# Satellite Internet Latency **URL:** \ **Category:** Factual Questions\ **Created:** [August 13, 2011, 9:18pm UTC](https://boards.straightdope.com/t/satellite-internet-latency/592609 "2011-08-13T21:18:15Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![human\_extinction](https://avatars.discourse-cdn.com/v4/letter/h/839c29/32.png) [@human\_extinction](https://boards.straightdope.com/u/human_extinction)\ **Post date:** [August 13, 2011, 9:18pm UTC](https://boards.straightdope.com/t/satellite-internet-latency/592609/1 "2011-08-13T21:18:15Z")
What is the primary cause of latency with satellite internet connections? Since the signal travels at the speed of light it shouldn’t be the distance, right? ---
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [August 13, 2011, 9:31pm UTC](https://boards.straightdope.com/t/satellite-internet-latency/592609/2 "2011-08-13T21:31:15Z")
It’s very much the distance. Your signal goes to a satellite in geostationary orbit, 35,786 km above the earth, then back down to the target, then there’s the trip back. That’s over 140,000 km when the speed of light is 300,000 km /s. So the latency is just under half a second, just from using the satellite. ---
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [August 13, 2011, 11:12pm UTC](https://boards.straightdope.com/t/satellite-internet-latency/592609/3 "2011-08-13T23:12:52Z")
Ditto distance. ---
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [August 13, 2011, 11:48pm UTC](https://boards.straightdope.com/t/satellite-internet-latency/592609/4 "2011-08-13T23:48:02Z")
While the distance is the primary delay, most data nowadays is “store & repeat,” where a packet is completely received before being retransmitted. This can happen a dozen times or more from source to destination, each relay adding a short delay. ---
**Author:** ![Shagnasty](https://avatars.discourse-cdn.com/v4/letter/s/9dc877/32.png) [@Shagnasty](https://boards.straightdope.com/u/Shagnasty)\ **Post date:** [August 13, 2011, 11:53pm UTC](https://boards.straightdope.com/t/satellite-internet-latency/592609/5 "2011-08-13T23:53:31Z")
There is processing overhead as well with each jump and it adds up even if every step is extremely fast. It doesn’t take much to throw off the rhythm of a computer application operating in real-time or even a human conversation going through a satellite. At work, we have to keep in mind where we move servers because even a a move of a few hundred miles can have an impact on some critical applications that constantly talk back and forth to each other. ---
**Author:** ![Martin\_Hyde](https://avatars.discourse-cdn.com/v4/letter/m/47e85d/32.png) [@Martin\_Hyde](https://boards.straightdope.com/u/Martin_Hyde)\ **Post date:** [August 13, 2011, 11:53pm UTC](https://boards.straightdope.com/t/satellite-internet-latency/592609/6 "2011-08-13T23:53:44Z")
A few years ago I heard Bill Gates had put some money into a company that was deploying satellites that orbited at 1,000 km and would provide a form of WiFi to most of the planet. No idea what ever happened with it, though or the long term feasibility. I believe [Microsoft Systems Canada, Inc COMMStellation](http://www.commstellation.com/constellation/leo-vs-meo.html) is what I read about. Since it is much closer to the earth I imagine it would have vastly reduced latency. ---
**Author:** ![Martin\_Hyde](https://avatars.discourse-cdn.com/v4/letter/m/47e85d/32.png) [@Martin\_Hyde](https://boards.straightdope.com/u/Martin_Hyde)\ **Post date:** [August 14, 2011, 12:00am UTC](https://boards.straightdope.com/t/satellite-internet-latency/592609/7 "2011-08-14T00:00:01Z")
It actually looks like the Gates backed company was called “TeleDisc” and it seems to have come to naught. But it does look like Microsat Systems Canada is deploying a pretty legitimate network that seems to be mostly designed around amplifying smartphone connectivity. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [August 14, 2011, 1:13am UTC](https://boards.straightdope.com/t/satellite-internet-latency/592609/8 "2011-08-14T01:13:42Z")
> [@Martin\_Hyde](#): > > It actually looks like the Gates backed company was called “TeleDisc” and it seems to have come to naught. But it does look like Microsat Systems Canada is deploying a pretty legitimate network that seems to be mostly designed around amplifying smartphone connectivity. [Teledesic](http://en.wikipedia.org/wiki/Teledesic). ---
**Author:** ![human\_extinction](https://avatars.discourse-cdn.com/v4/letter/h/839c29/32.png) [@human\_extinction](https://boards.straightdope.com/u/human_extinction)\ **Post date:** [August 14, 2011, 3:18am UTC](https://boards.straightdope.com/t/satellite-internet-latency/592609/9 "2011-08-14T03:18:03Z")
Thanks. You guys are right. I thought the same, and then yesterday someone called me retarded because “it travels at the speed of light” - so I second guessed myself. So: 71572km (distance to and from a geostationary satellite) divided by c (the speed of light in kilometers per second) (71572) / (3 x 10^5) = ~.2385 Which is about 238ms. Laaaaaaag (high ping). ---
**Author:** ![chorpler](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chorpler/32/2888_2.png) [@chorpler](https://boards.straightdope.com/u/chorpler)\ **Post date:** [August 14, 2011, 7:00am UTC](https://boards.straightdope.com/t/satellite-internet-latency/592609/10 "2011-08-14T07:00:46Z")
> [@human\_extinction](#): > > Thanks. You guys are right. I thought the same, and then yesterday someone called me retarded because “it travels at the speed of light” - so I second guessed myself. > > So: > 71572km (distance to and from a geostationary satellite) > divided by c (the speed of light in kilometers per second) > > (71572) / (3 x 10^5) = ~.2385 > Which is about 238ms. Laaaaaaag (high ping). And that’s how long it takes your packet to get from your computer to the destination (not accounting for any additional delays caused by processing time, etc.). To receive the response adds an additional quarter-second of lag, so overall, the sheer distance adds a lag time of nearly half a second. Very annoying when you’re trying to do something real-time like telnet, ssh, etc. ---
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [August 14, 2011, 12:28pm UTC](https://boards.straightdope.com/t/satellite-internet-latency/592609/11 "2011-08-14T12:28:38Z")
Be grateful it isn’t 7 seconds, as [Clifford Stoll](http://en.wikipedia.org/wiki/The_Cuckoo's_Egg_(book)) found a hacker was subject to, due to the number of bounces he had set up to cover his tracks. And they weren’t using satellites in those days. ---
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [August 14, 2011, 12:40pm UTC](https://boards.straightdope.com/t/satellite-internet-latency/592609/12 "2011-08-14T12:40:38Z")
Correction to my previous post: _some_ satellite links were used in the German hacker’s communication as reported in Clifford Stoll’s book, The Cuckoo’s Egg.