Polar Orbit Research Paper

Criteria D Physics - Ana Maria Montoya

Satellites are devices that orbit around the earth, they allow us to communicate and track events as well as movements in the Earth, they may collect more data, faster than any device on Earth. This devices, may orbit the earth in a variety of different ways; for example there are low earth orbits, were satellites rotate around the earth in a relatively close distance to it, then there is the highly elliptical orbit which is closer at one point in its rotation meanwhile at other times it is very far away. The polar orbit; consists of a rotation from one pole to the other and may circle the Earth various times a day. Finally, the geostationary, will orbit at the same frequency than the earth but at a

The low Earth orbits; will orbit between 160 km up to 2,000 km above sea level, but satellites do not usually orbit below 300 km due to the atmospheric drag (collision with gas molecules frequently which occur in the thermosphere and/or exosphere), therefore low Earth orbits at a height around 160 km will reach faster an orbital decay. Not only will this orbits remain less amount of time in the atmosphere; but also they will have to be launched with a significantly fast speed so that it may orbit for a longer period due to the balance between its speed and the “pull of Earth’s gravity”(NASA, September 16, 2015). Depending on the altitude at which the satellite is located, the speed at which it orbits varies, as closer to the sea level; the more speed the satellite will have to orbit at to prevent orbital decay occurring instantly. Low Earth orbits usually have a speed of 7.8 km/sec.

The highly elliptical orbits; vary both, their speed and height at different points in their rotation; their perigee (Lowest height) is usually below 1,000 km meanwhile their apogee (highest height) is usually above 35,786 km, this means that at the perigee the speed of orbit will be a lot higher than at apogee to prevent orbital decay, therefore at the perigee the speed will be around 7.8 km/sec and at the apogee around 4 km/sec.

(Iowa state university,