
​Europe Is Building a ‘Space Data Highway’ - denzil_correa
http://motherboard.vice.com/read/europe-is-building-a-space-data-highway-with-lasers-esa-edrs-satellite
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ape4
Why drop "With Lasers" from the headline?!

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igravious
Yes indeed we are: [http://www.esa.int/spaceinvideos/Videos/2016/01/EDRS-
A_launc...](http://www.esa.int/spaceinvideos/Videos/2016/01/EDRS-
A_launch_highlights)

(I take partial credit for this as a European.)

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restalis
Satellite communication won't "drastically cut down delays". On the contrary -
it will increase it, as the signal will have to physically go through a much
longer geostationary orbit detour between two points on the earth. Satellites
offer you additional bandwidth for somewhat lower costs (compared to
establishing fiber optic land line), bigger delay, and penalizing partial
dependence on atmospheric conditions.

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idorosen
Why stop at 2 gigabits/sec? Why not go all the way up to 10g, 40g, or even
100g? It's not like rain or fog or other atmospheric effects will cause much
problem for free space optics or tighter band RF (e.g. 60-90ghz millimeter
wave) communication in space, so was it a physical or budget limitation? At
these higher throughputs, the same relay network might be usable for other
things in the future, such as streaming terapixel video...

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dogma1138
Atmospheric conditions actually have quite a bit of effect on satellite
communications.

As far as the link speed between nodes in space well 1.8 gigabits is fast even
for fiber optics, when you add the distance between the 2 nodes and the fact
that at least one of them is moving at very high speed when counting for beam
dispersion and phase shift due to movement 1.8 gigabit seems very impressive
(this is considerably faster than pretty much any point to point IR link here
on the ground[1]).

That said satellite internet doesn't makes much sense at least not how the
internet infrastructure is setup today going to space means that you add at
the least 80-70,000KM to your round trip no matter what kind of bandwidth you
are getting in return (which in every case will be very asymmetrical) it's not
worth adding sometimes seconds worth of latency to the round trip of your
packets, the internet today simply can't really work like this.

I would've said that in the future you might get a super smart home hub that
can negotiate a single internet address (probably not going to be standard
TCP/IP at this point) over multiple links (yes I'm aware that multi-link PTP
has existed for decades) and automatically route the traffic based on it's
nature; uplink can go over fiber/DSL; downlink for something like say netflix
can go through your sat link; web browsing including streaming can start over
fiber/dsl for a more responsive experience and if you are streaming say
YouTube just offload it to your sat link transparently; applications that
require low latency such as games and video/voice comms will always go over
your fiber/dsl.

The only problems with this is that it seems to be too expensive and
complicated and by the time you'll have good enough coverage of satellite
internet the adoption of fiber will increase and since you can push upwards of
1gig these days over copper DSLlike technologies might actually catch up also.

[1][https://en.wikipedia.org/wiki/Free-
space_optical_communicati...](https://en.wikipedia.org/wiki/Free-
space_optical_communication)

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smoyer
In the '80s we built circuit boards for a company called Laser Communications
in Lancaster Pennsylvania. They could transmit fast (at the time) data over
2-3 miles pretty easily, but water particles in the air (rain, fog, etc)
caused enough refraction that the links would go down. I'm curious to know how
they solved that problem when going through so much atmosphere (I'm not buying
the 50% to 100% without an explanation).

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lern_too_spel
It communicates with other satellites by laser. Ground communication is over
Ka-band radio. The 50-100% figure is simple geometry. A satellite with an
orbit that is always in view will have 100% coverage. Other satellites will
have at least 50%.

~~~
tempodox
Are all satellites out far enough to cover a complete hemisphere?

