way than we were 50 years ago. The other thing that has been a change is geopolitical as opposed to technological. That great power competition has returned as opposed to our focus after the end of the Cold War on relatively weak rogue states like Iraq or Serbia or terrorist groups like al-Qaeda. We're again concerned about competition and potential conflict with countries like Russia or China that are really quite capable across the board, including in space, and the rise of China in particular as a space power has changed things. So what do I mean by spaces in everything? Given our time is limited, I won't try and go through all the ways that it affects your daily lives, but you've all grown up in a world where GPS is widely available. Nobody gets lost, everybody has a map available. In addition to GPS, your cell phones for positioning, your cell phones themselves depend on timing signals from space. If you take out the GPS satellites, the whole cell phone network crashes. It's similar for the banking system, the role of weather satellites, communication satellites, tracking airplanes and ships from space. For all sorts of civilian applications, our modern digital economy relies on our space assets, including government satellites like the GPS constellation. At a military level, that's become even more true, and just as you depend on space-enabled technology for navigating and communicating, so does the military, all the way down to a tactical level. You can marine there on a small satellite phone. Whereas in the 1960s, we needed space for strategic level nuclear operations. We used spy satellites to see where the Russian ICBMs were. Those initial navigation satellites were used so that our nuclear submarines would know where they were when they launched a missile. We now use space in every day, all the way down to the individual soldier, sailor and marine tactical level. The slide you see at the lower left, I'm not going to try and go through that. You saw a slide similar to that from Paul's keynote speech. DoD is full of PowerPoint showing lots of satellites and lines and diagrams, but the general point is our whole way of warfare is enabled by a dense network of communication satellites, reconnaissance and intelligence satellites, imaging satellites, navigational and timing satellites. We've developed a very technological way of warfare in the United States. Across the board, that depends on space technology. The globe that you see there in the lower right is to highlight the fact that in one of the more likely conflicts that we now worry about, if we were to get into a conflict with China in the East China, South China, Xi or otherwise Western Pacific, is that we're operating a long, long way from the United States across huge expanses of water that will absolutely depend on satellite communication, satellite reconnaissance, satellite navigation, whereas the Chinese would be operating much closer to their own shores. You can imagine if the U.S. were fighting a war in the Gulf of Mexico, their communications lines and their ability to know what's going on nearby is not so space dependent. It's certainly, they have their own space assets and it helps, but if we're fighting a war so far away from our own shores, we're going to be absolutely, it'll be absolutely critical to have a space network that supports operating across the Pacific Ocean. Well, and again, as I mentioned, the other big changes we do now imagine that we might need to be able to compete and potentially win wars against China or Russia again, capable space powers. The Russians recently have done some tests, not blowing anything up and creating debris, but tests of an anti-satellite missile system. They've long been a capable power in space. China got a much later start in the Cold War. They were not really very active in space until the 1980s, but they've been catching up quickly. There's now a Chinese equivalent of the GPS constellation. China has military reconnaissance and communication satellites. China has tested an anti-satellite weapon a little over a decade ago, probably has tried to use lasers to blind U.S. reconnaissance satellites, jamming capabilities. They're capable near peer powers in a way that we haven't faced since the end of the Cold War. So, what does that all mean? And here, a concept, some of you may have taken some international relations courses and seen this idea. And Paul Samansky's presentation highlighted this as well, but one worry in space is that it really leads to something we call a security dilemma, where it's very, it's difficult for countries to feel secure, which can lead to incentives, to strike first, to engage in arms races, to be very fearful and unstable. And there are a couple of reasons for that. One is that space technology tends to be extremely dual use. You may know that SpaceX will be launching another human crewed capsule to the International Space Station tomorrow on their Falcon 9. They also use the Falcon 9 to launch U.S. military satellites. It's exactly the same technology. The Chinese used a heavy lift booster that they recently developed to send a probe to Mars this summer. They'll use the same booster to launch heavy military satellites. If you can guide a satellite into orbit, you can guide an ICBM to its destination. You can guide an anti-satellite weapon. If you have learned how to make clever little, and this is the middle graphic you see there, is a concept of a Northrop Drummond satellite docking with a communications satellite to refuel it. Well, if you can dock with a satellite to refuel it, you could also, you know, James Bond style have an arm reach out and cut off the solar panel or spray paint the sensor or just give it a big whack and disable it. Very similar technology or in the bottom you see pointing up the Hubble Space Telescope pointing down a CIA reconnaissance satellite. More or less the same space telescope technology differing in whether they point up or down. So if there's really no way for a country like China or Russia to have good space capabilities and not potentially pose a military threat, let alone the actual military systems we see them developing. And as Paul discussed, it's pretty easy. Whoever strikes first is probably going to win. Satellites are pretty easy to attack. You know where they're going to be. I mean, we can compute weeks in advance when two satellites might collide, something that we've seen happen a few times. They're not very hard to track. You can try to make satellites stealthy, but overall they're up there and their positions are pretty knowable. They're pretty fragile.  It'd be too heavy. You can't have it bristling with defensive weapons systems or as Paul Samanski explained, even if you shoot at an incoming interceptor, the chunks of it are still going to be coming at you at several miles per second and it may not help very much. So it's really hard to defend satellites. And then at a broader level, space itself is surprisingly fragile. We learned from those early Cold War nuclear tests that if you set off a nuclear weapon in space, you fill space with radiation belts. That test over Hawaii actually knocked out the very first test communicate television relay satellite that AT&T had launched a little earlier that year. We learned pretty quickly that if you tried to have a nuclear war in space to take out enemy satellites, you'd kill everybody's satellites pretty quickly.  Many of you may have seen the movie Gravity a few years ago. They talked about the Kessler syndrome where one satellite gets destroyed and then that breaks up other satellites and soon debris is killing everything. The movie was kind of was dramatized, but there is actually a real point here. You can see in the lower right, I highlighted the Feng Yun anti-satellite test in 2007. One test of blowing up one satellite caused a massive increase in the total amount of debris in space. So it really wouldn't take much of a space war to render the whole environment unusable. So you put all that together and we have what we call the security dilemma where anybody's space capability can look pretty threatening. Even if their intent is defensive, even if they have mostly civilian capabilities, that leads to a natural counter reaction and then counter counter reactions and pretty soon you're spiraling into a space arms race with a lot of incentive to strike first if you fear that war is coming. The fact that the U.S. has this asymmetric dependence because we're fighting so far away and have such a space-enabled way of warfare, that really increases the stakes both for potential adversaries to want to take out U.S. capabilities. We have to fear that even if we're the clear number one in space, because of that offense dominance, even a number two power in space could take away our space advantages pretty quickly and it'd be very hard to stop that. So that underlies a lot of the worries about this new technology and new geopolitical competition in space. So last slide here, where's this going to lead? And you sometimes see American space leaders saying that we want dominance, we want nobody to be able to threaten us in space. That's going to be almost impossible to achieve. If the standard is nobody should be able to threaten us in space, we would have to blow up everybody's launch sites and everybody's existing satellites first, because it's almost impossible to achieve that kind of invulnerability. So then what do we do? We may try and chase that spiral, that security dilemma and try. The Chinese or the Russians might put us in a position where we don't have much choice. We can learn to live with a certain amount of vulnerability. We can figure out, and this is something we're absolutely doing, how to make our space assets, how to make our way of fighting more resilient. So if we lose some satellites, how do we keep on fighting? Instead of relying on a few big, expensive satellites, maybe we kind of go the SpaceX direction and start launching thousands of small, cheap satellites. And that's a lot harder to take out. In the Cold War, the U.S. and the Soviets actually both did come to realize that given all this instability, given how quickly you would degrade the space environment, that we actually both showed some restraint and used space for relatively passive purposes, reconnaissance, communication, navigation. But we stayed away from the worst kind of arms race or worst kind of offensive concepts. And maybe we can achieve that again. But we are now moving out of a period of U.S. dominance and being able to think of space as something of a sanctuary and having to think about what a new era of geopolitical competition with space peers looks like. So let me stop there, stop my screen share. And after we hear from our other two speakers, look forward to any questions. Thank you, Dr. Birbeck. So now we'll be moving on to Dr. Damon Coletta. So if you have any presentation ready, you can go ahead. Well, thank you very much. Thank you for the invitation. I think what I'll do is I'll lay out three questions that we've been seeing at the Eisenhower Center and at the Eternal Four Space and Defense. And it does go along the lines of what Paul Samansky and Dr. Birbeck were talking about. We started this center during the Second Bush administration. So it's been about 15 years. And in the last 10 years, we've had several articles that have nibbled around the edges of questions that are becoming more and more common. Dr. Birbeck just spoke about the security dilemma. And we've had several folks try to unpack the problems of deterrence as they relate to the space domain. So we'd call this first topic, new thinking on deterrence. The old thinking on deterrence comes from the Cold War and nuclear weapons. And if the basic idea there is that you're involved in a game of chicken with the adversary, neither side wants to escalate to a general nuclear exchange, but at the same time, they want to defend their interests. The idea of new thinking on deterrence comes from the fact that the first attack might not even be kinetic. And so the idea that a defender like the United States would respond with some sort of nuclear strike seems disproportionate and not very credible. So if we are still very interested, particularly if the United States is one of the more vulnerable actors in this resurgent great power competition, how do we deter attacks against our assets in space that we've become more upon, which would become more and more dependent? So one of the ideas that's come up is this notion of layered deterrence. And Dr. Samansky had talked about the difficulties with space law. That has come up in the journal and journal articles as well. And the idea is that even if you can't enforce it in every case, having rules of the road, if not space law, confidence building measures and rules of the road, they can act like a plate glass window. So if you can monitor well enough, if you have good enough space situational awareness, that could be the plate glass window so that when the adversary breaks the window, that's a first signal that your relationship is moving into a different place. And then what would be the next layer in layered deterrence? So trying to figure out what would be a proportional response well below the idea of a nuclear exchange. So does it need to be symmetric or could there be an asymmetric response? Do you remember the story that Dr. Samansky was telling you about the Russian response to the attack that he suspected on their satellites? It was a cyber response, it was an asymmetric response. So as you go through these different layers, way before you get to the result of a chicken game or mutual assured destruction, there are many places where you can think about trying to stop the damage and discourage aggression. The other idea that's come out that if anybody who's interested in doing research in these areas is probably going to run into is the notion of cross domain deterrence. And it's related to layer deterrence because you have all these other activities that are involved in delaying an attack on your space assets. The difficulty there is that the governments are set up so that you have specialists in each of these areas, in each of these domains. So you have space force, you have a new bureaucracy which will specialize in the space domain, but they're going to have to work very closely if we're going to attempt layer deterrence or cross domain deterrence, they're going to have to learn how to work very closely with partners. And if you think about the situation in Iraq and the idea of a whole of government approach, you're going to have similar problems just with dealing with space deterrence. So there's a lot of new thinking going on in deterrence, trying to figure this out. The second question that I would like to put on the table for the Q&A is related again to what Dr. Rovak was saying about the resurgence of great power competition. You have, and what he said about spaces and everything, you have the resurgence of great power competition at the same time that you have the opportunity for high levels of cooperation through the provision of public goods. So what do I mean by public goods? These benefit folks who haven't necessarily paid for the goods and it is difficult, let's say, it is difficult to exclude people who haven't paid to play. So an example of public goods or potential public goods would be GPS. Now it is possible to exclude others from GPS, but if there's a norm that other countries and companies that are headquartered in other countries can go ahead and use these services, that approaches the idea of a utility or a public good. So navigation and timing, space situational awareness, which is important for private companies because they have to pay insurance in order to launch and operate their satellites. And so space situational awareness is an important thing, but the capability to provide that is very asymmetric. In fact, the U.S. government is one of the premier providers of that. The idea of manned exploration, manned exploration, manned missions in space are far more expensive because you have to keep the crew alive. So in terms of defraying some of those extra costs, that could be a potential public good. And then in more of the realm of science fiction and movies, talking about protection from asteroids, whether that could be a potential for global cooperation, asteroid mining, which again, in the realm of science fiction, they're thinking about the possibility there, the possibility there, and the idea of energy production from space. So this is technology that's further out, but people are thinking about it, showing the potential for cooperation. Again, you have the potential for public goods and greater cooperation at the same time that you have the resurgence of great power competition. And Dr. Burbach has laid out some of the ideas that we're seeing in the journal on great power competition. The idea of military advantage being independent of military vulnerability. So it's possible to have military advantage at the same time that you are more vulnerable than your adversary. And that does make space dominance a difficult idea. There's been a lot of interest in during this resurgence of great power competition in looking at the strategic culture. So we had an article in the last issue that was looking at the Chinese Communist Party's view of Marxism and how that would influence their strategic culture and their approach to United States assets and United States competition in space. So just like during the Cold War, there was a lot of interest in how the Russians and Russian strategic culture would deal with military problems. We see that same idea coming back in with the resurgence of great power competition. So I've given you two themes so far in the few minutes that I have left. But just to remind you, the new thinking on deterrence is one idea that we're seeing. The other one is this balance between the potential for public goods, a space-based public goods on the one hand, and the resurgence of great power competition on the other. The last thing in honor of allies' tradition that I'd like to lay out there is how will ideas about civil military relations, that's the allies' tradition, how will ideas about civil military relations relate to changes in how we address space, particularly the idea of the new space force. And for this one, we haven't had a whole lot of articles, but you saw at the very end of Dr. Semecki's presentation his concern about whether the space force is prepared to deal with the problems that are coming ahead. They haven't had the experience of being pressed. I might push back a little bit on that. I think the Air Force has had experiences that caused them to learn lessons, formative experiences. I think we could talk about the Berlin Airlift. I think we could talk about the post-Sputnik era, the post-Sputnik year, 1957, 1958, when the United States was behind in the space race. There have been those formative experiences, but I would agree with him that at least at the unclassified level, we haven't had that formative experience for the space force. Those formative experiences may be very important for developing professionalism in a new service. And professionalism in democracy is key to working together with civilian authority, with political authority, because to the extent that the President, under the oversight of Congress, needs to make decisions in a space crisis or in the opening stages of a space war, the professional development of that space force may be very important because they will be responsible for providing full-franc expert advice to the President so that the United States as a democracy can navigate any crisis. So I will stop there. What I put on the table for you, I'll hand it over to Professor Dolman, but the idea of you thinking on deterrence, public goods, the potential for public goods rising at the same time as you have the resurgence of great power competition, and new problems in civil military relations with the professionalization of the space force. Thank you, Dr. Coletta. Now we'll hear from our last panelist, Dr. Everett Dolman. Yeah, well, thank you, Damon and David. I really appreciate that. I'm going to go through this. I built some slides just in case I ran out of things to talk about. I have plenty of stuff on here, but I get to go through it pretty quickly because of the presentations that you've given already. We start with the idea that space is important, that's been going on already. It'll go on for the rest of this meeting, of course, but no nation relies on space more for its physical security and its economic well-being than does the United States. I work for the United States Air Force and the United States Space Force, and so this is what concerns me primarily, is fighting war in space. The first thing that we need to do to make sure that that is understood is to see space not as systems and satellites, things that give us all that we need, but think of space as infrastructure. We've had a lot of people talking here about how much value we get out of it. Let me just get to the, you know, from farming to, just in time supply, supply to Uber and Lyft to secure transactions. Let me get to the apocalyptic for you. If we were to lose space completely, your smartphones would not work. The U.S. military and most modern militaries require space support in order to operate effectively. In fact, today it's over 70% of the weapons that the army uses are space-enabled. That means they don't work effectively or even at all without space support within them. If we were to lose space for the United States military, we would be unable to carry effective missions out abroad. We probably have to go into an immediate defensive approach, and if we could not get space back, we would have to resort to ginning up a Vietnam era, early Vietnam era form of military force, and that could take years. I mentioned being working for the folks that are supposed to defend space. The United States Air Force is responsible for guaranteeing access to space for everyone in times of peace and ensuring no opposing force can access space in conflict and war. This is very similar to the mission that the U.S. Navy has on the open ocean. Space is a common area like that. Up until now, however, the U.S. military has been deprived of using weapons to do that, which makes it a very difficult job. The U.S. military is a martial organization. There are purposes to be prepared and when called upon to fight the nation's battles. Let me go a little bit into domain theory. It's something I've been working on quite a bit as of late. For every area of conflict that has developed historically for land, sea, air, and space, each one has developed based on their operating characteristics a different way of thinking about fighting, whether it's sailing or ramming for the seas, whether it's mustering forces, getting them into the air for long enough at the right time and place for the air or whether it's understanding the importance of orbital mechanics in Delta V or change in maneuver as it is for space and possibly even for cyber at some point with virtual space. When it's recognized that a war fighting domain has come into place, a service organization normally goes into responding for that. Space force is being created now not because it's ready to fight, not because it's proven itself as fighting, but because until you get a space force, no one's going to think about the purpose of military forces in domain and that is the command of the domain is job one. The purpose of military is to control or command a domain and that if you cannot control or command the domain, then you have to ensure that an opponent cannot get command of that domain and that is called contestation. Contestation is possible from an adjacent domain. Command is only possible from within the domain. For example, we've talked a lot about folks targeting space with weaponry from the earth. That means that they can prevent access to that domain. We see it with the army and their ground to air capabilities and missiles that prevents the enemy's air forces from flying over the top, but just because you can prevent someone else from accessing a domain doesn't mean they can't keep you from accessing the domain as well. The only way you can command it is if you can operate in the domain and the reason you need to operate in the domain is to be able to generate military effects from that domain to be able to contest adjacent domain and to use it. You must be prepared if you're looking at it from a military perspective to operate in the domain to fight in the domain and fight from the domain and that means to generate effects from the domain. We generate those effects in the air force. Say for example, humanitarian aid is delivered or a bomb is delivered to a target. Those are effects. That is not the purpose of the air force to do those things. The purpose is to be able to get into the air and then the effects it can generate are limited only by the imagination. For example, bombing a factory is not called economic warfare. Some might call it that, but in a military jargon it is air power having an effect on the ground. We wouldn't call bombing a school educational warfare and we shouldn't be bombing schools anyway. This gives us some real problems, however, with deterrence. One of the things that's happening now is the idea that we can deter nefarious actors from affecting us in the space domain by cross-domain deterrence or by other methods that in fact some would say, hey, if somebody attacks one of our satellites, that's our national sovereignty and we reserve the right to go ahead and drop a bomb on them where they live. But is that really a credible deterrent threat? Would we, the United States or any other country, if a satellite suddenly goes inactive, decide to bomb a person with a nation we thought that had done that? Would we lay down a fire barrage on Shanghai? For example, I doubt it. I doubt it very much and I don't think we should be thinking that way. So when deterrence doesn't work, when deterrence fails, we need to defend those assets and is war in space likely? Probably not. Well, not in the near term. In the long term, the Chinese state is inevitable and the basic reason for that is we consider confidence building measures are not necessarily confidence building measures. We mirror image. For example, in the United States, we think if we have a transparent capability from space that we can see into China, for example, that we can see if they are marshaling, getting ready for an attack, we can see if they're in Russia, if they're abiding by treaties. And this gives us great confidence. It does not give the Chinese great confidence. The idea that we can see what they're doing is very much against the cultural attitude going all the way back and allows that way the enemy can see you and knows what you're doing. They can defeat you in detail. Russians have a very similar attitude that never let the world know how strong or how weak you are because that will hurt you in the long run. We have fought in space and we fought around space. I'm going to just bring up, we've been doing it for a long time or thinking about it. One of those thoughts were the Star Wars or SDI program from the 1980s, which was the idea that we could put a perfect shield over the world with a anti-ballistic missile system. The idea that we could defeat nuclear war from space was one that was brought up in the 1980s. It was a little problematic at the time. The United States and Soviet Union had over 60,000 nuclear warheads between them. And even if a system could be developed, it would defeat 99% of those that are still 600 getting through in life as we know it on this planet, which looks very different if that should happen. The problem was, and this is where deterrence also has a huge issue, and SDI was extended into the Bush administration because the least likely scenario, the least likely thing that was going to happen, was a massive nuclear strike from the Soviet Union to the United States or vice versa. Our ability to have a guaranteed second strike had seemed to be keeping the peace. The problem with deterrence is that when it fails, it fails utterly. And the real problem, too, is there are things that cannot be deterred. The Bush administration's most likely scenarios was that there might be an accidental launch. How do we make sure that an accidental launch doesn't reach its target? A rogue state strike, others have talked about these, terrorist and non-state actors. This is primarily an issue of attribution. Something we call the mad boat captain, the hunt for red October scenario or the Dr. Spangelift Spantenario. And the big one was third party warfare. What if Pakistan were to launch a nuclear India or vice versa, Iran, and Israel, or vice versa, and North Korea launch more that lands in Japan? How could we deter that or stop that? When deterrence fails, we must defend. The idea was we would have 350 or so kinetic kill vehicles circling the earth, each one with about 24 shots on it, to take advantage of the fact that space has a global, it is inherently global by nature. Under the Bush administration, it was estimated that if a system like this could be put into effect, it could stop 100 ballistic missile launches simultaneously from anywhere on the world and that would take care of the most likely smart. It was not developed, it was going to be very, very expensive. But it brings up the idea that when we look at space from a warfighting perspective, we see it not as an open area, an open ocean that everyone can sail upon. We see these orbital characteristics. We see it in gravity wells. In fact, the gravity has only ability to get from here to there. What I'm depicting here is gravity, as it would be in the Earth-Moon system, and that area in red that you see would be what we call low Earth orbit. It looks a lot different when you depict it like this, but the other really important thing to see here is that from the perspective of the solar system, the Earth is a single place. We can launch from different areas, they launch from around the world, but the Earth is actually a single port. It is a launch facility, no matter where they are, can be seen as a pier. The port of New York has different docks and piers. Every single thing going into outer space has to pass through low Earth orbit, and as long as it goes in 1958, we were looking at the idea of if you could seed space with enough weapons, and if you were willing to use them to prevent anyone else from getting to space, you could effectively have a blockade of the Earth. Well, I've just made things a little bit quicker. I'm looking at, that was something I worked with a long time ago as what it was, and today I'm looking at kinetic energy, excuse me, directed energy, primarily lasers, microwaves, and the like, plasma bursts even as a possibility. And this is because the technology of lasers has come a long, long, long way. We can build 15 kilowatt laders from off the shelf parts we get from electronic stores. We can put them on, attach them to an iPhone 6, put some solar panels on them, and get these very small lasers into the air, and they're very, they have a tremendous capability. I'm throwing 15 kilowatts out as just a general idea, because a 15 kilowatt laser with a microsecond burst can penetrate nickel quarter, that type of metal and metal skin, and it wouldn't cause the kind of kinetic damage that would come from a blast, as is projected by many of those who think there'll be a war in space, and it could only be dirty, it would have to create debris. A small level of laser power on solar panels could degrade those panels very quickly, making spacecraft inoperable, it could blind the spacecraft making it inoperable, or it could displace the critical components in a burn through that would not be destructive or cause additional damage. The other great thing about lasers in space is that anything that could be used to clean up space, in other words, take out the debris that we already have, and lasers could push small amounts of debris into the orbit to be burned up, or perhaps out of orbit, or destroy them completely, vaporizing those items, and that would also be great practice, sharp shooting practice for the operators. Now, the way I see this operating today, it's not great that lasers can threaten the surface of the earth. I see them, as I mentioned, massive networks of satellites at low-earth orbit, very small satellites operating connected to each other, and the idea here comes from something I read about in the medical field. In the medical field in 1930s, doctors started experimenting with lasers to defeat cancer. In other words, a laser could sign the beam to defeat cancer, and it would have the effect of destroying the cancer cells inside the body, but the problem is it could also destroy healthy cells on the way in and on the way out. For large directed energy systems like the airborne laser, or the large heavy ground-based lasers, you're going to burn out or destroy things in the path to the target and on the way out. There's a real problem with that. Now, what was happening was we were getting about a 10% survival rate from that sort of effort.  That means if I have 250 kilowatt lasers, I have the effect of 30 kilowatts of power. If I have 100, it multiplies by 100 times. The way you do this to kill healthy cells in the body is you have several lasers all around the body, each one of them targeting the unhealthy cells, and where they intersect, these are low-level lasers, but where they intersect, they can have a cell killing effect at that point at the cancer cell without harming the body anywhere else. I'm imagining we can do the same sort of thing in outer space, having hundreds of small, each laser not being able to do much damage at all, but several lasers being targeted on a single place, one laser painting the target, the rest of them simply going after it, and we could get tremendous warfighting capability in space, and this is also the speed of light. When we look at that in an ideal like this, we have something also that gives an advantage from space to the earth that is much like the gravity well advantage that you would get in targets from space and to the earth. And by the way, yes, we know where satellites are, we know where they're going, mostly because of the United States Air Force publishes that data for the rest of the world to see, but that doesn't mean that they're easy to hit. They're traveling at 17,500 miles per hour, and to climb out of the gravity well and get up there creates a very big plume, but what if you use a laser to attack those satellites? Well, if you're willing to attack the laser before it goes operational, maybe that would stop that, but there's a tremendous advantage that you get, and it's based on something called the shower curtain effect. If we look at a laser going from space to the ground, it has a very tight, very close beam as it goes through the vacuum, but in return, let me get back, you can see that a laser going from the ground to space starts to bloom in the atmosphere, gets dispersed, and then that keeps on going in the vacuum station. That's a very, very powerful laser on the earth in order to affect the satellite with catastrophic damage. From space, however, going the other direction on the left, you keep a tight beam until you get to the atmosphere, and then it starts to bloom. You need about 10 times as much power to go from ground to space, that's from space to ground to get the same effect. That gets accelerated if you're not directly above the target as the bloom gets bigger as it goes out, and you can see going from the earth to space, it gets even larger. With this idea in global satellites being part of the equation, you've always got a satellite with a laser at some point over the earth. Now, it can't do a lot of damage, it's not going through any war in space, wouldn't necessarily damage on the ground, but it's an idea that I'm playing with and having some interest in. I get to as a member of the military, I need to and getting paid for thinking about war in space, and we would be derelict in our duty if we didn't think. We don't want to go to war in space, we'd rather not have it, but if we do get a war in space, we'd better have been thinking about how we fight it. That's kind of the way we're looking at it. I've run out of time, I'm going to go ahead and call it at this point, and I'm giving your question. Thank you, Dr. Dolman. Now we can move on to the audience Q&A portion of the panel. So, if you are an audience member, please click on the Q&A button at the bottom of your screen, and you can submit questions for me to read to all the panelists or just one of them, but to start things off, while people think of questions, I'll ask a general question to all three of our panelists.  Does the lack of human targets change how actors approach space security? Yeah, I'll go ahead and start on that. I think it does, in that we've seen that there is, if you destroy property as opposed to killing people, that doesn't seem to generate as much of a response. We know last year when the Iranians shot down a U.S. reconnaissance drone over the Persian Gulf, President Trump considered airstrikes, but eventually called it off. And one of the factors that seemed to weigh heavily on him and many others who didn't want to do strikes as well, nobody died. And would we strike back at Iran in a way that would kill people over an uncrewed vehicle being shot down? This comes up with cyber attacks as well. And there's actually been research by a number of political scientists that find that, yeah, if you tell people how much do you want to retaliate against a cyber attack or shooting down an uncrewed drone, it just doesn't generate the same kind of response. So, taking out a satellite that doesn't, the notion, and Professor Dolman alluded to this, would we really strike back in a way that would harm humans because a hunk of solar panels and antennas in space is destroyed? Maybe not. Both the general public and policymakers seem hesitant about that. So, in that sense, I think there are some space relevant lessons we're learning from what we've seen with combat involving uncrewed drones, cyber, etc. Sorry, I would say that links into the idea of new deterrent thinking that we've been talking about. So, when you're not killing people directly, it's difficult to have or threaten a punishment, a severe punishment for that. One of the ideas that we're thinking about is that it might not be a chicken game when you don't have people involved. It may be more like a war of attrition. So, you can get the idea of a frozen conflict where the two sides are, if you think of a biological metaphor, it'd be two stags that are butting each other for competition. They're not trying to kill each other, but they're fighting over something of strategic value and they keep banging and banging and banging. So, one side destroys property on the other side, then there's a response, a similar response. The trouble is that's a plausible scenario, but when you have the asymmetries in space, there's going to be a temptation to have that war of attrition, to have that response in another domain. Again, as Dr. Samansky was illustrating, and I haven't seen in the unclassified level a whole lot of thinking about how a war of attrition would play out across several domains and how you would keep a war of attrition from turning into a much more dangerous game of chicken. Well, you know, it's an international law standard of reciprocity and proportionality. So, if you're taking out someone's machine to take out someone to respond with that with taking out more machines, is proportional and it highlights the problem of deterrence in war. As the more damage you do to these satellites starts to accumulate and it has tremendous effects on both the economy and the military capacity to react, there's going to be a real desire or effort to start moving that into other areas where it can be effective or where you use that deterrent threat of cross domain or other area activities. I like the idea of being able to respond in space and with only into space. The other part of our human targets, of course, without people in space, it's a lot easier, I suppose, to go to war because there is just sort of a cost to the calculation that is pretty safe before. Where we do have humans in the way, and this is the idea of UN peacekeeping efforts. Peacekeepers don't make the peace. When a piece is settled, peacekeepers are sent in to go between the two sides and put themselves in harm's way so that if they do go back to war, there could be some deaths involved and then the states will get involved. We do the same thing with aircraft carriers when we put them in the straits of Taiwan when the Chinese are doing a military exercise where they're practicing taking a large island, for example. If we really wanted to defend Taiwan, we put them about 200 miles on the other side of the island rather than right there on the way, they're there to be sunk in a sense. You take Taiwan and you take it will the United States really go to war with China to go over that? But if you sink a carrier with 6,000 people on board, you bet we will. So that's the kind of ratcheting up that humans do. Now the problem with humans in spaces, they're really, really, really expensive to keep there. But if we're looking at kinetic weapons, blowing things up in space and causing massive amounts of debris, the international space station is probably the most deterring thing that we have up there at the current time. We've got astronauts from all countries up there and they would be in harm's way. The U.S. military, the Air Force thought in the 1950s and early 1960s that manned space bombers and manned space fighters would be the way things go. It's going to be like drone warfare in space. It's all virtual as far as the operators are concerned. And so the more people in space, this is where commerce really comes into play. As Jeff Bezos and Elon Musk and Richard Branson start doing getting more people into space just even for tourism, it becomes a lot more difficult to start having those dangerous wars that cause debris that might hurt people. And so in a way, they'll have a they'll have a deterring effect, but history also shows that flag follows commerce. Wherever economic value and human beings have gone and that economic value gets great enough, the military is called in to protect that. The military is going to have to go into space to do things like search and rescue, removing obstacles to danger, weather prediction and practice and regulating and making sure that piracy is limited. Piracy mostly works but at this point, but eventually possibly physical. And whether the military wants to go in or not is a good point. It'll be a call from all the people that may be going in there and all the values that we are getting. Can I have another attack because Professor Dolman made me think of something. It's putting people in the way is related to Dr. Burbach's dual use slide. So remember when he was talking about the commercial in the military. So one of the layers in this idea of layer deterrence is this notion of entanglement that if you can't put people in the way, it's not convenient to do that. You can perhaps put commercial technology in the way or you can entangle commercial military technology so that when your asset is destroyed, when the property is destroyed, there are a number of private concerns across the world that care about that. But let me take one attack on that, Damon. If you do that, you put military capabilities on civilian satellites, you technically make them a legitimate target. I don't disagree that that helps in deterrence, but that's one of the problems. Right, but I'm saying not necessarily that. It could be that, but just having military use of commercial technology, just the dual use technology there, if they are going after one of those dual assets, then they're entangled. So you could design your military infrastructure so that it was further entangled so that that asset now when it's disabled, it's affecting commercial entities around the world and not just the military. So I wasn't thinking about aircraft carriers so much as a communication satellite that had dual use. Thanks for your responses. We're starting to get a few audience questions coming in. So I'll pick one of those and hopefully we'll hear your answers and feedback. So one audience member says this one's a long one. International cooperation in space seems to be at an all time high right now when you look at the ISS Artemis lunar gateway and plans to go on to Mars. All this is heavily dependent on cooperation as NASA Administrator Jim Bridenstein repeatedly explains. Why emphasize your realist security dilemma approach so much when you could instead be focused on opportunities for international cooperation? Couldn't the U.S. military end up actually sparking the security dilemma itself? Sure, let me take that and I would even lump in the previous question. Why is it difficult to practice that restraint that we saw during the Cold War? Kind of an unrelated note. Several things there. Maya, I hope I'm pronouncing that correctly, is correct. There is actually a lot of space diplomacy going on now too. The Artemis Accords is a set of diplomatic agreements that NASA and the State Department are trying to negotiate with other countries on how we would do moon exploration together. So that's absolutely true. It's a somewhat separate track than the security lane and one thing that is important to note about that diplomacy is China and Russia are not involved.  We're actually not involving them in those Artemis Accords Russia also has not really wanted to be involved and has kind of grumbled, you know, raised some objections to how we're thinking of doing the moon exploration. So we sort of have a parallel track of civilian space diplomacy at the same time that on the military side we are raising these concerns. I don't think that security dilemma, well the dilemma is somewhat inevitable in the sense that it's such an offensive dominant and so dual use. It's hard to get away from that. I would like, I hope that we are able to show some restraint. Now if you look at the Cold War, although we kept ending up back showing some relative restraint and if Paul Samansky were here he may know about some secret ways that we didn't show restraint that I'm not familiar with, but it certainly could have been worse, but we kept as with the Strategic Defense Initiative, the Star Wars Missile Defense that Everett just told you about, we never, the military, you know, militaries aren't comfortable being in that position of we have to accept mutual vulnerability. I mean, militaries want to be able to say we are able to prevent this from happening. We're able to be invulnerable and since the end of the Cold War we've been in a position where we haven't really faced a lot of space threats in a serious way and I think we we're now seeing those threats evolving and are going through an initial phase of well how do we absolutely guarantee that we keep space access and adversaries don't. I think that's going to be very hard to achieve and I think maybe, you know, I think we probably, you know, a good outcome would be that we get to some tacit or even more formal restraint, perhaps some agreements. It's hard to verify arms control agreements in space because, you know, as Samansky explained, it's hard to see exactly what's going on up there. So I hope we are able to get out of this dilemma because I think the goal of we're invulnerable and no other peer powers cannot access space. I think that's a really difficult goal to get to and so I would like to see us avoid kind of the spiraling arms race end point of the security dilemma and instead seek some diplomatic ways or even if it's informal to avoid the worst competition. Well, I'll take a stab at that. I understand your concerns about realism. It's something that we deal with all the time. The idea that comes from strength through peace, peace through strength is the old Roman adage, if you want peace prepared for war and that is a problem that you're preparing for war all the time, you're probably going to get it and I understand that. The other thing is though the military tends to be pretty conservative when it comes to actually wanting to go to war because they're the ones who suffer the hardships of it the most their families, but we don't make the decision to go to war. We prepare and we plan and if called upon then we go to war. International cooperation except international cooperation with other militaries is really not in the purview of what we do. We're sort of at the limit, but we do can do we can influence it by understanding that debris is a common enemy. Planetary defense, comets, asteroids are a common enemy and the ability to deny that to clean it up to stop it generally is going to call to the military. The military is going to be doing other things like search and rescue, which causes potential for a lot of international cooperation. When the outer space treaty was first being negotiated in the early, well in 1959-1960 as early as that, the hope was that we would get a united nation space force sort of a police force for the world that could be operated by all nations whether regardless of their ability to actually participate in that. I'm much in keeping with the idea of the outer space treaty. It's problematic because of the realist notion that sure I like it, but I'm not going to put my forces under anyone else's command and it just sort of falls apart. We're as long as going out into space as nation states and the outer space treaty requires that almost in a sense because it says nation states are responsible for all damages in space. It's going to be tough, but we can look at it from a diplomatic and from an economic way and if we go in that direction the army will military the space force will be told to just keep planning, but don't deploy, don't test. That's not up to my boss. And I guess I can afford to be a little more optimistic because I'm at the pre-commissioning level and part of the professionalization of the space force will be how we educate college age students who are going to be going into the space force or working with the space force. And the journal, the space and defense journal tries to take a political economy approach and when you think about a political economy you think about mixed gains, potential for cooperation as well as conflict and that's where that second point came from, the idea that public goods and your question about international cooperation, the possibilities for cooperation are rising at the same time as great power competition. What Dr. Brubeck said, I think is relevant. If you try to go back to the Cold War and build historical analogies, I think what helped the military be involved in arms control and provide professional advice about arms control was the mutual vulnerability. So it was a recognition mutual assured destruction. You don't have that right now in space, so it does make it very difficult. In fact, based on what I'm reading at the unclassified level, I would estimate that there's asymmetric vulnerability. So we're actually more vulnerable because we're more reliant and this is a offense dominant environment and so it's very difficult then for the military to sign off on cooperation. So you see that when Russia and China put proposals on the table in the United Nations, there's a real reluctance to say, well, how are we going to verify this? How are we going to be better off with this treaty than without it? And one chilling idea to think about is that we may have to go to a point where there is a crisis and there's a real concern and there's a mutual recognition of danger before we can put those cooperative measures in place like as we saw with the salt treaties during the Cold War. One way where we might not have to go there that's more optimistic is again that our adversaries, which are involved in cooperation as well as competition with us, see real value in the public goods that the United States is providing. And so they're just a little more reluctant to destroy US assets because they don't want to lose the public goods, they don't want to lose the services the United States is providing. It may be a while before other countries start to think in those terms. In fact, in some ways they're moving away in that even our allies, the Europeans built their own navigational constellation, not wanting to be completely dependent on US GPS. They built their Galileo network. Russia has blown ass, China now has Baidu. One good news is that these systems are mostly compatible, the advantage you all have is your cell phones and your cars can now rely on a bunch of different country satellites. Even the Europeans didn't want to be in a position where if the US system was turned off or was destroyed, a situation where somebody wants to take away US GPS and not European Galileo, I'm not entirely sure what that would be. But one general point, any great power, I mean in general, great powers like to be autonomous and we absolutely see that in space where what China has been doing has been kind of building out those space capabilities so that it has its own navigation, its own weather satellites, its own communication satellites. The US provides a lot of public goods. We do provide GPS, we've got the best weather data, but countries don't like to, what we see is as countries become capable, they want their own national capabilities and don't like to rely on US public goods. Okay, so I think we have time for potentially one more question. So another attendee asked, does the US, both government and industry, still have a technological advantage in the space domain over China? How are those trend lines changing? I've studied the Chinese program a bit so I'll go, in fact, if any of you want to look up, there's a podcast called Cosmic Controversies that Forbes puts out. I was just a guest on that discussing the Chinese space program. Bottom line is no, China does not have a technological advantage either in government or industry. One thing worth noting is if you follow space at all, you're probably aware of SpaceX. SpaceX has absolutely eaten the Chinese space program's lunch when it comes to the global market for launching satellites. SpaceX is able to do more for less money. And when it comes to technology, the Air Force Secretary Barrett noted that, expressed some, said that the Chinese little rover they have on the moon right now is ominous. I'm not so worried about that. What they have on the moon right now is the equivalent of the Pathfinder rover that we put on Mars 25 years ago. In general, Chinese technology, I would nobody who really knows space would trade what China has for what we have. What is relevant and guess is where that offense dominance comes in is if China is merely a strong number two, that's still enough to threaten us. In a military sense, they also are not as dependent upon space, especially if we were fighting, you know, if China wanted to try and, you know, fight a war in the Gulf of Mexico, they would need a lot of space assets that they don't have and they went that we could threaten. If we are fighting over Taiwan, we're more dependent upon the capabilities that space gives you to fight far away across a big ocean. So I think a better way to think of China is they have moved into the number two position. And they want the world to mean China has no pretensions that they're better than the U.S. in space, but they would like the world to think that they're better than certainly better than the Indians or the Japanese, better than the Russians, you know, better than the Europeans. So, you know, think of China as a strong number two, but we're still ahead, but merely being ahead doesn't necessarily guarantee space safety. And another reason why it doesn't guarantee it is because it's hard to stay ahead. So sometimes it's cheaper to be the follower than the leader. And the other, the other thing is, is that just because you're ahead in many things, even the most important things doesn't mean that you're ahead in everything that matters. So if you go back to historical analogy, the Japanese made some progress that we didn't anticipate and you got Pearl Harbor. So I'm not saying that there's going to be a space Pearl Harbor. I'm just saying that technological leads are not safe in any case, particularly if you have a strong number two, who seems to be a pretty proficient follower. Well, time will tell, that's for sure. We have this with the Russians and it's interesting that they were preparing for a military space program, a war in space. We were preparing for probably not having a war in space. And we both had command economies at the time. And the reason was we didn't want people launching rockets from their backyard or from someplace deep in Texas because it might look like a nuclear strike and we didn't want to start a nuclear war. That's why we don't really get licensing for private space companies until the mid-1990s and beyond because, again, the state is responsible for all actors and supporters. But we've got now, we've unleashed a free market economy onto space and the dot-com billionaires have taken up on it and they are making extraordinary strikes. Command economies are terrific to get exactly what you want in the short term. That's why we go to it in the wartime. But as long as peace continues on, I'm not sure I think the fast follower is as useful as it is for wartime. But as long as peace continues, so as long as we can deter and it looks like, if not deter, at least cooperate, the greater the advantage that they're going to come from that free market system coming up with all sorts of different ideas. And that also will bring in some other issues. One problem, though, and nothing good comes without problems. The question that I worry about is how much of our national security should we rely on business and making war a business is never a good idea. So it's while we're gaining advantages in technology in other areas that I think are going to be extraordinarily useful, the military is looking at those technology advantages, how they can adapt to military needs and uses. I just hate paying private business to do our national security anywhere. At least not more than we're already doing. Okay. Thank you. I think we have time for maybe one more quick question. Another attendee asked, what does the ladder of escalation look like in space warfare? I think you're going to have some disagreement on this panel because they're still trying to figure that out. We don't know what the ladder looks like in limited nuclear warfare in the second nuclear age. And we don't know what it looks like in space. And Professor Dolman was talking about we might have a better sense of it if we had more options to stay in space. What we're seeing at the journal, again, this is at the unclassified level, is that that's at least today, that's not the way they believe it would happen. They think that it would cross domains. And there isn't a lot of evidence that we have, a lot of data that we can rely on to see how that would go. My sense is that there would be reluctance on the part of the great power since they all have nuclear arsenals. There would be a real reluctance to shoot up that ladder very quickly. And I think that there should be more thinking at my level, at the undergraduate and first year graduate level, but also where they're doing the real exercise, the detailed exercise at the classified level, there should be more thinking about what a war of attrition would look like. And that's not exactly a ladder, but that's a long-term competition over something of strategic value. And how do you maintain yourself in that if you don't escalate? That could also, you could have strategic defeats or defeats of strategic significance without ever going up the ladder. So I think we need to think about the problem that your questioner puts on the table, but I'm also worried about this idea of a war of attrition that goes across domains. I would agree that I don't think we have a clear sense of this yet. And one complication to go back to something Paul Samanski said is that in some ways space is a little less like physical airstrikes and more like cyber or more like counterintelligence, in that a lot of stuff can happen secretly. And we've acknowledged in the U.S. we have at least one system designed for jamming enemy satellites. We know the Russians have such systems, cyber attacks, or even if you have quietly have a little satellite come up on a satellite and disable it, as Paul noted, from my perspective, did an adversary just destroy my satellite, or did it just fail because something broke? And I think we, you know, there were likely to see a lot of, you know, either transient interference, jamming cyber attacks or fairly secret attacks, which on the one hand can help slow escalation because there isn't necessarily a big public, oh my God, the other side attacked us. On the other hand, it could lead to problems of false, you know, we also need to be careful. We don't accidentally, you know, conclude there was an attack when a satellite happens to break in the middle of a crisis just because of bad luck.  So now I'll, you know, I'll drop two bombs on you in response. It's probably a lot more covert and uncertain than a lot of what we're used to terrestrially. Okay, before Professor Dolman goes, I could I get in one more thing and it ties to the third bullet that I laid out on the table, which is civil military relations in the space force. I think personally, I don't know that there's a lot of background to this, but I guess there's a little bit, the general Raymond's talked a little bit about this, but I think that the space force is going to have to get awfully good at gaming and games to try to try to get a sense of what that escalation ladder looks like, or what that war of attrition looks like. And part of professionalization is figuring out education. I think the education, the professional education of the space force is going to be different. And I think it's going to use gaming. And the question is, do we know how to use gaming very well at that level? Professor Dolman, I'm sorry about that. Oh, no, no, not at all. There's the escalation ladder that I wrote about 20 years ago was to secretly seek space, take over low earth orbit, and it's a pay to complete. And I think that's the holy grail of escalation for space to just get it over with. The problem is that was never realistic back then, and it's not realistic today as more competition has come in. The big thing that a lot of folks here would be worrying about is if we can keep war out of space and it won't filter down onto the terrestrial sphere, the problem is that's not a one way arrow. Every war on the terrestrial sphere has gone up into space. The escalation ladder for space is going to look awful, like the one on the ground, because that's probably where it'll kick off. We are, unfortunately, out of time. But again, I would like to just finish up this panel by again thanking our panelists, Dr. Burbach, Dr. Coletta and Dr. Dolman for donating their time to speak to us today and also answer our questions. And thank you all and audience for coming and listening. Our next panel is at 1.30 p.m. and it'll be regarding the U.S. Space Force. So we look forward to seeing you there.


Hey everyone, thanks for tuning in. Today, I wanted to talk to you about WebAssembly, what it is, why it's awesome, and how you can start using it in your own web applications. So let me start by introducing myself. So my name is Robert Buquilio, and my background is a mix of software engineering and bioinformatics. I'm the maintainer of the library Biowasm. So this is a collection of bioinformatics tools that we've pre-compiled to WebAssembly and are hosting for free on CDN so that other bioinformatics web apps can make use of it. I'm also the author of the book, Level Up with WebAssembly. So if you're just getting started with WebAssembly, feel free to check it out. All right, so what is WebAssembly anyway? Well, I like to think of WebAssembly as really just being yet another language that you can use in the browser alongside JavaScript, HTML, and CSS. Now, to give you a sense for what this language looks like, let's take a look at a simple example. Here I'm defining a function called hello, and all this function does is return the string openJS world. Now, you don't need to know anything about WebAssembly, just looking at this. You can tell this is not a language that you probably want to code, and that's good because you don't have to. In fact, the whole idea of WebAssembly is that you can take code written in other languages and compile that down to WebAssembly. And so that's why it's called a compilation target, because you take code written in these other languages, compile it to WebAssembly, and then you run it in the browser. So where is WebAssembly actually useful though?  One is code reuse. You know, all these applications I'm showing here are very large code bases, hundreds of thousands, millions of lines of code. Where WebAssembly was really essential to let them transition these apps from running on a desktop or in a command line onto the web without having to rewrite everything in JavaScript. So this is very convenient from the code reusability perspective. The other big use case is performance. So in these four applications, what they've done is look at the most compute-intensive part of their apps that were written in JavaScript and replace those with WebAssembly. And what they noticed was a large speedup and better performance. Now, of course, so I know this is not guaranteed to work, just because you use WebAssembly does not mean that your app will always be faster, but for a certain category of data-intensive applications, it can help. The other use case behind WebAssembly is portability. So the idea here is that you can also use WebAssembly outside the browser, really anywhere where you can find a WebAssembly runtime that can execute your code, you can have WebAssembly. And so here I'm showing, for example, for example, Cloudflare and Fastly, these are providing serverless functions that run WebAssembly at the edge. The nice thing about using WebAssembly for serverless is that they initialize a lot faster and are cheaper because WebAssembly is a lot more lightweight than using containers, for example. You can also run WebAssembly on your server if you use runtimes like WasmTime, WasmR, or even Node.js can run WebAssembly. You can also run your WebAssembly by an Arizona Raspberry Pi as shown in this screenshot from the Wasm3 team, which also build a WebAssembly runtime. So all these use cases look great, but can you actually use it today? And the answer is yes. About 93% of users on the web today are running browsers that support WebAssembly. And so this is great news. One thing that's interesting, though, is how many developers actually use WebAssembly? And so to get a sense for that, what we can do is look at the state of JavaScript. This is a survey that's done every year. They pull 20,000 JavaScript developers. And one of the questions they ask is, are you familiar with WebAssembly? And so here are the results. About 75% of developers who answered this survey know what WebAssembly is, but had not had a chance to use it. 15% have never heard of it. And only about 10% of the respondents for that survey said that they had actually used WebAssembly. So we only have two data points here, 2019 and 2020 for the percentage of developers who have used WebAssembly, around 10%. But if we're interested in projecting future WebAssembly usage, what we can do is use very sophisticated mathematical modeling techniques to try to impute what is the usage going to be in the future. And so what we can see is by 2047, over 100% of JavaScript developers will be using WebAssembly. Now, I'm kidding, of course, that's not how anything works, but it will be interesting to see how that number actually plays out over time. All right, now what I'd like to do is concretely give you two examples of applications that I had the chance to work on where WebAssembly was really useful, both in terms of performance and code reuse. So the first one is FastQBIO. This is an interactive WebTool that lets the user input DNA sequencing data and rapidly evaluate the quality of that data while the data stays inside the browser. So when we set out to build this, we kind of looked around and there were several tools that could help calculate these statistics that we're interested in, but none of them were written in JavaScript, right? So we have one in C, C++ and Java. And at the time that I built this, I hadn't really heard of WebAssembly. So we figured the only options were, number one, host one of these tools on a server and expose an API that lets you make custom queries to that tool. And while we could have done that, that gets expensive real fast, especially if you have a lot of users that need to scale it up. It's also problematic because you need to make sure that it's secure and it doesn't accidentally let users execute arbitrary commands on your servers and start mining Bitcoin. But also there's a data upload issue, right? The main use case for this application was to analyze files that were already on the user's local computer. And so this would be inconvenient to have them uploading the data to the cloud before they can even analyze it. So the second approach would be to rewrite a part of these tools in JavaScript. A few problems there as well. One, this takes time, obviously. Number two, it's error prone, right? Anytime you're rewriting a complex algorithm that has edge cases, you're gonna likely introduce errors. The other thing is that we're now maintaining a separate copy of this tool written in a different language. And so we won't be benefiting from all the updates and all the bug fixes and new features that get added onto those original tools. So despite the challenges, we ended up going with option number two. So we rewrote a small portion of the tool, CCTK in JavaScript, and it worked. However, then I came across WebAssembly and that's when the third option opened up. And this is really where WebAssembly shines. Like these are all existing tools that are written in languages other than JavaScript that we can now compile to WebAssembly and run directly in the browser. So not only do we get to run it in the browser, but there's also no need to rewrite any of the code. So we get the best of both worlds. What's interesting here is also that on top of the code reuse that we got, we also saw some performance improvements. So what we are able to do is actually speed up the app by 20X by switching to WebAssembly from our JavaScript implementation. So if you want all the details for this, you can check out my Perf Matters 2019 talk on YouTube. All right, case study number two. So this is an app that's called Ribbon. It's an interactive tool, lets you explore complex rearrangements in genomes. Part of this application involves parsing a special bioinformatics binary file format. And to do this parsing, we have a few existing tools that we can use, written in C and Rust. Again, this is very often the case in bioinformatics, by the way, where a lot of the tools are written in C and C++ and Rust and so on. And so here we kind of end up with the same situation, right? In terms of implementation, do we host a tool on a server? Probably not, same issues as before with the cost of security and uploading the data to the cloud. The other option being rewriting it. This time, however, it won't take us much time because someone else had actually already rewritten portions of SAM tools in JavaScript. And so we just ended up using that. But after the success that we saw with FastQ Bio, we figured, well, let's try WebAssembly here as well. And so what we saw was, again, interestingly enough, we saw a two to three X improvement in terms of runtime. But probably even more important than that we're now able to reuse 100,000 lines of very complicated C code that parses unique genomics file formats. And what's really nice about that is that we're now able to use features that are available in the C library, but we're not implemented in the JavaScript one. For example, we can now do a very quick check on the validity of the file formats. We can down sample the data randomly to reduce the amount of memory that we're using and how much compute we need on the user's computer. And all of these are only possible because we're just relying on the off-the-shelf tool that we've compiled to WebAssembly. All right. So if you're building these kinds of data intensive web apps, there are several interesting tools that you can use with WebAssembly. And one is threads. Obviously a lot of tools use threads to speed up execution. And WebAssembly does support threads using web workers and the way that shared memories implemented between threads is using this thing called share array buffer. However, with the Spectrum malware that showed up around 2018, what happened was that browsers ended up turning off support for shared array buffer until relatively recently. And so a few years later, we're still at about 70% of users running browsers that support shared array buffer. So we're getting there, but we're not quite all the way there. And so if you are using threads, it's probably a good idea to use feature detection where you test, does the user support share array buffer then use WebAssembly with threads otherwise use the version of the WebAssembly binary that does not have threading in it. Another really powerful tool is SIMD. So SIMD stands for single instruction, multiple data. And the idea is that this is a way to parallelize code that is very commonly used in data analysis, image processing and so on. And so the idea is as the name suggests, you can process multiple data sets within a single CPU instruction. So just to give you a very concrete example, let's say you have points in a three-dimensional space and you're interested in calculating the distance between these points using this formula. So here what you could do is calculate these three subtractions one after the other, therefore taking up about three CPU instructions or you could use SIMD and insert those coordinates in an extra large CPU register that can fit four of these numbers at a time and do the same for the second data point. And then what you can do is use a SIMD instruction that will subtract all three coordinates within a single CPU instruction. So obviously this has a lot of potential for speeding up the calculation, which is why it's so commonly used in a lot of mathematical and data analysis heavy tasks. And the reason why I mention SIMD is because there is a WebAssembly SIMD proposal currently focused on 128-bit registers. For most browsers, this isn't actually supported unless you enable a flag, but it will be enabled by default in Chrome 91. Now I recently did a test drive of WebAssembly SIMD. What I wanted to do was essentially align DNA sequences to a reference genome and benchmark the runtime with and without WebAssembly SIMD. And what I found was really, really interesting where as you can see the WebAssembly with SIMD gives us pretty close to the native SIMD performance but in the browser, which is really fantastic for those applications that can benefit from SIMD. And what's really interesting about this is that when we compare performance between JavaScript and WebAssembly, one can always argue, well, you didn't optimize your JavaScript enough and it's not because of the WebAssembly that your app is faster. And that could be very true, but when now we're talking about SIMD, this is a whole new game because JavaScript does not have access to SIMD instructions whereas WebAssembly does. And so this is why this is a really, really exciting advancement. I'm looking forward to seeing that enabled in all the browsers. If you're interested in learning more about WebAssembly SIMD in particular, you can check out my recent WebAssembly live talk that is available on YouTube. All right, so so far, I focused mostly on how awesome WebAssembly is, but before we end, I do wanna spend a moment talking about when you should not use WebAssembly. So to me, it kind of comes down to three things. If your app is not compute-intensive enough or it's too compute-intensive, or if WebAssembly adds too much complexity to your code, then you should not use WebAssembly. And so I wanna just dive into each of those a little bit deeper. So first, if your app is not compute-intensive enough, so if it doesn't involve graphics, if it doesn't involve data processing, simulations, audio processing, video, image, you know, all these kinds of compute heavy tasks, for example, if you're building a CRUD app, just use JavaScript. That's kind of the idea here. At the other end of the spectrum, if you're trying to do too much compute-intensive work, it's just not gonna work in the browser whether you use WebAssembly or not. You know, for example, if I'm trying to assemble very large genomes in the browsers, it's just not gonna work, right? I'm gonna need to deploy that in the cloud where I can have more hefty compute power. And finally, you know, code reuse and performance are really nice and all, but it's also important that we consider the complexity that WebAssembly adds to our code base, to our build process, but also to the maintainability of the code for your entire team, right? It's a bit hard to give concrete examples here because this will really depend on your team and how comfortable they are with introducing something like WebAssembly, but at the end of the day, WebAssembly is a really powerful tool. You just have to make sure that the added complexity is worth it for your application. All right, so that's all I had to share. Please check out my book. If you're just getting started with WebAssembly and you're looking for a practical guide, I also have a whole bunch of other articles and videos that you can check out. And with that, I wanna thank you very much for being here.


The key takeaways from the previous lecture or as follows, it is possible to affect a certain transfer of work to the rotor of a turbo machine by means of the change in specific enthalpy of the fluid in the rotor passage or by means of a change in specific kinetic energy of the fluid in the rotor passage or both. The fractional contribution of the change in specific enthalpy to the total specific work transfer is defined as the degree of reaction as indicated here. In addition, in the case of an axial machine, any change in specific enthalpy of the fluid across the rotor passage always results in change in the relative velocity of the fluid blade passage. Furthermore, in the case of an axial or radial machine, any change in relative velocity in the rotor passage determines the change in pressure along the streamline which passes through the rotor blade passage. Now, it is clear from this discussion that when work transfer takes place to a rotor, the absolute velocity of the fluid, the relative velocity of the fluid as well as the blade velocity in the case of a radial machine can change between the inlet and the outlet of the rotor. We have also seen that it is customary to indicate these velocities by means of a velocity triangle since the absolute velocity of the fluid B at any location is some vector sum of the blade velocity plus the relative velocity. So, it is imperative that we gain a clear understanding of velocity triangles and also be in a position to interpret velocity triangles and try to get as much information from velocity triangles as possible. So, this is what we will discuss next. So, here we are given two velocity triangles, one at the inlet to the rotor, one at the exit to the rotor. Let us see how much information we can infer from these two velocity triangles. Now, we notice right away that U2 is not equal to U1. So, the blade speed actually increases from inlet to the exit of the rotor which implies that the machine is a radial flow machine. Furthermore, since U2 is greater than U1, it follows that R2 is greater than R1. So, the machine is actually a radial outflow machine. Next, since R2 is greater than R1, DR is positive and judging by the magnitude of the relative velocity from inlet to outlet, we can see that C2 is less than C1 which means that DC is negative and so this term contributes positively to the overall right hand side and so DR is positive, DC is negative. So, both these things together give rise to a DP being positive in this case which means that P2 is greater than P1. So, this corresponds to the rotor of a compressor or a pump. We notice further that at inlet, the relative velocity C1 is perpendicular to U1 and it is clear from this that beta 1, the blade angle at inlet is equal to 0. In this particular case, since the machine is a radial machine, this implies that the blade at entry is actually a radial blade. That is, it is aligned in the radial direction. Since beta 1 is the angle that the tangent to the blade profile makes with respect to the reference direction. So, in this case, because the reference direction is the radial direction, we call this a radial blade. Now, in case the reference is the axial direction, beta 1 equal to 0 would suggest that the blade is axial, it is an axial blade. In case it is an axial machine. Now, in contrast, if alpha 1 is equal to 0 at at inlet, for instance, that situation will be referred to as radial entry in the case of a radial machine and it will be referred to as axial entry in the case of an axial machine. So, beta equal to 0 would imply that the blade is radial or axial as appropriate and alpha equal to 0 would imply radial or axial entry or exit as the case may be and depending on whether it is a radial machine or axial machine. Furthermore, since the relative velocity c curves away from the direction of the blade speed. Notice that the blade speed is in this direction and that the relative velocity curves away from the direction or angular velocity direction, we can infer that the blade is a backward curved blade for this particular case. So, here we are again given the velocity triangles at the inlet and exit of a rotor. It is also said that u1 is equal to u2. So, that is also indicated here. So, that means that I am sorry that means that it is an axial machine since u2 is equal to u1 and since c1 is not equal to c2, there is a change in the relative velocity in the blade passage. So, that means it is the reaction machine. As we have already discussed, there is a reaction machine. Furthermore, since c2, the magnitude of c2 is less than the magnitude of c1, the relative velocity actually decreases in the blade passage which means the blade passage acts like a diffuser or it is a diverging passage. And so, what we are looking at here is actually a compressor or an axial compressor or an axial pump. Again, application of this information to this equation makes it clear that this term is 0 because it is an axial machine and dc is negative. So, that means this term becomes the overall term contributes positively to the pressure change. So, that means the pressure increases in this case. Let us move on to the next example. So, here we are given once again velocity triangle at the inlet to the rotor and at exit to the rotor and it is given that u1 is equal to u2 which means that this is an axial machine. It is also clear from the velocity triangle that c2 is not equal to c1 which means that it is a reaction machine. And if we now look at this equation dr is 0 because it is an axial machine and c2 is greater than c1 that means dc is positive. So, that means this term contributes in a negative fashion to the dp term. So, dp is less than 0. This is equal to 0 and this entire term is negative. So, dp is less than 0 which means that the pressure decreases in this passage. C2 is greater than c1 implies that the blade passage is a converging passage. So, the flow accelerates which means the pressure decreases. Therefore, this is the rotor blade of a turbine. And furthermore, we see that the relative velocity at inlet is perpendicular to the blade direction which means that beta 1 is equal to 0 in this case since this is an axial machine we refer to the blade at the inlet or the blade profile at the inlet actually is in the axial direction. So, it is an axial blade at entry. So, this is an axial reaction machine with axial blade at or the axial blade profile at entry. So, looking at this velocity triangle it is indicated that u1 is equal to u2 and furthermore it is also indicated that c1 is equal to c2. So, let us see what information we can glean from this velocity triangles. So, u2 equal to u1 implies that it is an axial machine, c2 equal to c1 implies the following since it is an axial machine dr is 0 and since it is given that c2 equal to c1 dc is equal to 0. So, that means dp is equal to 0 for this rotor which means that the pressure remains constant and there is only a change in direction of the fluid. So, that means it is an impulse machine. Is it an impulse type of work absorbing machine or an impulse type of work producing machine may be determined by looking at the tangential component of the absolute velocity. Notice that v theta 1 is in this direction here and v theta 2 is 0 because v2 is perpendicular to u2. So, v theta 1 is positive, v theta 2 is 0. So, that means that from Euler turbine equation what is w dot is positive. So, this is an impulse axial impulse turbine. So, this discussion makes clear how much information can actually be presented or associated with velocity triangles between the inlet and outlet of a rotor and students should actually go through this very carefully and make sure that they are able to interpret the velocity triangles given any particular situation and draw these types of inferences even before doing any calculation. What we will do in the next couple of lectures is to work out examples where we try to draw velocity triangles based on the given information in the in the example and try to do some calculations.