An Essay About Orbits Communications Essay

An Essay About Orbits Communications Essay The word orbit we hear it very often, whenever the space shuttle launched or it meets up ISS (International Space Station) or when a rocket launches a payload, we always come across the word ‘orbit’. But what actually the orbit is? An orbit is a specific path on which an artificial satellite revolves/travels around another body or planet .This path is regular and repeating .Satellite can be natural and artificial, like Moon .Moon itself acts like a satellite which travels around the Earth in a particular path. In the solar system , nine planets including Earth ,revolves around the sun in an orbit .Satellite that travels around the Earth are not in a constant distance from Earth, it varies .Sometimes its closer and sometimes far away. The closest orbit of satellite around the Earth is called â€Å"perigee† and farthest orbit called â€Å"apogee†. The time required for a satellite to complete full orbit is called a â€Å"period†. According to Isaac Newton’s first law of motion, a moving object will remain in motion unless something pulls it or push it, and that is gravity. Without Earth’s gravity, satellite would go off in the space along a straight path .With Earth’s gravity it keep on pulled satellite back to Earth. To maintain the orbit, the gravitational force and the momentum of moving object have to be balanced. Another factor is Escape velocity. It is the speed of an object (satellite) to break free from the gravity of the planet and enters into a certain orbit. It depends on the mass of the planet and varies from planets to planets and the distance from the centre of the planet to the object (satellite) is also important. The escape velocity of Earth is approx. 11.3 km (7 miles)/hr. Orbital Velocity: Orbital velocity is the required speed needed for an object (satellite) to stay in an orbit. It is about and altitude of 242 km, approx 17,000 miles /hr. [4] SATELLITE ORBITS There are three differ ent types of orbits High Earth orbit (Geostationary orbit), Medium Earth orbit (MEO), and Low Earth orbit (LEO).The orbit selected for satellite is depend on its usage and application. Direct Broadcast Programmes and weather communication satellites use Geostationary Orbit, as they are far away from the Earth and they travel in the Earth’s direction therefore looks stationary .Satellite navigation systems (NAVSTAR or GPS [global positioning system] ),designed to navigate a particular region or area and satellite phones are in MEO(Medium Earth Orbit). NASA’s Earth Observing System and other scientific satellites uses LEO (Lower Earth Orbit). [5] [6] Earth orbits. [7] ORBITAL DISTANCES [8] , [9] Orbits Orbit Initials Miles Km 1-way Delay Orbit altitude (KM above earth’s surface) Low Earth Orbit (LEO) 100-500 160 – 1,400 50ms 200 – 1200 Medium Earth Orbi t (MEO) 6,000 – 12,000 10-15,000 100ms 1200 – 35790 Geostationary Earth Orbit (GEO) ~22,300 36,000 250 ms 35790 Circular and Elliptical Paths There are two types of orbit paths, in which satellite travels around the Earth, circular and elliptical. In circular orbits, the distance between the earth and satellite remains same all the time. When a satellite orbit around the Earth, it creates a plane, which goes across the geo -centre or centre of gravity of Earth. If the satellite orbit with Earth’s rotation, it is called â€Å"posigrade† and if it is in opposite direction, it is â€Å"retrograde†.