WEBVTT - Space Debris (featuring Dr. Jonathan McDowell) 0:00:05.519 --> 0:00:09.160 In nineteen sixty two, the United States detonated a one 0:00:09.240 --> 0:00:13.200 point four megaton hydrogen bomb four hundred kilometers above the 0:00:13.240 --> 0:00:15.720 surface of the Earth. This was part of a project 0:00:15.800 --> 0:00:20.239 called Operation fish Bowl. Not Surprisingly, it created a huge 0:00:20.239 --> 0:00:23.800 explosion which lit up the sky and disrupted radio transmissions. 0:00:24.200 --> 0:00:27.440 It also knocked out street lights in Hawaii, which may 0:00:27.440 --> 0:00:31.960 have worried partygoers who, according to Smithsonian magazine, were gathering 0:00:32.000 --> 0:00:36.600 on hotel rooftops for h bomb explosion viewing parties. It 0:00:36.720 --> 0:00:40.680 also messed up six different satellites, whour belonged to Americans, 0:00:40.840 --> 0:00:43.639 one was Russian, and it also messed up the very 0:00:43.680 --> 0:00:47.760 first British satellite. The Soviet Union was conducting similar tests 0:00:47.760 --> 0:00:50.800 of nuclear weapons in space at the same time. This 0:00:50.960 --> 0:00:53.880 didn't bode well for the future of satellites in space. 0:00:54.360 --> 0:00:58.120 This amazing new technology of satellites held a lot of promise, 0:00:58.520 --> 0:01:00.280 but who would want to invest in it? If the 0:01:00.400 --> 0:01:03.840 United States and the Soviet Union kept making satellites inoperable 0:01:03.880 --> 0:01:07.119 with nuclear weapons tests in space, well lucky for all 0:01:07.160 --> 0:01:10.600 of us. In nineteen sixty three, both nations agreed to 0:01:10.640 --> 0:01:13.000 stop screwing up space for the rest of us and 0:01:13.080 --> 0:01:16.440 signed the Partial Nuclear Test Ban Treaty, which banned the 0:01:16.440 --> 0:01:20.280 test of nuclear weapons in some places, including space. In 0:01:20.319 --> 0:01:23.280 this year, you also get a UN resolution saying weapons 0:01:23.319 --> 0:01:26.440 of mass destruction can't be orbited in space. And you 0:01:26.520 --> 0:01:29.559 get a United Nations Outer Space Treaty which comes into 0:01:29.600 --> 0:01:32.560 force in nineteen sixty seven, which reiterated all of these 0:01:32.600 --> 0:01:33.959 points for other nations as well. 0:01:34.800 --> 0:01:41.560 New Now satellites are safe, right, well, probably well, space 0:01:41.720 --> 0:01:44.440 is really vast. We've put a lot of stuff in 0:01:44.520 --> 0:01:47.040 orbit around Earth, and the pace at which we're sending 0:01:47.040 --> 0:01:50.040 stuff up is ever increasing as the cost of sending 0:01:50.040 --> 0:01:51.080 that stuff up drops. 0:01:51.520 --> 0:01:54.080 Could it get too crowded up there? Could some of 0:01:54.120 --> 0:01:56.680 the space litter we've left behind smash into the stuff 0:01:56.680 --> 0:01:59.760 we're still trying to use. I'd be really bummed out 0:01:59.800 --> 0:02:02.800 if I couldn't watch cat videos using my Starlink satellite 0:02:02.840 --> 0:02:06.280 provided internet. To answer some of these questions about the 0:02:06.360 --> 0:02:09.400 risks of stuff bumping into each other in space, we're 0:02:09.400 --> 0:02:13.400 interviewing doctor Jonathan McDowell, who has been tracking objects sent 0:02:13.480 --> 0:02:16.760 to space since nineteen sixty one, when the Soviet Union 0:02:16.840 --> 0:02:21.280 sent up Sputnick, the first ever satellite in space. Welcome 0:02:21.480 --> 0:02:23.760 to Daniel and Kelly's Extraordinary Universe. 0:02:37.000 --> 0:02:40.200 Hi, I'm Daniel. I'm a particle physicist, and I feel 0:02:40.200 --> 0:02:42.760 like my house is constantly filling up with junk. 0:02:43.520 --> 0:02:46.920 I'm Kelly Winer Smith. I'm a parasitologist and I have 0:02:47.080 --> 0:02:51.600 felt that way since I married Zach. And the rate 0:02:51.680 --> 0:02:54.799 at which the junk has been increasing has exponentiated since 0:02:54.800 --> 0:02:57.680 we had children. So we might have a Kessler syndrome 0:02:57.720 --> 0:02:59.840 situation happening in our house in the near future. 0:03:00.600 --> 0:03:02.880 That's only if your children collide with each other and 0:03:02.919 --> 0:03:04.200 make more children or something. 0:03:05.680 --> 0:03:07.960 The biologist in me is not okay with that metaphor. 0:03:09.200 --> 0:03:11.480 No, that was bad. So which of you is the 0:03:11.520 --> 0:03:13.919 cleaner upper or are you both contributing to the junk? 0:03:14.280 --> 0:03:17.400 I am the cleaner upper. I am also the less 0:03:17.440 --> 0:03:21.119 bringer stuffer into the houser. I don't like to buy 0:03:21.160 --> 0:03:23.960 a lot of new stuff, but that's not my husband's 0:03:23.960 --> 0:03:26.360 attitude about stuff. What about in your family. 0:03:27.680 --> 0:03:31.799 I'm the thrower away. I'm the person constantly carding out 0:03:31.919 --> 0:03:35.680 bags of junk in the house, whereas my wife and 0:03:35.760 --> 0:03:38.800 daughter like going thrift store shopping and so they're bringing 0:03:38.800 --> 0:03:40.800 stuff in, and then I'm like taking trips to the 0:03:40.800 --> 0:03:42.760 thrift store. When I take a trip to the thrift store, 0:03:42.800 --> 0:03:47.000 for example, it's a negative impact on our house, and 0:03:47.040 --> 0:03:48.960 they have the opposite effects. So we have like a 0:03:49.000 --> 0:03:50.120 thrift circuit going. 0:03:50.520 --> 0:03:50.840 Man. 0:03:51.120 --> 0:03:53.280 So I've gotten myself in trouble for being the person 0:03:53.280 --> 0:03:55.680 who throws stuff out in the house because my daughter 0:03:55.680 --> 0:03:57.680 will not let go of things, and Zach doesn't want 0:03:57.720 --> 0:03:59.400 to let go of things either, and I got in 0:03:59.440 --> 0:04:01.200 trouble once. I was like, well, if I just throw 0:04:01.240 --> 0:04:03.720 it out, they won't notice. But then they notice, And 0:04:03.800 --> 0:04:06.840 so for a while I moved everything to a storage unit. 0:04:07.040 --> 0:04:10.240 You might be noticing it's a whole thing, Yes, the 0:04:10.280 --> 0:04:10.800 whole thing. 0:04:10.920 --> 0:04:13.720 I see. See, you've moved to the multi stage throwout techniques. 0:04:13.760 --> 0:04:15.800 I'm gonna put it over here, and then when nobody notices, 0:04:15.840 --> 0:04:17.640 I'll move it over there, and then eventually I get 0:04:17.640 --> 0:04:18.320 to throw it away. 0:04:18.440 --> 0:04:20.960 And that's why I have a whole farm. I've got 0:04:21.560 --> 0:04:24.599 lots of spots to squirrel their junk away. Oh and 0:04:24.640 --> 0:04:27.160 I just remembered that Zach has been listening to the podcast, 0:04:27.160 --> 0:04:31.880 which is so nice of him. Don't check the tenant house. 0:04:33.640 --> 0:04:35.520 Well. The danger of moving on to a farm in 0:04:35.560 --> 0:04:37.719 a big house is the more space you have, the 0:04:37.760 --> 0:04:39.680 more junk you get. I feel like we have a 0:04:39.720 --> 0:04:41.680 constant density of junk, and if we lived in a 0:04:41.720 --> 0:04:43.919 smaller space, we would have less stuff. 0:04:44.080 --> 0:04:46.039 The belief has been that because we have all of 0:04:46.080 --> 0:04:49.080 this space, we can get more stuff. But I don't 0:04:49.120 --> 0:04:51.599 want the junk outside. I don't want more stuff. I 0:04:51.640 --> 0:04:52.719 don't want more stuff. 0:04:53.160 --> 0:04:56.680 Yeah. Space is more valuable than almost any stuff. Whenever 0:04:56.680 --> 0:04:58.720 we throw something away, I'm like, Ah, look at all 0:04:58.720 --> 0:05:00.320 that empty space. It's wonderful. 0:05:00.440 --> 0:05:01.840 Yes, right, isn't it nice? 0:05:01.839 --> 0:05:03.640 So when when you come home with like a bag 0:05:03.680 --> 0:05:05.120 in your hand and to just be able to like 0:05:05.120 --> 0:05:07.000 put it on the counter because there's clear space on 0:05:07.040 --> 0:05:09.440 the counter and not like have to elbow cups out 0:05:09.480 --> 0:05:09.880 of the way. 0:05:10.560 --> 0:05:15.240 Ah, agree with you? All right? 0:05:15.480 --> 0:05:17.039 All right, team clean over here. 0:05:17.279 --> 0:05:19.520 And if we were in charge of the atmosphere around Earth, 0:05:19.520 --> 0:05:21.200 maybe you and I we keep it pretty clean. 0:05:21.440 --> 0:05:23.760 Yeah, But the people that we keep interacting with would 0:05:23.760 --> 0:05:25.080 be like, well, there's a lot of space, so we're 0:05:25.120 --> 0:05:27.080 just gonna move it somewhere else, you know, And then 0:05:27.080 --> 0:05:30.520 the graveyard orbit would get all crowded. And I don't know, 0:05:30.560 --> 0:05:32.039 I'm a pessimist, Daniel. 0:05:32.320 --> 0:05:35.239 Yeah, Zach and Katrina would fill the universe with junk. 0:05:38.200 --> 0:05:42.080 There's there's room. Don't worry. Buy more books, buy more books. Well, 0:05:42.080 --> 0:05:43.360 we don't have to keep them. We're not going to 0:05:43.400 --> 0:05:45.039 read them again. No, I can't let go of a book. 0:05:45.080 --> 0:05:46.039 Books gotta stay forever. 0:05:47.520 --> 0:05:50.080 Zach, you can keep all your books in orbit near Pluto. 0:05:50.279 --> 0:05:55.040 M I love you, And today on the podcast, we're 0:05:55.040 --> 0:05:57.800 going to be talking about junk and space junk with 0:05:57.880 --> 0:06:00.839 somebody who has spent their whole career thinking and tracking 0:06:00.920 --> 0:06:02.400 bits of garbage in space. 0:06:02.680 --> 0:06:06.080 I have loved interacting with Jonathan McDowell on Twitter. When 0:06:06.080 --> 0:06:07.560 we were writing A City on Mars. He was my 0:06:07.600 --> 0:06:10.000 go to person where I was like the needles from 0:06:10.040 --> 0:06:13.039 Project west Ford, are they still in space? Jonathan, the 0:06:13.160 --> 0:06:15.919 glove that got lost during the EVA number five hundred 0:06:15.920 --> 0:06:18.440 and forty three, is that still in space? He knows 0:06:18.480 --> 0:06:21.560 the answer to all of these questions. He is the guy. 0:06:21.760 --> 0:06:23.640 We're excited to have him on the show today, So 0:06:23.800 --> 0:06:31.640 let's jump right in. On today's show, we have doctor 0:06:31.720 --> 0:06:36.119 Jonathan McDowell. He's an astrophysicist at the Harvard Smithsonian Center 0:06:36.160 --> 0:06:39.880 for Astrophysics in Cambridge, Massachusetts. He's also the editor of 0:06:39.960 --> 0:06:43.919 Jonathan's Space Report, a free internet newsletter founded in nineteen 0:06:44.040 --> 0:06:48.039 eighty nine which provides technical details of satellite launches. His 0:06:48.080 --> 0:06:52.400 website provides the most comprehensive historical list of satellite launch information, 0:06:52.720 --> 0:06:55.320 starting with Sputnik. And he's a fellow of the Royal 0:06:55.360 --> 0:06:59.400 Astronomical Society, an American Astronomical Society fellow, and he has 0:06:59.440 --> 0:07:02.800 an astro named after him forty five eighty nine McDowell. 0:07:02.800 --> 0:07:05.039 So he's now officially the second person on the show 0:07:05.200 --> 0:07:08.200 who has an asteroid named after him. Martin Elvis beat 0:07:08.240 --> 0:07:09.640 you by a few months there. 0:07:09.640 --> 0:07:13.280 My old boss. Yes, he was your old boss. He's 0:07:13.320 --> 0:07:16.800 the one who conned me into crossing the pond and 0:07:16.880 --> 0:07:20.440 coming to work at Harvard instead of staying in England, 0:07:20.520 --> 0:07:24.280 which I'm now sort of regretting. Yes, no, Martin, I 0:07:24.320 --> 0:07:24.920 go back away. 0:07:25.440 --> 0:07:27.920 Ah, wonderful. Well, he's absolutely lovely. And he talked to 0:07:27.960 --> 0:07:31.000 us about asteroids. We're talking to you about stuff that's 0:07:31.000 --> 0:07:33.760 floating around in space. So we had a listener who 0:07:33.800 --> 0:07:35.600 asked a question, and we're going to play the question 0:07:35.640 --> 0:07:37.840 a little bit later. But that got us interested in 0:07:37.840 --> 0:07:40.720 space debris. So I think for starters let's just talk 0:07:40.760 --> 0:07:43.400 about what kind of stuff we have up there, debris 0:07:43.520 --> 0:07:46.000 or otherwise that's orbiting the Earth right now. 0:07:45.960 --> 0:07:50.520 So there are about twenty five thousand objects that the 0:07:50.560 --> 0:07:52.760 Space Force radars are tracking every day. 0:07:52.920 --> 0:07:53.640 It's a lot. 0:07:53.960 --> 0:07:57.000 Twenty five thousand. Wow, that's an incredible number. 0:07:57.080 --> 0:07:59.360 That's just the ones big enough to see. Right. They 0:07:59.400 --> 0:08:02.559 go from the four hundred and fifty ton International Space 0:08:02.600 --> 0:08:07.040 Station down to little shards of debris that are only 0:08:07.120 --> 0:08:10.280 about five or ten centimeters across to aally bit about 0:08:10.320 --> 0:08:14.360 where they come from. But below that, between like say 0:08:15.040 --> 0:08:18.280 one centimeter and ten centimeters, we think there might be 0:08:18.360 --> 0:08:20.880 as many as a million pieces of debris that we 0:08:20.920 --> 0:08:22.840 don't even know about because they're too small for the 0:08:22.920 --> 0:08:27.080 radars to see. So now space is big, but everything 0:08:27.120 --> 0:08:30.160 in space, because of Kepler's laws, is traveling like seventeen 0:08:30.200 --> 0:08:34.520 thousand miles an hour. And so you know, it's pretty 0:08:34.520 --> 0:08:39.559 crazy up there. And we have now ten thousand working satellites. 0:08:40.160 --> 0:08:42.760 Just five years ago it was only one thousand. Now 0:08:42.760 --> 0:08:45.800 it's gone up to ten thousand. Is that all starlink, 0:08:46.040 --> 0:08:48.560 well about half of them a starlin Ghia. And so 0:08:48.600 --> 0:08:53.120 there's Internet relay, there's Internet of things relay, there's ship 0:08:53.160 --> 0:08:57.680 and the airplane tracking. There's weather satellites, there's SPIC satellites, 0:08:57.760 --> 0:09:03.440 resource monitoring satellites, those intelligence which is like intercepting communications 0:09:03.480 --> 0:09:06.240 and radio signals for the military, and of course a 0:09:06.280 --> 0:09:09.880 few science satellites. People often think that space is like, oh, 0:09:09.920 --> 0:09:13.800 that's science, but science is a pretty small fraction of 0:09:13.840 --> 0:09:16.480 what's going on and what can happen is every time 0:09:16.520 --> 0:09:19.520 you launch a satellite, you use a rocket to do it, 0:09:20.120 --> 0:09:22.400 and to put it in orbit. The upper rocket stage 0:09:22.440 --> 0:09:25.560 has to get into orbit along with the satellite. So 0:09:25.640 --> 0:09:28.000 now you've launched your satellite, but you've also made a 0:09:28.040 --> 0:09:31.559 piece of space junk the rocket stage. And nowadays, if 0:09:31.600 --> 0:09:34.240 you're like prudent, you have a restartable engine. You can 0:09:34.240 --> 0:09:36.520 bring the rocket stage down in the ocean afterwards. But 0:09:36.559 --> 0:09:38.120 we didn't used to even bother to do that. So 0:09:38.160 --> 0:09:42.120 if you look in the catalog of there's now over 0:09:42.280 --> 0:09:46.000 sixty thousand objects in the Space Object catalog, including all 0:09:46.000 --> 0:09:49.040 the re entered ones. The second entry in the catalog 0:09:49.280 --> 0:09:54.560 is Sputnik, Russia's first satellite, but the first entry satellite 0:09:54.640 --> 0:09:58.800 number one is actually the rocket stage that puts Putnik 0:09:58.800 --> 0:10:02.679 in orbit and so the very first entry in the 0:10:02.720 --> 0:10:04.240 catalog is a piece of space jump. 0:10:04.720 --> 0:10:06.920 Oh that's interesting and depressing. 0:10:07.720 --> 0:10:10.600 Yeah, what's worse if you leave a little extra fuel 0:10:10.640 --> 0:10:13.120 in the tank of your rocket stage, which you can 0:10:13.320 --> 0:10:14.960 tend to do because you don't want to arrive at 0:10:15.000 --> 0:10:18.680 your destination running on empty rocket stages? Have you know 0:10:18.880 --> 0:10:22.960 fuel and oxidizer that combine to burn to make the flame, 0:10:23.280 --> 0:10:26.240 but they're in separate tanks, separated by often like a 0:10:26.360 --> 0:10:29.880 rubber gasket or something like that, which over years can erode. 0:10:30.480 --> 0:10:32.920 The two can get together and depending on your mix 0:10:32.960 --> 0:10:36.360 of propellant, ten years after you abandon your rocket stage 0:10:36.440 --> 0:10:39.080 in Earth orbit, the fuel and oxidizer can have a 0:10:39.120 --> 0:10:41.440 party and suddenly you don't have a rocket stage. You 0:10:41.600 --> 0:10:43.800 have three hundred pieces of space to breathe. 0:10:43.880 --> 0:10:45.559 Oh my god. So you're saying they explode? 0:10:45.840 --> 0:10:49.480 That will be the technical term, yes, whereas the space 0:10:49.520 --> 0:10:53.760 guys like to say an RUD a rapid unplanned disassembly. 0:10:56.160 --> 0:10:58.840 We have all kinds of euphemisms right for the bad 0:10:58.840 --> 0:11:00.600 things that can go wrong in sp It's another one 0:11:00.640 --> 0:11:03.160 of my favorites. Say is you know ICIBM into continent 0:11:03.280 --> 0:11:07.320 balistic missile, But do you know IOBM, which is in 0:11:07.400 --> 0:11:08.480 ocean by mistake. 0:11:08.760 --> 0:11:15.080 Oh no, So what's the sort of natural context, Like 0:11:15.320 --> 0:11:17.480 we are creating these little bits of space junk, But 0:11:17.960 --> 0:11:20.920 was the near Earth atmosphere sort of empty before that? 0:11:21.120 --> 0:11:22.920 Or are there are like a lot of natural things 0:11:22.920 --> 0:11:23.680 floating out there. 0:11:23.840 --> 0:11:26.600 So within the orbit of the Moon, we do have 0:11:26.720 --> 0:11:30.480 like meteors coming in on escape trajectories. Right, they're not 0:11:30.600 --> 0:11:33.160 orbiting the Earth. They have escape colostoy respect to the Earth. 0:11:33.160 --> 0:11:36.640 They're going much much faster than satellites, and so they 0:11:36.679 --> 0:11:39.880 come in, they burn up, they're gone. They don't hang 0:11:39.960 --> 0:11:43.559 out in Earth orbit. The only piece of natural space 0:11:43.640 --> 0:11:45.640 junk we have orbiting the Earth is the Moon. 0:11:47.920 --> 0:11:49.640 You can't call the moon junk. 0:11:49.800 --> 0:11:55.240 Come on, you know, it's a big love huston. You know. 0:11:55.280 --> 0:11:57.839 We added to that with Spootnak and we've added ever since. 0:11:58.200 --> 0:12:02.160 Again not just rocket stages blowing up, but also satellite's 0:12:02.200 --> 0:12:06.520 hitting each other. So in two thousand and nine and 0:12:06.559 --> 0:12:10.760 an Iridium communication satellite hit an old Soviet dead communication 0:12:10.880 --> 0:12:14.400 satellite at about twenty thousand miles an hour in orbit. 0:12:14.440 --> 0:12:16.079 And to give you an idea of the kinetic energy 0:12:16.120 --> 0:12:19.360 involved in that, right, I mean it's like some number 0:12:19.600 --> 0:12:22.360 of gigajuls. And now you don't have a feel for that. 0:12:22.520 --> 0:12:25.960 So I calculated in terms of my unit of how 0:12:26.040 --> 0:12:30.360 hard something hurts is. Imagine being hit by a one 0:12:30.440 --> 0:12:33.320 ton truck. You can kind of sense how much that 0:12:33.360 --> 0:12:37.320 would hurt. The energy involved in one of these orbital 0:12:37.360 --> 0:12:41.040 collisions is about fifty thousand times that. 0:12:41.360 --> 0:12:43.400 Wow, wow, oh my gosh. 0:12:43.559 --> 0:12:46.080 And so what happens is a hypersonic shockwave goes through 0:12:46.120 --> 0:12:51.000 both spacecraft, reducing them to shrapnel. The clouds of shrapnel 0:12:51.000 --> 0:12:53.800 passed through each other largely unchanged, and you end up 0:12:53.840 --> 0:12:57.160 with them in the original orbit, but many many little 0:12:57.160 --> 0:13:00.280 pieces instead of one big one. So we don't like that. 0:13:00.000 --> 0:13:02.480 That's bad. It can cause it. Ultimately, if you have 0:13:02.600 --> 0:13:04.640 enough of those, you can get a chain reaction called 0:13:04.640 --> 0:13:08.280 the Kestler syndrome that could make space unusable. And then, 0:13:08.320 --> 0:13:11.400 you know, some people think it's fun to fire a 0:13:11.480 --> 0:13:14.000 missile at one of their own satellites and blow it 0:13:14.080 --> 0:13:18.160 up just to show how powerful they are anti satellite weapons, 0:13:18.280 --> 0:13:21.320 and that causes yet there's more debris due to that. 0:13:21.760 --> 0:13:25.000 There's been a move in recent years to go, you know, guys, 0:13:25.200 --> 0:13:27.000 that's probably not a good idea. 0:13:27.640 --> 0:13:29.640 Yeah, let's stick into that a little bit more so. 0:13:29.679 --> 0:13:33.600 I know that the Soviet Union, the United States, India, China, right, 0:13:33.640 --> 0:13:36.680 they've all blown their own satellites up in space, is 0:13:36.720 --> 0:13:37.079 that right? 0:13:37.400 --> 0:13:40.199 That is correct? Fortunately, so far they've only been tests 0:13:40.240 --> 0:13:42.920 on their own satellites and not attacking somebody else's. 0:13:43.559 --> 0:13:45.600 So for our audience who's maybe not familiar with this, 0:13:46.120 --> 0:13:48.920 why are countries blowing up their own satellites. 0:13:48.679 --> 0:13:50.760 Right, it's to prove that they could blow up your 0:13:50.800 --> 0:13:53.640 satellites if they want it. And so the idea, you know, 0:13:53.720 --> 0:13:56.520 what people may not appreciate is so much of our 0:13:56.600 --> 0:14:01.679 lives today actually invisibly depends in space technology. I mean 0:14:01.720 --> 0:14:05.520 the most obvious case, of course is GPS. I actually 0:14:05.520 --> 0:14:07.240 know how to read a map, but the younger generation 0:14:07.360 --> 0:14:10.000 are going to be really hosed if GPS ever goes down. 0:14:10.000 --> 0:14:11.720 They're not going to be able to get home. And 0:14:11.760 --> 0:14:15.360 that was originally a military system to target CRUISMUSS and 0:14:15.600 --> 0:14:19.360 so that's in a war, taking out the GPS satellites 0:14:19.400 --> 0:14:23.160 would be something that an attacker might want to do. Similarly, 0:14:23.440 --> 0:14:27.760 military allund space communications. There are missile warning satellites that 0:14:28.160 --> 0:14:30.800 spot when a missile is launched, and that's you know, 0:14:31.000 --> 0:14:34.320 how you get that warning. And there are these sort 0:14:34.320 --> 0:14:37.720 of very spic satellites, right, and so the military, even 0:14:37.800 --> 0:14:41.160 more than normal people, are so very invested in space. 0:14:41.320 --> 0:14:45.720 Their systems are integrated with space systems, and so in 0:14:45.760 --> 0:14:49.440 a war, those space systems are obvious targets. And so 0:14:50.040 --> 0:14:52.440 the idea of anti satellite weapons has been around for 0:14:52.440 --> 0:14:55.000 a long time. The first attempt that I'm aware of 0:14:55.160 --> 0:14:58.880 was in nineteen fifty nine when they fired a test 0:14:58.920 --> 0:15:02.640 missile against the Explorer six satellite and missed it. But 0:15:03.680 --> 0:15:06.040 it's not a new idea, that's what I'm saying. So 0:15:06.200 --> 0:15:08.120 all of these things, you know, very early. The fifties 0:15:08.160 --> 0:15:11.200 were a crazy time, man, They tried all kinds of 0:15:11.200 --> 0:15:12.240 stuff very early. 0:15:12.800 --> 0:15:15.280 And so every time we blow up a satellite, you 0:15:15.360 --> 0:15:18.080 go from one object in space to like a million 0:15:18.160 --> 0:15:20.840 objects in space. Do we then track all of those 0:15:20.840 --> 0:15:22.040 individual components? 0:15:22.240 --> 0:15:24.680 Yeah, well, the ones above ten centimeters we track. And 0:15:24.760 --> 0:15:27.640 so sometimes people talk about shooting down a satellite, but 0:15:27.720 --> 0:15:30.520 I hate that phrase because you don't actually shoot it down. 0:15:30.760 --> 0:15:33.120 You add energy, you especially in the pieces, but those 0:15:33.160 --> 0:15:35.920 pieces still have orbital velocity and they stay in limit. 0:15:36.440 --> 0:15:38.440 And so if you have a satellite that's say in 0:15:38.440 --> 0:15:42.680 a five hundred kilometer circular orbit. The pieces are in 0:15:42.760 --> 0:15:45.840 elliptical orbits that are one end is five hundred and 0:15:45.880 --> 0:15:47.680 then the other end might be lower, or it might 0:15:47.720 --> 0:15:49.720 be higher, as much as one thousand kilometers or two 0:15:49.720 --> 0:15:52.920 thousand kilometers coming down to the ones that go down 0:15:53.040 --> 0:15:55.400 where you know we'll re enter quickly. The ones that 0:15:55.480 --> 0:15:57.640 go up will stay up for a long time. And 0:15:57.760 --> 0:16:01.040 so the worst one was a China Ease anti satellite 0:16:01.080 --> 0:16:04.080 test in two thousand and seven, and that created three 0:16:04.200 --> 0:16:07.840 thousand pieces of tracked debris. And so in my catalog 0:16:07.920 --> 0:16:09.560 that I have on my website is each one of 0:16:09.560 --> 0:16:13.160 those three thousand pieces has a catalog number from the 0:16:13.200 --> 0:16:17.160 Space Force, It has orbital parameters that are updated every day. 0:16:17.640 --> 0:16:20.280 It's quite a tusk keeping track of these things. 0:16:20.400 --> 0:16:22.320 So there's some random chunk of a satellite that has 0:16:22.360 --> 0:16:24.880 like a name and a place in your database, and 0:16:24.920 --> 0:16:27.040 you're tracking and it's just like a hunk of metal 0:16:27.040 --> 0:16:27.720 floating through. 0:16:27.560 --> 0:16:31.440 Space that's exactly right. And you know, every now and again, 0:16:31.480 --> 0:16:35.080 for example, the International Space Station has to dodge one 0:16:35.120 --> 0:16:38.560 of these things. So the Space Force tressing goes, oh hey, guys, 0:16:39.120 --> 0:16:42.120 about twenty four hours from now, this chunk of metal 0:16:42.200 --> 0:16:44.160 is going to go within a few hundred meters of 0:16:44.160 --> 0:16:44.760 the space station. 0:16:45.120 --> 0:16:46.920 Wait before we get to the ISS, how do we 0:16:47.000 --> 0:16:49.720 track all these things? Like who is tracking this random 0:16:49.800 --> 0:16:52.760 chunk of Chinese satellite? How do we monitor these things? 0:16:52.880 --> 0:16:55.320 So mostly it's the US Space Force route. For low 0:16:55.520 --> 0:17:01.120 orbit satellites, they use radars, so you bounce radar radio 0:17:01.200 --> 0:17:04.160 energy off the satellite and the echo gives you its 0:17:04.200 --> 0:17:07.199 position and velocity. But it's a problem because if you 0:17:07.280 --> 0:17:09.680 have like say one hundred new pieces that you're tracking, 0:17:10.359 --> 0:17:12.720 so you see them come over, Okay, you get measurements 0:17:12.720 --> 0:17:15.440 of one hundred pieces. An hour and a half later, 0:17:15.480 --> 0:17:18.520 they've orbited the Earth. You look again, you've got another 0:17:18.520 --> 0:17:21.399 one hundred pieces. But matching up which one goes with 0:17:21.440 --> 0:17:24.919 which one is very non trivial. Yeah, and so it 0:17:24.960 --> 0:17:28.440 takes a long time to catalog the debris, and that's 0:17:28.440 --> 0:17:31.560 a period you're not getting warnings from those new objects. 0:17:31.560 --> 0:17:35.119 So that's why new debris is very bad. Radars are 0:17:35.160 --> 0:17:38.280 great up to about one thousand kilometers. A few thousand kilometers, 0:17:38.920 --> 0:17:41.880 they're a one over art of the fourth law. If 0:17:41.880 --> 0:17:44.760 the thing is ten times further away, it's ten thousand 0:17:44.800 --> 0:17:48.960 times weaker reflected single. So for high orbit satellites, radars 0:17:49.000 --> 0:17:51.240 really aren't the way to go, and we've been using 0:17:51.400 --> 0:17:55.320 regular optical telescopes to observe the objects. And now we're 0:17:55.359 --> 0:17:59.359 actually starting to deploy satellites in high orbit whose job 0:17:59.520 --> 0:18:02.520 is to catalog all the other satellites and keep track 0:18:02.520 --> 0:18:02.840 of them. 0:18:03.320 --> 0:18:04.919 Why is it one over out of the fourth? Is 0:18:04.920 --> 0:18:06.560 it because you get one of our r squared from 0:18:06.600 --> 0:18:08.440 your signal and then one of o are squared from 0:18:08.480 --> 0:18:08.879 the bounce. 0:18:09.400 --> 0:18:11.720 Exactly right, it's one of our squared each way. 0:18:12.119 --> 0:18:14.919 Wow, I see. So that's difficult. It seems to be 0:18:14.960 --> 0:18:17.240 like a really hard problem, even if you know where 0:18:17.240 --> 0:18:19.879 everything is, even if there's nothing new, because radar is 0:18:19.920 --> 0:18:22.320 just giving you locations, right, it doesn't measure velocities. 0:18:22.480 --> 0:18:26.760 Yes, there's a dopplers, but it's only one component. Oh right, okay, right, 0:18:26.840 --> 0:18:30.120 you have arrange an arrange rate, and then you only 0:18:30.200 --> 0:18:34.520 have a very approximate angular position on the sky because 0:18:34.560 --> 0:18:37.399 the radar is very sharp, and so you need multiple 0:18:37.400 --> 0:18:40.800 observations to kind of resolve that and do it. So again, 0:18:40.840 --> 0:18:42.880 this is something they've been doing since the nineteen fifties, 0:18:42.880 --> 0:18:45.640 and it was kind of manageable back then, and there 0:18:45.800 --> 0:18:48.639 weren't that many satellites, and now it's getting a really 0:18:48.680 --> 0:18:52.320 tough problem and you can see them struggling. There was 0:18:52.359 --> 0:18:56.000 a recent Chinese satellite launch. Eighteen satellites went up about 0:18:56.000 --> 0:18:58.680 a month ago, and it was only yesterday that Space 0:18:58.720 --> 0:19:01.600 Farce started issuing orbital for them because it took them 0:19:01.600 --> 0:19:04.040 that long to sort it out. It's a fascinating problem 0:19:04.119 --> 0:19:07.600 and really technically challenging, and in the circumstances they do 0:19:07.640 --> 0:19:11.320 a pretty good job, but it's not really good enough 0:19:11.359 --> 0:19:12.320 for what we need today. 0:19:12.880 --> 0:19:14.880 Yeah, it seems like a lot of compute is required. 0:19:14.920 --> 0:19:17.280 You have to know all these trajectories, predict where they are, 0:19:17.359 --> 0:19:19.840 get the new data, update the trajectories if they are 0:19:19.920 --> 0:19:23.520 dev from your prediction. I'm wondering about the security here, 0:19:23.560 --> 0:19:25.840 Like there must be things in space that are like 0:19:25.920 --> 0:19:28.720 secret spy satellites. Are those parts of your database? Is 0:19:28.760 --> 0:19:31.440 the NSA watching you to see if you're tracking that stuff. 0:19:31.720 --> 0:19:33.240 If they're not, they're not doing their job. 0:19:35.720 --> 0:19:39.480 You've really acclimated to life in the United States Johnson, Yeah. 0:19:39.359 --> 0:19:43.400 Right, exactly. The secret satellites are tracked by the Space Force. 0:19:43.520 --> 0:19:47.200 The US secret satellites, they don't release the orbital data 0:19:47.200 --> 0:19:51.120 for that publicly. The Russian and Chinese secret satellites they do. 0:19:52.240 --> 0:19:55.480 The Israeli and French ones they sometimes do sometimes that 0:19:55.880 --> 0:19:57.879 so our friends they keep the cle one secret. But 0:19:57.920 --> 0:20:00.880 for people we don't like, we just publish them. Very recently, 0:20:01.119 --> 0:20:04.159 there was maybe one hundred or so secret US and 0:20:04.200 --> 0:20:08.679 Allied satellites, and most of them were pretty big. Some 0:20:08.800 --> 0:20:11.160 of the old big Bird Spy satellites are like ten 0:20:11.240 --> 0:20:14.840 tons right in low orbit, and so they're as bright 0:20:14.880 --> 0:20:17.879 as the brightest stars in the sky. And so in 0:20:17.960 --> 0:20:20.560 order to get their orbits, all you really need are 0:20:20.560 --> 0:20:24.640 binoculars in the Stopwatch, sometimes not even binoculars. 0:20:24.720 --> 0:20:27.359 So it's in this category of like officially secret but 0:20:27.560 --> 0:20:28.960 totally obvious exactly. 0:20:29.000 --> 0:20:32.000 So, you know, we figure that a bunch of amateurs 0:20:32.040 --> 0:20:34.800