Ep. 766: How Spacecraft End

Interactive Transcript

spk_0 Oh

spk_0 A

spk_0 episode 76 how Spacecraft End. Welcome to a

spk_0 astronomy cast a weekly facts based journey to the

spk_0 cosmos. We help you understand not only what we know, but

spk_0 how we know what we know. I'm Fraser Kane. I'm the publisher of University

spk_0 with me as always is Dr. Pamela Gay, a senior scientist for the

spk_0 planetary science institute and the director of Cosmic

spk_0 Quest. Hey Pam, how you doing? I am doing well. I have to point out for the

spk_0 audience for those who don't know because they only listen to the podcast. I

spk_0 come up with the initial graphics and name of it and then you give it a much

spk_0 more SEO friendly, but this is one of those episodes where I'm super proud. My

spk_0 title was End of Life Planning for your Spacecraft. Yours more SEO friendly.

spk_0 Mine amused me more and I just need to share. You are the master of titles. I am

spk_0 the person who writes hockey titles that amused me. Yeah, yeah. I mean this is

spk_0 always a tension between us. People's like wonder what is the what is the core

spk_0 tension between Fraser and Pamela as a as a production duo here? Yeah. Is

spk_0 that I want the episodes to be very no nonsense as a as a stand on and

spk_0 different from the other stuff that we do because both of us are doing much

spk_0 more whimsical news based current events like that's our bread and butter.

spk_0 And so this is something that is timeless. We'll stand, you know, we'll be here

spk_0 forever. You know, the episode about Mercury. It's called Mercury. Yeah. Yeah.

spk_0 And so yeah, no, and so often what will happen is I will pitch you a whole

spk_0 bunch of subjects and mine are very much, you know, gravitational lensing. Right.

spk_0 Right. Spiral galaxies and you will be like, you know, on the deepness of

spk_0 thought regarding me. I don't do that. I do usually plays on words. Yes, you are

spk_0 very punny. Yeah. Yeah. You are very lyrical in the way you describe these in

spk_0 a and for me, like normally, yeah, I'm all over that. That sounds great. Those are

spk_0 the kinds of titles that I would do. But for astronomy cast, I know. It needs to

spk_0 be this archive of just very straightforward, easily accessible things. So we,

spk_0 this is a creative tension and sometimes, you know, I win. Sometimes you win.

spk_0 Mostly neither of us care enough to make a big stink about it. So yeah.

spk_0 Your spacecraft has reached the end of its mission. You've done everything you

spk_0 can to keep it operational. But now it's time to say goodbye. How do space

spk_0 agencies deal with spacecraft to shut them down gracely, protect future

spk_0 missions and life on other worlds? And we'll talk about it a second, but it's

spk_0 time for a break. And we're back. So what led to your thinking about this

spk_0 episode? Because this topic came from you. So I basically we first did, okay,

spk_0 so you need to get a launch license. Then we looked at rockets versus the

spk_0 environment. And I was like, I'm out of creativities or anything else that

spk_0 naturally follows on that cycle. Well, once they're born, they have to die. And

spk_0 that's literally where this came from was now that we've launched them. What do

spk_0 we do with them? But there was a really dramatic mission end that happened

spk_0 earlier this year with the guy mission. And we got this sort of blow by

spk_0 below explanation of what was going on. And I think a lot of people were quite

spk_0 puzzled by the extremes that the European Space Agency was going to to shut

spk_0 down the guy mission. It wasn't just, all right, we're just going to leave it

spk_0 there, turn off the switches. Hopefully we'll come back in a couple of years

spk_0 and maybe somebody will be able to get guy going again. Who knows? No, no, they went

spk_0 scorched earth on guy. Yeah, they needed it into a heliocentric orbit. And

spk_0 dismantled its memory block by block overwriting it with garbage to make sure

spk_0 they had to do. Yeah, well, so the rationale for that was that they didn't want

spk_0 this spacecraft to accidentally come back online and to interfere with any

spk_0 other missions that were going on. They wanted to not only be non-functional

spk_0 propellant wise power wise, because it was still had lots of power, right? It just

spk_0 didn't have a propellant. And so they had to it was going to and it was built to

spk_0 be super redundant. Really try hard to connect with earth-based satellite. Like

spk_0 it was really going to keep trying to do its mission. And so they had to go in

spk_0 and they had to rewrite its memory block by block, filling it with I think

spk_0 the names of everybody on the team. Yeah, right? Imagine you just go through your

spk_0 memory of your of some software application you've worked on replacing it

spk_0 block by block on the hard drive with the names of people. Like it is not going

spk_0 to be a functional piece of software by the time you're done with it. No, yeah. No, and

spk_0 and this really when you think about how hardcore that is like in my

spk_0 universe, sure, you just like overwrite whatever the equivalent of the

spk_0 bios part of the memory is. But no, they did the whole darn thing. Yeah, they did

spk_0 the whole thing. They made sure that there is no possible way that that spacecraft

spk_0 can lurch from the grave and interfere and that their concern about it, messing

spk_0 up comms, providing a false signal was just so extreme that they went to this

spk_0 level of finality for the mission. And and this is the kind of thinking like I

spk_0 wanted to start with a very dramatic example because this is the kind of

spk_0 headspace that mission planners are in. And I think that for a lot of people,

spk_0 that is going to feel very surprising that the expectation is you've already

spk_0 spent all this money all this time, all this expenditure to get this thing out into

spk_0 space. Why won't they just leave it? And then maybe some future generation

spk_0 could come along and use it and continue to bring it back operationally. So we'll

spk_0 get to all of that. But let's sort of just talk about this limited lifespan of

spk_0 satellites in spacecraft. So we have two major things that that bring

spk_0 spacecraft to a natural end, depending on how they've been constructed. One is

spk_0 you run out of propulsion so you're no longer able to change your orbit,

spk_0 lift your orbit, do whatever to your orbit. Now there are some spacecraft that

spk_0 they put them where they want them. They are fine where they are. Let's just

spk_0 leave them there. And even with those, you start to then run into the risk of,

spk_0 okay, so propulsion isn't necessarily my problem, but they could hit something.

spk_0 They could land on somebody. They could land someplace that doesn't

spk_0 currently have somebody's and put somebody's there. There are a whole

spk_0 variety of ways that your no longer fully functional mission could cause a

spk_0 very bad day for a planet where the Earth is a planet or other spacecraft that

spk_0 are out there trying to live their best life. And we see this happening about

spk_0 once a year where someone didn't take the end of life for their spacecraft or

spk_0 their space station very seriously and it's going to come back down at a random

spk_0 location almost certainly into the Pacific Ocean, but maybe just maybe into a

spk_0 populated center. And we've also started to see a whole lot of near misses where

spk_0 they've had to radically move spacecraft. And at some point as the number of

spk_0 spacecrafts continues to grow exponentially, it's going to hit the point where

spk_0 we don't just have near misses, we have actual collisions that create warm

spk_0 massive debris clouds than anyone really wants to deal with. Right. So we've got

spk_0 the situation like in lower orbit, these things could potentially come back down

spk_0 to Earth in random locations, even leaving them in lower orbit, they're going to

spk_0 be it's a very dense environment relatively speaking, you know still space, you

spk_0 know it's wide open, but still satellite to do crash into each other. And that if

spk_0 you leave your satellite, it's going to potentially crash into others and you're

spk_0 going to get more debris and that debris can crash into more debris, you've got a

spk_0 problem. And then the issue that we mentioned with Gaia is that they can also be a

spk_0 communications that they're going to be, you know, there's a limited amount of

spk_0 bandwidth you've got guy over there screaming, give me a job. Let me give you

spk_0 something to do. I'm over here. I mean, we're all monos. Yeah.

spk_0 I didn't have to deal with that situation, but there was there's one more issue

spk_0 with in the outer solar system. We saw this with the Galileo mission and the

spk_0 Cassini mission. What's that about? And this is the concern of the spreading

spk_0 somebody's where the somebody's are microbes bacteria and other life forms that

spk_0 get carried out there from the planet earth. And we are learning more and more

spk_0 about worlds in the outer solar system that either in the past or continue to

spk_0 have sub ice oceans. And there is potentially transfer of materials through

spk_0 cracks through processing from the surface down into those seas. And we don't

spk_0 want our life to potentially destroy life somewhere else or just make it so

spk_0 that we're not sure of what we're eventually finding came from us or got there

spk_0 on its own. Yeah, I always use this example, right? We send the first life mission

spk_0 to Enceladus. And they're like, cyanobacteria, weird. And then they, you know,

spk_0 when they search for your own, but cyanobacteria, weird. And they run Mars.

spk_0 Cyanobacteria, weird. Cyanobacteria is everywhere. It's all related. It's all just

spk_0 from Earth because cyanobacteria just loves an opportunity to take over. All right,

spk_0 we're going to talk about this topic some more, but it is time for another break.

spk_0 And we're back. All right. So we talked about sort of the reasons why spacecraft are

spk_0 that some level of intelligence needs to go into what you do with your spacecraft at the end.

spk_0 You don't just walk away from your spacecraft. You got to do something with it. So what do they do?

spk_0 So there are a number of different ways to dispose of your spacecraft. And

spk_0 there's actually international guidelines that when you have something in orbit around the Earth,

spk_0 I purred UN guidance. They make arrangements with different other organizations.

spk_0 25 years after your mission is over, your spacecraft should be put somewhere safe.

spk_0 The FAA has upgraded that now that we have so many more things out there to five years.

spk_0 You have five years to dispose of your spacecraft people. And, and so what they're looking at,

spk_0 is let's put solar sails on it. Let's put drag systems on it. Let's do something with those

spk_0 lower Earth orbit satellites that allow us to make sure with certainty that atmospheric drag

spk_0 is able to de-orbit them with things that are further out. We lift them up into higher orbits,

spk_0 or as they did with Gaia, send them on a journey round the Sun. And remember, it is

spk_0 energetically easier to remove something from the solar system than to crash it into the Sun.

spk_0 So don't ever try and crash anything into the Sun. Unless you're trying to study the Sun.

spk_0 Yeah, I think the idea is really important to go over this because we get this question all

spk_0 the time, which is like, why don't they just crash spacecraft into the Sun? And you've got to know,

spk_0 if you ever say, why don't they just, then you know already there's a really good reason why they

spk_0 don't just you just don't know the why yet. And that is because the Sun is actually the most

spk_0 difficult place to reach in the entire solar system. That the Earth is orbiting around the Sun

spk_0 at 30 kilometers per second. And the only way to make your material actually crashing to the Sun

spk_0 is to cancel out that 30 kilometers per second of orbital momentum. 30 kilometers per second is

spk_0 faster than any spacecraft has ever been launched from Earth. It would require propulsion systems

spk_0 that are unyet dreamed of. We literally cannot make a spacecraft crash into the Sun. And I defy

spk_0 you, play Curvel Space program, make a spacecraft go into the Sun. You will realize how difficult

spk_0 and challenging a problem this is only through multiple flybides of Mercury and Venus,

spk_0 Silling Shot Manuvers can finally get something into the Sun that things don't drift off into the Sun

spk_0 in space. We're at the bottom of a mountain. And to get up to the lunar orbit, you have to climb a

spk_0 mountain to get from Earth orbit to the Sun. You have to climb a different mountain or backwards.

spk_0 I don't know. Anyway, that moving spacecraft dramatically far away from where they currently are

spk_0 requires expenditures of propulsion that is way beyond what it took to even just launch the spacecraft

spk_0 in the first place. So you got to deal with what you got. Yeah, momentum is the law. It is going

spk_0 to be conserved. You have to transfer it somewhere. Yeah. So you mentioned this idea that they put it

spk_0 somewhere. Can you describe these sort of parking orbits or what's the term that got them for the ones

spk_0 that? Graveyard of orbits. Graveyard of orbits. Yeah. So with your stationary satellites, there is

spk_0 a set altitude where when you are at that distance from the Earth and in a circular orbit,

spk_0 key is circular orbit, you go around and around the world every 24 hours, which means that if you

spk_0 are planted directly over the equator, you stay over the exact same place in orbit. If you are

spk_0 north or south tilted, you would clearly be both north and south tilted depending on where you

spk_0 are in the orbit. You're going to go up and down a single line of longitude. And

spk_0 geostationary orbits are super useful for communication, super useful for weather satellites.

spk_0 And while it is a huge orbit, because it's so far away from the Earth,

spk_0 they are still squabbling over space. And so when something is no longer in use, they boost it to a

spk_0 higher orbit. The idea being it's in a higher orbit, it's now it's going to get out of sink

spk_0 with staying over the same place. It's going to actually be orbiting in more than 24 hours at that

spk_0 point. But atmospheric drag is not going to pull it back down to the Earth because higher, safer,

spk_0 less stuff. And so they just stick stuff in parking orbits with the idea that maybe someday someone

spk_0 will go out with their junk collector, the wallies of the future in orbit, and start scooping these

spk_0 missions up to do whatever we decide to do with them in the future. That works for things in

spk_0 geostationary orbit. Gaia was out in a Lagrange point and that is another place that has the

spk_0 potential to get super crowded because we really like to put things there. Now luckily the Lagrange

spk_0 points are only semi-stable. It doesn't take very much energy to get yourself out of this balancing

spk_0 point where the gravity of the Sun, the gravity of the Earth keeps you balanced so that the Earth and

spk_0 that Lagrange point go around the Sun at the same period. It's different rates. You're at different

spk_0 distances from the Sun. So if you're on the inner Lagrange point, you're going to be going

spk_0 slower to keep pace with the Earth. If you're further out, you're going to be going faster. But it's

spk_0 really easy to remove yourself from those semi-stable points. And as Gaia did, just put yourself into your

spk_0 own solitary orbit around the Sun that allows the Earth and your dead self to meet every few months,

spk_0 I guess. But it's more than that. It's that you have to expend energy to remain at the Lagrange.

spk_0 It's true. Yeah. So you just stop, you know, and this works well. If you no longer have propulsion,

spk_0 then you're no longer able to remain at the Lagrange point. You are going to naturally drift.

spk_0 And then if you do have like a little bit of propulsion luck, you can sort of decide where you're

spk_0 going to drift. They really want you to remove yourself. Yes. So the issue with allowing things to

spk_0 eat themselves, I just love that word by the way, is you don't know what you're going to hit

spk_0 on the way out if you're not steering. And this is the difference between you and I both slutted

spk_0 as kids and some sleds you can steer because they have little blades on them and others. You just

spk_0 sort of lean and hope. And a spacecraft doesn't even have the ability to lean and hope as it

spk_0 allows either the atmosphere or just instability to move it over time. So the idea is you have a

spk_0 controlled exit from that orbit. You should know on your stay in within five years of end of

spk_0 mission. And while you're still under control, we don't want any out of control spacecraft if we

spk_0 can help it, they expect this to only be a 90% success rate. It's spacecraft. Space is hard.

spk_0 Yeah. But the goal is 90% within five years for US spacecraft. The rest of the world is more

spk_0 like, we'll give it 25. That's where we are. All right. We're going to talk about the dramatic

spk_0 end of missions in the outer solar system, but it's time for the last break.

spk_0 And we're back. So we've talked about how you sort of deal with spacecraft here around Earth.

spk_0 But we saw a very interesting decision made for Galileo and Cassini. So how did that operate?

spk_0 So with Cassini is referred to as the grand finale. This was back in 2017. NASA made this a massive

spk_0 press event. They actually asked me to delay launch of a bunch of my programs because they didn't

spk_0 want my little tiny programs to potentially distract from from Cassini's attention. Cassini was

spk_0 a flagship mission that gathered gigabytes and gigabytes of data at a time when gigabytes were

spk_0 new and phenomenally large before we entered the terabyte and petabyte world of today.

spk_0 And the thing about this grand finale was this was a mission that had been extended such that

spk_0 they were able to capture the entirety of seasons of Saturn as it went around the sun. And we

spk_0 didn't know that would be something we could do. They were able to evolve the orbit to get closer

spk_0 and closer to the surface and study the clouds in detail. But at the Saturn system, you have Titan,

spk_0 which is a methane, methane world that we know because of Cassini has lakes and deltas. The Huygens probe

spk_0 was able to catch amazing imagery of this. And this is all the stuff of life. These are

spk_0 carbon molecules. And with so many organics at Titan and the recognition that the chemistry of

spk_0 this atmosphere is out of equilibrium in ways that require either active geological processes,

spk_0 active biological processes, or both both as loud. Titan is a world we don't want to mess with.

spk_0 We want to allow it to be its special little amazing self even though we already dropped Huygens on it.

spk_0 So we didn't want to crash there. We know that Enceladus is another one of these ocean worlds with

spk_0 its tiger stripes. We didn't want to mess with things there. And so that meant we had to dispose of

spk_0 our spacecraft somewhere where we weren't worried about Earth's life being compatible. And the

spk_0 atmosphere of Saturn and plunging through it to the high density extreme temperatures of going

spk_0 through that atmosphere seemed like a really good way to dispose of a spacecraft while not

spk_0 risking contamination. So that is exactly what they did back in 2017.

spk_0 Yeah. And I think that again seemed kind of weird to people like why are you keeping around?

spk_0 And it's just that you can't predict the future chaotic movements of the spacecraft as they

spk_0 continue to orbit around the planets and their moons that crashing into one of those moons is

spk_0 kind of inevitable. If you run the math into the future, it's end. So it may take thousands of

spk_0 years, tens of thousands of years. But eventually it's probably going to crash into one of the moons or

spk_0 or crashing to Jupiter or getting to weird orbits through through body interactions. So

spk_0 as we kind of get close to closing out this episode, I think it's important to say that

spk_0 that these ideas about end of life you sort of mentioned it briefly that you know people are

spk_0 looking at putting drag shoots, putting various other methods of slowing spacecraft down. And

spk_0 that this is actually a very under invested. Yeah. People aren't taking this seriously yet.

spk_0 And that there are committees coming together for the European Space Agency and international groups

spk_0 that are trying to put some kind of regulation that all spacecraft must have an end of life

spk_0 plan. And this is not the case today. So right now you can launch a spacecraft and people are going to

spk_0 say, look, what are you going to do when this thing reaches the end of its operations in the

spk_0 volcano? Who cares? Right? And that's perfectly no longer acceptable. Well, it is. I mean,

spk_0 like nobody is going to take it at ask yet. But we are probably just a couple of years away from

spk_0 that being the case that there are zero debris, zero remnant policies that are being put together

spk_0 now by, especially the European Space Agency. The Kessler syndrome is something we truly wish to

spk_0 avoid. The Wally future is not the one I want. And unless it's only the cute robots, I'm happy to

spk_0 take the cute robots and leave all of the death and destruction behind. Who can gently push away

spk_0 satellites as they fly out into space as opposed to the reality where they're moving at 28,000

spk_0 kilometers per hour and are like bullets tearing things apart. So yeah, we want to avoid the Kessler

spk_0 syndrome. We want to avoid landing things on people's houses. There is amazing statistics that

spk_0 if the current growth of satellites goes up, we're going to start to see human beings getting hit

spk_0 on the decade scale of time. Right. And just like cleanup after yourself's people,

spk_0 we've, we've no, nothing but footprints take nothing but pictures on space footprints. Yeah. Yeah. Yeah.

spk_0 Yeah, I mean, it's like again, it's another tragedy of the comments that we are knowingly

spk_0 stumbling ourselves into that we have this resource space. It is incredibly useful for us to be able

spk_0 to do our operations down here on earth to be able to communicate, be able to navigate all,

spk_0 you know, learn about the weather, predict, see our impact on the environment. Like it goes on

spk_0 and on. It's farmers to track their fields. Like there's so many benefits from us having this resource

spk_0 of space. And yet like we always do, we are filling it and not thinking too deeply about how to share

spk_0 it as a, as a space. And we are already starting to experience some consequences, but they have not

spk_0 gotten bad yet. We are in the pre-consequence phase of this process. And now is the time to think

spk_0 about how to deal with it. And it's going to be an amazing future. And I look forward to doing an

spk_0 update on this where we talk more about the new technologies to refuel, to grab and move, to

spk_0 de-orbit forcefully. Oh, that sounds great. Yeah. Yeah. Let's let's, I mean, because it's not just,

spk_0 like you shut off your spacecraft and call it a day, that the kinds of things that people are

spk_0 yelling into their devices right now. Why don't they refuel them? Why don't they refurbish them?

spk_0 This is all an industry that is starting to take off. And in fact, various spacecrafts have done

spk_0 this. So I think you're exactly right. Let's come back around in the future and talk about what are

spk_0 the cool ideas to deal with space junk, refurbish satellites, make them operational longer, try to live

spk_0 that dream of a reusable, repairable future. And we'll be five years from now talking about how

spk_0 ISS is getting de-orbitated. That is something like, I'm going to travel to see a office fly by.

spk_0 I'm going to travel to see why our four potentially hit the moon. And the ISS launching is going

spk_0 to be absolutely amazing. Like seeing the ISS come down. Yeah. Yeah. Yeah. But I mean, it will be

spk_0 happening in the middle of the Pacific Ocean, hopefully. Hopefully. Yeah. All right. We'll see.

spk_0 Thanks, Pamela. Thank you, Fraser. And thank you, everyone, out there. This show is supported by you

spk_0 through Patreon. If you don't have money to throw, we're fine with that. Just go follow for free so

spk_0 that you can get regular updates on everything we're doing. And I will be reading names separately.

spk_0 Rich, that file is coming to you later today. We are here thanks to the amazing support of

spk_0 everyone at patreon.com slash astronomy cast. This week we would like to thank in particular Abraham

spk_0 Catrell Alex Cohen Alexis Andrew Polestra Andy Moore Arctic Fox Brett Mormon Brian Cook

spk_0 Brian Kilby Buzz Parsec Claudia Maastriani Danny McLucci Diane Philippine Fairchild just as it sounds

spk_0 Felix Good G Calibs Xston Gerhard Schweitzer Glenn McDavid Gordon Dewis Helga Bjorkock J.

spk_0 Alex Anderson Janelle Jarvis Earl Jeanette Wink Jim McGee and Joanne Movy Jonathan H. Staver

spk_0 Jordan Turner Katie Baron Katie and Ulyssa Christian Golding Lee Harborn Masaholeu Matthew Crampton

spk_0 Michael Purcell Michelle Cullen Mike Dog Noah Albertson Paul Esposito Paul El Hayden Peter

spk_0 Planetar Rajev Achari Robbie the dog with the dot Resard with AZ Sergio Sencevo Sachi Takaba

spk_0 Skone Scott Briggs Steven Coffee the lonely sand person Tim Garrish thank you all so very much we

spk_0 wouldn't be here without you thanks everyone and we will see you next week bye bye

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Ep. 766: How Spacecraft End

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