SATELLITE

Hello all, 

today I explained the satellites. study carefully.

satellite is nothing but an object that revolves around the planet in a curved path.

satellites are two types:

1. natural satellites(the moon is a satellite because which revolves around the earth)
2. artificial satellites(human-made)

coming to the topic of artificial satellites;

artificial satellites are made by the human and launched by the human through the rockets into the orbit of the planet.

the satellite launching involves two steps:

1. the satellite has to be taken into the desired altitude.
2. pushed out from the spacecraft at the right velocity to begin and maintain it's orbit.

the satellite launch vehicle moves straight only for a few seconds.

A satellite launch vehicle is a multistage rocket, consists of a smaller booster rocket for boosting.

boosters give the rocket initial thrust during the launch and carry the vehicle rarely part of the flight.

when the fuel completed in the boosters they fall away from the rocket other boosters take over.

due to the multi staging rocket gets light by completing its stages.and also moves faster.

when the rocket reaches the proper altitude satellite is pushed out from its into orbit with a definite velocity to maintain the orbit speed.

HOW THE SATELLITES ARE WORK?

the satellite consists of three main systems for communication.

they are:

• uplink
• transponder
• downlink

uplink is nothing but transferring the desired signals to the satellite from the earth station or ground equipment.

a transponder is nothing but amplifying the incoming signals and changes its frequency.

downlink is nothing but the process of sending the signals from the transponder of satellite back to the earth station.

the satellite communication is done through the earth station by sending and receiving the signals to satellites.

coming to the orbit of satellites are three types:

equatorial orbit: where the satellite rotates in an orbit directly above the equator, usually in a circular path with zero degrees of inclination.

polar orbit: where the satellites are rotating at the poles of the planet like the north and south pole, and also perpendicular to the equator.with an inclination of 90 degrees.

inclined orbit: the satellites which they travel directly above the equator and north and south poles.with an angle of inclination are 0 to 180.

the satellites are allowed to space by calculating the altitudes.

coming to our earth have three have orbits they are;

LOW EARTH ORBIT(LEO): the orbit ranges from 160-2000km about to earth.here the satellite needs 90-120minutes to complete it's one revolution around the earth.

MIDDLE EARTH ORBIT(MEO): the orbit ranges from 2000-35786 km about to the earth's surface.it takes 2-6hrs to complete it's one revolution around the earth.

GEO STATIONARY ORBIT(GEO): the orbit ranges from 35786 above from the earth's surface. when the satellite is exactly on the 35786km altitude it takes 24hr to complete the revolution.

the orbits have two shapes;

circular orbit: the fixed distance around the barycentre. (geostationary and polar, equatorial orbits)

these orbits have eccentricity zero.

elliptical orbit: the eccentricity of this orbit is between 0 to 1 but not equal to 0 or 1. in this orbit, some times satellites are closer to earth called perigee. sometimes farthest to earth called apogee.

ARTIFICIAL SATELLITES ARE THREE TYPES:

navigation satellites: these types of satellites are used for the ground position of any object and determines the geographical location. this type of satellites is vital in the military for gathering intelligence and used as a weapon

GNSS=global navigation satellite system.

GPS=global positioning system. introduced by the united states.

galileo introduced by Europe.

Russia introduced the (GLONASS)=global satellite navigation system.

China introduced the (BDS)=beidou navigation satellite system.

(IRNSS)=indian regional navigation satellite system. introduced by India.

japan introduced the (QZSS)=quazi zenith satellite system.

weather satellites: weather satellites are used to monitor the atmospheric and climatic conditions of earth ex: like storms, cyclones, tsunami, temperature, rainfall, etc.,

communication satellites: this type of satellites are transmit's the signals to telephone, television, radio, internet signals over long distances, etc.,