Satellite Systems

From Isopedia

1 Technical Information
2 Historical Information
3 Resources
4 Team Members

Technical Information

How do satellites work?

A satellite is any object that orbits around a planet in an elliptical or circular path. Usually people only resort to naming man-made objects that are launched into space by rockets as satellites. There are different types of satellites, each with its own specific purpose. Because of the pull of gravity the satellites need to maintain a certain velocity depending upon their distance from the Earth. The closer the satellite is to the Earth the fasster of a velocity the satellite needs to maintain otherwise it will fall out of orbit and burn up as it enters the earths atmosphere. Without gravity a satellite would end up in space, but if the velocity being used to balance the satellite is too fast the satellite will inevitablly fly away, if the velocity is too slow the satellite will fall back to Earth. The use of the satellite is also dependent upon its location from the Earth. The farther away the satellite is the longer it will last in space. Otherwise it will eventually come into the Earth's atmosphere and creates what is known as a drag which will cause the satellite to decay.

What are satellites and what do they do?

Satellites are a way to communicate information from space back to Earth. Each satellite is dependent upon its design and orbit. The ways satellites are used are to portray TV/Radio programs, weather systems, locations, military usage, astronomy, and for navigation. Some of these themes use the same type of orbit. TV/Radio and weather can both use geosynchronous orbits. This means that the satellite floats in a specific place over the equator. Geosynchronous satellites have a receiving point on Earth that will aim towards the satellite to pick up information. Geosynchronous orbits make life easier because they do not require the control centers to search for the satellite in space, it is known where it will be.

The inclination of the satellite is how much the orbit is inclined and tilted in regards to the equator. If the inclination is 0 degrees, the satellite is hovering over the equator. This is also known as a geosynchronous satellite. If the inclination is 90 degrees, the satellite orbits over the North and South poles and perpendicular to the equator. Shuttle flights typically have an inclination of 28.5 degrees but also orbit, less frequently up to an inclination 57 degrees.

The Hubble Space Craft is an example of an astonomy satellite. At approximately the length of a school bus and using only 2800 watts of power, it hovers in a geosynchronous orbit, traveling at five miles per second around the earth. To make a full rotation of the earth would take this satellite 97 minutes total. Typically, the Hubble Space Craft orbits 150 million miles per year. The Hubble Space Craft reports its findings back to control centers here on earth. </nowiki>

Historical Information

To begin, in 1948, the United States Army Signal Corps transmitted radar signals to the moon and sent them back to earth showing signals could be transmitted into space and that they could be identified on earth. This lead to many other discoveries and becoming the satellites of today. Later in 1954 the United States Navy was able to send voice messages, creating a huge step forward. On October 4, 1957, the Soviet Union created the first artificial satellite that was sent into orbit, which was called Sputnik 1. Sputnik 1 was known to be the creation of the "space age." Before the U.S. was able to send a satellite into orbit, the USSR had sent two. On January 31, 1958, the U.S. launched their first satellite, called Explorer 1. The U.S. satellite just gave information on the environment and conditions in space outside earth's atmosphere. In the same year NASA was created, helping new defensive, technological, and scientific developments. Since the first satellite launched into orbit in 1957, there have been tremendous developments in satellite systems that have now effected people’s everyday lives. NASA took control of the American satellites and since then there have been many important milestones. The Relay I launched in 1962 made the first 2-way calls possible over a satellite. In 1962, with the launching of AT&T’s Telestar I, the first phone calls between Europe and the US were made. Then in 1964, a series of satellites called Syncom, were the first ones placed in synchronous orbit and was used to telecast the first television programs over the Pacific Ocean (the 1964 Olympic Games in Tokyo, Japan). In 1960, another series of satellites were launched called TIROS (TV Infrared Observation Satellite). This became a milestone for meteorological studies. These satellites carried cameras and were able to observe cloud cover and helped forecast weather. Then from 1978-1993, the Nimbus series was sent into orbit and was used to watch hurricanes and helped in the study of the Ozone depletion that continues today. Starting before the Cold War era, satellite development was a race to display a nation’s power. Over the course of almost 50 years, satellite systems have developed into a technology that is now able to track weather, link people in a way no one could imagine and many other useful reasons.