Space Race. Space Tech. Space War.
The terms sound familiar because I’m sure you have heard at least one of them in the recent past. What do they mean? They all mean the same thing: Conquer Space!
As if our gigantic planet, dear Earth, wasn’t enough, now the race is in space!
We are far too ahead in this race to retreat. So, we can only look back to its origin. What led to the situation we are in today?
The answer: Satellite Communication.
Let’s begin from the beginning.
The genesis
The idea of communicating through a satellite first appeared in the short story “The Brick Moon,” written by the American clergyman and author Edward Everett Hale and published in The Atlantic Monthly in 1869–70.
The story described the construction and launch of a satellite made of bricks, 200 feet (60 meters) in diameter, into Earth’s orbit. The brick moon aided mariners in navigation, as people sent Morse code signals back to Earth by jumping up and down on the satellite’s surface.
Well, this was just the idea.
The practical concept of satellite communication was first proposed by 27-year-old Royal Air Force officer Arthur C. Clarke in a paper titled “Extra-Terrestrial Relays: Can Rocket Stations Give World-wide Radio Coverage?” published in the October 1945 issue of Wireless World.
Clarke, who later became an accomplished science fiction writer, proposed that a satellite at 35,786 km (22,236 miles) above the Earth’s surface would be moving at the same speed as the Earth’s rotation. At this altitude, the satellite would remain in a fixed position relative to a point on Earth.
And voila! The formula for geostationary satellites was created!
The start of the race
The first artificial satellite, Sputnik 1, was launched successfully by the Soviet Union on October 4, 1957. Sputnik 1 was only 58 cm (23 inches) in diameter with four antennas sending low-frequency radio signals at regular intervals.
It orbited Earth in an elliptical orbit, taking 96.2 minutes to complete one revolution. It transmitted signals for only 22 days until its battery ran out and was in orbit for only three months, but its launch sparked the beginning of the space race between the United States and the Soviet Union.
Okay, so let’s understand this technology.
The basics
Satellites are relay stations in space for the transmission of voice, video, and data communications.
They are ideally suited to meet the global communications requirements of military, government, and commercial organizations because they provide economical, scalable, and highly reliable transmission services that easily reach multiple sites over vast geographic areas.
Transmissions via satellite communications systems can bypass the existing ground-based infrastructure, which is often limited and unreliable in many parts of the world.
Satellite communication involves four steps:
- An uplink Earth station or other ground equipment transmits the desired signal to the satellite
- The satellite amplifies the incoming signal and changes the frequency
- The satellite transmits the signal back to Earth
- The ground equipment receives the signal
To summarize,
A satellite is a self-contained communications system with the ability to receive signals from Earth and to retransmit those signals back with the use of a transponder—an integrated receiver and transmitter of radio signals.
How are satellites designed?
Satellites are built using sophisticated electronic and mechanical components that must withstand the vibrations of a rocket launch and then operate in the environment of space–without maintenance–for periods of 15 years or more.
They consist of the spacecraft bus (which is the primary spacecraft structure containing power, temperature control, and directional thrusters) and the communications payload (which receives, amplifies, and retransmits the signals over a designated geographic area).
Two critical considerations in spacecraft design are power and coverage. A satellite contains multiple channels, called transponders, that provide bandwidth and power over designated radio frequencies. The transponder’s bandwidth and power dictate how much information can be transmitted through the transponder and how big the ground equipment must be to receive the signal.
In addition, the satellite’s antennas direct the signal over a specific geographic area.
Satellite Applications
Commercial satellite communications services are grouped into three general categories:
Fixed Satellite Services (FSS), which use ground equipment at set locations to receive and transmit satellite signals. FSS satellites support the majority of our domestic and international services, from international internet connectivity to private business networks.
Mobile Satellite Services (MSS), which use a variety of transportable receiver and transmitter equipment to provide communication services for land mobile, maritime, and aeronautical customers.
Broadcast Satellite Services (BSS), which offer high transmission power for reception using very small ground equipment. BSS is best known for direct-to-consumer television and broadband applications such as DIRECTV.
What does the future hold?
Mega-constellations of thousands of satellites designed to bring Internet access to anywhere on Earth are in development.
Future communication satellites will have more onboard processing capabilities, more power, and larger aperture antennas that will enable satellites to handle more bandwidth.
Further improvements in satellites’ propulsion and power systems will increase their service life to 20–30 years from the current 10–15 years.
In addition, other technical innovations such as low-cost reusable launch vehicles are in development. With increasing video, voice, and data traffic requiring larger amounts of bandwidth, there is no dearth of emerging applications that will drive demand for satellite services in the years to come.
The demand for more bandwidth, coupled with the continuing innovation and development of satellite technology, will ensure the long-term viability of the commercial satellite industry well into the 21st century.
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