The Unexplained - Howard Hughes - Edition 156 - Space Debris

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May 10, 2014 - The Unexplained - Howard Hughes

01:05:13

Edition 156 - Space Debris

Dr. Hugh Lewis at Southampton University on how to clear up space debris...

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	Across the UK, across continental North America and around the world on the internet, by webcast and by podcast, my name is Howard Hughes and this is The Unexplained.
	Thank you very much for keeping the faith and for coming back to my show.
	I'm sorry this one is a couple of days late.
	The reason for that is that life has been particularly busy.
	I have to try and get some work to pay the bills.
	You know how it is.
	And work is tough.
	And on top of that, I've been balancing things like the clearance of my parents' home and the end of that particular saga.
	But never the end of my memories of my wonderful parents.
	And thank you for the nice things you've said on email.
	Yes, I'm going to be doing some shout-outs in just a moment.
	I did promise, and I will come good on that.
	Thank you for your emails, like I said.
	And thank you to Steve, who sent me a digital quality recording of my show with Al Bierlick, the late Al Bierlik, and much missed, from the Philadelphia experiment.
	So we're going to try and put that on at some point.
	At the moment, the only recording we have is one from AM Radio.
	I didn't keep, or rather, couldn't preserve, a copy of that.
	My own digital copy of that important interview actually got corrupted digitally.
	And you know that when a digital recording gets corrupted, it's finished.
	If a tape gets corrupted, the old analog style, you might be able to play it.
	If it's a digital recording, then forget it.
	So I'm very grateful.
	Thank you, Steve.
	Did receive it.
	Okay, let's do those shout-outs.
	Agnes in Long Island loved Richard C. Hoagland, our last show.
	Thank you for that.
	Rich in Pennsylvania says, we hear you, brother.
	Thank you, Rich.
	I hear you too.
	Steve in Australia prefers my show to Coast to Coast AM in America.
	That'll be news for them.
	Thank you for that.
	Of course, we do do different things.
	And of course, we don't festoon the site with ads or the show with ads.
	That's one difference between us and them.
	And they are big media.
	And we are definitely very small media.
	Peter in New Zealand, who is doing some fine work rebuilding Christchurch.
	Good to hear from you, Peter, says that Adam Cornwell, my great webmaster at Creative Hotspot in Liverpool, does a fantastic job.
	And quite a few of you this time round have mentioned Adam.
	So on his behalf, thank you very much.
	Michael in Surrey, UK, remembers me from my days on 95.8 Capital FM with Chris Tarrant in London.
	But he's not impressed with Richard C. Hoagland or his interpretation of those pictures from the moon.
	Okay, well, I hear what you say.
	Michael, thanks for that email.
	Wilhelm Mortimer, hello to you.
	Ben Diggins wants Aussie ufologist Bill Chalker on.
	I've tried emailing him.
	Can't get hold of him.
	If you know of a way, Ben, to get hold of him, I'd love to get him on the show.
	Steve Simmons in Australia also wants me to talk about zero-point energy.
	We'll try to do that.
	David Jones in the UK is annoyed at Richard C. Hoagland, thinks I gave him an easy ride.
	I don't know about that, David.
	The first question I said is, you know, a lot of people, Richard, think that you just make stuff up.
	That was a bit of a hard start, and he took that in good part.
	But David says, and I understand what you say, that Richard C. Hoagland has a scattergun approach to it all.
	And I think that's just because Richard's head is so full of science and information and he just wants to get it all out there.
	I don't know, but I understand what you say.
	Bob from Boston listened to all of my shows, the entire archive, and he believes that Richard C. Hoagland was using the wrong physics.
	I know that Richard would love to reply to that, so we'll see if we can fix that up.
	Richard Points, thank you for your email.
	Andy Evans cleared his own father's house recently, so knows what I've been through.
	Andy, I can tell you stories.
	Darren suggests a guest, Philip Inrgno, I think is his name.
	I'll check out that name.
	Anne Claire, good to hear from you again, Anne Claire, thinks that Richard C. Hoagland might be right this time, quote.
	Trudy in Brisbane, Australia, nice to hear from you, suggests Mary Rodwell.
	I will check her out.
	Rich Vadino at Green Apple Tattooing.
	I don't do commercials, but there's one for you, Rich, in Island Park, New York.
	And thank you, I might have that tattoo one of these days.
	Just have to decide what to have.
	Maybe a UFO.
	Justin Crable wants better indexing and scheduling on the site.
	We'll do that when we can afford it, Justin, but it's a good suggestion, and I know it's been in my mind for a while.
	Carolla or Carolla, I think it's Carolla, suggesting win-free.
	Carolla, we did him.
	Look back in the archive, and I think it was about show 120, 122, 123, something like that.
	Aaron McWilliams suggesting James Fox.
	We do have a contact in for him, so let's see what happens.
	Marty, nice to hear from you, Marty.
	Thought that Catherine Austin Fitz was not clear enough.
	A few of you said that, but a few of you were very, very impressed with her.
	George Sellis in Connecticut is a cartoonist.
	Nice to hear from you, George.
	Wonder if you could do a cartoon for this show.
	Maybe me and a UFO would love that, and we'll put it right on the homepage and give you a credit for it.
	You know, we'll put your name underneath.
	Lorraine McFarlane, nice to hear from you again.
	Prefers this show to Coast to Coast AM.
	Somebody else and loved Catherine Austin Fitz.
	You see, we say over here, horses for courses.
	You're not going to love everybody.
	Hank in New York City, good to hear from you.
	Nikki Butler in Kenya.
	Hello, Nikki.
	Keen listener.
	And sent me a really good email.
	Really nice to hear from you, Nikki.
	So that's the round-the-world audience that we have here growing all the time.
	Please tell your friends about this show.
	If you want to make a donation to the show, that is utterly vital.
	And then I will be able to expand the number of shows that I do and the way that I do them.
	And maybe I won't have to go out and do quite as much work as I have to do to pay my bills because energy and food and everything, it's very boring, but cost an awful lot these days, as we know.
	Just keeping things going is expensive.
	Yeah, if you want to make a donation, go to the website www.theunexplained.tv is the website, and you can follow a PayPal link there, and that is also the place to go, www.theunexplained.tv, to send me an email, give me your feedback about the show.
	And the website designed and created by Adam Cornwell at Creative Hotspot in Liverpool.
	The guest this time is a man I think you're going to enjoy hearing.
	His name is Professor Hugh Lewis.
	He's based at Britain's Southampton University.
	And if you watch the movie Gravity and you watch the documentary at the end of that on the DVD about space debris, space junk and its dangers, which of course was the whole point of the film, then you will be very interested in the research that Hugh Lewis is doing, so let's not hang about.
	Let's get to him right now.
	Professor Hugh Lewis in Southampton, UK.
	Thank you for coming on The Unexplained.
	Oh, you're very welcome.
	How's the weather in Southampton, Hugh?
	Oh, it's a bit miserable today, unfortunately.
	Lots of rain.
	But at least you're near the Solent and the lovely Isle of Wight.
	And for that, you're a very lucky man.
	I worked down there for a few years.
	Now, you tell me a little bit about yourself then.
	I know that you're an academic.
	You work for a university.
	What are your qualifications?
	Okay, I actually have a PhD from the University of Southampton.
	That was actually in remote sensing and image processing.
	Following that, I worked with a very good friend and colleague, Dr. Graeme Swynard, who I guess pioneered space debris research at Southampton.
	So that was a postdoctoral bit of research.
	And then through that, really, that's a subject that stuck with me.
	So I started that in 1999.
	And I've been working on the space debris modelling and so on for quite some time.
	And you said that you were working with a man who was already researching space debris.
	Was it something that you'd been interested in before?
	Or was the fact that you got connected with this person the catalyst?
	No, it was say in 1999, it was Dr. Graham Swynard was the person who invited me to work with him to develop a new space debris model.
	And that was my first exposure, really, to the problems and challenges involved in space debris.
	I have a feeling, and obviously I know about your work because I watched this movie Gravity, and I'm very interested in space, which is why I do the show that I do.
	And I occasionally, and it's only a passing thought, give some consideration to what happens to all that stuff we put out there.
	And then that thought goes away very quickly.
	And it seems to me, I don't know what you think, Hugh, it's very much analogous to the way that we consider rubbish on Earth.
	We put it in bin liners here.
	We leave it out for the bin man to take in a weekly or fortnightly regular collection.
	It is then taken to a landfill site or maybe incinerated or disposed in some other way.
	And it's out of sight and out of mind.
	Well, actually, it's probably even worse than that in the space environment because there is no rubbish collection.
	There is no landfill.
	So basically what happens is spacecraft, if you're not going to be complying with any kind of mitigation measure at all, then the spacecraft is literally just abandoned.
	It's switched off or it reaches the end of its mission and it's just left there.
	And if you give this some thought, it must be a huge problem by this stage because we've been putting stuff into space since the 1950s, haven't we?
	We've sent all sorts of satellites and boosters and Apollo moon missions and goodness knows what else, and that's only the stuff we actually know about.
	And all of those things have an element of non-reusability about them, almost anyway.
	Indeed, I think what you find is that simply because space is such a difficult environment to get to and to operate in, most of the objects that you put there are not really reusable.
	They're there to fulfill a particular mission and that mission only.
	So it's, if you like, it's the ultimate disposable kind of attitude that you have towards technology and so on.
	You're designing a satellite which could be worth $500 million.
	You're launching it for a very specific purpose and then you're just leaving it there.
	So that's a huge investment.
	If we were to do that down on the ground, there'd be an outcry about just leaving all of that kind of potential material, technology, you name it.
	There'd be an outcry about just abandoning that.
	But here on Earth, if you dump something, say for example, you decided to buy yourself a light plane and you had 20 years of fun out of it and then it outlived its usefulness and you decided to dump your light plane on the Isle of Wight, it would rot away within another 20 years and cease to be a problem.
	Unless you stored it in the Mojave Desert where it wouldn't rot or deteriorate or rust, then nature would take care of that for you here.
	In space, I'm guessing that doesn't happen.
	Well, surprisingly, there is an element of erosion that occurs in the space environment.
	Normally at lower altitudes, it's a function of atomic oxygen.
	So you do actually have some processes that are ongoing that eroding the spacecraft.
	So why do we need to worry?
	Well, you know, that erosion, also ultraviolet light is very strong up there, and that has effects on spacecraft materials as well.
	That kind of aging process can lead to the spacecraft, it's not going to, you know, be disposed of completely, not by any means.
	But what you find is that actually that process can actually generate more debris simply because the surfaces can peel away.
	Flakes of paint can come off the spacecraft and each one of those can potentially cause some damage to other satellites.
	So there is a kind of a degradation process that is going on, but it's nowhere near as efficient as what we see on the ground.
	The founding fathers of space exploration, the Werner von Brauns and people like that, and the Soviet equivalent, whoever that may have been, do you think at any stage they gave, during that headlong race to get into space and beat the other side, any thought to what would happen to all the stuff they were putting in space?
	I'd say probably not.
	That said, I think that there have been people from quite an early stage of the space age have been considering the fact that actually what is happening to all of these objects that we're putting up there.
	So the IADC, which is the Interagency Space Debris Coordination Committee, they've been meeting for quite some time now.
	Prior to the IADC, it used to be bilateral meetings with the USA and Russia to discuss these kind of issues.
	So that actually has been happening for quite some time.
	And I'd like to think that actually, you know, from a relatively early age, we were thinking of those issues.
	But certainly, I would think that the pioneers probably weren't thinking about these particular issues.
	And now, of course, they will be, or they would be if they could, if they were still with us, then they would be considering them.
	But too late.
	We've been doing this for decades.
	We've been using it as our junkyard up in space.
	And now there is a problem.
	What is that problem?
	Well, the problem really is that we have a lot of objects on orbit.
	So the US Space Surveillance Network is tracking and cataloguing something like 22,000 objects that they can see with their radar facilities in low Earth orbit and with telescopes in geostationary orbit.
	22,000 that we can see?
	Yeah, indeed.
	So this is, I mean, that's a relatively large number.
	There are probably half a million objects that are a centimeter in size or larger that we're not really observing.
	And if you get down to sizes that are smaller than a centimetre, then you're looking at millions of objects that are up there.
	And each one of those has the potential to damage or even to completely destroy an operational satellite.
	22,000 objects.
	What?
	So you said they were objects down to a centimetre.
	Just give me a picture of the biggest.
	So you've got at the top end, you've obviously got the International Space Station, which is probably the largest structure in orbit at the moment, unless somebody's been doing a very good job of keeping something secret.
	And then the smallest, you're looking at micron-size, very, very small elements.
	They're typically things that have eroded away from spacecraft, so the order of paint flakes and so on.
	So just to be clear, it's about 22,000 objects that are 10 centimeters in size or larger.
	So that's about the size of a softball.
	I think that's what the US liked to describe the size of these things.
	But you've got many objects that are much bigger than that.
	And you've got operational satellites, MVSAT, for example, which is just over eight metric tons.
	The new Sentinel satellite, which is pretty large as well.
	So there's a huge range of object sizes, object configurations that you have on orbit.
	Well, thousands and thousands, as you say.
	You have to forgive the public for having a view that everything we put into space is made of what the Americans call aluminum foil and is not very dangerous.
	Why might that be wrong?
	Well, even if it was just aluminum foil, as you say, the issue you have is the speed that is required to maintain an orbit.
	Typically, you're looking at 7.5, 7.6 kilometers per second is the orbital velocity that you have.
	Now, anything traveling that speed has an awful lot of kinetic energy.
	So even if it's something that is small, even if it's just a small piece of aluminium foil, let's say it's no bigger than your fingernail, that's probably enough to put quite a big hole in something like the space station or something like an operational satellite.
	Give us an idea of the kind of force, the kinetic energy that would be involved here.
	Is this like firing a bullet from a rifle?
	Well, firing a bullet from a rifle, you're probably looking at, that's probably equivalent to something that's maybe one or two millimeters in size, traveling at orbital velocity.
	You're looking at something the size of a tennis ball having the same energy as several sticks of dynamite.
	You know, it's a tremendous amount of energy that you're talking about.
	So if you've got 22,000 absolute minimum, and probably many, many, many, many, many times more than that, objects flying around there at ridiculous velocities in different orbits, that to me sounds like a great soup of disaster.
	Well, this is where the thinking of, you know, probably from the 1960s, 1970s onwards starts to come in because space is big.
	And space in a way is, you know, near-Earth space is big enough such that we're not seeing all these objects colliding all the time.
	You know, we've had a handful of collisions that we've been able to detect since the beginning of the space age and no more.
	So space is big.
	I mean, it's a huge volume that you're talking about.
	If you include geostationary orbit, the distance from the center of the Earth up to geostationary orbit is 42,000 kilometers.
	And the spherical volume there is just enormous.
	So 22,000 objects sitting within that volume is not too bad.
	The issue really comes because they're not all evenly distributed in that volume of space.
	There are concentrations of objects at particular orbital altitudes and so on, and those areas are where we're particularly concerned.
	And are they the kind of altitudes that satellites would be at?
	Is that what we're talking about, the kind of places where we normally park satellites?
	Oh, absolutely.
	So there's one critical altitude and orbital regime, which is known as a sun-synchronous orbit.
	And these orbits are typically used by very expensive, very important remote sensing satellites.
	They're fulfilling quite an important Earth observation task, monitoring the climate, monitoring the land surface, monitoring the oceans and the atmosphere.
	And they're all occupying these kind of orbits.
	So they're all roughly between 700 and 900 kilometers in altitude, and they have the same orbital inclination, which is roughly around about 98 degrees with respect to the equator.
	So all of these objects traveling at orbital speeds, there's bound to be an issue in the future in that orbital environment.
	And of the satellites in that most popularly used Region that you told me about.
	How many of those are still functioning?
	What's the percentage of functioning to non-functioning?
	Well, we're probably looking at in that particular region, you're probably looking at a couple of hundred satellites that are functional.
	Overall, of all the objects that the Space Surveillance Network is tracking, only about 1,000 are actually operational satellites.
	So you're looking at a very small percentage of the objects that we can track that are actually operational satellites.
	But if a lot of these things are in the same region, because it's a viable and good operational region rather for our purposes down here, how come they're not constantly clacking into each other?
	Well, as I've said, space is big.
	So whilst we see many times where these objects are getting close to one another, so conjunctions do occur and close approaches, the chances are very small that they actually do collide.
	We have the added advantage, if you like, that these operational satellites are able to maneuver.
	So if a particular conjunction is detected, a close approach is detected that is quite worrying, then they can always maneuver the satellite.
	And that's exactly what happened with the Sentinel satellite just a few days ago.
	And it's been happening with operational satellites for quite some time.
	And what happens if the object heading towards your prized satellite that is worth millions upon tens of millions of dollars, if the object is softball size and very hard to track, so you don't know quite which bit of your satellite might get hit, you're not quite sure how it's coming in, it's very, very hard to track.
	What do you do about that?
	Well, if it's an object that is, if you like, falls below the detection threshold for the space surveillance network, then there is very little that you can do because you wouldn't have detected this object in advance of the conjunction.
	So you wouldn't have known that you needed to have maneuvered the satellite.
	So say you have a satellite up there that depends, like all of them do, on solar power.
	Perhaps it has a couple of these big armature arrays getting power from the sun.
	If there was something softball size headed at tremendous velocity towards one of those solar arrays, then it's just going to go right through it, isn't it?
	Well, the interesting thing is that the physics starts to become quite interesting when you're talking about these very high speeds.
	The materials behave like fluids.
	So you see rather strange behavior.
	So even if it hit the, well, if it did hit the solar array, then that's probably your best case in the sense that the solar array would no longer exist, but the main body of the satellite, the satellite bus, may still be there.
	And I think that was a possible conclusion when they looked at the fragments from the Iridium 33 collision.
	I think they suspected it wasn't a direct body-to-body impact in that particular case.
	So there were some large fragments that did remain.
	But as I say, the behavior is such that you can have complete catastrophic destruction of the spacecraft almost regardless of where it hits.
	So the potential here is pretty serious, isn't it?
	If one object hits another object, you're not left with two objects anymore.
	You're left with potentially thousands of small pieces, which themselves are all a risk.
	Yes, that's exactly the scenario that we are very concerned about in the sense that there's a potential cascade, if you like, of collisions that could occur.
	One collision generates thousands of fragments that you can track and many more that you can't track.
	Those fragments then go on to cause another collision and so on.
	We're certainly not seeing that really happening at the moment.
	What we're seeing is that collisions are occurring and they're kind of random in the sense that there's no real connection between one collision and the next.
	But it's only really a matter of time before what we start to see are these collisions that are linked with fragments from one being the cause of the next collision.
	That's certainly something that we're doing our best to try and prevent.
	Before we discuss the other risks, of course, the first risk is to our communication, isn't it?
	Because if one of our major satellites for communication is taken down, or maybe two of them are taken down, then it doesn't take a Philadelphia lawyer to work out that expensive and important communication networks down here are going to be somehow affected.
	Oh, absolutely.
	I think it's even beyond the communications because there are many services that are provided by space, space-based assets, which essentially are embedded now into our everyday life.
	I mean, weather satellites provide us with information and farming provide information for farmers in terms of when to harvest.
	We're talking about enjoying the World Cup on television.
	It's a sporting event which is occurring the other side of the world, essentially, from the UK.
	We wouldn't be able to watch it were it not for satellite-based television services.
	And we are all staggeringly dependent these days on GPS global positioning, aren't we?
	Which is a network of satellites.
	Oh, yes.
	Even again, beyond everyday use in smartphones and satellite navigation systems in cars, aircraft making use of GPS systems and many other things that perhaps we're not aware of from the defense and security side of things that make use of those signals.
	Very important everyday uses.
	I was listening to a documentary on the radio in the UK the other day that was describing how until very recently, and some of them are still doing it, airline pilots used to take readings by sextant from the stars to know roughly where they were in those routes that are very far from land.
	And of course, these days they're just able to triangulate their position from GPS.
	Yeah, exactly.
	And I think, you know, if you look at the upcoming Galileo system, they're trying to embed, you know, the positioning signals into a huge range of infrastructure, including, you know, air traffic, car traffic, you name it.
	So, our dependence and reliance upon space is always going to be, if you like, our Achilles heel, if we can't tackle this space-debberry problem.
	Now, a lot of us don't know as much as we should, but we have watched an awful lot of space programs on TV.
	And those space programs have encouraged us to believe that anything that is errant, if that's the word, anything that is wayward up there in space is either A going to go into a deteriorating orbit and spiral its way down to burn itself up in the atmosphere, or it's going to catapult itself off into space and be perfectly harmless.
	Clearly, from what you're saying, both of those views in most cases are wrong.
	Indeed.
	There's only one natural sink mechanism for space debris, so the one mechanism by which space debris is removed from orbit, and that is through the process of atmospheric drag.
	And, you know, so essentially the atmosphere, very sparse as it is, extends up to quite a high altitude.
	So satellites experience and debris experiences a drag force, which ultimately will cause the orbit to decay and the object to burn up.
	That's the only mechanism that we have.
	If you want to make use of that, for example, if you want to deorbit a spacecraft, then you have to expend some energy.
	You have to use propellant or some other device.
	And that's expensive.
	That costs money in order to do that.
	So most satellites, they wouldn't consider, for example, a direct deorbit of the vehicle.
	They might now with space debris mitigation guidelines, they might consider lowering the altitude so that it takes 25 years for it to decay and then to burn up.
	But going beyond that, the cost is too high.
	And the same is true if you wanted to boost the object out into a higher orbit or beyond.
	It costs, and typically the spacecraft just don't have the resources in order to do that.
	And you're saying that it takes 25 years.
	It stretches credulity a bit to think that even the most diligent organization could monitor something for two decades or more.
	Well, this is where the space debris mitigation guidelines coming in, because 25 years is actually, if you like, it's an informal guideline that the IADC have put forward.
	They suggest typically that you just limit the amount of time that your dead spacecraft spends in low Earth orbit or in geostationary Earth orbit.
	And many people have looked at this and they came up with this idea that 25 years is the longest you want to leave your spacecraft in low Earth orbit, because any longer than that, you're looking at disruption to the other objects in low Earth orbit.
	So 25 years, yes, it's a very long time, but what we've noticed is that it's a reasonable amount of propellant that you need to reserve in order to maneuver the spacecraft so that it lasts no more than 25 years in low Earth orbit.
	And when you say propellant, you mean that you needed to have sent that thing up there with enough fuel on board for booster rockets?
	Well, it's just normal propellant.
	You can use the typically most spacecraft have some form of thrust capacity on the spacecraft.
	So you're just using that existing capacity.
	But yes, you need to have planned ahead.
	You need to have said we need to reserve a certain amount of propellant in order to lower the altitude so that our spacecraft is going to be out of low Earth orbit within 25 years.
	And would they have done that in 1983, say?
	Absolutely not.
	Because this is a relatively new guideline.
	So the IADC guidelines, which formed the basis for United Nations Space Debris Mitigation Guidelines, were really ratified only in 2007.
	So spacecraft before that weren't really obliged to comply with those kind of mitigation guidelines.
	This is where NVISAT is a case in point because that was launched before the ratification of these space debris mitigation guidelines.
	It didn't have enough propellant on board.
	Even if had it not failed, it wouldn't have had enough propellant on board to have lowered its altitude sufficiently to limit the amount of time it would spend in low Earth orbit.
	And even if the Americans, who were the prime players in space for a long time, even if they kept copious details of every aspect and parameter of what they put up there, we couldn't guarantee, I guess, that the failing Soviet Union, say in the 80s, in the 70s, when they were starting to go through a hard time, were quite as diligent at cataloguing what they have and how it works.
	Well, that's true.
	I think the great benefit of the U.S. Space Surveillance Network really starts to shine through there because they essentially are monitoring all of the near-Earth space environment.
	And they are effectively providing that information about the objects they're seeing, but also warning about possible conjunctions.
	And they're providing that service for free.
	The worry that you've got, though, you see, as soon as your spacecraft is abandoned, the orbital information deteriorates very rapidly.
	So unless you're making very frequent observations of that spacecraft, that object, your orbital data is actually out of date very quickly.
	And that translates into a position error.
	So you're not quite sure where the objects are.
	And that's the major cause for concern when you're looking at things like collision avoidance and so on.
	In the last 25 years or so, apart from the space shuttle and multitudinous satellites, we've put all sorts of things up into space.
	How come none of the things we've been firing up there on launch or thereabouts has not been hit up to now?
	Well, they actually have.
	I think we've got very, very good evidence now that most objects on orbit are being hit all the time.
	Not by anything large, certainly not by anything large enough to destroy the spacecraft.
	But we're seeing from surfaces that were returned from orbit, such as the Hubble Space Telescope, its solar arrays, which have returned to Earth and analysed, we're seeing many, many impacts on their surfaces.
	We're seeing on the space shuttle, the windows having to be replaced because they were impacted by flakes of paint, and that left craters on the windows.
	We're seeing, again, on the shuttle, the thermal protection system on the underside of the shuttle being impacted just in a mission that lasts two weeks.
	So there's very good evidence to show that space debris is being felt by all objects in orbit.
	Now, we haven't seen many really large collisions.
	So I guess the best known is the Iridium-33 Cosmos 2251 collision, which occurred in 2009.
	That's really been the only accidental collision between two intact objects.
	And I guess the interesting thing is one of those objects was an operational satellite with maneuvering capability.
	And so...
	Well, I think it's quite a complex situation, really.
	I think, you know, if you look at the Iridium constellation, there are many satellites there.
	They would be experiencing many warnings of conjunctions.
	Virtually every day they will receive conjunction warnings.
	And the question is, which one of those is the one that's going to kill you?
	And you just don't know that.
	So if you were to maneuver for all of those, then you would very rapidly run out of fuel.
	You wouldn't be able to provide your service that you're trying to provide.
	So you take, if you like, an educated gamble.
	Well, I was going to say this comes down then, my God, to best guess.
	Well, it's more than best guess because through the Space Surveillance Network, we have very good information about where operational satellites are.
	They're continuously transmitting information, which allows us to pinpoint their position pretty accurately.
	So through that process, we're able to determine a collision risk, a collision probability.
	And then what we're doing is we're then falling back on judgment.
	In our judgment, does that risk warrant the maneuver of the satellite?
	The loss of the service that that entails, the potential risk that entails from maneuvering the satellite as well.
	So it comes down to judgment.
	What is an acceptable risk?
	And I think at the moment, most satellite operators, most satellite insurers would argue that the risk is still acceptable.
	Certainly there are no premium hikes that are being put on satellite operators from the insurers as a result of space debris.
	So I think most people assume that there are acceptable risks.
	And then occasionally you have a risk that is not acceptable and you maneuver the satellite.
	But that happens relatively rarely.
	And the percentage level of risk, the kind of thing that insurance assessors use to work out how much operators should pay for a policy, presumably that level of risk is going up all the time?
	Well, yes, that's certainly true.
	So whilst at the moment, you know, satellite operators and they're not paying any additional amount to cover the risk from space debris, that may not be true in the future.
	And in fact, there are many people who are putting forward the idea that the insurance industry could be a really good driver for tackling the space debris problem, you know, in terms of providing an incentive, reduce premiums or increase premiums, depending on which way satellite operators want to go.
	But of course, in a completely free market, they're not going to do that without some pressure, are they?
	Well, absolutely.
	I think there is pressure already.
	And this is where the work that has been done by the IADC, also the International Standards Organization, and other organizations around the world, looking at the space debris problem, proposing guidelines, this is where that work is really important because it's now widely recognized by satellite operators and manufacturers that space debris is an issue and that they need to take some steps in order to mitigate that risk.
	So it's becoming virtually impossible to launch a satellite without taking these risks into account.
	The reason that you and I are having this conversation is that I watched the movie Gravity, along with millions and millions of other people recently.
	Was transfixed by it, a great piece of drama, a great piece of Hollywood, I thought.
	How realistic, we don't want to give the whole plot of the movie away, but we're talking about impacts of space debris causing absolute mayhem and killing people up there.
	How realistic was that?
	Well, I think it's fair to say that they took a very sound scientific idea and then probably stretched it to tell their story.
	So this idea that space debris is a problem is very true.
	That if a satellite, worst case, if the space shuttle or the space station is hit by something relatively large or a cloud of fragmentation debris, then yes, that would be extremely bad day at the office.
	So that kind of principle was absolutely sound.
	What they did with the film was really probably accelerate the timeline to tell their story.
	Because they had multiple calamities, didn't they, all happening at the same time?
	Yes, Sandra Bullock catapulting herself between various spacecraft to survive.
	Yes, indeed.
	So there were some issues with respect to the relative positions of the various sanctuaries that she found herself in.
	But as I say, that aside, this was at its heart, this was a story.
	This is fiction.
	And you want to be able to tell a story that people will relate to, that people will appreciate and feel for the characters.
	And I think that they absolutely manage that whilst also remaining true to the, if you like, the core idea that space debris poses this very real, very dangerous problem to, you know, not just for robotic spacecraft, but for also for human spaceflight.
	So do you think the movie did you scientists a favour?
	Well, I think what it did is certainly it raised public awareness about the space debris issue.
	So I don't think now that there is many people who are not aware of space debris being an issue.
	And that's been great.
	So from that point of view, absolutely.
	And I think it's been a way in which we as scientists have been able to engage with a variety of people that perhaps we wouldn't have been able to do before to talk about space debris because we've now, if you like, got a common frame of reference.
	If there was a situation where something as big as a refrigerator was headed at some speed towards the International Space Station, which we certainly hope doesn't happen anytime soon, what would be the trail of events?
	What would happen?
	Well, the situation you're talking about has happened.
	Oh, absolutely.
	So quite recently, in fact, the spacecraft in the last month has made two maneuvers to avoid objects that have passed close by.
	And these have been trackable objects.
	So not necessarily the size of a refrigerator, but certainly something that we can see from the ground with the radar.
	So normally what would happen is that we have, as I said, I've already mentioned before, this idea that we're tracking, the US Space Surveillance Network is tracking all the objects in orbit, larger than 10 centimeters.
	Now, some of those objects we're not observing all of the time.
	So the orbital information deteriorates over time.
	We're not quite sure where the position is.
	So they make predictions with that information about what's going to come close to the space station.
	If anything is found to be passing close to the space station, then typically what they would do is they would try and get better information about that object, refine the orbital data so that they can really, really look closely at the risks to the space station.
	And then they start to make a decision about, okay, if the risks don't go down, then we start to think about moving the space station.
	I think the interesting thing is for some of these objects, there isn't enough time to make a follow-up in terms of to improve the orbital data.
	And those are the situations where they have to ask the astronauts to move to the Soyuz simply because there's not enough time to move the space station.
	Right.
	And that is effectively an evacuation?
	Well, it's the preparation for an evacuation.
	And that certainly has happened as well to the space station.
	So they have these procedures in place.
	Obviously, the most important, the most fundamental rule that they have is to protect life.
	The lives of the astronauts on board the space station come first.
	So if there's any kind of risk and they're not sure if the object is going to miss or if it's going to hit, and there's nothing, they haven't got time to move the space station, then the best, the safest thing they can do is to move those astronauts so that they are one step away from safety.
	Right.
	Terrifying if you're up there.
	I guess these people are trained and honed and selected to be able to handle a situation like that, but still a real frightener.
	Oh, absolutely.
	I think, you know, the risks that the astronauts face are ever-present from space debris and a host of other things as well.
	And they choose to put themselves in that environment.
	And they can do that because of the training that they've got.
	So absolutely, they are the, if you like, the best individuals to be in that situation.
	Which none of us would want to be in.
	Now, this is the interesting part.
	What do we do about it?
	You can't take a huge vacuum cleaner up there, but you have to have a plan.
	And that's what you're working on, isn't it?
	Absolutely.
	So one of the things that we do here in Southampton is to produce computer models of this based ebb environment that allow us, if you like, to forecast what that environment is going to be like into the future.
	And what we can do with those models is to try out a variety of measures that potentially would make the environment better.
	So that's certainly been the case.
	So not just here in Southampton, but around the world, there are groups who are doing this and who have been able to identify a series of mitigation measures that can be applied.
	So we've already talked about one, which is, you know, after your spacecraft has finished its mission, then what you do is you limit how long it would spend in low Earth orbit or in geostationary orbit.
	So you reserve a certain amount of propellant on board the spacecraft to lower its altitude and get it out of orbit.
	And actually, that's, if you like, that's the best thing that you can do is to get that mass out of orbit as soon as you can.
	If you think about a spacecraft that's the size of a small car, that's a lot of mass locked up there.
	And if it gets hit, then all of that mass typically gets converted into thousands of fragments.
	And that's what you want to avoid.
	So the best thing you can do is to get that mass out of orbit.
	So these mitigation measures that have been worked on for some time now, the satellite operators are actually complying with these mitigation measures.
	So what you're seeing is that the spacecraft finished its mission and the spacecraft is then moved to a slightly lower orbit.
	So it takes less time for it to burn up.
	And The issue we've found, though, is that that may not be enough.
	With the computer models, we've discovered that even if everybody was doing this, every satellite operator was to comply with this particular mitigation measure, they're also complying with other mitigation measures as well.
	That might not be enough to prevent the population of space debris from growing.
	So nowadays, what we're also looking at are ways in which we can actually go up and remove large objects from orbit.
	But that is a whole new ballgame, if you like.
	That's from a technological point of view, financial, political, and legal point of view.
	That's a really, really challenging idea.
	From all of those perspectives, because even if you had the technology, it would cost you an absolute fortune, perhaps the budget of a small country, to go up there and sweep these things out the way or tow them into safety.
	Also, of course, there are territorial issues here.
	You know, you may not be dealing with a threat that is your threat.
	You might be dealing with some old Chinese satellite or something that India put up there or something random from the Soviet era.
	Absolutely.
	So this is where, you know, international law starts to come into place.
	You know, there's something known as the Liability Convention.
	And basically what that says is that the launching state is liable for any kind of damages that might occur.
	And what happens if they disagree with you about the level of risk?
	In terms of...
	Well, I think that there's generally now there's widespread consensus on the risk, if you like.
	So we can identify objects that are on orbit at the moment, which are high-risk objects because of their orbital environment they're in, and also because perhaps they're very large objects for lots of mass.
	So if you tell the man in Moscow or the man in Beijing your satellite is, your old satellite is an impending danger to the International Space Station, you can guarantee that they'll do something about it or try to.
	Well, we can't guarantee anything, really, but I think the case in point really is if you look at NVISAT.
	So NVISAT was, it failed on orbit a few years ago.
	It's a very, very large satellite.
	It's one of the largest objects that you find in near-Earth orbit.
	And it has no maneuvering capability.
	And it's in an orbit that is very, very high risk.
	It's in this sun-synchronous orbit.
	And what ESA have done, they've essentially, they've launched a program to try and address the issue of MVSAT.
	It's also, you know, it's addressing much more widely the issue of space debris and so on.
	It's their clean space initiative.
	But they were looking at, okay, we have to take responsibility for this object that we launched, we left in this environment, we have to do something about it.
	So I think that's a really, really good example for the rest of the world, for them, whether it's Russia, US, to look at and say, okay, they recognize that this is an issue.
	We can't hide the fact that this object is a potential threat, and they're doing something about it.
	So we should do the same.
	I think that's a really nice example to set.
	And what about the various technologies that could be used to remove many of these objects?
	Wasn't there one plan for a sort of giant net to be towed up there and then net all of these things and troll them out of the way?
	Yes, indeed.
	I think people have been looking at ideas for removing space debris for quite some time now.
	And some of those ideas are being taken forwards, some not so much.
	But those technologies, the net and so on, they're all untested.
	And that's a particular issue, really, because you're dealing with a problem where really it's got to work.
	You really have no room for failure because if you're going up and you're targeting an object that is already high risk with the potential to break up into thousands of fragments, you don't want to make the situation worse.
	So these technologies have to be really robust.
	And this is partly why, certainly in Europe, but also across in the US, we're starting to see now talk of demonstration missions where these kind of technologies can be tested in, if you like, more controlled ways.
	So a good example is the DLR mission called DIOS, which is really about on-orbit servicing and demonstrating technologies for on-orbit servicing, but it's also demonstrating a technology for removing spacecraft.
	And through those demonstration missions, hopefully we get a clearer idea of what technologies are going to be viable, how we might need to upscale those technologies to deal with a more widespread problem.
	So there's a process going on at the moment.
	But I would say where we are now, we still don't know enough.
	We cannot guarantee the success of these methods to remove space debris.
	We need to do more work on improving that technology, but also in terms of making sure that we're pulling out the right objects.
	This is a particular issue.
	It's too expensive to remove every single object from orbit.
	We just couldn't do it.
	We'd bankrupt every single nation on the planet, I think.
	So we have to choose the objects that we remove quite carefully.
	So there's a challenge there that we need to address.
	And what would be the hallmark of the most risky object?
	That it's very large, massive, I mean.
	Large, true, as well, because surface area is a prime input, if you like, to collision risk.
	And also in a very densely populated orbit.
	So there are objects in sun-synchronous orbit that are large.
	There are objects that are in other orbits, spent upper stages, for example, which are left on orbit once you've delivered the payload.
	Well, because we never think about those, do we, Hugh?
	Because we all watched, well, I did, I'm of that generation that watched the Apollo launches, and you see these bits of cylindrical metal cascade their way into oblivion, and you just think, well, they're gone forever, but they're not.
	Absolutely not.
	So, typically, you know, for every satellite you're launching, there is a rocket that is used to put it into space.
	And what happened, I guess, prior to the mid-2000s was that the upper stage would be left on orbit.
	Nowadays, the launch providers realize that actually that's not such a good idea, and they're working on ways in which they can actually deorbit the upper stage immediately after it's delivered the spacecraft into orbit.
	Not all launch providers are able to do that, though.
	So absolutely, it's another source of space debris.
	Do you fear that as the world's population increases, economies have more and more problems, as the focus of economic power shifts in this world, that this whole issue, this whole problem will go down the agenda?
	Actually, I think the opposite.
	I think space debris is always going to remain on or near the top of the agenda simply because we're becoming ever more reliant on space-based infrastructure.
	So I never see it disappearing off the agenda, to be honest.
	I think there are interesting and important issues that are, I guess, becoming clearer now, certainly with respect to security, defense, and so on, and the role that space plays, which are quite worrying from a space-debbed point of view.
	But no, I think that there's definitely a desire to deal with this problem at all levels.
	When you say that there are issues, for example, related to defense that are quite worrying, what do you mean by that?
	Well, I think there are, if you like, if you think of any kind of conflict that might occur in the future, it would be the first major conflict that would occur where space has been an important asset.
	And, you know, conflicts are all about gaining the upper hand.
	So one of the ways in which you could do that is to limit your adversary's capabilities in space.
	To knock out the other side's satellites.
	Precisely, yes.
	And then if we start doing that, then we do have a problem.
	If we start to destroy them, then you're creating even more junk.
	Yes, absolutely.
	I think all you need to do is to look back at 2007 when the Chinese conducted an anti-satellite test against one of their own defunct satellites.
	That single event generated over 3,000 trackable objects.
	That sounds incredibly irresponsible.
	Well, again, there are different motivations that you have to consider.
	Space is part of our infrastructure.
	So one of the things that you do as part of a conflict is to try and weaken your adversary's infrastructure.
	But to do a test that creates more of a problem, all of those extra trackable objects, that sounds to me like somebody wasn't using their thinking head that day.
	Well, I think it's difficult to say, really, because at the same time, first of all, with my scientist hat on, yes, absolutely, you're right.
	I mean, it's something that was ill-thought and should never be repeated ever.
	But taking into account kind of political will and fears, political fears as well, then you can start to at least to explain why these actions might be taken.
	Not necessarily to justify them, but certainly you can explain them.
	So you can explain them, but not necessarily rationalize them.
	Well, exactly.
	I think one of the concerns we've got really is the military makes probably the most use of space amongst anywhere in any kind of industry.
	The military spending in space is just enormous.
	And that really does tell you some very important things about what might happen if a conflict were to erupt on the global stage.
	It's all strategic.
	And also, does it concern you, Hugh, that a lot of this military spending in space we don't know about?
	So as we hinted at the beginning of this conversation, there may be things up there that have been put up there a while ago or are going up there today that the military is putting up there under black operations budgets and we don't know a whole lot about them.
	Oh, absolutely.
	I mean, this happens.
	But there are, if you like, there's silver linings.
	One of the silver linings is the Code of Conduct, for example, which started life as the European Code of Conduct.
	And in reality, what that is, is essentially it's a mechanism for countries around the world, space-faring countries, to say, look, we respect everybody's rights to access space and to make use of space, and we're going to protect those rights.
	And that's something that is being seriously considered, certainly in the US and around the world.
	So that's the silver lining, if you like, that whilst the US says that it doesn't want to sign up to this if it undermines their capabilities and their desire to protect their own people and assets, they are looking at this very, very seriously and encouraging others to look at it very seriously as well.
	And if you like, it's the rulebook for how we will use space.
	And that's where the IADC space debris mitigation guidelines are sitting.
	That's where the United Nations Space Debris Mitigation Guidelines are sitting.
	they're not legally binding, but they are there to say, look, we sign up to this, so therefore we respect your rights to access space and your rights to use space as you would like, as long as it doesn't interfere with us, as long as it doesn't jeopardize or put our assets at risk.
	And so that's the silver lining.
	Sounds reasonably fair.
	Just quickly, at the end of this conversation, and thank you for doing this with me, Hugh.
	We've talked a lot about the risks to things that are up there, the International Space Station, all of our satellites, and all the rest of it.
	We haven't talked about the risk to us down here.
	Is there any?
	Well, the simple answer is yes, but it's a very small risk.
	The risk comes from objects that re-enter the atmosphere, and not all of the spacecraft, for example, might burn up in that re-entry process.
	So some elements of a spacecraft or upper stage could survive down to reach the Earth's surface.
	And that happens all the time.
	So, you know, if you look back at the number of launches and spacecraft that have gone into orbit, the number of objects that we've added to the environment, only half are still there.
	So the other half have already re-entered.
	And it works out to be one large object every day is re-entering the atmosphere.
	And for Joe Bloggs on the street, you just would not be aware that that's happening.
	But could we get to a scenario where something as big as a garage is tumbling uncontrollably towards Los Angeles?
	Well, I think all parts of the globe typically are at risk because of the orbits that we're making use of.
	We've got orbits that are inclined with respect to the equator and inclined 90 degrees to that.
	So all parts of the Earth are at risk from objects that are re-entering.
	But the chances of an object coming down in a populated area are actually really, really remote.
	I think that the highest risks that we've faced in modern times came from satellite German design, Rosat.
	Not Rossat, beg your pardon, ROSAT.
	And this was, I think the risk there was something along the lines of one in two and a half thousand was the chance that somebody would be injured anywhere in the world.
	So it's not the chance that I would be injured.
	It's the chance that any single person on the planet would be injured by that particular object.
	But it's the stuff of Hollywood.
	Nevertheless, strange things do happen.
	Would we try and shoot if something was coming down towards London like that?
	What would we do?
	Would we try and shoot it out of the way or would we just tell people to move quickly?
	I honestly couldn't tell you what would happen if we found something that was on a collision course, say, with a populated area.
	I guess we were unable to predict that event very well, simply because the timing of re-entry is very, very difficult to predict.
	Typically, you can break it down to one orbit, and one orbit covers most of the Earth.
	So it's very, very difficult to say where it's going to be coming in.
	So the time that you'd have from spotting it, say on radar, to actually doing something about it, would actually be very, very small.
	But potentially you could imagine that, yes, you could shoot that down or do something about it.
	And just finally, do you think we're at greater risk from asteroids and other natural objects heading towards us?
	Or are the risks about the same?
	Well, that's a whole new conversation really.
	The asteroid threat is actually quite interesting.
	So certainly there's an announcement today on Earth Day by the B612 Foundation about the frequency of large impactors hitting the Earth.
	They've used satellite reconnaissance data to observe high-energy bursts up in the upper atmosphere and correlated those with asteroids.
	And they're set to say, I think, that actually the risk, we've underestimated it.
	And certainly if you look back to last year, the event over Chelyabinsk, you see the potential consequences of an asteroid that's actually relatively small on the solar system terms.
	So yeah, the threat from asteroids is very real.
	I think that there are steps being taken now to do something about that.
	And that's a good sign as well.
	So yeah, it's a different kind of risk.
	And it's, you know, yes, it's a kind of space debris, isn't it?
	It's debris from the solar system.
	It's out there, as they say.
	So like most aspects of life, I guess we've just got to try and be lucky.
	Absolutely.
	And I think putting it into context, as I say, Joe blogs on the street, you take a bigger risk opening the front door of your house and going out into the street than you would with anything to do with space debris or asteroids.
	That's a nice point to leave it on.
	I think if people want to know more about you and your work, how do they do it?
	Because an awful lot of work is going on there at Southampton that people are more and more getting to hear about in the media.
	But how do they find out about you?
	Well, they can just Google us or visit the southampton.ac.uk webpages and search for us there.
	But yeah, we're involved in a number of different organizations and so on.
	So through any of those, we'd be able to be found.
	Professor Hugh Lewis from Southampton University doing pioneering groundbreaking research into what exactly as a species, as a human race, are we going to do about space junk, the debris that we've left up there that we have to act on sometime.
	Interesting stuff.
	I'll put a link to his work on my website, www.theunexplained.tv.
	That website designed and created and maintained by Adam Cornwell at Creative Hotspot in Liverpool.
	Great work he does always.
	And thank you for your emails about him and his work.
	He will be pleased.
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	Until we meet again here on The Unexplained, I'm Howard Hughes, I'm in London.
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	Take care.

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