Iridium

Iridium is a chemical element with symbol Ir and atomic number 77. A very hard, brittle, silvery-white transition metal of the platinum group, iridium is generally credited with being the second densest element (after osmium) based on measured density, although calculations involving the space lattices of the elements show that iridium is denser. It is also the most corrosion-resistant metal, even at temperatures as high as 2000 °C. Although only certain molten salts and halogens are corrosive to solid iridium, finely divided iridium dust is much more reactive and can be flammable.

Iridium was discovered in 1803 among insoluble impurities in natural platinum. Smithson Tennant, the primary discoverer, named iridium for the Greek goddess Iris, personification of the rainbow, because of the striking and diverse colors of its salts. Iridium is one of the rarest elements in Earth's crust, with annual production and consumption of only three tonnes. ¹⁹¹Ir and ¹⁹³Ir are the only two naturally occurring isotopes of iridium, as well as the only stable isotopes; the latter is the more abundant of the two.

Iridium satellite constellation

The Iridium satellite constellation is a satellite constellation providing voice and data coverage to satellite phones, pagers and integrated transceivers over the Earth's entire surface. Iridium Communications owns and operates the constellation and sells equipment and access to its services. It was originally conceived by Bary Bertiger, Dr. Ray Leopold and Ken Peterson in late 1987 (and protected by patents by Motorola in their names in 1988) and then developed by Motorola on a fixed-price contract from July 29, 1993 to November 1, 1998 when the system became operational and commercially available.

Iridium (disambiguation)

Iridium is a chemical element.

Iridium may also refer to:

See also

Shelby County Airport (Alabama)

Shelby County Airport (ICAO: KEET, FAA LID: EET) is a public use airport located four nautical miles (7 km) southeast of the central business district of Alabaster, a city in Shelby County, Alabama, United States. It is owned by the Shelby County Commission. The airport is situated in the city of Calera, Alabama.

This airport is included in the FAA's National Plan of Integrated Airport Systems for 2011–2015 and 2009–2013, both of which categorized it as a general aviation facility. This was a change from the 2007–2011 NPIAS Report, when it was categorized as a reliever airport.

Although most U.S. airports use the same three-letter location identifier for the FAA and IATA, this airport is assigned EET by the FAA but has no designation from the IATA.

Facilities and aircraft

Shelby County Airport covers an area of 125 acres (51 ha) at an elevation of 586 feet (179 m) above mean sea level. It has one asphalt paved runway designated 16/34 which measures 5,000 by 75 feet (1,524 x 23 m). The runway runs parallel to adjacent Interstate 65. The airport has its own interchange on that highway.