SpaceX and Iridium Communications have scheduled September 30 to launch the third wave of Iridium NEXT satellites from Space Launch Complex (SLC)-4E at Vandenberg AFB, California, with the fourth wave following sometime in November.
Liftoff Sep 30 is targeted for 6:30 a.m. PDT, with October 1 available as a backup.
The $3 billion Iridium NEXT global satellite network is quite incredible in that it will be one of the largest technology upgrades ever completed in space, completely replacing the aging network of its first-generation satellites, whose earliest members were launched two decades ago. In June 2010, the second-generation Iridium NEXT system was unveiled, with Thales Alenia Space and its subcontractor Orbital Sciences Corp. (later Orbital ATK) selected to build dozens of operational satellites and on-orbit and ground-based spares.
The inaugural “batch” of 10 launched in January 2017, followed by the second batch in June.
“Unlike previous launches where some Iridium NEXT satellites were sent drifting to an orbital plane different from where they were launched, all 10 satellites for this launch are currently planned to provide service in orbital plane four,” says Iridium. “The Iridium constellation’s unique architecture is designed with six polar orbiting planes consisting of 11 interconnected satellites per plane, with in-orbit spares, creating a true web of connectivity around the planet.”
SpaceX holds a contract to deliver a fleet of 75 Iridium NEXT birds into low-Earth orbit by mid-2018, which back in June 2010 (when the deal was made) marked the largest single launch deal ever signed, worth an estimated $492 million.
Weighing around 1,760 pounds (800 kg) each, the satellites are based upon the Extended LifeTime Bus (ELiTeBus)-1000 spacecraft design, previously employed for low-orbiting GlobalStar communications satellites. They are powered by twin solar arrays and capable of supporting a decade-long lifespan. The solar arrays—spanning 31 feet (9.4 meters) when fully unfurled and capable of generating 2 kilowatts of electricity—would offer a 50-percent uplift over the power-producing potential of the first-generation Iridiums.
“Iridium NEXT manufacturing has completed enough satellites for nearly the next three SpaceX launches,” says Iridium.
The would leave about 25 satellites to go, and Iridium says SpaceX’s targeted launch schedule currently accommodates completion of the Iridium NEXT constellation as planned in mid-2018.
An offshore landing attempt of the Falcon 9 first stage booster is expected after launching both missions.