00:01If you want to travel in space, prepare you to make about 55 millions of dollars.
00:07But in a close future, you may probably be able to travel in space
00:11by simply clicking on a button without you ruin it.
00:14Because the space ascenseurs could well enter in the game.
00:17So that the idea of a galactic ascenseur seems to come out of a science fiction movie,
00:22it is a real possibility that could revolutionize the space travel.
00:26With an estimated cost of 8 billion dollars,
00:28a such ascenseur could not represent an unique investment that would cost forever.
00:36The NASA, at her own, spends about 2 700 000 dollars in carburant for fusée at every minute of flight.
00:44For launching a fusée, they must thus bourses to 178 millions of dollars.
00:49These costs could be considerably reduced if we use ascenseurs.
00:54Most of the buildings the most high on Earth have massive foundations to help balance their weight.
01:00Plus you look in the air, the more it s'amincisent.
01:03Even the highest heaven above the world, the Burj Khalifa, is heavy at its base and effilé at its summit.
01:10If we wanted to build something that is apparent to a gigantic ascenseur,
01:14we would have so much needed to build a huge amount of concrete to build the foundations.
01:20This is what we call our original goal of saving money.
01:25Now, take a ficelle, attache a ball to its extremity and start to turn it.
01:30The ficelle in your hands will remain in place and the ball will turn around your hands.
01:35This is what we call the force centrifuge and the ascenseur will work in the same way.
01:40The ball will be a base in space and the cord will turn around the Earth.
01:47The station by which we enter into the ascenseur will be located in the Atlantic Ocean and the cable will
01:53be extended from there.
01:55For that possible, this one should be perfectly synchronized with the rotation of the Earth.
02:01Without what it will simply break or break around the Earth like a fouet.
02:06In addition, the orbit followed by the cable will form a perfect circle,
02:11because the line will not be able to spread nor to extend it.
02:14Many calculations have been made in the aim of finding the ideal solution.
02:18Wait a minute, it is so that it serves the algebra.
02:21Who knew?
02:22In the meantime, we will not be annoyed with more math.
02:27About the distance between the Atlantic Ocean and the space, which must be of 36.000 km above the Earth,
02:36where the orbit begins the geosynchronous orbit.
02:39There, the four ascendant forces are much stronger than the only descendant force.
02:45That's why the station would remain in place.
02:49When you build a house or a building, you start by the bottom and progress towards the bottom.
02:54But to create this merveille of engineering, we would need to take us to the top and start by the
03:00top.
03:01The main problem here would be the weight.
03:05If the line was too heavy, it would disturb the orbit.
03:09And the charge would not work.
03:12So we need to balance the space space to ensure a function without failles.
03:19L'acier is one of the most robust materials on Earth.
03:23The cable of each ascenseor is in fact made of acier.
03:27But when you need a cable of 36.000 km long, things can become a bit complicated.
03:33L'acier is difficult to romper, but it is encombrant.
03:37And when you have to use a lot, it is then that the problems begin to come.
03:42We use a lot of steel in the construction.
03:45But we have a lot of lighter materials in our disposal.
03:49It could have less pressure on the station and eliminate this problem.
03:53In addition, the cable should be fuseled because, at the end, the constraint would be practically inexistent.
04:00But it would always be more heavy than necessary, because of many security factors.
04:05At the beginning, the cable would be at least 1 mm of the thickness.
04:10After all, a lot of complicated calculations, we can determine its height in the course,
04:14which represents such a long number that we would be incapable of pronouncing it.
04:19But believe us, it is a very, very large number.
04:22So, the acid is out of question.
04:25Another candidate is the Kevlar, which is five times more resistant than the acid.
04:29And if we add materials such as the carbon and the titanium to this alliage,
04:33its resistance would be even more decupled.
04:35The cable would then have a wide diameter between 80 and 170 m.
04:40It is almost less small than what could be the diameter of a same cable in steel.
04:45The bad news is that it would cost quite a bit too much.
04:49So, if we don't find the ideal material for building this cable,
04:53the idea even of an space sensor will never be a vast loss of time.
05:00If we only had a hell of a light light light light light,
05:05able to increase a 60 Pa, and also a component of 1,6...
05:12Oh, but wait, we have a type of such a titanium.
05:16It is called the nitrous carbon nanotubes.
05:19They have a resistance of 130 Pa.
05:23Which is a much bigger than what we need.
05:25need. The nanotubes are made from carbon and are 100 000 times more thin than the human hair.
05:32This material is solid and has a good capacity of conduction, which is made possible
05:37thanks to its unique atomic structure. We use this innovation in many things,
05:43from batteries to optics, and they can be completely modified and adapted to many other uses.
05:50Bradley Edwards is the man responsible for this idea.
05:53The NASA was looking for new innovations and said,
05:56''Ne tentez rien de trop fou et commencez juste à nous construire un treuil spatial.''
06:01On suppose que Bradley a dû prendre cela pour un défi, car il a commencé à travailler sur
06:05l'ascenseur. Edwards a donc rédigé un article sur un transporteur galactique. Lorsqu'il l'a publié,
06:11il s'attendait à ce que de nombreux experts décèlent des failles dans ses travaux. Mais étonnamment,
06:17personne n'y est parvenu. Son concept était irréprochable. Il a ainsi eu l'idée d'attacher
06:23une ligne de nanotubes à une fusée et de la propulser dans l'espace. L'autre extrémité du
06:29câble retomberait sur Terre et des robots utiliserait ce dernier pour y grimper et l'allonger afin que
06:34nous puissions entamer la construction d'une station spatiale. Après cela, l'ascenseur pourrait
06:39commencer à acheminer tout et n'importe quoi, des panneaux solaires jusqu'aux touristes. À l'avenir,
06:46le tourisme spatial pourrait devenir accessible. Qui sait, nous pourrions même partir en vacances dans
06:50l'espace un jour. Eh, vous recherchez une atmosphère d'évasion ? Eh bien, ne venez pas ici,
06:56nous n'en avons pas. Oups, probablement pas le meilleur slogan publicitaire, n'est-ce pas ?
07:01Il y a quelques années, nous pouvions seulement créer des nanotubes de carbone microscopique. Mais
07:07avec le temps, davantage de recherches ont été effectuées pour les rendre plus grands. Aujourd'hui,
07:13ils atteignent jusqu'à quelques centimètres. D'ici vingt ans, ils pourraient être longs,
07:17de plusieurs kilomètres. Le carbone coûte un dollar le gramme. Si nous faisions le calcul,
07:23nous verrions qu'il nous faudrait environ un milliard de dollars pour construire cet ascenseur.
07:27Oui, cela semble coûteux, mais c'est une solution à long terme pour les voyages spatiaux,
07:31qui pourrait nous faire économiser énormément d'argent. Tout a l'air parfait sur le papier.
07:37Mais la raison principale pour laquelle la NASA a choisi de ne pas poursuivre ce projet,
07:42est qu'à l'heure actuelle, il y a probablement plus de 128 millions de débris flottant dans l'orbite
07:47terrestre. Et il pourrait ne présenter une véritable menace pour cet ascenseur. Il pourrait,
07:53certes, être conçu pour résister à quelques impacts de temps à autre. Mais être constamment
07:59bombardé ne faisait pas partie de l'équation. Néanmoins, Bradley soutient qu'une armada d'appareils
08:04de surveillance détectent ces débris spatiaux. Ainsi, l'ascenseur pourrait être capable de tous les
08:10éviter. Si quelque chose heurtait l'ascenseur, ou si le câble se brisait d'une manière ou d'une
08:17autre, les conséquences ne seraient chi pas trop sévères. Enfin, s'il n'y avait pas de passagers à
08:22bord, bien entendu. Si la ligne était coupée, l'ascenseur dériverait simplement dans l'espace
08:28et ne représenterait aucune menace pour quiconque. Au Japon, des ingénieurs tentent de construire un
08:34ascenseur spatial. Celui-ci pourrait également être utilisé pour l'exploitation minière dans
08:39l'espace. Nous pourrions facilement couvrir le cou de cet ascenseur en attrapant des astéroïdes
08:45au passage, car certains d'entre eux sont faits de métaux précieux. Nous pourrions alors les
08:49exploiter et les rapatrier rapidement sur Terre.
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