The ability of a satellite to stay in orbit is dependent on its velocity and the gravitational pull from the planet that the satellite is orbiting. The closer the satellite is to a planet, the faster it has to travel to maintain its orbit.
The orbit principles of Johann Kepler are the basis for the understanding of satellite orbit. Kepler was the first to describe the orbital shape of planets in a mathematical sense. He determined that Earth had an eliptical orbit around the Sun rather than the previous theory which stated that all planets orbited in a perfect circle. Kepler theorized that for an object to orbit the Earth, it must carry enough speed to maintain its path around the planet. Kepler's work helped scientists determine that the closer an object orbits the Earth, the stronger the gravitational pull on the object. Velocity must be increased or else the object would crash to Earth under the weight of the force of attraction.
Artificial satellites are launched into different levels of orbit. The most common satellite orbit is called geosynchronous orbit. Geosynchronous orbit means that it takes the satellite 24 hours to orbit the Earth. This type of orbit is used for communications and television satellites because the satellite remains in the same place over the Earth.Learn More
The U.S. Space Shuttles flew at a variety of altitudes depending on their individual missions, mostly between 190 to 330 nautical miles above the Earth. The highest mission flown by a Space Shuttle was STS-82, where the shuttle reached 335 nautical miles to service and boost the Hubble Space Telescope.Full Answer >
According to data collected by the University of Calgary, space begins and the Earth's atmosphere ends at 73 miles above the Earth's surface. However, other countries and agencies have a differing opinion on where space begins.Full Answer >
Due to its relative proximity to the planet, the International Space Station is easily seen from Earth. The station appears as a fast-moving, solid light in the sky and can be seen with the naked eye or with a pair of binoculars.Full Answer >
The International Space Station is usually visible for a few minutes near dawn or dusk. It travels from the western horizon and disappears from the eastern horizon with each pass. Near darkness is the best time because of sunlight reflecting off the station from the rising and setting sun.Full Answer >