SpaceX Falcon 9 set to fly Iridium-3 mission
VANDENBERG, Calif. — Working to continue its breakneck launch pace, SpaceX is set to launch two Falcon 9 rockets in two days. First up is the Iridium-3 mission, which will launch on Oct. 9, 2017, from the company’s West Coast launch pad at Vandenberg Air Force Base in California.
Liftoff of the 230-foot (70-meter) tall rocket is set for 5:37 a.m. PDT (8:37 a.m. EDT / 12:37 GMT) on Monday from Space Launch Complex 4E. This will be the fourth launch from this pad in 2017 with as many as two more planned before the year’s end.
The flight was originally scheduled for Oct. 4, but in a Sept. 26 tweet, the SpaceX postponed the launch by five days. According to Iridium Communications CEO Matt Desch, SpaceX was running late on processing the Falcon 9’s second stage at Vandenberg and needed more time.
“Patience [is] everything in spaceflight, but success [is] better than fast!” said Desch on Twitter. “Our sats are ready and looking [forward] to their (very) early morning flight!”
Replacing the world’s largest satellite constellation
As its name suggests, the Iridium-3 mission will see the third set of 10 Iridium NEXT satellites sent into space for Iridium Communications, which is in the process of replacing its entire constellation of more than 70 satellites. This second-generation network will be launched on eight Falcon 9 flights. The first two occurred in January and June 2017.
In total, 75 Iridium NEXT satellites are expected to be in orbit by the middle part of 2018. They are designed to provide better and faster call quality and data transfer speeds to the company’s customer base.
Built by Thales Alenia Space, each Iridium NEXT satellite is about 1,900 pounds (860 kilograms). They sport two deployable solar arrays that produce 2 kilowatts of power. The spacecraft support L-band as well as Ka-band antennas and have a planned on-orbit lifetime of about 15 years.
With 20 satellites already on orbit, many of which have already completed testing and validation, the company is well underway with switching out legacy spacecraft with the new ones.
A “slot swap” of this scale has never been done before. It involves rendezvousing the satellites at their operational orbit of about 480 miles (780 kilometers) and having the next-generation vehicle take over control of data and communications from legacy spacecraft without impacting customers.
Once all 66 primary satellites and on-orbit spares are switched out with the new vehicles, the company will begin the process of placing legacy spacecraft in higher or lower orbits in preparation for eventual de-orbiting.
In the lead-up to launch, SpaceX completed a static fire test on the Falcon 9 on Oct. 5, 2017. Just the day before, Iridium announced that the 10 satellites were mated and stacked in preparation for encapsulation inside the rocket’s payload fairing.
Should everything launch on time, less than 60 hours later on the other side of the continent SpaceX will send a second Falcon 9 rocket into space, this time with the SES-11 satellite. This Oct. 11 flight out of Kennedy Space Center in Florida will involve the third flight-proven booster to be re-flown. Additionally, it will be the first repeat customer to utilize a previously flown rocket, Luxembourg-based SES. The company’s SES-10 satellite flew atop the first re-flown rocket back in March.
The Iridium-3 mission will be SpaceX’s 14th Falcon 9 flight of 2017. Including the SES-11 mission, the company hopes to launch as many as six more for a total of 20. For comparison, only 22 rockets were orbited from the United States in 2016, tying China for the most orbital launch attempts that year.
Derek Richardson has a degree in mass media, with an emphasis in contemporary journalism, from Washburn University in Topeka, Kansas. While at Washburn, he was the managing editor of the student run newspaper, the Washburn Review. He also has a website about human spaceflight called Orbital Velocity. You can find him on twitter @TheSpaceWriter.