B1 · Episode 2 · 5:00
How Starlink gets into orbit
How the satellites go up in batches and form a network.
Source：Void · License：CC BY 3.0
Transcript
il est en effet prévu une phase 2, composée de 30 000 satellites qui
it is indeed planned a phase 2, composed of 30,000 satellites which
seront répartis entre 328 et 614km d’altitude. Autant vous dire que ça va être un
will be distributed between 328 and 614 km of altitude. As much to say to you that it will be a happy
joyeux
will be distributed between 328 and 614 km of altitude. As much to say to you that it will be a happy
bazar là haut ! 30 000 satellites, c’est un volume astronomique
mess up there! 30,000 satellites is an astronomical volume
puisque aujourd’hui on compte un peu moins de 2 000 satellites en orbite basse.
since today there are slightly less than 2,000 satellites in low orbit.
On peut donc présager que ce genre de constellation pourrait engendrer bon nombre
We can therefore predict that this kind of constellation could cause a good number of problems, in particular
de problèmes,
We can therefore predict that this kind of constellation could cause a good number of problems, in particular
le risque de collision notamment. Dernier exemple en date, en 2009 deux satellites
the risk of collision. The latest example, in 2009 two satellites
sont entrés en collision, Iridium-33 et Kosmos-2251. Les deux satellites se sont
collided, Iridium-33 and Kosmos-2251. The two satellites collided at
percutés à
collided, Iridium-33 and Kosmos-2251. The two satellites collided at
42 000 km/h et l’incident a engendré quelques 600 débris qui aujourd’hui doivent
42,000 km / h and the incident generated some 600 debris which today must be
être
42,000 km / h and the incident generated some 600 debris which today must be
monitorés constamment pour éviter de nouveaux incidents.
monitored constantly to avoid new incidents.
Je ne m’étends pas plus sur le sujet, car je réaliserais prochainement une vidéo
I do not dwell on the subject any further, because I will soon be making a video
portant
I do not dwell on the subject any further, because I will soon be making a video
sur le syndrome de Kessler, une conséquence de ce genre d’incident qui peut rendre
on Kessler syndrome, a consequence of this kind of incident which can make certain eye sockets
inutilisable
on Kessler syndrome, a consequence of this kind of incident which can make certain eye sockets
certaines orbites. Et avec Starlink, on est pas à l’abris de ce genre de scénario.
unusable . And with Starlink, we are not immune to this kind of scenario.
Pour le cas Starlink on peut essayer de faire une estimation très approximative des
For the Starlink case, we can try to make a very rough estimate of the costs of phase 1.
coûts de la phase 1
For the Starlink case, we can try to make a very rough estimate of the costs of phase 1.
On va commencer par les satellites
We will start with the satellites
SpaceX avait annoncé être capable de les produire pour un coût unitaire inférieur à
SpaceX had announced to be able to produce them for a unit cost of less than $ 550,000 in their
550 000$ dans leur
SpaceX had announced to be able to produce them for a unit cost of less than $ 550,000 in their
usine de Seattle. Pour les 4408 satellites ça nous donnera quelque chose comme 2,4
factory in Seattle. For the 4408 satellites that will give us something like $ 2.4 Billion.
Milliards de $
factory in Seattle. For the 4408 satellites that will give us something like $ 2.4 Billion.
Question lanceur, SpaceX effectue ses lancements sur son habituel Falcon 9 en
Question launcher, SpaceX is carrying out its launches on its usual Falcon 9 while waiting for
attendant que
Question launcher, SpaceX is carrying out its launches on its usual Falcon 9 while waiting for
le Starship soit opérationnel. Jusqu’à maintenant, SpaceX s’est contenté d’utiliser
the Starship to be operational. Until now, SpaceX has been content to use
les premiers étages réutilisés pour lancer ses satellites, de quoi réduire les coûts
the first reused stages to launch its satellites, which will keep costs as low
au maximum. On ne connaît évidemment pas le coût de ces lancements en interne,
as possible. We obviously do not know the cost of these launches internally, SpaceX
SpaceX
as possible. We obviously do not know the cost of these launches internally, SpaceX
n’aurait aucun intérêt à nous divulguer le coût de revient de ces lancements, ce
would have no interest in disclosing the cost of these launches to us, it
serait donner des arguments aux commerciaux de leurs futurs clients pour tirer les
would be giving arguments to the sales representatives of their future customers to pull the prices
prix
would be giving arguments to the sales representatives of their future customers to pull the prices
vers le bas. Cependant, certaines études pensent qu’un lancement avec un étage
down. However, some studies believe that a launch with a reused stage
réutilisé
down. However, some studies believe that a launch with a reused stage
couterais entre 40 et 50 millions de dollars à SpaceX c’est donc le chiffre
would cost SpaceX between $ 40 million and $ 50 million, so this is the figure
qu’on va prendre tout en gardant en perspective que ce calcul n’est qu’à titre très
we will take while keeping in perspective that this calculation is only for very good reasons. indicative.
indicatif.
we will take while keeping in perspective that this calculation is only for very good reasons. indicative.
La coiffe de la Falcon 9 est quant à elle capable de contenir jusqu’à 60 satellites,
The Falcon 9 fairing is capable of holding up to 60 satellites, so
nous aurons donc besoin de 74 lancements pour mettre la totalité de la phase 1 en
we will need 74 launches to put the entire phase 1 into orbit.
orbite.
we will need 74 launches to put the entire phase 1 into orbit.
2,4 milliards pour la production des satellites et 3.7 milliards pour les
2.4 billion for the production of satellites and 3.7 billion for launches.
lancements.
2.4 billion for the production of satellites and 3.7 billion for launches.
Il y’a beaucoup d’éléments qui n’entrent pas en compte dans le calcul, mais
There are a lot of elements that are not taken into account in the calculation, but overall
globalement
There are a lot of elements that are not taken into account in the calculation, but overall
ça nous donne un ordre d’idée de l’ampleur des investissements nécessaires avant
it gives us an idea of the extent of the investments necessary before even
même
it gives us an idea of the extent of the investments necessary before even
d’avoir un produit fonctionnel. Ce n’est pas pour rien si OneWeb a connu quelques
having a functional product. It is not for nothing that OneWeb has experienced some difficulties recently
difficultés récemment
having a functional product. It is not for nothing that OneWeb has experienced some difficulties recently
L’aspect financier n’est pas la seule barrière à passer pour parvenir à avoir une
The financial aspect is not the only barrier to overcome to achieve a functional and efficient constellation.
constellation fonctionnelle et performante.
The financial aspect is not the only barrier to overcome to achieve a functional and efficient constellation.
La gestion du signal par exemple est l’un des défis techniques à relever, car comme
Signal management, for example, is one of the technical challenges to be met, because as
on l’a vu précédemment, la latence et le débit sont des éléments clés dans cette
we have seen previously, latency and throughput are key elements in this technological revolution
révolution technologique
we have seen previously, latency and throughput are key elements in this technological revolution
D'un point de vu materiel, pour se connecter à la constellation
From a hardware point of view, to connect to the constellation
il faudra nécessairement passer par une antenne. Antennes qui sera mise à
it will necessarily go through an antenna. Antennas that will be made available for
disposition pour
it will necessarily go through an antenna. Antennas that will be made available for
499$ en plus de l’abonnement à 99$ pour les Americains du moins.
$ 499 in addition to the $ 99 subscription for Americans at least.
Les terminaux tels que les téléphones n’ont en effet pas la capacité de capter les
Terminals such as telephones do not in fact have the capacity to pick up the
bandes
Terminals such as telephones do not in fact have the capacity to pick up the
ku, ka qui serviront à transmettre le signal entre le sol et l’orbite.
ku, ka bands which will be used to transmit the signal between the ground and the orbit.
Lorsque vous essaierez d'afficher une page sur votre téléphone;
When you try to view a page on your phone;
Le téléphone devra se connecter à l'antenne qui emettera une requête en direction
The telephone will have to connect to the antenna which will send a request towards the satellite satellite
du satellite
The telephone will have to connect to the antenna which will send a request towards the satellite satellite
satellite qui redescendra celle ci vers la station au sol qui est elle même
which will bring it down to the ground station which is itself connected
connectée
which will bring it down to the ground station which is itself connected
au serveur. L’information fera le chemin inverse et affichera la page sur votre
to the server. The information will do the reverse and display the page on your terminal.
terminal.
to the server. The information will do the reverse and display the page on your terminal.
Sur le principe ça paraît plutôt simple, en pratique il faut avoir beaucoup de
In principle it seems rather simple, in practice you need to have a lot of ground
stations
In principle it seems rather simple, in practice you need to have a lot of ground
au sol pour pouvoir relayer l’information. C’est un problème qui pourra se poser
stations to be able to relay information. This is a problem that could arise in
dans
stations to be able to relay information. This is a problem that could arise in
le cas où l’information devrait transiter d’un côté à l’autre de l’océan.
the event that information should travel from one side of the ocean to the other.
En effet, s’il n’y a pas d'îles sur lesquelles installer de station, l’utilisation
Indeed, if there are no islands on which to set up a station, using the network
du réseau
Indeed, if there are no islands on which to set up a station, using the network
depuis des navires lors de traversées pourrait se révéler compliquée.
from ships during crossings could prove to be complicated.
SpaceX, conscient du problème, travaille sur cette problématique, puisqu’ils
SpaceX, aware of the problem, is working on this problem, since they plan
envisagent
SpaceX, aware of the problem, is working on this problem, since they plan
d’équiper tous les futurs satellites de lasers, pour leur permettre de communiquer
to equip all future satellites with lasers, to allow them to communicate with
entre eux et s’affranchir de la nécessité de station au sol sur de longues
each other and free themselves from the need for a ground station over long distances.
distances.
each other and free themselves from the need for a ground station over long distances.
Et qu’est ce qu’on peut espérer en terme de débit ?
And what can we expect in terms of throughput?
Eh bien les premiers tests qui ont filtré à travers la béta, montrent un taux de
Well the first tests which have filtered through the beta, show a download rate of
download
Well the first tests which have filtered through the beta, show a download rate of
compris entre 35 et 65 Mbps et entre 5 et 18 Mbps en upload. Ca correspond
between 35 and 65 Mbps and between 5 and 18 Mbps in upload. It roughly corresponds
grossièrement
between 35 and 65 Mbps and between 5 and 18 Mbps in upload. It roughly corresponds
à de la VDSL. Le ping quant à lui varie entre 30 et 100 milliseconde, on est un peu
to VDSL. The ping varies between 30 and 100 milliseconds, we are a little
limite pour du gaming, mais ça reste plus que correct.
limited for gaming, but it's still more than correct.
Il faudra cependant garder en perspective que ces chiffres vont beaucoup dépendre de
However, it will be necessary to keep in perspective that these figures will depend a lot on
la charge du réseau, si vous êtes au milieu de la campagne avec personne à 10km à la
the load of the network, if you are in the middle of the countryside with no one within 10 km
ronde, ça ira beaucoup plus vite que dans une métropole densément peuplée. Le
, it will go much faster than in a densely populated metropolis. The satellite
satellite
, it will go much faster than in a densely populated metropolis. The satellite
n’est en effet pas illimité en termes de capacité.
is indeed not unlimited in terms of capacity.
On voit bien sur cette représentation de la phase 2 que c’est un problème qui est
We can clearly see on this representation of phase 2 that it is a problem that is
pris en compte par SpaceX pour l’avenir du réseau. Les traînées blanches sont en
taken into account by SpaceX for the future of the network. The white trails are
réalité des satellites qui sont placés sur la même orbite. Certaines de ces orbites
actually satellites that are placed in the same orbit. Some of these orbits
Et qui passent au dessus des principaux foyers de population de la planête
And which pass over the main population foci of the planet
Certaines de ces orbites contiendront plus de 7000 satellites et ça pourrait
Some of these orbits will contain more than 7000 satellites and that could make it possible to reduce the load of the
permettre de réduire la charge du
Some of these orbits will contain more than 7000 satellites and that could make it possible to reduce the load of the
réseau ou de la repartir plus efficacement.
network or to distribute it more efficiently.
Sa forme est assez atypique puisqu'il est plat en position de lancement et ne
Its shape is quite atypical since it is flat in the launch position and does not look like anything known.
ressemble à rien de connu.
Its shape is quite atypical since it is flat in the launch position and does not look like anything known.
On aurait pu s’attendre à un satellite format CubeSat pour réduire les coûts, mais
One might have expected a CubeSat format satellite to keep costs down, but SpaceX decided that this
SpaceX a décidé que cette
One might have expected a CubeSat format satellite to keep costs down, but SpaceX decided that this
forme était plus adaptée à la coiffe de la falcon 9. De cette façon, la société
shape was more suited to the falcon 9 fairing. That way the company
peut maximiser le nombre de satellites par lancement en utilisant la pleine capacité
can maximize the number of satellites per launch using the full capacity
de la coiffe du lanceur. SpaceX produit en interne ses satellites;
of the launcher fairing. SpaceX internally produces its satellites;