Japan Launches "Super-Speed" Internet Satellite 159
A number of readers wrote in about the launch this morning of a Japanese H-2A rocket carrying a Kizuna ("Winds") satellite into orbit. Kizuna is intended to provide "super high-speed data transmission" for Japan and Southeast Asia. The news stories on the launch, such as the AP's linked here, are short on technical detail. For example they say the satellite successfully achieved orbit 175 miles above the earth — hardly suitable for Internet communications to a specific area on the surface (remember Teledesic?). Reader nebulus4 provided a link to the Japan Aerospace Exploration Agency site with an illustration and a little more detail. Such as the fact that Kizuna is destined for geosync orbit, and that a 45-cm antenna will equip eventual users for 155 Mbps down / 6 Mbps up, whereas a 5-m antenna will allow enterprises and ISPs to tap into 1.2 Gbps down. Given the latency to geosync orbit, you probably wouldn't want to use Kizuna to play an online shooter.
In other news... (Score:4, Funny)
Re:In other news... (Score:4, Funny)
Re:In other news... (Score:4, Insightful)
Now featuring... (Score:1, Insightful)
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I believe geosync orbit has a MINIMUM lightspeed latency of 119.4ms.
Not a fun starting point BEFORE collisions and noise.
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and another tally on the mind-is-dying meter.
=)
Re:Now featuring... (Score:5, Insightful)
You have to multiply times four to get a useful figure. Latency is normally measured round trip. Hop up, hop down, return hop up, return hop down. Latency to geostationary orbit is half a second.
However, 175 miles up is NOT geostationary. Geostationary is 35,786 km up, give or take. The orbit is geosynchronous. That just means the orbital period is the same as the earth's rotation, so it returns to the same spot at the same time every day. It will NOT stay in the same place, however. They'll have to have several of these things in a similar orbit flying over periodically like we do for GPS satellites. It also means the round trip latency is about 3.76 msec (just less than a millisecond per hop), a heck of a lot shorter than half a second.
Re:Now featuring... (Score:5, Interesting)
From the JAXA site about Kizuna:
"Scheduled orbit: Geostationary orbit at 143 degrees East longitude and at an altitude of about 36,000 km"
It is, even though the summarizer slipped up a bit (technically the term is correct, but somewhat misleading), destined for geostationary orbit.
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Ah. I wondered how you could possibly have an orbit as low as 175 miles. I would think you'd get horrible atmospheric drag, not to mention how fast it would have to be moving.... Apparently, the summary was massively wrong....
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I can't think of
latency = what? (Score:2)
How are people computing latency?
I saw this [bbc.co.uk] on the BBC News website [bbc.co.uk]:
"Data sent over fibre optic networks is subject to the limitations of the speed of light, which means interactivity between the server and gamer will never have a latency below 70 milliseconds."
70ms latency being a minimum over fiber optic networks? Is the speed of light slowed down in fiber optic cables?
Speed of light
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First, the speed of light is slowed down by fibre optic cable, just as light is slowed travelling through any medium. Roughly light in optical fibre travels 2/3 the speed of light in a vacuum.
So, to compute minimum latency, take the length of fibre, divide by the speed of light, divide by 2/3, and then double it, as the data must go there and back.
Thus, if we had a 1300 km cable: 1300km / 299,792.458 km/s / (2/3) * 2 = 0.013009 s = 13 ms round-trip-time.
So, for our 1300
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Do you happen to know about the speed of an electrical signal over copper? I.e. is fiber really any
better in terms of speed? Or does its main benefit come from capacity?
Here's an odd question, maybe... So fiber is "efficient" because the light stays fairly trapped within the fiber as it snakes along. What would be the effect if, instead of a solid core (glass?), one were to create a "tube" with the center bein
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You're looking for velocity of propagation [wikipedia.org], which is limited in electrical media by distributed reactance, and by similar means in fiber. That article states the twisted pair ethernet cable can have velocity factors between .42 and .7 - that's pretty slow!
Amateur radio operators have to account for this when making antennas and matching
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But other than satellites, there've been mumblings about possible geo-stationary *balloons*. Solar powered and tethered at a specific height. I think there was some mention of Google possibly doing it over a small area like the Bay Area to provide Bay-wide internet access. Apparently the cost of putting balloons up is considerably lower than putting satellites up, and maintenance is a tad easier as well (don't have to hire a shuttle crew).
That could dovetail w
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I'd sure prefer their speeds over 512k though.
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The 5 Mbps uplink is kinda weak, though. Forget about bittorrent...
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Here is the result of a ping session over a satellite link. It was done at a rest area along IH-35 in Texas:
$ ping xxxxxx.net
PING xxxxxx.net (xx.xx.xx.xx): 56 data bytes
64 bytes from xx.xx.xx.xx: icmp_seq=0 ttl=50 time=1177.625 ms
64 bytes from xx.xx.xx.xx: icmp_seq=1 ttl=50 time=837.073 ms
64 bytes from xx.xx.xx.xx: icmp_seq=2 ttl=50 time=848.406 ms
64 bytes from xx.xx.xx.xx: icmp_seq=3 ttl=50 time=1072.072 ms
64 bytes from xx.xx.xx.xx: icmp_seq=4 ttl=50 time=1079.655 ms
64 bytes from xx.xx.xx.xx: icmp
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The Japanese are going to have to tap into subspace to avoid all that latency. When is that going to happen?
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I dunno. If I had the choice between no internet or satellite, I wouldn't complain about the latency.
Of course it might suck if it rains a lot, but I suppose it is far better than not having any internet. Secondly, if you are a SE Asia islander or boat traveler you might not even have dial up seeing there is no fiber to your location. You might have a LAN line, but it might be incompatible or really slow seeing regular modems don't work well with satellite phones.
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You cannot be serious (Score:3, Insightful)
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Don't worry the kiwi's have apparently come up with a sheep powered device that's even faster. Coming to Australia soon.
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Yup, if it weren't for the Kiwis we'd still be sending our email by morse code. (The next biggest cable, between Australia and Japan isn't anywhere near big enough and came online several years after the SCC)
Gotta hand it to them; they wanted a big cable for themselves but probably couldn't
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Don't you mean "Coming in Australia soon"?
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Get that chip off your shoulder before your hurt yourself.
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For cednturies, "First world country" meant the Europeans only. That's why there was "First world", "New world", and "3rd world", etc. http://en.wikipedia.org/wiki/New_World: [wikipedia.org].
According to the original definition, Australia isn't a first world country. Neither are the US, Canad
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Sure, nothing makes him better... but the money he/she pays certainly makes him more DESERVING.
strike
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Have you ever tried using satellite internet before? You'll soon realize that speed isn't everything.
-matthew
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Then you will have subsistence internet too.
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Payback for Yahoo Serious is a bitch.
Geosynchronous Latency (Score:4, Insightful)
round trip = times 4 = 88,932 miles
speed of light (wave propagation) = 186,282 mi/sec
latency = 88,932 / 186,282 = 0.477 seconds (on top of regular network latency)
Curse you speed of light. You win again!
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Re:Geosynchronous Latency (Score:5, Funny)
Except, possibly chess.
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The connection sucks for anything interactive
Except, possibly chess.
I know you were joking, but as an administrator on a chess server, I can tell you that people get pretty pissed off when lagging half a second. It's acceptable for playing long games, but most over-the-net chess games are 1 to 5 minutes per player per game. Yes, it's a whole different game that just shares moving rules with "chess".
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Use bittorrent to download to a fast server, and them download it over the satellite link from there.
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Also your upstream won't be as good, so not great on those ratio trackers.
Easier to just download over night when your not trying to use the connection for other stuff, and let your fast server build you a good seeding ratio.
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Note:
I know nothing at all about this stuff, so be nice when you call me a idiot.
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In any case, a Molniya orbit would only require three satellites for coverage, looks ideal for Japan as a nation, and the perigee can be as low as ~400km. The round-trip latency for 400 km would be (400*4/300,000), or 5ms (if my mental mathematics is not off by a decimal point or so).
Yes, you'd need three satellites, admittedly.
Molniya orbits (Score:3, Insightful)
Problem is, a Molniya orbit requires three satellites for coverage at the apogee, which is at about the same altitude as the geosynchronous orbit. At the perigee the satellites move faster, so you need more of them to keep one always on sight.
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It's still impractical though (more "research" than anything) - the trouble with satellite for "internet" is the connections/$$$ ratio is usually not very good. You're basically doing something like a "cell phone station" but with a very very big cell.
If you can somehow have millions
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Don't use a dish, use something like a collinear array that has it's gain spread along a thin line (the path of the satellite as seen from earth). You'll need a reflector of course. You only have to aim it once (if the satellite is passing nearly overhead -- won't work as well if the sat is describing an arc nearer to the horizon
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what, you don't think it would be appropriate to put your servers in geosynch orbit as well?
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Is there a reason the satellite has to be up this high? Could it be at a lower altitude?
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Not if the satellite is going to appear to sit in one spot in the sky. At geosynch altitude, the sat has an orbit of 24 hours, thus, appears to be stationary.
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If I remember right (it's been a while since I've studied any physics) a simplified explanation looks something like this:
(1) a = v^2 / r [equation for centripetal acceleration]. For an object to maintain a constant speed in a circular path, it must accelerate at a rate of v^2 / r perpendicular to the direction of motion, where v = velocity and r = radius of circle.
(2) a = m_Earth
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Bit more details here (Score:2, Informative)
Am I the only one... (Score:1)
175 miles (Score:5, Informative)
As a satellite dish internet installer & user. (Score:2)
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Latency? What latency? (Score:1, Redundant)
I always thought the reason for latency was a combination of signals going through slower copper wires and being processed by various routers and servers along the way.
Can someone clear this up?
Re:Latency? What latency? (Score:5, Insightful)
175 miles? Try more like 22,230 miles. That's pretty much the only place you can put it unless you want your internet connection to only work 3 minutes out of every 90 minutes...
The reasons are simple physics. Gravity causes everything to want to fall towards the center of the Earth. Satellites manage to stay in orbit because they are constantly "falling" ahead of the Earth. That's why things in "low earth orbit" are referred to as being "in freefall" and not REALLY in zero gravity. Gravity is still there, only the velocity of the satellite is so high that all gravity manages to do is curve the trajectory of the satellite, not cause it to lose height. This means your satellite is going to be moving VERY fast with respect to the ground.
It's only at 22,230 miles out where the circle is so big that your satellite now appears fixed with respect to the ground. It's still moving. It's still "free-falling". But it appears to be hovering over a fixed spot over the equator - very useful for communication satellites since now you know where to aim your antenna and you don't have to bother moving it.
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From the article:
The satellite, equipped with two large multi-beam antennas, separated from the rocket and successfully entered its intended orbit 175 miles from Earth, JAXA said in a statement.
I hope that's right. I'm so ready for fast satellite, weather balloon, stratellite or similar internet communications.
Your application of bold formating is misleading. Try mine instead and you will see the truth:
The satellite, equipped with two large multi-beam antennas, separated from the rocket and successfully entered its intended orbit 175 miles from Earth, JAXA said in a statement.
Editors.
But... (Score:1)
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6Mbps uplink (Score:2)
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Now what we need (Score:2, Funny)
Fantastic ! (Score:2)
This means that new series are available to fansubbers even sooner than previously ! Yarrrr !
What happens when (not if) ... (Score:3, Insightful)
With all this reliance on satellite technology for GPS, communications, and weather prediction what happens when (not if) the sun hits a more active solar cycle eliminating all of these satellites in one fell swoop? We have become terribly dependent on satellite technology (that I agree is cool). However, there have been solar storms that would knock out all of our satellites in recent memory -- only we did not have any satellites up yet. Now the satellites are up and the next large solar storm is just lurking out there getting ready to strike.
As usual, beware any significant reliance on any one technology.
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We launch more satellites, possibly with additional radiation shielding?
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Broadband Penetration (Score:1)
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No, it's not. We were the first connected country. That others have leapfrogged with new technology is to be expected.
If we were to adopt whatever is absolutely fastest today...and somehow roll it out to every house and business in the next 60 days...infrastructure, last mile, everything...by the end of the year, some other country would be 'more connected'.
Every year, some new, faster tech comes out. You want to rewire
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New type of fiber? No. New technologies and specs to deliver broadband to a house or business? Yeah, just about.
In the last decade:
DOCSIS - 1, 2, 3, and intermediate versions
Multiple flavors of DSL
FIOS
WiMAX
Satellite
BPL
Kizuna = "Bonds" not "Winds" (Score:5, Informative)
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Comment removed (Score:3, Insightful)
misleading title (Score:2)
Speed? How about slow but free global access? (Score:2, Insightful)
But. Why can't we use the already existing technology to provide (initially) slow but "pervasive" internet access everywhere? The developed world could easily afford to build a network of satellites that provides both "super-speed" data capabilities for their own wealthy subscribers while offering slower but free access to anyone else interested. Free internet access (ie. communications), independent of the policies of
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;-P
Sorry - couldn't resist. I'll get my hat...
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The fact that you posted this racist crap in the first place or the fact that you posted anon so you could mod down anyone that responded to you.
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Then log back in and try to use your mod points in that thread.
Anonymous isn't so anonymous.
Maybe it's just IP based, but it could easily be more complex than that.
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The Dune cycle's Golden Path involved doing whatever possible(up to and including genocide) to spread humanity far beyond the reach of any one human or organization. It
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Re:Bad idea. Too much bloat and cruft (Score:2)
Even the maps and TV listings of yahoo have become just fucking annoying with all that interactive bullshit, classic mode is the way to go.
web developers can quit turning webdom into a fucking goddam pinball machine.