Low Earth Orbit

Mankind has always had a fascination with space. Today, space continues to beckon us, even in low orbit. Understanding what low earth orbit is, as well as its associated properties, can help further our knowledge of space.

 

Low Earth orbit can be defined as an orbit at somewhere between 200 miles and 930 miles above the Earth. Objects flying in low orbit cannot escape the force Earth's gravity without moving extremely quickly, namely at a rate of about 17,000 miles per hour. At this high speed, objects can fully orbit the Earth about 90 minutes.

 

Sir Isaac Newton discovered gravity. With this discovery, Newton became the first person to theorize about satellites in space (around the late 17th and early 18th centuries). However, it would take almost 300 years before the satellite became an actuality.

 

During the 1950s, the Soviet Union and the United States were locked in the midst of the Cold War. Both countries were scurrying to be the first in space for both technological and propaganda-related reasons. The countries both announced their plans for building satellites in 1955. Russia won this race with the launch of the Sputnik 1 on Oct. 4, 1957. Thousands of satellites from countries around the world have since been launched into space.

The majority of manned space flights have taken place in low Earth orbit. Similarly, most artificial satellites circle in low orbit. These satellites are used for:

Interestingly, weather satellites can also detect distress signals.

 

As people have sent objects into space, they have also left behind debris. According to the New York Times, the United States government had documented approximately 10,000 pieces of space debris 4 inches or larger in width by early 2007. Space debris includes:

Most of this space debris is concentrated between 550 and 625 miles above the surface of the Earth. While most manned space flights operate at lower altitudes, scientists are concerned about collisions between debris and spacecraft, as well as about how to remove the debris. At this point, an economic method for debris removal has not been developed.

 

 

Mangiacapre, Tony (1997). The First Satellites. Retrieved January 21, 2008, from the Smgaels.org Web site: http://www.smgaels.org/physics/97/CMATHIEZ.HTM.

Mangiacapre, Tony (1997). The Theoretical Ground Work for Satellites. Retrieved January 21, 2008, from the Smgaels.org Web site: http://www.smgaels.org/physics/97/CMATHIEZ.HTM.

 

Oberright, John E.(2004). Artificial Satellite. Retrieved January 21, 2008, from the World Book Online Reference Center Web site: http://www.nasa.gov/worldbook/
artificial_satellites_worldbook.html.

Schmid, Randolf E. (2006). Space Debris a Growing Problem NASA Report Says. Retrieved January 21, 2008, from the Space.com Web site: http://www.space.com/news/ap_060120_space_junk.html.

Tech-Faq (2007). What is Polar Orbit? Retrieved January 21, 2008, from the Tech-faq.com Web site: http://www.tech-faq.com/polar-orbit.shtml.

Tech-Faq (2007). What is Low Earth Orbit? Retrieved January 21, 2008, from the Tech-faq.com Web site: http://www.tech-faq.com/low-earth-orbit.shtml.

The New York Times (2007). Orbiting Junk, Once a Nuisance, Is Now a Threat. Retrieved January 21, 2008, from The New York Times Web site: http://www.nytimes.com/2007/02/06/science/space/06orbi.html?

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