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A wide variety of sources [5] [6] [7] define LEO in terms of altitude.The altitude of an object in an elliptic orbit can vary significantly along the orbit. Even for circular orbits, the altitude above ground can vary by as much as 30 km (19 mi) (especially for polar orbits) due to the oblateness of Earth's spheroid figure and local topography.
Indicated altitude is the reading on the altimeter when it is set to the local barometric pressure at mean sea level. In UK aviation radiotelephony usage, the vertical distance of a level, a point or an object considered as a point, measured from mean sea level; this is referred to over the radio as altitude.(see QNH) [2]
The required altitude depends on the type of terrain, such as low vegetation or low buildings, tree canopy layer of less than 45 m (148 ft), presence of tall buildings or concrete pylons with heights of up to 25 m (82 ft) international standard, or emergent tree layer canopy and lattice steel electricity pylons to 100 m (330 ft) being present ...
Very low Earth orbit is a range of orbital altitudes below 400 km (250 mi), and is of increasing commercial importance in a variety of scenarios and for multiple applications, in both private and government satellite operations.
At an altitude of 19,000 m (63,000 ft), the atmospheric pressure is sufficiently low that water boils at the normal temperature of the human body. This altitude is known as the Armstrong limit .
Average altitude of 384,403 kilometres (238,857 mi), elliptical-inclined orbit. Beyond-low Earth orbit (BLEO) and beyond Earth orbit (BEO) are a broad class of orbits that are energetically farther out than low Earth orbit or require an insertion into a heliocentric orbit as part of a journey that may require multiple orbital insertions ...
The rule affected only those aircraft operating under IFR when in level flight above 3,000 ft above mean sea level, or above the appropriate transition altitude, whichever is the higher, and when below FL195 (19,500 ft above the 1013.2 hPa datum in the UK, or with the altimeter set according to the system published by the competent authority in ...
Haley also cited other technical considerations for that altitude, as it was approximately the altitude limit for an airbreathing jet engine based on current technology. In the same 1959 paper, Haley also referred to 295,000 feet (55.9 mi; 90 km) as the "von Kármán Line", which was the lowest altitude at which free-radical atomic oxygen occurred.