Network Reference - Constellation Lifetime
In 2001, the U.S. Air Force funded The Aerospace Corporation® to carry out a constellation study of the Iridium network. Using actual on-orbit satellite hardware failure history, The Aerospace Corporation forecasted global availability of the Iridium constellation services beyond mid-2010. In 2003, ISLLC and Boeing® followed up with a more thorough constellation lifetime study and forecasted global availability of the Iridium constellation services beyond 2014. The ISLLC/Boeing study was more reliable because it was based on accumulated on-orbit satellite performance of more than five years (stable hardware loss trends are below original predictions), accumulated on-orbit satellite battery life (battery was the key life-limiting element in The Aerospace Corporation 2001 study) and Service-Extending Software Initiatives implemented in 2002 to mitigate potential loss of critical attitude control system hardware.
Presently the Iridium constellation has 66 operational satellites and 13 spares orbiting in six separate planes. With these spares, the Iridium constellation lifetime is forecasted to be around 2014 with no additional launches. ISLLC intends to launch replenishment satellites as required to support continuing system service. The current plans indicate a potential first replenishment launch in 2013.