Iridium 77 Iridium 77 Iridium 77 is a communications Satellite which is part of a satellite constellation known as Iridium, named after the 77th chemical element of the periodic table, "iridium". It was launched in 1998 and as of 2014, operational. It is owned and funded by Iridium, a communications company. Iridium 77 is a part of a space-based communications system called Iridium. Conceived, designed, and built by Motorola, the Iridium system provides wireless, mobile communications through a network of 66 satellites in polar, low-Earth orbits. Inaugurated in November 1998, under the auspices of Iridium LLC, this complex space system allowed callers
Names for sets of chemical elements the name used is "category". Very often these categories are marked by a background color in the periodic table. Category names used here, without any claim to universality, are: Many other names for sets of elements are in common use, and yet others have been used throughout history. These sets usually do not aim to cover the whole periodic table (as for example "period" does). Some examples: Names for sets of chemical elements There are currently 118 known chemical elements exhibiting a large number of different physical and chemical properties. Amongst this diversity, scientists have found it useful to use