Satellite communications
We know that many satellite orbit our planet everyday. and they're helping us in several ways ,you almost surprise to know around 4900 satellite orbiting the earth .
The most obvious question that comes to our mind
.why are these satellite in different orbits
How satellite work ??
What are the components inside them??
Let's see in detail .
We know satellite stay in orbit because of the balance between gravitational pull and centrifugal force when satellite is deployed it is given sufficient speed to balance there two factors .. satellite continue their circular motion without any external energy due to negligible resistance in space so they never lose speed .
Which satellite is placed on which orbit it depends on the application and purpose of satellite .
LOW EARTH ORBIT ..
If a satellite bulid for earth observations ,weather forecast , geographic area surveying , satellite Phone calls ..etc
Then orbits close to be chosen. satellite
placed between 160 to 2000 km and its orbital period is approximately 1.5 hour's.. but disadvantage are it covers less area of earth so many satellites are required to cover globally...this is why geosynchronous earth orbit are chosen..
Geosynchronous earth orbit
This geosynchronous orbit is about 35,786 km height from Earth surface..it takes extremely 2 hour's 56 minutes 4 seconds to complete one revolution...
In geosynchronous orbit a special type of orbit geo stationary belt the satellite maintain same speed as earth in order to keep ideal due to this since it means you do not have to adjust the angle of tv antenna again and again so it crowded with more number of satellites these satellites are managed by the international space station called ITU
MEDIUM EARTH ORBIT(MEO)
Meo occupied by the few navigation satellite ..this can cover 1/3 of the earth .so 24 satellites are enough to cover entire earth
And they revolve with heigh speed . GPS satellites uses in the Meo ..orbital period is about 24 hour's...altitude of 20,2000km
Let's look at main communication satellites and along with their functions...heart of the satellite are transponders..
Transponders
The main task of transponders is to change the frequency of the received signal remove unwanted noise signal and amplify the power signal converts from 14 megahertz to 24 megahertz each satellite have 20 or more transponders .. transponders need energy supply so battery's and solar panels are used ...in satellite sun sensor helps to angle the solar panels in right direction so maximum power can be extracted from sun.... satellite have thruster used for position Ans control after completing the life span of satellite ...using thrusters satellite reach to graveyard orbit .
You can see a gold color layer on satellite is to protect from sun uv rays and temperature variations..
I hope you liked this article .thank you