A low Earth orbit (LEO) is generally defined as an orbit below an altitude of approximately 2,000 kilometers (1,200 mi). Given the rapid orbital decay of objects below approximately 200 kilometers (120 mi), the commonly accepted definition for LEO is between 160 kilometers (99 mi) and 2,000 kilometers (1,200 mi) above the Earth's surface. With the exception of the lunar flights of the Apollo program, all human spaceflights have taken place in LEO (or were suborbital). The altitude record for a human spaceflight in LEO was Gemini 11 with an apogee of 1,374.1 kilometers (853.8 mi). All manned space stations to date, as well as the majority of artificial satellites, have been in LEO.
Read more about Low Earth Orbit: Orbital Characteristics, Human Use, Space Debris
Famous quotes containing the words earth and/or orbit:
“Some of us still get all weepy when we think about the Gaia Hypothesis, the idea that earth is a big furry goddess-creature who resembles everybody’s mom in that she knows what’s best for us. But if you look at the historical record—Krakatoa, Mt. Vesuvius, Hurricane Charley, poison ivy, and so forth down the ages—you have to ask yourself: Whose side is she on, anyway?”
—Barbara Ehrenreich (b. 1941)
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—E.T.A.W. (Ernst Theodor Amadeus Wilhelm)