Editing Internet access (section)

====Satellite broadband====
[[File:Ghana satellite.jpg|thumb|Satellite Internet access via [[VSAT]] in Ghana]]

[[Satellite Internet access]] provides fixed, portable, and mobile Internet access.<ref>[http://iml.jou.ufl.edu/projects/Fall99/Coffey/ "Internet in the Sky"] {{webarchive|url=https://web.archive.org/web/20121216120858/http://iml.jou.ufl.edu/projects/Fall99/Coffey/ |date=2012-12-16 }}, D.J. Coffey, accessed 8 May 2012</ref> Data rates range from 2&nbsp;kbit/s to 1&nbsp;Gbit/s downstream and from 2&nbsp;kbit/s to 10&nbsp;Mbit/s upstream. In the northern hemisphere, satellite antenna dishes require a clear line of sight to the southern sky, due to the equatorial position of all geostationary satellites. In the southern hemisphere, this situation is reversed, and dishes are pointed north.<ref name=how>[http://computer.howstuffworks.com/question606.htm "How does satellite Internet operate?"] {{webarchive|url=https://web.archive.org/web/20110927053708/http://computer.howstuffworks.com/question606.htm |date=2011-09-27 }}, How Stuff Works, Retrieved 5 March 2009.</ref><ref name=geostationary>{{cite web| url=http://searchmobilecomputing.techtarget.com/definition/geostationary-satellite| title=Geostationary Satellite Definition| author=Margaret Rouse| publisher=Search Mobile Computing| access-date=June 24, 2015| url-status=dead| archive-url=https://web.archive.org/web/20150610040610/http://searchmobilecomputing.techtarget.com/definition/geostationary-satellite| archive-date=June 10, 2015}}</ref> Service can be adversely affected by moisture, rain, and snow (known as rain fade).<ref name=how/><ref name=geostationary/><ref>{{cite web| url=http://searchmobilecomputing.techtarget.com/definition/rain-fade| title=Rain Fade Definition| author=Margaret Rouse| publisher=Search Mobile Computing| access-date=June 24, 2015| url-status=live| archive-url=https://web.archive.org/web/20150622005223/http://searchmobilecomputing.techtarget.com/definition/rain-fade| archive-date=June 22, 2015}}</ref> The system requires a carefully aimed directional antenna.<ref name=geostationary/>

Satellites in geostationary Earth orbit (GEO) operate in a fixed position {{convert|35,786|km|mi|abbr=on}} above the Earth's equator. At the speed of light (about {{convert|300,000|km/s|mi/s|abbr=in|disp=or|sigfig=3}}), it takes a quarter of a second for a radio signal to travel from the Earth to the satellite and back. When other switching and routing delays are added and the delays are doubled to allow for a full round-trip transmission, the total delay can be 0.75 to 1.25 seconds. This latency is large when compared to other forms of Internet access with typical latencies that range from 0.015 to 0.2 seconds. Long latencies negatively affect some applications that require real-time response, particularly online games, [[voice over IP]], and remote control devices.<ref>{{cite book| title=The Basics of Satellite Communication| author=Joseph N. Pelton| date=2006| publisher=Professional Education International, Inc.| isbn=978-1-931695-48-0}}</ref><ref>{{cite book| title=The First 100 Feet: Options for Internet and Broadband Access| author=Deborah Hurley, James H. Keller| date=1999| publisher=Harvard college| isbn=978-0-262-58160-8| url-access=registration| url=https://archive.org/details/first100feetopti00debo}}</ref> [[TCP tuning]] and [[TCP acceleration]] techniques can mitigate some of these problems. GEO satellites do not cover the Earth's polar regions.<ref name=how/> [[HughesNet]], [[Exede]], [[AT&T]] and [[Dish Network]] have GEO systems.<ref>{{cite web| url=http://about.att.com/mediakit/broadband| title=AT&T Broadband Services| publisher=ATT| access-date=June 24, 2015| url-status=live| archive-url=https://web.archive.org/web/20150610121009/http://about.att.com/mediakit/broadband| archive-date=June 10, 2015}}</ref><ref>{{cite web| url=http://www.hughesnet.com/| title=Home| publisher=Hughes Net| access-date=June 24, 2015| url-status=live| archive-url=https://web.archive.org/web/20150623192705/http://www.hughesnet.com/| archive-date=June 23, 2015}}</ref><ref>{{cite web| url=http://www.exede.com/| title=Home| publisher=Exede Internet| access-date=June 24, 2015| url-status=live| archive-url=https://web.archive.org/web/20150617072311/http://www.exede.com/| archive-date=June 17, 2015}}</ref><ref>{{cite web| url=http://www.dish.com/bundles/| title=Bundles| publisher=Dish Network| access-date=June 24, 2015| url-status=live| archive-url=https://web.archive.org/web/20150613031716/http://www.dish.com/bundles/| archive-date=June 13, 2015}}</ref>

[[Satellite internet constellations]] in [[low Earth orbit]] (LEO, below {{convert|2000|km|mi|abbr=in|disp=or|sigfig=4}}) and [[medium Earth orbit]] (MEO, between {{convert|2000|and|35786|km|disp=or|abbr=in}}) operate at lower altitudes, and their satellites are not fixed in their position above the Earth. Because they operate at a lower altitude, more satellites and [[launch vehicle]]s are needed for worldwide coverage. This makes the initial required investment very large which initially caused OneWeb and Iridium to declare bankruptcy. However, their lower altitudes allow lower latencies and higher speeds which make real-time interactive Internet applications more feasible. LEO systems include [[Globalstar]], [[Starlink]], [[OneWeb]] and [[Iridium satellite constellation|Iridium]]. The [[O3b]] constellation is a medium Earth-orbit system with a latency of 125 ms. COMMStellation™ is a LEO system, scheduled for launch in 2015,{{Update inline|date=April 2021}} that is expected to have a latency of just 7&nbsp;ms.