j1s20su
A brief history of space communication
The first artificial satellite "SPUTNIK I" was launched by the erstwhile USSR, in 1957. This began a series of space initiatives by USA and USSR.
The first satellite communication experiment was the US government's project SCORE (Signal Communication by Orbiting Relay Equipment), which launched a satellite on December 18, 1958. This satellite circled the earth in an elliptical orbit and retransmitted messages recorded on a magnetic tape. It lasted for about 13 days after which the batteries ran out!
In 1964 a global initiative was undertaken leading to the formation of INTELSAT, which has been one of the major driving forces for the large scale commercial exploitation of satellite technology for communications. Since then there has been no looking back.

VSAT
The term Very Small Aperture Terminal (VSAT) refers to a small fixed earth station. VSATs provide the vital communication link required to set up a satellite based communication network. VSATs can support any communication requirement be it voice, data, or video conferencing.
The VSAT comprises of two modules - an outdoor unit and an indoor unit. The outdoor unit consists of an Antenna and Radio Frequency Transceiver. (RFT). The antenna size is typically 1.8 metre or 2.4 metre in diameter, although smaller antennas are also in use. The indoor unit functions as a modem and also interfaces with the end user equipment like stand alone PCs, LANs, Telephones,etc.
In the outlink (download) direction from the hub to the VSATs continuous carriers are used, typically more than 256k bit/s and up to 60 Mbit/s
The data transmission rate on the return link, in the direction from the VSAT to the hub, is typically from a few 100 bit/s to 512 kbit/s

Benefits of VSAT
Ease of Implementation - The wireless nature of VSAT system allows its installation at virtually any location within the footprint of the satellite.
Availability - Customers may setup offices in a promising location without being constrained by the availability of terrestrial lines
Reliability BER of 10-9 ,VSAT ensures continuous operations in case of failure and each VSAT remote unit receives the same level of performance and signal quality.
Network Management - VSAT equipment can be remotely managed avoiding any risks that might occure.
Recovery
One of the great advantages of wireless VSAT technology is its direct connectivity between end-points. Every VSAT link is established directly through the satellite, bypassing intermediate terrestrial lines.

Benefits of VSAT
Security
Satellite networks offer excellent security against unauthorized access. All transmissions in any VSAT system are scrambled in digital format. Gaining access to a VSAT system is virtually impossible without authorization.
Every remote VSAT earth station is controlled and monitored. Banks and financial institutions around the world predominantly use VSAT system to carry critical and sensitive financial transactions. The Canadian and U.S. Armed Forces also use VSAT for their communication networks, further testifying the security of the network.
Lower Cost
The service costs are distance insensitive, Customers pay only for the amount of data throughput used

Applications of VSAT
The great advantage of VSAT is its flexibility. It permits any kind and size of network based around a central hub and remote locations. Through a VSAT network, a corporation can communicate freely and constantly with branch offices.        
Some of the applications can be classified in interactive applications, File Transfer or File Broadcast.Here are some examples: Interactive computer transactions
Internet
Video Teleconferencing
Database inquiries
Bank transactions, ATM
Voice communications
Sales monitoring & stock control
Distributed remote process control and telemetry

Is there an advantage of VSAT over cable?
Installation: A satellite network can be installed and operational in a matter of weeks,since there are not countless miles of wires to be installed.
Geography: Versatile satellite networks provide the capability to spam rain forests, deserts, or connecting remote island connections.
Bandwidth: Satellite networks offer bandwidth advantages that provide a bigger “pipe” for transmitting video, voice and data.
When it comes down to cost, making general comparisons between VSAT services and their terrestrial equivalents is almost impossible.  Charges for terrestrial services are nearly always distance-dependent, while VSAT connections cost the same whether sites are 1 or 1.000 km apart.