SPACE COMMUNICATION

 Space Communication:

           Communication is more important to astronauts(or spacecraft) while they are in space because they have to communicate to their team who are in the ground so that they can complete their mission.

What is space communication?

            The Communications between vehicle or astronauts in outer space and Earth. Here the high frequency radio waves is used to communicate. Space communication depends on two things, the transmitter and the receiver.

Transmitter -  It encodes the message into electro magnetic waves.

Receiver - It collects electro magnetic wave and  decodes the message. 

Why we have to use high frequency waves?

          Because the space  communication is from million or  billion miles away ,the atmosphere acts to bend these rays and bounce them back towards earth, so that they can travel all over the world.

 Major reasons to use high frequency waves:

1. It gives greater pointing accuracy.
2. It minimises ionospheric effects.
3. It allows larger bandwidth(passes more information per unit of time).

How do astronauts communicate in space?

          We know that sound cannot travel through space(vacuum).So that the astronauts in space cannot communicate. But it is essential to communicate with the other crew members(other astronauts) and the team in the earth .Since radio waves propagate through vacuum , they fit devices in their helmets which converts sound waves into radio waves and transmit it to other astronauts or to the ground.

How do we receive and send signal to space?

          Spacecraft send information and pictures to earth using  Deep Space Network (DSN). DSN is the collection of big radio antenna from different parts of world. It is evenly spaced around the planet(as earth turns, it won't lost the sight of space craft). Spacecraft send images and other information to these big antennas. The antennas also receive details about where the spacecraft are and how they are doing. The DSN also sends list of instructions to the spacecraft. Once the data is received at DSN site, the data is processed and shared.

Role of amateur radio(HAM) in space communication:

          Amateur Radio on the International Space Station (ARISS) - operating in the Amateur-satellite service. Amateur radio operators all over the world are able to speak directly to astronauts through  their mobile or home radio stations. It is also possible to send digital data to the space station through same radio and antenna connected to laptop or computer.