Cette conference n'a rien à voir avec le célèbre module AMIGA du même nom ! Http://modarchive.org/index.php?request=view_by_moduleid&query=57934
Une véritable poubelle de l'espace est en orbite autour de la terre et ces débrits spaciaux sont en rotation autour de la terre à très grande vitesse ( environ 8 Km/s en orbite basse ! ) C'est un véritable problème pour le présent et pour le futur car c'est une couche à traverser lors de chaque lancement de nouveaux projets dans l'espace.
Marek Möckel ( https://www.tu-braunschweig.de/ilr/da... ) explique tous les details du projet de simulation des objets en orbite réalisé par l'université technique braunschweig. Grace à ce projet les équipes qui préparent des lancements dans l'espace peuvent simuler si une impacte avec un débris spatiale pourrait se produire et ainsi corriger leur lancement. Ces informations sont accèssibles au public, j'ai donc fais le test de leur demander par mail les DVD et effectivement ces chercheurs délivrent l'information le plus rapidement qu'ils le peuvent.
Il existe si vous voulez vous amusez un petit peu un plugin Google Earth qui permet de visualiser ces débris spaciaux et les autres choses qui passent à grande vitesse au dessus de nos têtes. Http://www.wired.com/2009/03/howtojunk/
Cette traque est également possible sur mobile ! Https://play.google.com/store/apps/details?id=us.xyzw.spacejunk&hl=en
Des infos complèmentaires peuvent être trouvés sur Wikipedia sur ce sujet passionant. Http://fr.wikipedia.org/wiki/D%C3%A9bris_spatial
Most stock right away. Space to breathe. What is it space debris. Defines non functional uncontrollable object left behind to in space missions so anything that is out of control and so it's no specific purpose of function is classified the space debris we have arrived sources of debris and drive sizes which go over in detail very soon and the the big problem about space to 3 is that the high speeds at points objects in orbit are moving of can render small particles very very dangerous to space Croft as a rule of thumb an object that is larger than one centimeter in diameter can completely destroy any other object to it so whenever satellites in orbit and it's hit by an aluminum born of one centimeter in diameter it will be completely fragmented causing thousands of more pieces that are potentially dangerous. Space debris generally has long lifetimes than orbits because the forces that that decelerate and slowly over the the objects down so they can of burn up in the atmosphere of very long 25 years is considered acceptable and most of the stuff stays on there for hundreds of thousands of years and there is no effective way to actively remove those objects so. As we progress in the. In shooting stuff into space this problem is going to arrive. With a firm ground test results you can see an aluminum ball of about one centimeter in diameter hitting a massive phenomenon block access speeds much lower.
Then the highest speeds in orbit which are about. 15 kilometers per second if you have a frontal collision but usually 879 kilometers per second. This is the way of shielding of satellites you have one very small plate of flu minimum then you put a little bit of of kevlar between those of place and then you have the back plate I don't know if you can see them the the the object of him through there was a letter on the back phase so when you have your your electronics on the side there is a very good way to shield against small debris but as I said at high speeds this won't help anymore. So I'll give you a few basic spend a few space of resources. Of to counter measures that are possible and some of the challenges that are interesting especially in the field of computer science. Some babies concerning all the parameters that is basically all you need to know.
This is the orbit of an object this is the equatorial plane Aurora of planet earth. The main things you need to know are a semi major axis and eccentricity of the orbit which define its shape the semi major axes the radius of the larger portion and. But the this here and eccentricity is a value between 0 and 1 that defines the shape of the in the. SO 0 would be a circle and anything closer to one foot flat in the in the. Other important thing is the inclination which says this angle that defines how the the orbit is tilted against the equatorial playing the other values on fairly important here they define all the orbiters is rotated around the earth and the positions of the satellites. The other thing that's important is the perigee which is simply apogee is on the opposite side this is the point of the over to where the object is closest to us at the apogee at the office that would be the point where it's almost from and at the closest point if we move faster and that's the opposite point of the move slower. Most important order times of a low earth orbit which are mostly circular orbits anything below 2000 kilometers of which are mainly used for imaging satellites manned space craft the I. F. as for example would be a perfect example of Leo already. These are the ones that are most frequently use and of the ones with the highest speed so in terms of space debris the for the most dangerous.
And G. O. region hold television satellites. In a way that they'll fix when you look for a from the other you have them orbiting at the same speed as the move so they've always appear to be at the same position of the monuments are interesting they've been used by former Russian satellites of that name. They have a very high eccentricity I'm not sure if you can see it here which cost them to go very far off the ground track of ammonia all birds very fast around the pole and then come up here and slow down so that they have a lot of time over Russia to brought cost and and I think that we use for our telecommunication and then go down again incidentally with the 12 hour all of it so on the other end. Would come over the US and stay long time there so I'm not sure about the Soviet satellite program but it might be might have been used for spy satellites as well. This one is the typical Leo or beds and the points you won't be able to see someone about it would be and she all but just the thing then talk at a single spot.
Then we have a thing called the castle syndrome which was defined by Donna Kessler in the seventies he predicted that explosions and catastrophic collisions meaning those collisions that of completely destroyed object and because a lot of debris will create a large degree offset which in turn collide with other objects and cause more debris and phone some kind of a chain reaction of debris creating more than free and he predicted that around all of this was sent in and also relations show about it apparently did. At least in the neo region so if you would stop any kind of space flight the amount of dangerous debris in me or what's what's still in 3 this means that we really have to actively remove objects from space to continue space flight in the future. What we're doing at the institute as well creating a model of the space debris environment so we try to to simulate every object that is also from one micrometer 2 several meters in diameter all model is called the monster model which we developed FOR Esau. Now also has a different model court order I'm. Which has a slightly similar approach with slightly different results and currently trying to work out the differences so we have a. A single of space debris model the idea is to get a look objects that are tracked by radar and telescopes is the objects and are about 10 centimeters and above because everything that small it's very difficult to see so we create physical models of the sources.
That these 2 brief created by and we end up with billions of objects. Greater than. One micrometer then we go on to create a statistical model of the optic flocks and we can use that to assess the risks of of specific satellites so we have this this month the tool which is free as in beer. Which you can get from you so for me I have a few copies here and you can input on a target ordered for your satellites and the tool will generate a few. A few graphs about how dangerous about specific or would would be for the office today currently in New York orbit with a lifetime of about 7 years the risk of being destroyed by debris would be about 2 or 3 percent at the moment but. As I already said. The numbers will be arriving. Okay I'll give you an overview of with a variety of sources of to brief the thought the catalog objects first we have the the payloads which are the main ones satellites on the main main payload objects of. So if the purpose. We have about 3 on 3200 object in the database with only 800 of them functional so 3 quarters of all the satellites all of them are debris. The sizes ranges. Around several meters there in all orbits mostly in the and the geo region for example the navstar satellites which CPS are somewhere in between.
Then we have a rocking buddies pizza office stages which don't burn up in the atmosphere yeah what an multistage rocket and the the lowest 2 or 3 stages will fall down a burn up in the atmosphere but the top most states that hosts the payload will usually stay in orbit and so if the firm very locks targets for a collision. There are 1800 objects of those 5 catalogued as of may 2009 which is the basis for all the daytime giving you may 2009 again several meters in size and mostly in the U. orbits or cheer transfer over. Then we have a mission related objects the silence cups bowls loss tool bags anything that can fall off during a space flights we have 900 of those objects in the database 10 centimeters or above in size and again mostly the neo region is affected. Then we have solid rocket motor docile snack. If you listen to. Live rocket motor engine talk by down beat on the second day. You will probably have learned that by using aluminum visits to make sense of the the rocket fuel for better combustion the problem is that these aluminum bats clog up in these parts of the engine and then gets blown up and also. S. aluminum oxide with a size of approximately.
I think the largest one would be 70 centimeters so about the size of a fifth. With a simulated by also we cannot defense all of them of course so we simulate the the rock and the solid rocket motor firings and estimate how much to breeze generated by them and we have about 180000 objects larger than one centimeter in all out war with. Then we have sodium profession droplets. Interesting because this will cost by a very specific type of satellite Russian former Soviet satellites that use a nuclear power engine and when one of those engines crest over Canada which the Canadians didn't like very much of course. The Russians rebuild their own best satellites filled with the call gets injected. At the the end of life of the satellites and can burn up separately but the injection cost a few of the the coolant truck that's to me. And these form that the that the metal balls of 0.5 millimeters 8 centimeters so again about the size of a fist. And these are these are equally distributed. Rounds of earth and low orbits which I will show you in a minute. Then we have explosion and collision fresh ones so far we've come to.
Little more than 200 explosions and 10 collisions that have happened in the past we simulate those events an estimate how many particles and what sizes are generated. Explosions are mainly caused by few remain this offense remote functions so remaining fuel gets heated up and sunlight and explodes or battery footnote function can explode. We have around 10000000000 objects with 400000 exploding fragments and about 100000 collision fragments larger than one centimeter so these are very very dangerous because of course they all.
Existed in very high frequented or with. Then we have an effect on pain flakes is a very small particles that won't cause a catastrophic collision would still can clog up and and because he'll he'll solo at race pay you. These are both sizes up to 3 millimeters in orbit we have billions of objects of that type pain flakes of particles from. Well from paint of course that loosen after some time in order to to service degradation. Then we have the west for needle close this number interesting sauce because in the early sixties. There were 2 experiments with copper needles as should be sent into orbit to reflect radio waves to improve radio communication.
Bad to. 2 experiments of that time the first one failed completely because the need of didn't inject properly and form clusters. So we estimate that they look something like this several needles stuck together and then maybe. Can a larger boom of needles that still clung together. The second experiment was a success and really reflected radio waves for 2 days and then the needle started to tilt. So they were thought to to stay in this position for the waves could be reflected on them but you too perturbation fourth of they tell to and now they don't reflect anyway fit on and don't serve any purpose anymore so.
This is another full of debris now but they are mostly in non critical orbits when no other space Crofton location. Another over here we have the west for me the clusters tear the background without the catalog Dr. Any of the others different size reasons we also simulates the meter right back from some micrometeoroid steps. Enter the UPS. Surrounding and influence. Be found not technically debris but of course if the same effect a space craft was simulate them as well. And again anything larger than one centimeter will completely destroy any objects. Hello showed a simulation of all these that we developed at the institute to hope we can get it to work here. It takes a few seconds to load. Okay. There we have. And. I'll just put in all the object types. Press the satellites. And I hope you can see everything on the move of course. You can see the geostationary orbits. Just around here the now well now you can see it anymore.
This ring here would be the geostationary orbit. Click any object. Ingredients over parameters when its catalog of course of we don't have any catalog information and course with hunt this play and. So again 3200 objects most of them are using this now. Then we have broken bodies and. Mission related objects which adds another. 2500 object. The west for needles. Which former rain okay concealed. Somewhere here. So does the ring of copper needles which should have been evenly distribute tennis but this seems to be an error on our model. That. They someone didn't distributed evenly. What did so well then sodium potassium droplets. Which form. This. Beautiful looking ring around and send the information doesn't change. You can see that over the polls there are no drop the. This Orbitz. Try to show you one. Here for example.
The objects will go around there so they want circle around the poles of course. By telephone these holes together. Okay let's see what else we have. Okay that's just put in the rest pain flakes slackened off collision fragments that explosion fragments. And they look like this. The 5 of course is exaggerated these thoughts are about 20000 times the size of the actual object. In relation to the other but you can see the law for lots of junk out there. We have a. 620000 objects with a representative object so to save calculation computation time objects with very similar or bits of put into one so any of these thoughts. Can represent hundreds of thousands of objects. But of course if I what would enter the be checked out this would add another 4000000 representative objects and then I guess.
The GPU of the computer would fail. Okay this of course goes for earth space. The space currently looks. Like this by the way. Okay. So. We have the objects and. You can see that you really have to reduce space debris to ensure a safe space flight for the future. Possible options are close wait for natural courses which takes a long time you can count on the atmospheric drag of course whiskey federates off sick of the solar pressure which can decelerate objects to butterfly fence 25 years of time. Are considered acceptable and a small so. Other measures have to be taken and then you have a passive measures like preventing debris from occurring and to have active removal mission so any kind of space Croft that will will fly into orbit take down an object or multiple of 6 and then we move itself. For prevention the United Nations committee on the peaceful use of outer space has released a few guidelines that hopefully being followed by everyone because of course is the global concern for any country that wants to to space flight. We have of course the prevention of mission related object twenties so don't just ejection lens cap for you both into space but fix them some also they cannot fly away failure proof design to prevent any object from accidentally exploding by good design. Active satellites can of course take evasive evasive action if there is a danger of debris occurring been there a preservation measure which is basically to charge batteries and release still remained up so the objects cannot explode.
No intention of breakups which means no anti satellite test the no space weapons very important because well this because a lot of debris the last anti satellite test has increased the debris in the over 3 engines by 30 percent so one of these tests were really drive the progress forward. Then we have control of re entry and view or with you can just the federation object with the remaining fuel so burns up in the atmosphere which is usually done for spy satellites which you don't want anyone to to find and. And for geo regency dues graveyard orbit just use the remaining fuel to accelerate the space Croft and put it into an orbit several 0 kilometers higher or lower into a region that is not used by active satellites so they can collide and they can create a free but it won't harm any reason any reason that it's important for space flight of course. This is just a temporary measure and should not be. You for always. Now the problem of active removal of. A lot of questions are open and there's no active removal mission that has been conducted successfully yet so we really really need a great idea there but there are several main problems for example who pays for debris removal mission no one is willing to invest several $0 for such a mission without benefits and there are no legal obligations for anyone so we have to develop legal.
Guidelines loss to determine who would have to pay for such a mission because otherwise people simply won't do that. We have to determine which all checks should be removed this is. Possible we have used the Moscow software to determine which objects are most likely to Costa Rica and generated to kind of priority list to determine which objects should be removed first. Another problem how to get lots of heavy objects into space efficiently. There was an idea for example to use solar sails decelerate on 6 Bucks. There is no way to get a large enough solar sail into space without breaking it to have to have a very sophisticated on folding mechanism. And of course you have to prevent the favor from breaking which would cause even more debris so no one has successfully presented an idea here.
Of course there over to physics with some of the. I DO someplace seem to forget. Of the 2 just cannot cannot do anything in space like fly directly towards an all 6 get it down and fly somewhere else yeah of course use over to physics or have ludicrous amounts of energy which is not possible at the moment. Ben. Some.
Yes the using the space craft that just 5 behind debris objects pacman Stein and goals of the object the problem is that the specially in the Endangered reason regions most of the large degree comes from the side. So. This is impossible unless you have in a space debris prove space Croft so any kind of material that is strong enough to survive such collision which is currently not possible. And essentially of course of prevention anti space debris space crop from becoming space debris itself so you have to really.
Be able to move it really quickly and bring it down so it doesn't end up as to breathe fell. So some of. Who require ideas that don't need ludicrous amounts of energy sci fi technology does not track to be no make up made.
That require no on obtaining them and the laws of physics we are bound to. So. I give you a possibility of an idea of its being. Being followed at the moment tamari usable satellites and use a robotic arm some kind of connection that can capture an object or space tavern which is basically a large role that too attached to a satellite. And then roll out the role which will cost the active satellites to increase in height. And the jungle object to decrease so you can grab some all with the tether and lower it down to the atmosphere work will burn off they have been successful tests with this but so far no debris removal mission and our priority list shows that most of the objects on the priority list are of the same type of the same type of rocket body the same type of large satellite so you can design sets and the space craft to attach to a specific kind of objects and of course for the future. You can design rocket buddies with a certain mechanism that. I have a son that's can hook on to. Okay for computer science this is interesting because maybe we have a huge numbers of all 6 of us talking billions of objects that have to be.
Calculated on we have complex algorithms especially when it comes for things like atmospheric track and. For all program would basically take one of 1.in time which we simulate and then go from there and propagate all the off sick so we predict whether they will be 2 years later and this means that we have to do those calculations on every of these billions of objects which of course requires large amounts of computation power and of course my colleagues will hate me for this but engineer seems like fortune because it's always been there and it's easy to learn but if you want to do some stuff most sophisticated stuff like databases graphical user interfaces networks and stuff then with fortran you're basically stuck. A possible solution for going into is GPU computing. The simulation I've shown you for example can handle those 600000 off checks very easily a CPU of. Would slow down to an acceptable frame rate at about at say 20000 object so that the real speed up we get here in this simulation the the auto check propagation is done on the GPU via vertex shader so every object is basically one vertex and its position is determined by the shade on the C. P. U.. So this shows. Huge speed of which we can use in the same way for all computational models and degree source models we've had first tests with done OpenCL which are basically libraries that allow general purpose computing on graphical. CPUs on a graphical processes and we can achieve the same speed ups and we achieved on the animation but the the problem we're currently facing us that accuracy comes at a high performance cost shaded font optimize for of. For the kind of accurate calculations that we will need quota and OpenCL are a bit better about but double precision floating point for example comes at off the speeds of single precision floating point and a good case on a special Tesla GPU a specially built for GPU computing unusual consumer level graphics cards double precision would be 112 of the speed.
A single precision. Okay conclusion we have billions of space debris objects that are potentially dangerous. I think about several 0 of objects larger than one centimeter that can really wreak havoc on existing satellites other officer. This large number versus only 800 functional satellites that are in orbit at the same time so the amount of debris is massive and. The large objects have to be removed so the the amount of debris were nothing trees and make. Space flights impossible in the future. And I give you a brief overview of showing the simulation again. About how high performance computing can be used to it calculate these models this works of course because all these objects are independent from each other and can be calculated in parallel on the GPU at least until it comes to things like collision than what needs different models but we're working on that. The monster 2009 model is free as in beer as I told you I've got 25 DVDs here so if you want to grab a copy you can come up front and get one and if there are no more left you can email me and we will send you a copy free of charge you won't even have to pay us shipping something will just send you a DVD if you leave us a shipping address. And I'll show you the program really quick. I have it here. Okay so this is the graphical user interface masa 2009. Which is basically laid over the. The the monster tool which is a,nd line tool so you can can use it and scripts and stuff. Give you a target orbit scenario for example for you and to. Your target ordered for example started satellite it 5/1/2009.
And and the lifetime one year later with a semi major axis of 7 calls launchers so that's the typical low earth orbit nearly circular. Then you can select rifles of debris that you wish to account for when there are collision or explosion events we release of a new cloud of debris. That you can copy into the program and then activate here. So whenever this collision in space you will have the latest data. Then you can define services. The symbols one would just be a sphere so. Spherical satellite representing your object or you can be precise and enter all the services the content light has. And then selects which kind of clothes he would like to.
To see. And just. Execute monster and I hope it works you know. Take some time. So basically no it's running the,nd line tool on the input is generated and uses influx to. Create beautiful prints of what's coming. And show them on the graphical user interface. Okay it's finished. Hello moving as a way. Sure how. Get to work open to yet okay here the plot. The small on the screen and fortunately the Y. axis is always the object flux. So. Object impact per square meter of satellites every all per year. And. You can. Can plug over variety attribute night the mass of the impacting objects you can see that. Most of the objects nearly all of the object that impact are less than one kilogram in weight. The diameter of the object said with its use of for this or but these are very very small. Optics mostly and the centimeter of 6. Which would be around here all of course been. Please but also the most dangerous. I'll show you another animation. Which I forgot to do. Okay this is.
One explosion that occurred in space. Very. Hard to see. This. Is the spot where it happened. And this is. The amount of debris that was simulated from this explosion. And when you start the animation. You will see all the clouds will distribute over time.
Inform. I need to ring like this. The interesting thing is that every object will go to through the point of origin so when you have a satellite that for example as in orbit going around here through that point then you have a problem. And if we left it running now you would see that this cloud would even need distribute around the US just like the sodium potassium droplets that I showed you earlier. Okay that's all I have. As I said masa DVDs are available here if you're interested that's a lot of documentation on the DVDs on all of the models and very large details so you can have a look then or email me for any questions thank you. Okay. We have about 15 minutes for questions. One if you would like to come in at some if people would like to come in and speak of the may Mike fund that would be wonderful we also have questions coming from online that's okay says about 15 minutes and then I'm gonna give you some rounds with the end and that's what it. Hey you talked about doing the calculations and maybe go into a GPU solution.
And I wasn't sure but it came across to me that you're doing everything on one computer is that correctly I'm sorry I didn't get the you doing the whole calculations on one server room one or a bunch of CPUs in one computer or are using multiple computers next to each other to do that that's the plan for the future. As of now is access question you. We have one at university which I'm trying to get access to but currently I have one Tesla GPU which is the. Especially if you're computing cars and a consumer level graphics cards and they use those. To simulate the object. So when you look at the night the night sky it's quite usual to see.
I think it's called the footing starting delicious R. meet Mr rights the explanation given in schools for instance usually make a size that is our natural like grains of sand that entered the atmosphere so I wonder how much is how much of that today is actually artificial inquiry and. Artificial objects like space degrees and how much of that this natural background of me to write. Okay so how much meteoroids in months. A 3 or anything I don't dominated by our professional. At this point in time is this economic bark to crystal objects or not or that's been an interesting question I don't have any numbers on this but you can usually determine when it's an artificial objects that it usually breaks off so you have a cloud of all 6 of course they can be of breaking up meteoroids but usually that some kind of debris that's breaking up and burning up in the atmosphere so when you have a friend a large cluster of objects in this space debris in most kind.
Or a spy satellites that someone doesn't want anyone to find. Hi ed you mentioned dome was willing to pay for the cleanup presumably the cooktop life insurance industry they would reduce the costs by reducing the chance of one of the satellites they're insuring being destroyed is there any sort of a movement from them to say you know we'll pay will put a bounty of there a couple of 0 or. Of $1000000 when these large rocket stages the gets removed or is that anything on us for some kind of space debris insurance. Of a company that that will ensure space debris impact. Well it is an existing insurance industry for satellite so if you're looking support that company those insurance companies I I assume will if you'll satellite is destroyed by debris will pass compensation depending on what kind of insurance deal you have with them I should mention that the insurance industry doesn't want to pay ours so if they can which uses the debris risk they increase their profits so that point he makes economic sense for them to to pay bounties to have the degree would you use has that in any sort of cleanings you know of any communication with the insurance industry tossed normally willing to pay out but they don this is a natural calculations as to what it is and what's a good price to 17 as a sort of markets that reducing the rate.
As far as I know there's no such thing yes but I'm not a legal experts and computer sciences really no idea about that but that's a really good question and maybe a very good idea so I have a look into that and thinking maybe thank you for the question. Do you have any more questions have good time is left to. Question. How exactly do simulate the collision cascade of the production of them. We don't have a model to simulate of a test case but we have models to simulate of certain events so what we do is we simulate one events than look well all the particles go and then as of but try to to calculate the possibility of one of these objects causing another collision and we put that into the models so. If there's a collision and to simulate a number here for example then the probability with winds of one of these generated objects because another collision will be accounted for. Come on there must be something else. How we look on the drawing for line.
Come on. Toggle 10 minutes with him written. Must be some. I guess we're all tired. He misses you calculated to the the sort of that the party has been talking about home online someone no that's currently not available we did that for a for a third party. Institution who might make it available in the future so if there's anything it'll probably come out on institute's website. He's a decision I'm sort of at the office most I mean he just looks a lot on local bodies in crowded with its with what it is that easy or is it actually other any surprises in the there are some surprises and most of most of this list the screen comprised of. Old broken bodies which is not surprising at all because satellites can usually be removed by other means for example controlled me entry so the rocket bodies so what staying up there and those are the ones that cause most collisions and exploding so these are the most dangerous objects so it does make sense there were some objects that we don't have data for mainly US spy satellites of course we get the the object data from the US military but they don't put in their own spy satellites so we don't know if there's any but. If there is a an endangered spy satellites and the operator will surely know and. Wouldn't want anyone to remove that object for and for. HM what one question okay. How do you. Thought about using the technology used by.
The all of the bill here affects companies of visual effects of these amazing exact the same sort of issues in terms of simulations of objects having to power lines. Okay to violence 30 very similar issues about whether they want a C. P. versus GPU. Yeah she talked with them because a lot of them using pencils products and and all parts of open source projects. And I think also the kind of interested in the body to. Who knows computational skills and billing math skills because they say the fun of these people rather than Steve 7 people you might want to find people who are desperate to work and. Well we currently the only ones who do this on space debris but in essence it's all numerical calculus so there lots of other scientists that go into this field for example in the pharmacy and physics and of course in the video game industry to so I I many get papers from everywhere and try to to is that what they are doing 12 courses. Tell just what I'll just minutes to stop most. Home sick Ralph about these issues and it seems remarkably similar to what people are worrying about to say for offline now okay I haven't haven't followed the latest a gruff but. Thanks for the tip I will surely look into the. Do we have anyone else anything else coming up.
Do you have his relations what will happen if the launch is going as it is without any reduction is all country doctor recently opened. One of the women of this is wrong in the really problematic. I don't have any chart here right now sorry. Bucks that seems to be some kind of. Given points in about maybe 60 years I'm not sure if I remember the numbers correctly I'm sorry but there will be a point where. Taking measures to prevent space debris that may be very expensive will cancel out the calls that will be caused by satellites rendered on operational by space debris so. In about I think it was something like 60 years the cost. Will be. Will be canceled out so you invest something now to decrease the cost in about 60 years. Thank you. N. K. looks like we're coming to an end. So Caroline thank mark for an incredibly interesting I'm Frank.