The Supermassive Podcast - 18: A Hunk of Space Junk

Episode Date: June 25, 2021

Grab your dustpan and brush… This month, Izzie and Dr Becky get to grips with the leftovers from space activity, it's all about space junk. Joining them are engineer Dr Hugh Lewis from the University of Southampton, who models how the debris builds up over time, and space archaeologist Dr Alice Gorman explains its historical significance. Plus, Robert Massey joins in to take on your questions and shares his top stargazing tips. The podcast is looking for sponsorship to keep the series running. It'll help fund the recording, editing and time needed to bring you the latest from space. If you have a business that would be interested in supporting the series - or just a single episode - then email [e-mail] with the subject “sponsorship” for more information. This is a Boffin Media production by Izzie Clarke and Richard Hollingham 

Hello, Izzy from the Supermassive Podcast here. Just a quick one to say that the podcast is looking for sponsorship to keep the series running. It will help fund recording, editing, and the time needed to bring you the latest from space. If you have a business that'd be interested in supporting the series, or just a single episode, then email podcast at ras.ac.uk with the subject sponsorship for more information. Now, on to the show. How is space debris interfering with launches? There is an idea called a laser broom.

You can look at these objects as a response to human social needs. Welcome to the Supermassive podcast from the Royal Astronomical Society with me, science journalist Izzy Clark and astrophysicist Dr Becky Smethurst. Yeah, grab your dustpan and brush everybody because this month it's all about the leftovers from our space activity. We're talking about space junk. We'll be speaking to an engineer who has been watching the debris in space increase over the years, plus space archaeologist and queen of space junk. Dr. Alice Gorman explains its historical significance. Space archaeologist, right? That definitely gives astrophysicist

a run for its money, right? Like, it's like the coolest job title title i'm just picturing like indiana jones but in space yeah exactly um i could honestly say our chat with alice was brilliant so i'm very excited for everyone else to hear that but you know that's not all dr robert massey the deputy director of the royal astronomical society is here too so robert why is space junk a concern? Well, I absolutely agree, by the way. Space archaeologist is a way cooler title than the ones we have. But yeah, why is space junk a problem? Well, it is because it's material that's cluttering Earth orbit. And unlike on Earth, where I guess, you know, litter on the ground is unpleasant, but you can move out of the way.

When you're talking about things in space, they're going around at high speed. They can bash into the stuff you want to protect, whether that's the International Space Station or some sensitive space telescope or communication satellite or all of those things. It really does matter. It's really important we get a handle on this. And I think, I guess, we didn't worry about as much in the early days of the space age

in the same way that we didn't worry about polluting terrestrial environments when, say, oil was first recovered, because nobody thought about it. It takes a little while for people to catch up and think, oh, hang on a minute, we really do have a problem here. Some of our fellows are very heavily involved with that kind of work and actually thinking about how you do launches that minimize it, how you bring stuff down from space at the end of its life, and how you're a good actor in space, So you're not cavalier about it. You're certainly not recklessly trying to increase the amount of debris. And it was good that apart from,

you know, clogging up bits of cornmeal and doing lots of cheesy beach shots at the G7, you did have world leaders agreeing in the sidelines to a better way to handle space debris too. You know, they committed to what they call the sustainable use of of space which very much includes this area nice that's good to hear cheers robert um we'll catch up with you later in the show when we tackle our listener questions for this week so what goes up doesn't necessarily come down so space debris has been building up ever since we started to explore space it consists of of spacecraft, satellites, stages of rockets that put the satellites there in the first place. And the biggest category is all of the fragments of those things

as they've broken down over time. Yeah, it's amazing what's up there. There's even leftovers of like nuclear-powered spacecraft and then the odd tool like, you know, dropped by an astronaut mid-spacewalk. Can you imagine that? It's just like, oh, oh, oh, there it goes. Lost forever. Goodbye.

There's all sorts. So I spoke to Dr. Hugh Lewis from the University of Southampton, who also leads the UK Space Agency's efforts on modelling space junk. He started by explaining just how much space debris there is. So European Space Agency estimates

put about 34,000 objects that we can track, objects about the size of your smartphone or bigger. And then when we go to sizes, probably the size of your thumbnail and larger, we see probably about 900,000 of those. And if you want to go smaller, down to a millimetre in size and larger, just to give you a bit of context, a millimetre is about the size of the to give you a bit of context, a millimetre is about the size of the ball bearing you'd find in the end of a ballpoint pen. There are probably about 128 million of those in orbit. Wow. Okay. So there is a lot of stuff up there of all different sizes. Where do we tend to find all of this space debris? Most of our space debris

actually exists in the low Earth orbit region. And even within that, we can find a kind of a band of debris at an altitude somewhere between about 700 and 900 kilometers altitude. That's where most of the debris that we've created actually exists. And that is the region that we're perhaps mostly concerned by because of the amount of debris. But it's not the most valuable region. The most valuable region is actually that geostationary ring. That's where really big, expensive satellites are. They provide us with satellite TV, for example. And that's also a region that we're also concerned about.

Right. And we're going to get on to the the reasons why we need to be concerned in a moment but you have been looking and tracking all of this build-up of space debris since 1999 so how has that built up over time and how are you able to monitor all of this? Yeah, it's interesting because, you know, when I started my research in this area, we were making use of some data that was provided by the European Space Agency. And we were looking in our data at the number of objects that we'd use for our computer simulations. And it was something like 11,000, perhaps. And now we've got a population

that's 20,000 in the data that we're currently using. So that's grown quite a lot in actually quite a short amount of time. That growth trend is actually accelerating. We're starting to use space and in particular, that low earth orbit region, much more than we have been doing. particular low Earth orbit region, much more than we have been doing. Even just five or six years ago, we're starting to see very large numbers of satellites being deployed into low Earth orbit to provide us with global internet, for example. And what we're seeing is that the population is growing non-linearly or exponentially. By studying this, what are those questions that you're trying to ask and work out? What is it that modelling all this space junk can tell us? So I think there's a perception that actually we're using these computer models to predict the future.

Yeah. But that's not the case. So what we use our models for, first of all, to understand the nature of the population growth. Is it something that we can control? Is it exponential, so out of control, that kind of thing? And we also use it to evaluate how effective different countermeasures for space debris might be. So we can actually simulate the spacecraft that are in orbit, and we can tell those spacecraft to behave in a particular way. And then that allows us to see whether that behavior has a good outcome or a bad outcome. That information is really,

really critical if we want to be able to help real spacecraft operators to behave in a responsible way in the space environment. And so I guess this leads us to this big question of why do we even care about space junk? You know, why is this a problem? Why can't we just leave it all up there floating around in space? This question, I think, is the one that I get most often. And it's also the hardest one to answer. Space debris and other objects that are in orbit are travelling extremely quickly. So the International Space Station, for example, is travelling at 17,500 miles an hour, which is, it's like going from London to New York in about 10 minutes. Yeah, which would be nice, yeah.

Yeah, I suppose it would be. But when something hits you traveling that quickly, the amount of energy that it has is enormous. And it doesn't even have to be a very large object to cause damage or even to destroy a spacecraft. have become so reliant upon for things like positioning, for things like weather forecasts, satellite television and so on, they could be destroyed by a single impact from a space debris object. So we really want to try and avoid that. And that's what all of the countermeasures are about, trying to prevent those collisions from occurring. Yeah. In terms of solutions, I remember reporting on a story in 2018 for BBC Five Live, which was a project called Remove Debris, and they'd invented like a harpoon or a net and just trying all of these

different methods to try and capture space debris and clear things up a little bit. So what are the solutions that are out there? These things are going so fast. It's not a case of, oh, let me just get up like a little garbage truck and scoop it all out and, you know, jobs are good. It doesn't work like that, does it? No, I wish it did, but unfortunately it didn't.

I mean, the speeds, I mean, they are the biggest problem. So what you have to do is you have to kind of neutralize that speed by matching your trajectory with that of your target. You've got a really big problem typically because the types of objects you want to remove from the environment are the ones that are risky because they have a lot of mass and they're involved potentially in lots of close passes with other things. So you've got a really difficult job of handling something that is big. And by big, I mean something that is eight tons. You know, it's the size of a double decker bus. And you're going in there with a little robotic arm, perhaps to grab onto it, or you're going to throw a net over it

and you're going to remain connected via this long tether. There are all sorts of ways in which that could go wrong. The potential outcome of that, of course, is that you collide and you generate more debris. So you have to handle these things very, very carefully. And the technologies, such as the ones you mentioned on the Remove Debris Mission, are still really under development. We're still trying to figure out whether or not they will work for this purpose. So we've got some more demonstration missions that are taking place at the moment. For example, the ELSA-D mission,

which is a mission controlled by a company called Astroscale. So they're going to be testing out a variety of different manoeuvres and a technology involving a magnetic attachment. And is it a case of adapting future spacecraft to make sure that this isn't a problem? Or is it a case of trying to clear up what's already there? Or is it both? The simple answer is we need both. We need to be able to tackle the legacy of our space activity. So those are the objects that have failed in orbit already. They've been abandoned in orbit as well. But we also need to make sure that any spacecraft we launch in the future, if they were to fail,

we'd be able to grab those as well. And that, I think, is an easier problem because we're aware of what we need to do. So we can put a handle on it or a hook, or we can put a plate on that we can use a magnetic attachment for. All sorts of different things that we can include in the design that will help us to remove it should that become necessary later on. The legacy object's a bit harder to deal with, and we probably need different types of technology to handle that.

One of the debris mitigation measures that we have is that once the spacecraft has finished its mission, it can use the thrusters on the vehicle to push the altitude down so that the spacecraft burns up in the atmosphere. That's a way to remove it from the environment. We have to be careful with that the spacecraft burns up in the atmosphere. That's a way to remove it from the environment. We have to be careful with that though, because recent research has suggested that if we keep depositing the satellites and burning them up in the atmosphere, we're actually adding to the methyl deposits that exist in the atmosphere and they can have all sorts of effects on climate. It's not straightforward. And we do have to, I think, work a little bit harder

to understand what the implications might be. Just in case we weren't worried about the climate crisis enough, that was Dr Hugh Lewis from the University of Southampton. So, Becky, as Hugh was saying, this is an ever-increasing problem. So how is space debris interfering with launches? Yeah, I mean, a little bit. Just to put into context, so we're launching more a month than we used to do in a year. And all of those have got to go through this debris field around Earth. Now, if you're putting into low Earth orbit, you obviously got to navigate a lot less than if

you're trying to go beyond and sort of beyond the Earth, perhaps even beyond the Earth-Moon system as well. So something like the James Webb Space Telescope, for example, has got to make it through the entire debris field around the Earth before it gets to 1.5 million kilometers away from us. Now, space is big. So, you know, this debris field, you're probably picturing it like sort of that Star Wars asteroid field, right? It's not like that, you know, you really can't see anything. You know, if you see footage of the International Space space station you won't see a lot of debris out there but it still is a big issue especially for these smaller pieces of space debris that we can't track that are going very fast and then see the launch is going very fast as well so back in april 2021 uh the spacex crew

dragon launch that was taking astronauts the international space station um they actually had a near miss with a piece of debris that they only spotted at the last minute. Right. So, you know, that takes a day or so to get up to the International Space Station. They like slowly higher their orbit. So the astronauts were sort of after the stress of the launch, were about to go to sleep and sleep a little bit when NASA was essentially like, oh, hang on, no, suit up, strap yourself back in.

We think this is going to come quite close but we think it should miss but as a safety precaution yeah you know get strapped in and i think that just highlights you know the fact that we take for granted that these launches will be fine and they'll just sort of happen to make it through and yeah okay we can track the bigger pieces and know to avoid them but these smaller pieces can come as a little bit of a surprise and there always has to be a mitigation strategy for that and they always cause damage it doesn't really matter the size because they as we've discussed they're going at such high speeds that it can be it can be really dangerous and you know there is obviously that huge risk of space tank hitting the international

space station which actually happened a few weeks ago. Luckily, no one was injured. But is there any way that spacecraft can protect against that happening? Yeah, I mean, for those who hadn't heard, what happened was the International Space Station's robotic arm that's managed by the Canadian Space Agency got hit by quite a small but reasonably sized piece of space junk.

You can see these pictures of just this hole in the sheathing around the robotic arm, is sheathed in kevlar you know like bulletproof material and then the arm itself is made of titanium so that thing packed a punch wow yeah just to put it into context of like the the energy involved in this as well i mean this kind of thing is a huge issue for the international space station so just back in september 2020, the ISS had to do an avoidance maneuver to avoid a piece of space debris that they knew was coming within at least a kilometer. And even then they were like, that's too close. And they evacuated the astronauts to the Soyuz craft that takes them up and down from the ISS and said, let's get in there just in case you have to evacuate completely and come back down to Earth from the ISS. So obviously big pieces like that, that we track, fine.

The smaller pieces are an issue. So that's why the ISS and a lot of other satellites are covered in shielding, essentially. And I like to think of it like a thermos flask of just layers of shielding, right? And these stop the smallest of pieces. So that the first layer of shielding essentially tries to break up the piece of debris that's hit and then the sort of the secondary and third layers they essentially try and then absorb the impact and the energy from that so it never penetrates into the actual spacecraft or satellite itself um you know if we're talking about spacecraft like the sawuz and the Crew Dragon as well,

SpaceX's Crew Dragon that takes astronauts up, you know, even the hit from a tiny piece of debris, for example, on its heat shields would be a huge issue for re-entry back to Earth. You know, we've seen that time and time again with the space shuttle. So it is a big issue and there's only so much that shielding can do. Right. And we're now at a stage where so many satellites are being launched into low Earth orbit. We're seeing these mega constellations to give us high speed Internet from space. You know, SpaceX's Starlink springs to mind, but more are popping up. So why are people so concerned about these mega constellations? Yeah, I mean, we've talked before about how we're concerned from an astronomy perspective,

because we don't want satellites going all over our night sky. But from a sort of space junk perspective, you know, at the minute, we've got, say, like 5000, you know, large sort of working satellites in orbit, plus all the space junk. And they're talking about doubling tripling that you know with tens of thousands if not more satellites in low earth orbit so if you think about sort of sort of onion layers of orbits you can have around earth low earth orbit is the smallest volume we have because it's closer to us so it's getting very congested there and and the and the concern is that if you've got more of these things in low Earth orbit, where there's more space junk, where things have to try and go through to launch off the Earth as well, you've got a higher risk of collisions. Collisions make lots of smaller pieces of space junk in sort of a cascade. These are the things that we then can't track as well.

And it just exacerbates the problem completely so you know people are talking about having more advanced tracking systems but if you've got these tiny tiny pieces that can cause a lot of damage that's where the issue really lies yeah and can i bring robert in here because i know that you've also from with your royal astronomical society hat on you've been looking into this quite a fair amount haven't you yeah we have and i think i mean beck is right you know our primary concern and the stuff we put forward has been around the impact on astronomy and ground-based astronomy space-based astronomy it's all it's all affected to some extent the scale of it is fascinating and a bit depressing at the same

time so back in 2018 2019 there were about 2000 active satellites in low Earth orbit. There's now about two and a half times as many. And by the end of the decade, there could be 100,000 and possibly as many as 200,000. So that's a huge increase in its own right. And the problem is that although you assume the companies launching them are going to be good players and they're going to do the right thing and the rest of it, even if say only 1% of those fail, say they're no longer, and by fail, it might mean just that they're not responding to commands from the ground, you suddenly have possibly several thousand satellites that aren't under control. Now, in the past, what we've seen with that kind of thing is that if they're low enough that we wait for them to deorbit and burn

up and the problem removes itself. But with that number, there is just this risk that the traffic management issue becomes so much harder. I mean, imagine that, a 1% failure rate. Now, that sounds pretty good, doesn't it? If you build a whole load of things and 1% of them fail, that's not terrible. It's just that when you've got these things that are weighing at least tens, hundreds of kilograms going around at speeds which are many times faster than bullets and not under control in the way that you'd like that there is a risk associated with that so it's a problem that's got to be taken seriously and i think it can't just be about missions that are sent up to bring these things down and rescue them and so on there's got to be sort of some better passive systems that you know

it just needs to be dealt with i don't think we can sit there and be complacent about that kind of step change. And added to the fact that, you know, while companies like SpaceX and OneWeb are being good about it and at least talking to us and considering the problem, we don't necessarily know that all companies around the world will take the same view. Some of them might be a bit more cavalier about it.

They might just say, well, there's no national regulation in my country preventing me from being the person launching all this stuff or the company launching all this stuff. So I'm not going to adhere to the same standards of guidance. So I think we do need something at an international level that people are, it's very difficult to persuade them legally, but strongly encouraged to adhere to, to get a grip on all this. You know what we need? Space lawyers. It's very true. Space archaeologists, space lawyers.

All of these people that are competing with astrophysicists with the coolest job title. Maybe not space lawyers. Well, I don't know. Space accountants. No, quite. I was going to say. They exist.

It's a very strange merger of titles, isn't it? I apologize to all space accountants. There will be some. So, yes, space junk can prove problematic if we don't keep it under control and well-regulated. But it can also tell us much about the history of space exploration. Joining us now is space archaeologist Dr Alice Gorman from Flinders University in Australia. Who better to

talk to us about space than Twitter's Dr Space Junk. So Alice, first of all, you've got to explain to everyone, what is space archaeology? Well, space archaeology is studying the objects and the places that are associated with space exploration so that it's pretty recent stuff. It's all 20th century, 21st century stuff. Rocket launch sites on Earth, tracking stations and antennas. In Earth orbit we have all of the space junk that we're just going to talk about. There's over 80 places on the moon where humans have sent material.

I'm looking at the objects and the materials and their relationship with the environment to try and discover new things about how humans interact with space. You can look at these objects as a response to human social needs, I guess. The growth of these mega constellations, which are going to be a whole interesting archaeological record to themselves is a reflection of the fact that nobody on earth can live without their smartphone accessing the internet every day so I guess I'm kind of really interested in what the

patterning of all of these objects in earth orbit tells us about what our needs and expectations are as we go about our everyday lives on Earth. If we're thinking about those needs and interests, what can space junk tell us about the needs and interests of those at the beginning of the space age? Well, at the very beginning of the whole thing in the 1950s, we really didn't even know what space was like out there. All we knew was what we could tell from Earth. So you get the first satellites getting sent out and they're interested in scientific data, they're interested in testing new technologies like telecommunications and navigation and a lot of the spacecraft are experimental. Something you see in the early space age is a lot of spherical satellites which make a lot of sense uh if you want something robust shiny so you can see

it and that won't get biffed about and broken up by when a micrometeorite hits it i must mention here two of my other favorites dodecapole and 2, which look like sea spiders with 12, 7-metre long antennas sticking out of this little beautiful sphere in the middle. They were experimental satellites too and they're quite beautiful. And then what we see is these technologies get tested as they gain engineering heritage. We start to see spacecraft looking the same and they're coming off big factory production lines as they gain engineering heritage, we start to see spacecraft looking the same.

And they're coming off big factory production lines and you'll have a big aerospace corporation selling a particular design to numerous users around the world. So they start to become more similar to each other and that diversity is reduced. And in that we can see how the big aerospace corporations operate and the kinds of people that are buying their products. That's so interesting to think that if you could, you know, the age of all the satellites and junk up there could literally track the sort of technological revolution that's been undergone over the past 60 years. It's just amazing. amazing. Could you give us a bit more insight of some of the sort of like the interesting specific pieces that you're studying at the minute in terms of what specifically they are in terms of space

junk? The things I'm looking at at the moment are some objects that kind of get overlooked a little bit when you're looking at space history. And one of these is a really interesting object called the yo-yo d-spin weight. I just love it because, you know, how can you not love something that's called a yo-yo? And this is a piece of very simple technology. So when you launch a satellite or a payload on a rocket, the rocket will be spinning. And when it releases its payload, it has the same spin as the rocket but you have to it has to slow down to work properly so one way of slowing it down is to take heavy weights wrap them around the satellite with long cords sometimes they're kind of spring loaded cords

and when the satellite gets released these weights hurl out and they're like they cause it to to lose momentum and slow the spin down and then the weights are let go they're space junk now but they are literally lumps of metal and if you collide with a lump of solid metal traveling at an average speed of seven kilometers a second then that's not going to be so great for the spacecraft that you collide with. The good news, I guess, is there's only 263 of them that we know of out there. Only?

Only. Okay. But if we're looking at... So that's a real comfort to astronauts. Yes. There's only 263. But if we're looking at... So that's a real comfort to astronauts. Yeah. They're only 260,000. Just skip this part of the podcast for any astronauts listening right now. But there's still so much we don't know.

So when they're modelling collisions between debris, this is often done, you know, in classic physics style, it's done with a hypothetical point or a sphere and the modelling is done on that basis. But, of course, these objects aren't. You know, in classic physics style, it's done with a hypothetical point or a sphere. And the modeling is done on that basis. But of course, these objects aren't. Well, some of them are spheres, but most of them are not spheres or points. And in this case, we have something with very particular physical characteristics that will have a distinct effect when they collide with something. So it's not a generalized effect,

it'd be a very precise effect. So it's really useful, I think, to try and understand more about the physical characteristics of some of these debris types, because in the long run, that's going to help us in devising mitigation strategies. Just on that, these pieces, as we've discussed, obviously have historical significance, but we can't deny the fact that they are also a problem. So how do you feel about that conversation of removing these items from space? So we know we have to clean up space junk. There's too much of it out there. The number of bits of debris are only growing. But if we're going to start removing debris, I think it's really important to leave a sample of space material

that comes from every nation on Earth so that they can preserve their national heritage. And that makes sense from a heritage management perspective, but there's also an aspect of this which is about demonstrating your right to use aspects of space. So at present, the Outer Space Treaty of 1967 says that space is free and accessible to everyone. But things can change. We've certainly seen that happen in many other areas.

And particularly with commercial operations wanting to put dibs on particular regions of orbit, if we inadvertently removed all of Nigeria's satellites or all of Indonesia's satellites and a situation arose about who had the right to use certain areas of orbit, a use it or lose it argument could be made. And this has certainly happened on Earth as well, where someone says, well, you don't have any right to be here because you can't demonstrate your historical use of it. And in that case, being able to say, here is our satellite that has been in orbit around the Earth since 1976, in the case of Indonesia's Palapa A1 satellite, could actually be a critical factor in maintaining the principle that everyone has equal access to

space. So while it is about the incredible heritage of the space age, there are also some political implications about removing the national space heritage of other nations on the pretext that they're just junk. So none of this stuff, I think, is just junk. this is the supermassive podcast from the royal astronomical society with me astrophysicist dr becky smethurst and with science journalist izzy clark this month we're investigating all the junk that's been left in space but before we get on to our listener questions i have to know did you both get to see the partial eclipse i i just i just caught it so my my office is west facing and then I call it my office it's the spare bedroom the spare bedroom is west facing the main bedroom it's east facing to where it was actually you know you can see the sun in the morning so I was just constantly keeping an eye of if if it looked ever so slightly brighter outside during the clouds and was just

running back and forth across the house but then like literally I did it and just caught this glimpse in like a tiny mini break in the clouds that must have lasted for about 30 seconds enough so that it was like thin cloud so my phone even could take a picture of it so it was awesome it actually made seeing it you know quite a lot easier but my pinhole camera was was rendered useless basically because I, it was absolutely sod's law that we'd had a week of glorious sunshine, blue skies. Oh, partial eclipse on Thursday. Oh, yeah, no, we're going to schedule loads of cloud then

and just deal with it. I did see it, and I was not for anything more than a few minutes in total. I was with my local astronomical society. We thought we'd do a live stream, all these things. I had a couple of phone calls and radio stations saying, what can you see? Most of the time I was looking up thinking, well, I've got a very dramatic English sky, but sadly no sun. And like Becky, I was kind of standing there thinking, oh, there's some shadows. That means the sun's coming up and grabbing this solar filter I had just to take a look.

It was, I think, although it wasn't great weather, a lot of people did see something and that's nice. And, you know, I did see lots of pictures. I saw a colleague of mine who did do the colander thing, which I didn't think would really work. So this is where you hold up a colander, get the little pinholes. I didn't think it would work because it wasn't a very deep eclipse, but it did.

And she had these little, these hundreds of little suns with a bite taken out of it so there are some nice fun photos and there were a couple of sunspots on the sun at the time as well so not too bad i think we're happy enough um for for an english weather event it's a uk weather event it's not too bad yeah yeah what about you az did you catch it well fortunately my internet completely went down on that day. So I cancelled all of my work meetings and was able to watch it, you know, when the clouds broke. And I've also got a solar filter. So I sort of spent my morning sitting in my office trying to get the internet to start and then

rushing to the window with my solar filter to be like, oh my god, I can see it. But yeah, it was quite a exciting day because we had that and then in the afternoon i got my covid vaccine so i was just like what an absolute win for science that day i was just what a day a lovely day and so i think let's get back onto some space junk we've got a few more questions as per. So Becky, Peter Hennis wants to know, is it possible that a piece of space junk could leave our orbit after a collision with another and head out into the solar system, taking any earth contamination with it? Or are they always bound to the gravitational pull of earth? That's a good one. I mean, yeah, a hundred percent possible.

You know, thinking about collisions on a pool table, right? Stuff collides, one thing pings off in another direction. And if it collides with enough energy for it to escape the pull of Earth's gravity, then yes, theoretically, this is completely possible. And it would ping off into the sunset, the space, I don't know how you would call it, out of outer space. I mean, it wouldn't be the first piece of human-made craft that's, you know, headed out that far from Earth.

You know, the Voyager crafts have left the solar system, of course. All those kind of things usually have been, you know, irradiated with UV radiation to kill off anything, like contaminants, as Peter put it, perhaps, you know, from microbes or anything like that. I'm not sure what the protocol is necessarily for things like satellites and space junk. But, you know, you would hope that it would just be sort of in a metal, essentially, like we were talking about with Alice, right? It was like recycling it back

into the cosmos. Yeah, okay. And Robert Timo on Twitter asks, could we use a ground based laser to vaporize space debris? I love I love the idea of this please say yes well what it is isn't it yeah it's uh well when i read this i thought oh surely not and then um i looked into it uh the last day and actually there is a sort of alarming trend in connection which is that the both the u.s government and the chinese have considered ways to fire ground-based lasers to damage satellites. So you can certainly build lasers that are powerful enough to do this kind of thing. Whether it would be easy to vaporize a piece of debris, I don't know. My guess is that what would happen is that you'd be more likely to make it break up or distort.

It would be probably not a trivial thing to do it in the way that you'd imagine with some big death ray. And also, I think we'd have to be a bit concerned about what it meant for the militarization of space. I'm not sure I really want all these countries around the world building mega powerful lasers and blasting them into the sky. There is a connection with a more benign use, which is something called satellite laser ranging. And the UK has a base down in Herstman's and Sussex doing this, where you fire a laser up towards a satellite to measure its position so you time the reflectance back down and a friend of mine does this work i just remember going down there years ago and seeing this green laser pointing into the night sky that was quite exciting but the answer yeah the answer is that there are i think it's probably not the easiest way to do it and there would be you know more peaceful ways to think about it too uh the u.s laser had the weird title of a miracle when the test was back in the late 1990s but didn't work particularly well at the time i'm sort of of the view we probably shouldn't encourage this stuff i guess there's also that concern of with any of these attempts to break

it up and remove it you're just like do not add to the problem like don't just split it in half and then you've got two things precisely it's like with asteroids where you don't want to break the asteroids into two pieces that just slightly that are then continuing towards the earth you know you need to actually to vaporize something is quite hard you don't want to end up in like deep yeah much better to think about things in all i was traumatized by deep impact can i just say i watched that as a child far too early and I had nightmares. So I think it's so funny. The career path that I've taken is not anticipated by anyone.

Now you can join the heroic movement to present it. Exactly, exactly. I got as intrigued by this as you did, Robert, because I read the question and was like, surely not. But then I went down the other route of there is an idea called a laser broom.

Have you heard of this? A laser broom. So this is for really small pieces of debris. So like less than 10 centimeters, the stuff that you can't really track. You wouldn't vaporize it, but you would fire a laser at it enough that the material would ablate. So essentially like evaporate if it was water, right? And that would actually take a little bit of thrust with it. You'd reduce the energy of this little piece of space debris so that it would then reduce its orbit and then

burn up in the atmosphere and because it's a tiny piece of space debris it would definitely burn up it wouldn't be an issue but i just love the fact that it's called a laser broom as if you're just like sweeping up the the little particles of dust you know like i said at the beginning of the episode grab your dust bat and brush. Yeah, yeah. Or your laser broom. I mean, and that sort of leads into what Tyler asks, because Becky, perhaps you can help with that.

He said, we've been looking at proposals to remove large pieces of space debris, but is there a way of deorbiting small pieces of debris under one centimetre? And if I can add my own thing to that it's how do we even detect those small pieces yeah i mean that's the thing you don't really know they're there until you know they scratch past your face like a piece of sand i guess really so it's the big bits of things like harpoons nets you know little robots like the claw i, but in space. And then it's the laser brooms for things above a centimeter. But for below a centimeter, I mean, less than a millimeter, you're talking about sand and dust. And yes, that is a big issue.

The ISS talk about how their solar panels degrade year on year because they essentially get sand blasted by these very small pieces. The things between like a millimeter and a centimeter are the things that this shielding on the iss and on other spacecraft it's called whipple shielding the stuff where it's many layers like a thermos that's the kind of stuff that deals with and i think it's again finding it is very difficult and so it's easier to protect than to remove so to protect against this stuff rather than to try and remove it at least I haven't heard of any missions that are attempting to do that.

Have you heard of any, Robert? No, and I think it's precisely the reason you're describing when you get to that unfortunate size where it's very difficult to track from ground-based radars and yet can still do damage. That's an issue. It's a reason for good space management and space sustainability. Not creating as much as this stuff in the first place is surely the way forward i mean presumably over i mean over long

time scales this stuff re-enters the earth's atmosphere but the higher it is the longer it will stay there and we just yeah shielding and making sure we don't add to the problem is the only thing i can think that will really help well thanks everyone and if you're listening and you're like i have a question for the team, then let us know. You can email podcast at ras.ac.uk or tweet at Royal Astro Sock and we will take a look. So there's one more thing to ask, Robert. What are some of the things that we can see in the night sky this month? Well, we're still in the middle of the summer in the Northern Hemisphere.

So we've got nice, bright, long days. So you still have quite a short night and it's still not quite properly dark in the uk uh but having said that there are we are starting to see a few more things and there's not very many easily visible planets right now but if you're if you're somebody like staying up all night then saturn is coming into view uh later in the evening down low down in the south in the uh it's in this capriconus I think one of the lowest zodiac constellations. And also, of course, take advantage of daylight. The sun is more active now. So we're starting to see it ramp up towards solar maximum. And what that means is that you will see more sunspots. So if you've got the equipment to do it, it's not too different from

the advice we gave on viewing the eclipse. You can project the sun with a small telescope or a pair of binoculars and see these things for yourself as ever. Please don't look through those at the sun because you can obviously cause serious damage to your eyes. And I was also thinking about, well, this is the season when people start to go on holiday. And all right, most of us are going to be doing that in the UK this year for obvious reasons. But you're quite likely, if you live in a city, to be going somewhere that's quite dark. And it is a fantastic opportunity, particularly from about late July onwards, in other words, the school holiday season, when the nights are a little bit darker, to see things like the beauty of the Milky Way properly. If you go out there and it's a night

when you've got a new moon or the moon is set, then most people really are quite gobsmacked when they go out into the countryside if they haven't looked at that before. So if you're camping or you're in some nice bed and breakfast in some village somewhere in, say, Wales or the remote parts of Scotland or even England, do take a look. You might be genuinely surprised by how much more you see than when you're in the city.

And actually, do take some photos too. It's not very hard to capture that with a smartphone camera. And in the summer, the summer triangle rises now late evening. some photos too you can uh it's not very hard to capture that with your smartphone camera and in the summer the uh the summer triangle rises now late evening you see these three very obvious stars of um out air vega and deneb and they film this beautiful triangle in this summer and autumn skies and that's where the milky way is running through so look out for that it rises over in the east and swings around towards the south later in the night and remember you're looking at the interior of our galaxy the one we live in and that beautiful vista of stars i am like head of the let's rename sun loungers to star loungers because they are both useful

for sunbathing and also for lying down and not getting a crick in your neck when you want to look at the sky it It's very true. I fully support this. I support this completely. No, as do I. It does get you unusual looks from your neighbours when you go out at 10 o'clock and stretch your sunluncher out. But, you know, I'm more than happy to ride this out, exactly. And did anyone happen to see the recent news on Beetlejuice

that they think that they found out why it's dimming? Yes. Yeah, that was fascinating, wasn't it? see the recent news on beetlejuice that they think that they found out why it's dimming yeah yes the the yeah that was that was fascinating so it is a combination of a cool spot and an ejection of a dust cloud blocking the light yeah so so there was some disappointment i think in in some astronomical circles that it didn't mark the beginning of the supernova that were i wouldn't say looking forward to but expecting in the next 100,000 years or so. And partly because there hasn't been one seriously bright one for more than 400 years. So that's why there's always excitement about this.

But yes, it's really interesting to see that mystery was solved. And I guess we can't rule it out happening again. It's such a random set of events. It could happen again quite easily. Yeah, I remember last year people were sort of arguing like, star spot, no, it's dust. No, it's star spot, no, it's dust. And then some people were like, it's both. Stop arguing.

You both get a cookie, okay? Okay, cookies for everyone. One thing I wanted to bring up as well is that everybody should keep their fingers crossed and pray to the universe or to whatever god you believe in that by the time this podcast comes out next week that the Hubble Space Telescope is back up and running because as of right now as we're recording the main computer which has been you know installed on it since the late 80s before it launched has failed they tried to reboot it and it didn't work and they're now trying to boot up the backup systems and there's lots of options that they have that nasa and isa are trying to get it back online and

they should get it back online fine but the idea that this main computer which runs the whole observatory has failed and you know there's now no observation taking place is quite scary especially for those of us with hubble proposals in right now who would like to use it. Crossing everything I have for thinking of you on that one, Becky, and astronomers generally, I think. Yeah, that would be a great shame, wouldn't it? It's, yeah, it's been such an amazing, fantastic observatory

and we've got a bit longer before web launches too. So definitely fingers crossed. I mean, it's expected to last through the late 2020s and we hope that it definitely will. But I mean, it's amazing the lifespan it has had, but we would like it tos and we hope that it definitely will. But I mean, it's amazing the lifespan it has had,

but we would like it to continue and we would like it to come back online, please. Yeah, crossing all my fingers and toes on that one. Well, that's it for this month. Join us next time where we'll be getting to grips with magnetism and the Van Allen belts. Yeah, we cannot wait for that one. And also tweet us if you try some astronomy at home.

It's at Royal Astrosoc on Twitter, or you can email your questions to podcast at ras.ac.uk. And we'll try and cover them next month. Until then though, happy stargazing.