The Iridium telecommunications satellites network spans the entire globe, offering worldwide voice and data transmission even in remote areas – and thereby assuring optimum accessibility from any point on the Earth’s surface. Commissioned back in 1998, the now aging satellites are gradually being replaced by a new, more modern generation of satellites led by Thales Alenia Space. In future, the Iridium NEXT satellites will also be able to provide global broadband internet access.
The Iridium NEXT satellites have been scheduled for placement in orbit in sets of 10 from a SpaceX Falcon 9 rocket launching from Vandenberg Air Force Base. The first 10 satellites launched in mid-January, with the next 10 scheduled for the weekend of 25 June. In all, 70 satellites should be in orbit by mid-2018. These will orbit the Earth at an altitude of just 780km on six different orbits. The remaining satellites will act as backup, either in space or in storage on Earth.
Smooth operation of the satellites over their planned service life of up to 15 years relies on stable temperature conditions in their interior. This is achieved by means of thermal insulation supplied by RUAG Space Austria. A covering made up of several layers of wafer-thin metal-evaporated polyimide film protects the satellites against the extreme temperature variations they encounter on their orbits. Despite their relatively modest size of 3.1 x 2.4 x 1.5 m, each Iridium NEXT satellite requires 147 individual insulation parts. The mostly completely different shapes and designs were developed and calculated by RUAG Space in Vienna. Production of the almost 12,000 insulation panels for the 81 Iridium NEXT satellites continued into 2017, and now concludes with the delivery of the final batch of insulation at the end of June. This is the largest number of insulation parts for structurally identical satellites that RUAG Space has ever had to manufacture.
It was possible to carry out this contract within the required period of just 36 months only by using machine-aided, partly automated production and continuously optimised production flows. Full-scale manufacturing was preceded by a design and production ramp-up phase lasting around 18 months. There was also a cleverly designed logistics operation to ensure punctual delivery of the individual insulation parts. On behalf of the main contractor for the satellites, Thales Alenia Space France in Cannes, RUAG Space delivered the thermal insulation directly to Orbital ATK in Chandler, Arizona for assembly.
RUAG Space in Sweden is also contributing the Payload Interface Unit, which, as part of the central computer, coordinates signal transmission for steering the satellite as well as for aligning the antennas and controlling the temperature system in the Iridium NEXT satellites.