SpaceX's Starlink constellation is growing and today we're going to
talk about three interesting features that aren't so widely known let's go
Hey guys Tory here from Overlook Horizon
At the time of this recording SpaceX has launched 955 Starlink satellites
into low earth orbit starting with the first set back in February 2018 those two were their
early prototypes named TinTin A and TinTin B the next 60 were an early version 0.9 model
and the other 893 are all part of the current version 1.0 platform but it's not like SpaceX
hasn't been improving them along the way and that brings us to feature number one
Linux Computers
Each launch of 60 Starlink satellites contains more than 4000 Linux computers
the constellation has more than 30,000 Linux nodes and more than 6,000 micro controllers
and this Linux infrastructure is actually shared across SpaceX's other platforms
like the Dragon capsule and the Falcon 9 and the Falcon Heavy rockets themselves
so although the Starlink concept is relatively new a lot of the tech behind it is already well proven
and as a software engineer myself I find their deployment methods pretty fascinating because they
treat each satellite like it's a cloud server in a web service and what I mean by that is that they
are rolling out updates to Starlink satellites every week they can test software updates on a
smaller subset of the constellation and compare performance to the rest of the constellation and
if things don't go well they can easily just roll back their changes and
try again in fact most of the time when a new set of Starlink satellites is launched into orbit
the brand new set of satellites is already a few software versions behind while it was
being prepared for launch but not everything goes to plan and that brings us to feature number two
Autonomous Navigation
The team behind SpaceX's Starlink program is relatively small at least for now so
things like automated orbit guidance and collision avoidance are must have features
one thing that's pretty neat is that the team tells the batch of satellites what their final
orbital slots are and the satellites figure out how to get there themselves
for collision avoidance the satellites receive updated data on close approaches
with other satellites multiple times a day and the Starlink satellites then calculate on their own
when and how to dodge something if it's necessary and on top of all that the satellites are also
designed to passively deorbit if something goes wrong and not everything has gone perfectly a
few satellites have done exactly that if one of the satellites doesn't hear from
the ground after a long period of time it will reorient itself into a high drag
state so it can be pulled back by orbital decay and burn up in the atmosphere during that time the
SpaceX team would keep trying to recover it but it does ensure that failed units don't stay up there
longer than they need to each satellite has some redundancies on board to prevent failures
but a lot of the redundancy in the service itself simply relies on end users being able
to communicate with multiple satellites at any time and that brings us to feature number three
The ground station
End users of the Starlink service get their own Starlink antenna that looks
something like this it kind of looks like a UFO but it's actually pretty sophisticated
first off the antenna can operate between negative 30 and positive 40 degrees Celsius
but it also has built-in snow melting capabilities using the heat from the onboard electronics
to fight against snow build-up also the ground station has no knowledge of any Starlink
satellites when it first powers on on its first use it scans the sky in a matter of milliseconds
looking for Starlink satellites once it locks onto a satellite it makes a request to join the network
and then the dish is able to download a schedule of which satellites to communicate with next
and point in the right direction and that pointing is probably my favorite feature of the antenna and
that's because this dish is called a phased array antenna it's actually not one big antenna it's
a whole bunch of little tiny antennas that use software and electronics to direct its
transmissions to each Starlink satellite and this means that it doesn't have to move around all the
time the current for each antenna passes through a phase shifter controlled by a computer the moving
red lines here show the wave fronts of the radio waves emitted by each element the individual wave
fronts are spherical but they combine in front of the antenna to create a plane wave a beam of
radio waves traveling in a specific direction the phase shifters delay the radio waves progressively
going up the line so each antenna emits its wave front later than the one below it this
causes the resulting plane wave to be directed at an angle to the antenna's axis by changing the
phase shifts the computer can instantly change the angle of the beam most phase array antennas
have two dimensional arrays of antennas instead of the linear one that's shown here and the
beam can be steered in two dimensions this here is another look at a phased array antenna's radiation
pattern where you can see the antenna starts transmitting at a 45 degree angle off of its
center and then almost instantaneously switches to a negative 45 degree angle now Starlink's
dish is said to have a field of view of around 100 degrees and that's on both the x and the y
axis so it could go about 50 degrees off center in pretty much any direction using just electronics
A youtuber named Ken actually sacrificed his Starlink antenna and tore the whole thing apart
just so you could see the inside and everything happening if you want to
see his expert insight and to see his full hour-long tear-down video check out the link
in the description below to see his full video and what's inside a Starlink dish
So that's where I'm gonna wrap up today's video
Are you excited about Starlink? Do you think this is something that you could use
like realistically at home? Let me know in the comments
As always be sure to click the like button consider subscribing here
and I'll see you on the next video
Goodbye