There have been attempts to profitably use satellites for data transmission; usually for applications where terrestrial connections to the Internet are not available or possible. There are satellite providers that offer telephone service virtually anywhere in the world. These providers offer data services, but the speeds are slow and the transmission latency/delay is long. A number of more recent industry entries are offering Internet access by satellite. These emerging providers plan to offer higher speeds with low latency/delay characteristics and nearly full global coverage.
Traditional Satellites
The coverage area and latency/delay experienced is a function of the satellite orbit. A geostationary orbit satellite appears motionless, in a fixed position in the sky. These satellites are orbiting at 22,300 miles above the Earth. This is because it circles at the Earth's own rotational speed once every 24 hours circling the equator. Their coverage area is large but does not cover the most northern and southern areas of the Earth.
This orbital location is useful for communications because the ground-based antennas are aimed at the satellite. The antennas face a fixed location above the earth thereby not requiring expensive antennas. Television distribution is a common application for this satellite location. The satellite may be expensive to launch but there are significant savings for the antenna installations.
A medium Earth orbit satellite (MEO) can be in orbit somewhere between 200 and 930 miles above the Earth's surface. The MEO satellites are visible for a period of time, usually between two to eight hours; they are not stationary in the sky. The higher the satellite orbit is above the earth, the larger the coverage times. MEO satellites have a smaller coverage area than geostationary satellites, and the latency/delay is shorter than the geostationary satellite location.
FCC Satellite Tests
The graphic below shows there is some variation among what providers advertise and what is delivered. Starting in 2011, the satellite industry launched a new generation of satellites with improved performance. Technical advances have decreased the latency/delay and improved the overall performance. The FCC tests " Measuring Broadband America – February 2014," demonstrated that during peak usage periods, 90% of consumers received about 140% of the advertised speed. The latency/delay still remains much higher than land-based facilities. The FCC report used the term broadband, but under the new broadband definition, none of the satellite providers offer true broadband Internet service.
Bandwidth and Latency
The bandwidth/transmission speeds vary considerably across existing service providers. These speeds will depend on the time of day and the number of simultaneous users.
Latency continues to be an issue. The minimum latency is 500 ms. Adding terrestrial facilities can extend the latency to 600+ ms. This can be compared to the average terrestrial latency of about 70 ms.
Some Providers
There are several providers for satellite Internet access. They vary in their offerings, speed, data plans, and how they access the Internet. Some offer Internet access using the phone as the modem. Speeds can be as slow as a dial up modem or as fast as DSL and maybe a slow cable service. Most services also have monthly data caps of 10 to 25 GB/ month.
Low Earth Orbits
There are companies that are planning low earth orbit (LEO) satellites. The goal is to launch 200 or more LEO satellites that can reduce the latency/delay, increase the number of simultaneous users, and increase the available speed.
A low earth orbit (LEO) typically is a circular orbit about 120 to 200 miles above the earth's surface. The time period these satellites are visible to a user on earth is about 90 to 120 minutes. At this low altitude, these satellites are only visible from within a radius of 620 miles. In addition, satellites in low earth orbit change their position relative to the ground position quickly. So even for local applications, a large number of satellites are needed if the application, such as continuous communications, requires uninterrupted connectivity.
Next Generation of Satellites
The MIT Technology Review article "Why the Time Seems Right for a Space-Based Internet Service; New micro-satellite technology is enabling satellite Internet services that could reach billions of new users," provides an interesting discussion of the future of LEO micro satellites.
"Providing Internet access from orbiting satellites -- a concept that seemed to have died with the excesses of the dot-com boom -- has returned thanks to SpaceX founder (and dot-com billionaire) Elon Musk," writes Dave Majumdar. "And while such a service would be expensive and risky to deploy, recent technological trends mean it's no longer so out-of-this-world."
The OneWeb satellite configuration is a proposed constellation of approximately 700 satellites. It is expected to provide global Internet service to individual consumers as early as 2019. The constellation is proposed by the company WorldVu Satellites Ltd. It is expected to require a capital investment of up to $3 billion by the time the full constellation becomes operational. OneWeb plans to orbit a total constellation of 700 MEO satellites, operating in 500 miles and 590 miles with half of the satellites operating at each altitude.
Improved Performance
The new generation of LEO satellites delivers advantages over the satellites now in service:
The satellites in service do not communicate directly with each other. To progress from one satellite to another satellite, the data must pass through a ground-based station to relay data to the next satellite. The plan for these LEO and MEO satellites is to pass the data from satellite to satellite until it reaches the destination location. This further reduces the latency issue.
