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Starlink's laser system is beaming 42 petabytes of data per day
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Re: Starlink's laser system is beaming 42 petabytes of data per day
#232In the long run that could become a massive strategic advantage for the US. A 2nd layer of resilience over undersea cables
Re: Starlink's laser system is beaming 42 petabytes of data per day
#233Earlier quoted context omitted.
> “Another really fun fact is that we held a link all the way down to 122 kilometers while we were de-orbiting a satellite,” he said. “And we were able to downstream the video.” > For the future, SpaceX plans on expanding its laser system so that it can be ported and installed on third-party satellites. The company has also explored beaming the satellite lasers directly to terminals on the Earth’s surface to deliver…
So what happens to the laser beam when there are clouds?
Interesting parallel to solar panels.
Re: Starlink's laser system is beaming 42 petabytes of data per day
#234Earlier quoted context omitted.
In general , how is the initial alignment performed? Is there rough pointing, followed by some rastering, until the sensor gets a hit? Maybe with some slight beam widening first? My assumption is that you would want exactly one laser, one sensor module, and probably a fixed lens on each? Is the sensor something like a 2x2 array, or pie with three pieces, to allow alignment? Or is it one big sensor that uses perturb a…
A laser that transmits data at 100Gbps can also transmit at 1 bit per second with an additional path loss of 110 decibels. You'd normally achieve this by transmitting a well-known pseudorandom sequence. You also need clock stability into the ppb range. A path loss of 110 decibels is huge . It can easily account for your lenses being hugely off axis.
What books or webpages do I read to learn how to understand the why of your first sentence?
Re: Starlink's laser system is beaming 42 petabytes of data per day
#235In the long run that could become a massive strategic advantage for the US. A 2nd layer of resilience over undersea cables
A privately-held strategic advantage?
Re: Starlink's laser system is beaming 42 petabytes of data per day
#236My understanding of the state of the art of inter-satellite optical links is that they have only been used between satellites that are basically in the same orbital plane and in more or less the same orbit. That is, the angle from one satellite to the other changes very very slowly, so that the optics don't have to do much tracking -- and consequently satellites can only form an optical link with other satellites tha…
With 266,000 acquisitions per day, I suggest they are regularly doing links across orbital planes.
If they could only do in-plane links, they would have barely any acquisitions per day, because most links would stay up for long periods of time.
Re: Starlink's laser system is beaming 42 petabytes of data per day
#237Re: Starlink's laser system is beaming 42 petabytes of data per day
#238Somewhat tangential: I assume that Starlink is not yet profitable. How many customers do they need to become profitable?
Re: Starlink's laser system is beaming 42 petabytes of data per day
#239In the long run that could become a massive strategic advantage for the US. A 2nd layer of resilience over undersea cables
Real time video and telemetry for military drones that’s nearly immune to electronic warfare counter measures is the real end game. The fpv drone carnage in Ukraine is currently limited to the contact lines plus or minus a few kilometers. Satellite comms change that drastically. Yes it’s available now but highly restricted.
Re: Starlink's laser system is beaming 42 petabytes of data per day
#240Earlier quoted context omitted.
> Basically this happens just before sunrise, and just after sunset. I've seen plenty of satellites in the middle of the night, from very dark areas (wilderness). They look like stars, only they move more quickly. These observations go back a decade, at least.
I was mostly referring to the brightest things like the ISS, Starlink and (formerly) Iridium satellites, which are in low Earth orbit. Higher orbits are visible for longer, due to the angles involved: because they're so high, such satellites can remain illuminated with the Sun further below the horizon. The Moon is the most extreme example: it's almost never in Earth's shadow.
> because they're so high, such satellites can remain illuminated with the Sun further below the horizon. The Moon is the most extreme example: it's almost never in Earth's shadow.
Very good point.