The name of which artificial satellite constellation system was taken from the name of the element with atomic number 77?
Iridium satellite constellation Earth latitudes with reliable satellite communication services. Early calculations showed that 77 satellites would be needed, hence the name "Iridium" – after the metal with atomic number 77. It turned out that just 66 were required to complete the blanket coverage of the planet with communication services. The first-generation constellation was developed by Iridium SSC, and financed by Motorola. The satellites were deployed in 1997—2002. "A drawback of Iridium’s concept was that the constellation required all of its satellites to be in orbit before commercial service could begin – resulting in high initial outlay." Iridium SSC employed a globally diverse
Satellite constellation Satellite constellation A satellite constellation is a group of artificial satellites working in concert. Such a constellation can be considered to be a number of satellites with coordinated ground coverage, operating together under shared control, synchronized so that they overlap well in coverage, the period in which a satellite or other spacecraft is visible above the local horizon. Low Earth orbiting satellites (LEOs) are often deployed in satellite constellations, because the coverage area provided by a single LEO satellite only covers a small area that moves as the satellite travels at the high angular velocity needed to maintain its orbit.