logging in or signing up Satellite dani420 Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: Embed: Flash iPad Dynamic Copy Does not support media & animations Automatically changes to Flash or non-Flash embed WordPress Embed Customize Embed URL: Copy Thumbnail: Copy The presentation is successfully added In Your Favorites. Views: 5479 Category: Science & Tech.. License: All Rights Reserved Like it (4) Dislike it (0) Added: April 27, 2009 This Presentation is Public Favorites: 3 Presentation Description No description available. Comments Posting comment... By: alok1989 (33 month(s) ago) its very excellent ppt Saving..... Post Reply Close Saving..... 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The word satellite originated from the Latin word “Satellit”- meaning an attendant, one who is constantly covering around & attending to a “master” or big man. For our own purposes however a satellite is simply any body that moves around another (usually much larger) one in a mathematically predictable path called an orbit. Launch Of Satellite : Satellite Adnan Qamar 4 Launch Of Satellite USSR Launched the first artificial earth satellite, sputnik in 1957 The world's first artificial satellite was about the size of a basketball, weighed only 183 pounds, and took about 98 minutes to orbit the Earth on its elliptical path. Satellite : Satellite Adnan Qamar 5 Satellite Since then, the United States and about 40 other countries have developed, launched, and operated satellites There are about 3,000 useful satellites and 6,000 pieces of space junk are orbiting Earth. Types of Satellite : Satellite Adnan Qamar 6 Types of Satellite Weather Satellites Communication Satellites Navigation Satellite Observing Satellite WEATHER SATELLITE : Satellite Adnan Qamar 7 WEATHER SATELLITE A weather satellite called the Geostationary Operational Environmental Satellite observes atmospheric conditions over a large area to help scientists study and forecast the weather COMMUNICATION SATLLITE : Satellite Adnan Qamar 8 COMMUNICATION SATLLITE A communications satellite, such as the Tracking and Data Relay Satellite (TDRS) shown here, relays radio, television, and other signals between different points in space and on Earth NAVIGATION SATELLITE : Satellite Adnan Qamar 9 A navigation satellite, like this Global Positioning System (GPS) satellite, sends signals that operators of aircraft, ships, and land vehicles and people on foot can use to determine their location NAVIGATION SATELLITE OBSERVING SATELLITE : Satellite Adnan Qamar 10 OBSERVING SATELLITE An Earth observing satellite surveys our planet's resources. This satellite, Aqua, helps scientists study ocean evaporation and other aspects of the movement and distribution of Earth's water How do Satellites Work? : Satellite Adnan Qamar 11 How do Satellites Work? Two Stations on Earth want to communicate through radio broadcast but are too far away to use conventional means. The two stations can use a satellite as a relay station for their communication. * One Earth Station transmits the signals to the satellite. Up link frequency is the frequency at which Ground Station is communicating with Satellite. * The satellite Transponder converts the signal and sends it down to the second earth station. This frequency is called a Downlink. Launching the satellite : Satellite Adnan Qamar 12 Launching the satellite Space shuttles carry some satellites into space, but most satellites are launched by rockets that fall into the ocean after their fuel is spent. Many satellites require minor adjustments of their orbit before they begin to perform their function. Built-in rockets called thrusters make these adjustments. Once a satellite is placed into a stable orbit, it can remain there for a long time without further adjustment. How does a satellite stay in it’s orbit? : Satellite Adnan Qamar 13 How does a satellite stay in it’s orbit? Slide 14: Satellite Adnan Qamar 14 Satellite orbits Classification of orbits: Classification of orbits: : Satellite Adnan Qamar 15 Classification of orbits: * Circular orbits are simplest * Inclined orbits are useful for coverage of equatorial regions * Elliptical orbits can be used to give stationary behavior viewed from earth using 3 or 4 satellites * Orbit changes can be used to extend the life of satellites Classification of orbits : Satellite Adnan Qamar 16 Classification of orbits Satellite orbits are also classified based on their heights above the earth: GEO LEO MEO Molniya Orbit HAPs Satellite orbit Altitudes : Satellite Adnan Qamar 17 Satellite orbit Altitudes Slide 18: Satellite Adnan Qamar 18 Satellite frequency band Apogee & Perigee : Satellite Adnan Qamar 19 Apogee & Perigee Apogee is the point at which a satellite in an elliptical orbit is furthest from the Earth. At its apogee, the satellite travels slower than at any other point in its orbit. Perigee is the point at which a satellite in an elliptical orbit is closest to the Earth. At its perigee, the satellite travels faster than at any other point in its orbit. Satellite - satellite communication : Satellite Adnan Qamar 20 Satellite - satellite communication It is also possible for satellites to communicate with other satellites Communication can be by microwave or by optical laser Components of a satellite : Satellite Adnan Qamar 21 Components of a satellite There are 3 major components in a satellite, they are : Transponder and antenna system- Power Package- Control and information system & rocket thruster system Slide 22: Satellite Adnan Qamar 22 Major problems for satellites Positioning in orbit Stability Power Communications Harsh environment Positioning : Satellite Adnan Qamar 23 Positioning This can be achieved by several methods One method is to use small rocket motors These use fuel - over half of the weight of most satellites is made up of fuel Often it is the fuel availability which determines the lifetime of a satellite Commercial life of a satellite typically 10-15 years Stability : Satellite Adnan Qamar 24 Stability It is vital that satellites are stabilised - to ensure that solar panels are aligned properly, communication antennae are aligned properly Early satellites used spin stabilisation - either this requires an inefficient omni-directional aerial Or antennae were precisely counter-rotated in order to provide stable communications. * Modern satellites use reaction wheel stabilisation - a form of gyroscopic stabilisation Harsh Environment : Satellite Adnan Qamar 25 Harsh Environment Satellite components need to be specially “hardened” Circuits which work on the ground will fail very rapidly in space Temperature is also a problem - so satellites use electric heaters to keep circuits and other vital parts warmed up - they also need to control the temperature carefully Slide 26: Satellite Adnan Qamar 26 THE END You do not have the permission to view this presentation. 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