In article ,
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On 2018-11-21 08:20, Jeff Findley wrote:

The video isn't a sales pitch, it's made by an expert in the field of
communications. So, you're drawing conclusions about how this will be
sold without actually knowing who SpaceX will be marketing this to.

The expert would be using examples that spaceX gave him, so it does
givce an indication of where SpaceX thinks there is market.

Why wouldn't the communications expert just pore over public documents
with technical information like the FCC filings made by SpaceX? Why
would he rely on information from their sales and marketing department?

Depends how they do the routing algorithm. A smart software developer
knows that you don't have to run the routing algorithm for every single
packet of data because the satellites move in *very* predictable ways
over time

Since the east-west lasers are directional, it takes time to re-aim the
laser to point to a new satellite that has come into view. north-sour
links are stable, but re-routing to the north south link while you wait
for the lasers to point to new satellite will change latency, and once
contact with new satteelte has been established, a new chage in route
happens.

Precison mirrors with servos/actuators on them are really damn fast and
if designed correctly can be very precise as well. Ever seen a laser
light show? That's exactly how those lasers are "moved". That's one
solution that SpaceX could use.

At any rate, I'm sure SpaceX engineers have thought of this and have a
solution that's better than what you or I could spitball in a Usenet
News forum. Just because you or I don't know their exact solution
doesn't mean it doesn't exist.

Also, fibre has far more capacity than a laser. Not only can fibre
support simulteneous wavelengths, but there are a lot of strands in a
trans-atlantic cable for instance

You're talking out of your ass again.

Please pray tell, explain how SpaceX lasers could match/exceed the
lasers used for fibre links. Do they use subspace and go faster thah light ?

You're kidding me, right? You did watch the video whose link you
posted, right? The expert gives examples of times. And guess what? He
says Starlink will be faster than fiber. I just threw a wiggle word in
my original statement because high speed communications isn't my field
of expertise.

Pray tell how the magical SpaceX laser could provide the capacity that
is given by a cable of say 32 strands, each capable of 4 wavelengths of
100GBPS each.

Here's a simple problem for you to solve.

Compare the two systems for, say, the distance over the earth's surface
from NYC to Hong Kong. Yes for Starlink you'll have to add in the
distance up to the first satellite and down from the last satellite and
take into account the larger radius from the center of the earth of the
Starlink satellites.

Hint: Don't forget to look up the speed of light in a fiber optic cable
and compare that to the speed of light in vacuum (which is where
Starlink's laser connections will be). If you forget to do this, your
answer will be completely wrong.

The fact is that Starlink will likely be *faster* than fiber
connections. This means that trading companies will be willing to dump
money into this project so they can reap the benefits (this has been
mentioned in other articles on Starlink because those are your biggest
potential initial customers).

It really depends on how many hops between satellites are needed to go
from A to B. Suspect New York-London may not be competitive because of
adjacency to trans-atlantic cables. But Chicago or Los Angeles to London
might compete, assuming the frequecy route changes in the sky maintain
jitter to a minimum.


Again, see the "hint" I gave above.

High frequency traders will be beating down the doors of SpaceX to
get
in on the ground floor of Starlink for the very reasons Krugman states
in his article above. And they'll have wads of cash in hand.

Until the first thunderstorm over their offices where traders lose
connection for a few minutes and lose millions of dollars.

The traders will surely have a backup connection *if* their connection
to Starlink goes down for a short period of time. For users "out in the
sticks" Starlink will still provide better service overall than existing
satellite services.

There are good reasons "serious" satellite applications want large
dishes. It's called "weather".

So you're a high frequency electromagnetic engineer now? Cool!

Phased array antennas aren't new technology. They're all over the
place. So SpaceX isn't blazing any new trails here. They're just
refining existing designs.

Actually nothing proposed for Starlink is new tech. They're just
assembling the various bits of tech into a very large network of
communications satellites.

Kind of like how they did with the tech for Falcon and Dragon. There
was nothing new there. Any other company with the will to do so and the
funding to do so could have done exactly the same.

Yes, SpaceX needs to promote their plan and PR it to death with all
soprts of fancy promises. But just like BFR/BFS, expect those plans to
be quietly slaled back once the accountants starts to tell Musk the
grandiose plan won't pay for itself.

You're damn funny. Even scaling back BFR/BFS it will still do far more
than any launch vehicle in history due to its full reusability and its
ability to refuel the BFS/Starship part.

Hell, even if their reuse plans go horribly awry and SpaceX has to
refurbish the BFS/Starship part once every 5 flights and refurbish the
BFR/Booster part every 10 flights, it would still beat hell out of
anything coming out of NASA, ULA, or Northrup Grumman Innovation Systems
(formerly Orbital ATK). The only real competition SpaceX might have
with BFR/BFS in the next 10 years will be Blue Origin, if they get New
Armstrong flying. And they're still working on getting New Glenn flying
so they've got a ways to go.

And even if BFR/BFS doesn't materialize in the next 10 years, your
comparison is still weak. SpaceX has literally taken the majority of
the global commercial launch market from all of the existing global
players with just Falcon 9 and Falcon Heavy. If SpaceX had to do so,
they could just keep flying Falcons for the next 10 years and still
maintain their position as the leader in low cost launch. Worst case
scenario, they could introduce a Falcon Block 6 if issue crop up with
Block 5.

Jeff
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