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Re:Musk files to provide Internet service from space by apkessl1 on Tuesday June 09, 2015 @10:14PM (#9689668)
Good question. The vast majority of satellite communications today are conducted via geostationary orbit, 35,786 km above the earth. This is the distance at which a satellite orbiting around the equator moves with the same velocity as the surface of the earth, keeping the satellite in a fixed position. This is good for communicating via the ground, since you can just set up your dish pointing in the direction of the satellite. Additionally, such a satellite can cover a wide swath of the earth since it is so far away; see, for example, the coverage of AsiaSat-8 (http://www.spaceflightinsider.com/wp-content/uploads/2014/08...). The disadvantage (especially for internet) is that the round-trip time of a signal at the speed of light is on the order of 250 ms.

As described in this article, the SpaceX constellation would be in a much lower orbit. The advantage is a much faster ping time (say, around 10 ms). The disadvantage is you need a large number of satellites to provide continuous coverage for the entire earth...but that's less of a disadvantage if your company also launches rockets.

Re:Musk files to provide Internet service from space by x0054 on Tuesday June 09, 2015 @10:24PM (#9689709)
Hmm, interesting. Well, I have Exede Satellite service as my ISP (best I can get) and my best latency, to any server, is 800ms. The way I figure it, 35,786 km / 300 miles per ms would be 120ms up * 4 for the round trip. So that's 480ms, plus another 20ms-100ms to a google or another large server. So that's theoretical latency of 600ms, so where are the other 200ms of latency coming from! :(

I am wondering because I maintain some linux servers for some of my projects, and any time I need to do something serious, I have to drive to a coffee shop and borrow their connection. SSH over 800ms latency is frustrating, to say the least.

Re:Musk files to provide Internet service from space by roamingryan on Tuesday June 09, 2015 @10:53PM (#9689813)
Much of the remaining latency is likely coming from FEC and interleaving needed for the RF links.

http://en.wikipedia.org/wiki/Forward_error_correction#Interl...

Re:Musk files to provide Internet service from space by havatar on Tuesday June 09, 2015 @10:38PM (#9689759)
look into mosh, a ssh replacement for high latency connections.
Re:Musk files to provide Internet service from space by azernik on Tuesday June 09, 2015 @11:08PM (#9689850)
And the other disadvantage is more expensive and complicated ground equipment that can handle changing angle to satellites and handoff on three order of every several minutes. But I imagine that's only getting cheaper...
Re:Musk files to provide Internet service from space by scotth on Wednesday June 10, 2015 @12:28AM (#9690040)
> satellite orbiting around the equator moves with the same velocity as the surface of the earth

To be specific, angular velocity.