Why SpaceX is Making Starlink

This episode of Real Engineering is brought
to you by Brilliant, a problem solving website that teaches you to think like an engineer. On the 24th of May, SpaceX launched a Falcon
9 rocket filled with 60 satellites into space. This marked the beginning of their ambitious
new project called “Starlink” which aims to provide high quality broadband internet
to the most isolated parts of the planet, while also providing low latency connectivity
to already well connected cities. [1] SpaceX aim to make their broadband as
accessible as possible, claiming that anyone will be able to connect to their network if
they buy the pizza box-sized antenna which SpaceX is developing themselves. This launch of 60 satellites, was just the
first of many. Spacex has 12,000 satellites [12] planned
for launch over the next decade, dramatically increasing the total amount of spacecraft
around Earth’s orbit. This will cost SpaceX billions of dollars,
so they must have a good reason for doing so. Let’s see how this network will work, and
how it will compete with existing internet providers. Back in 2015, Elon announced that SpaceX had
began working on a communication satellite network, stating that there is a significant
unmet demand for low-cost global broadband capabilities. Around that time, SpaceX opened a new facility
in Redmond, Washington to develop and manufacture these new communication satellites. The initial plan was to launch two prototype
satellites into orbit by 2016 and have the initial satellite consetllation up and running
by 2020. But the company struggled to develop a receiver
that could be easily installed by the user for a low cost, this delayed the program and
the initial prototype satellites weren’t launched until 2018. After a successful launch of the two prototypes,
Tintin-A and B, which allowed SpaceX to test and refine their satellite design, SpaceX
kept pretty quiet about what was next for the Starlink project, until November 2018
when SpaceX received the approval from the FCC to deploy 7,500 satellites into orbit,
on top of the 4,400 that were already approved. On May 24th, the first batch of production
satellites were launched into orbit and people around the world quickly started to spot the
train of satellites moving across the night sky. This launch is a sign of things to come, while
this initial group of satellites are not fully functional [8], they will be used to test
things like the earth communications systems and the krypton thrusters which will be used
to autonomously avoid debris and de-orbit the spacecraft once it has reached the end
of its lifecycle. Let’s look at these functionalities first. We have explored how ion thrusters work in
the past, which you can watch for more detail, but essentially they use electric potential
to fire ions out of the spacecraft to provide propulsion. Xenon is ideally used, because it has a high
atomic mass allowing it to provide more kick per atom, while being inert and having a high
storage density lending itself to long term storage on a spacecraft. However SpaceX opted for krypton, as xenon’s
rarity makes it a far more expensive propellant. [2] This ion thruster will initially be used
to raise the starlink satellites from their release orbits at 440 km to their final orbital
height of 550 km[1]. They will also be used in conjunction with
on board control momentum gyroscopes located here, and the US Governments’ space debris
collision prediction system to allow the satellites to adjust their orbits to dodge collisions,
which we have also spoken about in more detail in a previous video. When the satellites have reached the end of
their service life they can then use the same attitude controls and thrusters to de-orbit
the satellite. Space X have included all the necessary hardware
to minimise space debris risk. In their Federal Communications Commission
approval application [3], they claim that 95% of the satellite will burn up on re-entry. With only the ion thruster internal structure
and silicon carbide components, standing a chance of survival. Those silicon carbide components are likely
to survive, as they are essential materials for the operation of lasers and thus have
an extremely high melting point of 2,750°C. [9] Which brings us to our communications abilities,
the primary function of the satellite. Spacex have been tight lipped on many of the
details of the satellite, but thanks to that FCC filing [3] we know that the satellites
will contain 5 1.5 kilogram silicon carbide components, which indicates that each satellite
will contain 5 individual lasers. These lasers, like our fibre optic cables
here on earth, will use light pulses to transmit information between satellites. Transmitting with light in space offers one
massive advantage over transmitting with light here on earth however. The speed of light is not constant in every
material, in fact, light travels 47% slower in glass than in a vacuum. This offers starlink one huge advantage that
will likely be it’s primary money maker. It provides the potential of lower latency
information over long distance, in simpler terms let’s imagine this as a race between
data packets. A user in London wants the new adjusted price
of a stock on the NASDAQ from the New York stock exchange. If this information were use a typical route,
let’s say through the AC-2 cable [RI-3], which has a return journey of about 12,800
kilometres to make through our glass fibre optic cable. In a vacuum light travels at a speed of 299,792,458
meters per second [5]. The speed of travel in glass depends on the
refractive index and the refractive index depends on wavelength, but we will take the
reduction as 1.47 times slower than the speed of light in a vacuum [203940448 m/s]. [6] This means the data packet will take roughly
0.063 seconds to make the round trip, and thus has a latency of 0.063 seconds, or 62.7
milliseconds. With the additional steps that add to this
latency like the conversion of light signals to electrical signals on either end of the
optical cable, traffic queues, and the transfer to our final computer terminal, this total
time comes out at about 76 milliseconds. Figuring out the latency for Starlink is a
lot more difficult, as we have no real world measurements to go by, but we can make some
educated guesses with the help of Mark Handley, a communications professor in University College
London. [10] The first source of latency for Starlink will
be during the up and down link process, where we need to transfer our information to and
from earth. We know this will be done with phase array
antenna, which are radio antenna that can control the direction of their transmission
without moving parts, instead they use destructive and constructive interference [7] to control
the direction of the radio wave. Each satellite has a cone beam with a 81 degree
range of view. With an orbit of 550 kilometres each satellite
can cover a circular area with a radius of 500 kilometre. At SpaceX’s originally planned orbit this
coverage had a radius of 1060 kilometres. Lowering the altitude of a satellite decreases
the area it can cover, but also decreases the latency. This is particularly noticeable for typical
communications satellites operating in geostationary orbit at an altitude of about 36,000 kilometres. The time it takes data to travel up to the
satellite and back down travelling at the speed of light is around 240 milliseconds
[13] 369% slower than our subsea cable. However, since Starlink is intending to operate
at a much lower altitude, the up and down link theoretical latency could be as low as
3.6 ms. This is why SpaceX needs so many satellites
in their constellation in order to provide worldwide coverage. Each individual starlink satellite has four
phased array antenna located here, here, here and here. This directional beam was an essential part
of SpaceX’s FCC approval application [3], as thousands of satellites broadcasting undirected
radio waves would cause significant amounts of interference with other communication methods. Once that data is received by one starlink
satellite, it can begin to transmit that information between satellites using lasers. Each time we hop from satellites there will
be a small delay as the laser light is converted to an electric signal and back again, but
it is too miniscule to consider. Things get tricky here with using lasers,
as we need to accurately hit the receiver on neighbouring satellites to transmit that
data. Let’s look at SpaceX’s proposed constellation
to see how this will work. Space X’s first phase of 1584 satellites
will occupy 24 orbital planes, with 66 satellites in each plane inclined at 53 degrees. That will look something like this. Communication between neighbouring satellites
in the same orbital plane is relatively simple, as these satellites will remain in relatively
stable positions in relation to each other. This gives us a solid line of communication
along a single orbital plane, but in many cases a single orbital plane will not connect
two locations, so we need to be able transfer information between these planes too. This requires precise tracking, as the satellites
travelling in neighbouring orbital planes are travelling incredibly quickly and will
come in and out of view. This means the starlink satellite will need
to switch to a new satellite in the network. This can take time, the best figure I could
find is about a minute [9] for the European Space Agency’s Data Relay Satellite System,
which is a currently operating geostationary internet constellation designed to serve european
imaging satellites, and other time critical applications. Such as serving emergency forces in remote
areas, like those fighting forest fires. Starlink may be faster, but it won’t be
instantaneous, and thus it has 5 optical communication systems on board to maintain a steady connection
to 4 satellites at all times. If we now use this system, transmitting from
New York to London and back, with the shortest path possible, using the speed of light in
a vacuum as our transfer speed, we can achieve a latency as low as 43 milliseconds. Even if we took the shortest route possible
with an optic fibre, which does not exist, this would take about 55 milliseconds, a 28%
decrease in speed. The actual current return trip time for your
average Joe is about 76 milliseconds, as we saw earlier. A 77% decrease in speed. This is a huge deal for the two financial
markets working out of these cities, with millions of dollars being moved in fractions
of a second, having a lower latency would provide a massive advantage in capitalizing
on price swings. In fact, it wouldn’t be the first time a
communications company has made a massive investment to specifically serve these groups. The Hibernian Express cable is a privately
owned optic cable that is currently the lowest latency connection between the NY4 data centre
in Secaucus, New Jersey and the LD4 data centre in Slough, England at just 59.95 milliseconds,
39.4% slower than our best time with Starlink. [11] The previous best time was held by the
AC-1 cable at 65 milliseconds. At a cost of 300 million dollars this 5 millisecond
increase in speed was justified to just connect across the Atlantic. Imagine how much these time sensitive industries
will be willing to pay for a 17 millisecond increase in speed. It becomes even more valuable when you realise
this time differential increases with increased transmission distance. New York to London is a relatively short distance. The improvements would be even more pronounced
for a London to Singapore transmission, for every additional kilometre we travel the potential
gains in speed increase rapidly [5]. [RI-2] But SpaceX aren’t just planning on
serving this super fast internet to some customers, they primarily advertise this system as a
way to connect every human on this planet to the internet, and they should have plenty
of bandwidth left over to serve these people. Although the internet has been one of the
fastest growing technologies in human history, by the end of 2019 more than half of the world’s
population will still be offline (4 billion). Users will connect to this internet using
a Starlink terminal which will cost around $200 each, this will still be far outside
the purchasing power of many third world citizens, but it’s a start and vastly cheaper then
similar currently available receivers like the Kymeta version at a price of $30,000[15]. Elon Musk says that these will be flat enough
to fit onto the roof of a car and other vehicles like ships and airplanes. This will allow Starlink to compete with traditional
internet providers. It’s estimated that moving the US from a
4G to a 5G wireless connection will cost around $150 billion in fiber optic cabling alone
over the next 7 years, [16] SpaceX plan to complete their entire Stralink project for
as little as $10 billion. Each Starlink satellite cost around $300,000
which is already a massive cut in cost for communication satellites. SpaceX are also saving on launch costs, as
they are launching on their own Falcon 9 rocket, something that no other satellite manufacturer
has. If everything goes to plan, Starlink is estimated
to generate $30 billion to $50 billion in revenue each year on the back of premium stock
exchange memberships [14], demolishing their current annual revenue of around $3 billion. And this is a vital part of Elon Musk’s long
term goals. The money generated from Starlink will mean
SpaceX will have vastly more funding than NASA. Which could go on to fund research and development
of new rockets and the technology needed to monetise lunar and martian colonies. For now the project is simply connecting the
world even more and potentially opening avenues for education for third world countries that
do not have adequate connections to the internet. Imagine if Leonal Messi, the greatest footballer
alive, was never found and brought to Barcelona to develop his talents. Where he received vital medical treatment
for growth hormone deficiency. We would have been deprived of his talents,
and this happens regular for remarkably talented and intelligent children in countries where
simply do not have access to education. Widely available internet will help solve
this problem, and platforms like Brilliant have taken great steps to remedy this through
their high quality interactive math and science learning. Brilliant has helped thousands of users realize
their potential in math and science, and it’s stories like this why I am proud to promote
Brilliant every month. They have a huge number of courses that will
allow you to educate yourself. From foundational maths courses to courses
taylored for you to ace the American Mathematics Competition, with others geared for computer
science and physics. Brilliant recently introduced a new feature,
called “Daily Challenges”, which will present with you with interesting scientific
and mathematical problems to test your brain every day. If I have inspired you and you want to educate
yourself, then go to brilliant.org/RealEngineering and sign up for free.And the first 500 people
that go to that link will get 20% off the annual Premium subscription, so you can get
full access to all their courses as well as the entire daily challenges archive. As always, thanks for watching and thank you
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Comments 82

  • Stock exchange is NOT an industry.

  • This will be one of the greatest booms to the world of mankind…..
    Or one of the largest busts!

  • As if Nigerian scammers weren't enough…..
    Now we'll have the whole continent of Africa trying to screw the USA!

  • this will be the start of when we can finally throw away our current type mobile 'phone' and simply have a data connection .. also….. forget 5G

  • I really am thinking Musk's name will go down in history, as the the 20th centuries most famous person.

  • If i telling inteligent scientist on space program the fast name comes ISRO, then Elon musk spacex rest are using much cost, less knowledge and using other vendor…. In this earth only 2 company i follow them ISRO and Elon musk spacex… Rest are useless

  • Incredibly satisfying video, well done!

  • People think this is going to be a new ISP, this service is only for stock exchange and for third world countries without internet.

  • OneWeb is years ahead of SpaceX in securing rights in other countries. The FCC is just America. OneWeb also has ground infrastructure installed in many countries, as well as functional satellites already in orbit operating at 32ms latency. Airbus is building OneWeb two satellites a day. This will be the first network in low earth orbit.

  • A dyson sphere really isnt that unfathomable now.. And it's only 2019…

  • What is the problem with farm life, the internet and space bring much problems

  • Man, that video is awesome but… Did you really have to get into soccer opinions?

  • How is it that conversion for Electrical Signal to optical signal was significant enough to be added in the latency but electrical to laser was not?

  • This video is far too complicated to listen to passively

  • Elon Musk


    Starlink mission will be heaviest @SpaceX payload ever at 18.5 tons. If all goes well, each launch of 60 satellites will generate more power than Space Station & deliver 1 terabit of bandwidth to Earth.

  • We are (my household) very tolerative family. But we don't accept strays. I will destroy any strays who dare to look in my direction.

    I fucking mean it.

  • the sponsor integration was spot on and so fluid !

  • Oh my… could it be the real Skynet from Terminator movie…

  • No pricing info…Tesla cars $70k, the confort of a $30k gaz car with a $20k batterie. Where is the other $20k? And where are all promised super electric chargers? Now you know why sales and stock values are wayyy down. Reality sucks Elan

  • Can anyone please explain this, look at these photos, and can you explain why the earth in the second photo is smaller than the sun in the first photo,

  • Ok and why?

  • Do you know why we don't have superman???

  • Good video. I am against musk since I heard of Neuro link. But I am not against people, even musk, anyone inventing, and exploring,etc.
    I also understand that people generally hate people. The world, every system, every capital scheme, our matrix is broken. So after we invent you need to start putting billions into education. Into community building, public events(not just for holidays) to bring the communities togther, and I could keep going. But anything pro active towards humanity. Not hovercars, and spaceships. Or governments too for that matter with there black book budgets, and ponzi schemes. When any of them, democratic or communistic could have fixed atleast there country by now. Anyone? Nope, there all full of s***, and giving up on something already great. I don't get it

  • It just occurred to me that maybe starlink will result into the greatest increase of spam and scam not previously conceived of.
    Could perhaps result in new sub-internets that you connect to instead of the global web.

  • the flow of information was always a problem in the 1600s there were 3 months that 1800 who found the pipeline and 2 minutes was enough. then came the optical cables that did it in the blink of an eye. better than unnecessary.

  • You may notice a strange edit at the 14:18 mark. That's because I had to remove a tiny section of video as a result of FC Barcelona claiming all the monetisation on this video, and I was forced to remove a tiny clip of Messi scoring his first goal.

  • can is math much related to has science ?

  • Looks like Aquila was a predessor that should be named in the historybooks.

  • inb4 elon builds a dyson sphere outside our solar system

  • Starlink will be used to generate funds for future Mars operations end of reason.

  • Elon Musk seems to be a little two faced to me. I saw him in a interview telling the world he thought ai was dangerous and a threat to humanity.
    Now he’s invested billions in it.


  • 76ms trans atlantic??? WHAT???

  • Simple: SpaceX needs to invest in long-term projects that generate steady income and funding for the future.

  • means better streaming

  • My porn will load faster. Thanks Elon. Changing the world 🙂

  • this is world domination

  • lol..
    you think spacex works??
    this vid is LEGITIMATELY flagged as ''Scams or Fraud''

  • You didn’t mention the applicability to Tesla cars…

    I recently went to a talk on autonomous vehicles and one issue is the large amount of computing and processing required for all the real-time data. The cars literally have trunks full of computers. If these satellites provide a fast enough connection, processing could be done in separate central locations, making autonomous vehicles more viable. This is an amazing crossover from SpaceX capabilities to Tesla!

  • And he's going to finish building them all on September 20, 2019

  • Since game companies don't make servers for Africa anyways, it's nice to know it won't matter soon :')

  • I see you John Cena 14:17

  • A very well made video. Well done.

  • Can't wait to get a local SpaceX technician down to my house to get some internet.

  • حلاته☹💔

  • because CGI

  • I love this Idea however I can't help but wonder, how come SpaceX only has to get permission from the US government to launch so many satellites, after all they would circle the whole globe, who knows the US might want to piggyback on that for Spy craft etc. How come there is no International agency to govern such kinds of massive deployment.

  • This will be great for Kashmir where India has imposed a complete communications lockdown…even landlines are blocked.

  • Who permits/regulates this? And, not to be paranoid, how would this interface with neuralink? Musk talks about AI in a paranoid way, but I think thou dost protest too much.

  • I posted too soon regardling regulation, but still how does the FCC have control outside national jurisdiction? Hegemony of space?

  • when I was un Utah for mountain biking, while listening to music around the campfire my dad saw the satellites, and all the parents being drunk were dead set on aliens though, it was a really cool experience

  • Every time I hear about STARLINK I get very upset. It would not likely work and will probably destroy the view of the night sky as well as armature and professional astronomy and why is the area over Europe the only area of earth clear of these satellites, i.e. where there are none of these satellites in orbit and what is the proposed Arian-6 all about? Another thing is that SPACE-X wants to launch these satellites over the Northern US next, the main area of the US where astronomy is possible. If these 12,000 satellites are eventually orbited, how would small to medium size start-up companies get into space?. The idea is a disaster waiting to happen and I am vehemently against it!

  • ISP censorship will be from the past

  • Elon musk is in creative mode now

  • Just a small mistake in the video I noticed: Light does have a constant speed, its called E=MC^2 because C is the CONSTANT speed of light. The reason it take longer to travel through glass is because its taking a longer route, bouncing off the atoms in glass and almost zig-zaging its way through it.


  • This is evil. They will use this to track u everywhere. U can t hide.

  • In the voice of Pinky and the Brain cartoon.. the Brain, "…to take over the world!"

  • Tesla solar panels are now starting on fire. Just saying.

  • So what you’re saying is everyone will relatively be on the same internet playing field?
    No more excuses gamers it’s all down to skill from here

  • This. Is fucking awesome.

  • 3:13 is this to scale?

  • The lengths this man will go to make sure we don't see "disconnected" or "timed out" when we play minecraft ever again. Elon Musk is a god. Idc if we all turn into mindless robots with this and neuralink. If it means I can play minecraft forever without being disconnected then i'm happy

  • Wireless Electricity

  • nooo, noooo if superman goes in space he might go into these satellites that use krypton and he will not ha e this powers and die…

  • Wait a minute.. so from the Antitrust movie Tim Robbins = Elon Musk and not Bill Gates?

  • So they want to pollute the orbit for stock market?

  • INB4 Starlink is just Skynet in diguise.

  • Edit : Doesn' this close a whole bunch of orbits to others ? .. How can they make a large surface unavailable to others without any permission when they do not own that level ? …Aren't there any laws for space levels that occupy a large surface area in space ? Doesn't large scale projects require international cooperation …not because of funding but because they are stationed over the entire world and impact others ?… Who guarantees that as technology advances these thousands of satellites will also act like a cage that will prevent othersto go to space???..or at times of war they will emit radio waves to block communication between other nation's satellites and stations… . Lack of International cooperation and ownership makes this project … scary one ..

  • This is exciting stuff

  • Another huge improvement, no need for cables

  • Wow, this is so depressing if that is the reason for the satellites….

  • One sizable CME or Carrington Event would fry the entire constellation.

  • Hello if your opportunity rover is not working at mars planet we can fix it [email protected]

  • Worldwide Web(literal) of more Static. Oh with the Waves and the illuminated frequencies, zoingski! We're all slow roasting our bodies faster… "Eeeeewwwww"-Ernest!

  • I have a hard time believing there wont be massive functional issues that pop up given the large number of satellites in this insane network

  • Just used the brilliant link, it’s sad that 2 months later there still hasn’t been 500 uses of the link

  • Why? 30 billion to 50 billion annually! Interpretation: MORE money taken from you and put in their pockets. Your Servitude to Elites. Where do you think their profits will be gleaned? Your Wallet! 🤔#Awaken 😐#Asap

  • 3.6ms for the first hop? thats the speed of light, no? the data still has to go through silicon once it gets to the satellite, and for each relay thereafter to another satellite… are you assuming instant packet relay for the satellites?

  • Light: "Hi Earth!
    Bye Earth!"

    Mars: "😓"

  • When Elon Musk surpasses NASA and biggest names in car industries and electricity providers.. That is what I call a great man!

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