jump to other results. 1  1[countable] a particular attitude towards something; a way of thinking about something synonym viewpoint a global perspective Recent events seem less serious when put into an international perspective.
Low earth orbit is only slightly above the Earth, by outer space standards, 124 - 1240 miles (200 - 2000 km) in altitude. Below 124 miles, orbits rapidly degrade, causing surface impact, and above 1,240 miles or even less, the Earth's radiation belts damage electronic equipment, necessitating special shielding. The region from 1,243 miles altitude to geostationary orbit (35,786 kilometers or 22,236 mi) is known as Medium Earth Orbit.
For a very low orbit of around 100 miles a velocity of about 17500 miles per hour is needed and this means that the satellite will orbit the Earth in about 90 minutes. At an altitude of 22 000 miles a velocity of just less than 7000 miles per hour is needed giving an orbit time of about 24 hours. This is generally taken to be 3960 miles or 6370 km. 2  Orbit velocity: For a circular orbit it is always the same. 3  However in the case of an elliptical one this is not the case as the speed changes dependent upon the position in the orbit.