Iridium 51 & 61

Iridium provides global mobile telecommunications services using a constellation of 66 low earth orbit satellites in a 86.4° inclined orbit. Although 77 satellites were originally envisioned for the system and spawned the name based on the 77th element in the periodic table, the system has been scaled back. Motorola's Satellite Communications Group designed and manufactured the Iridium satellites with Lockheed Martin providing the LM-700A spacecraft buses.