简体中文
Satellite TV is common all around the world. Put a dish on top of your house and there you go.
But what about satellite Internet? Now it's a real thing in China, as the country's Shijian-13 satellite successfully established a 150mb/s connection to the ground on Tuesday.
CCTV reporters saw it in action. The equipment is quite similar to satellite TV: A dish and a modem, and right on the modem is the good old Ethernet cable slot. Plug and play.
"We use high-frequency lasers for the data transfer, which offers much larger data bandwidth, so we can enjoy faster speed," said Li Feng, lead designer of the Shijian-13 satellite. "It's many times faster than the current commercial solutions."
The typical speed of a satellite connection available in the US is 25mb/s.
Shijian-13 was launched in April 2017 by a Long March-3B rocket.
Reaching for the stars
The Internet we use today is based on a cable network－be it a telephone line, Ethernet line or optical fiber.
If someone in the US wants to chat with a Chinese, the most common way is to transfer the data through the inter-continental optical fibers buried in the Pacific Ocean.
Wireless solutions like WiFi, 4G and satellite are also built upon cable infrastructures.
But satellite networks can extend the reach to almost the whole surface of the Earth, and even into space.
Airlines can benefit a lot from this approach, as it's much faster than other on-plane Internet solutions currently available.
China lifted the airline cellphone ban last week. Airlines in the country are rushing to promote their on-plane WiFi features. They may resort to the new satellite network and become its first customers.
The satellite can also benefit people living in rural areas with no cable network nearby.
Slow while fast
With that said, there is a critical disadvantage with satellite Internet: Latency, or response time. If you make a phone call with heavy latency, what you said will be heard a second later by the other side, preventing the conversation from going fluently.
Latency is caused by the speed limitation of light. It's a basic law of physics that nothing can travel faster than light, which shines at almost 300,000 kilometers a second.
That sounds really fast, but it's not enough when our data has to travel to a satellite and back.
There are many other agencies and companies trying to extend the Internet to space, including NASA, SpaceX, Google and Facebook.
(CGTN)
