SpaceX has sent 10 more satellites into orbit for the Iridium NEXT constellation, passing the halfway point in its 75-satellite launch contract.

The satellites went into space aboard a two-stage Falcon 9 rocket launched at 5:27 p.m. PT today from Vandenberg Air Force Base in California, and were deployed sequentially into pole-to-pole orbits.

The first-stage booster was initially used for an Iridium mission in June, and then was recovered and refurbished for today’s launch. The contrail that was created during the booster’s descent provided a spectacle that was visible in sunset skies throughout Southern California:

What a show @SpaceX what a show! #spacex pic.twitter.com/ca8zgN7I3Z
— Danny Sullivan (@dannysullivan) December 23, 2017
Falcon 9 launch from Studio City in video form. Watch when the contrail hits sunset in the upper atmosphere and lights up. #AvGeek #SpaceGeek pic.twitter.com/zNEnKsnI1T
— David Biggar (@DavidNBCLA) December 23, 2017
This time, SpaceX decided against trying to have the booster fly itself to an oceangoing platform for yet another round of reuse. Instead, it made a controlled splashdown into the Pacific Ocean.

Iridium NEXT is an ambitious, multibillion-dollar project to replace the satellite company’s existing constellation with a fleet of next-generation spacecraft in low Earth orbit, marking what’s arguably the biggest “tech upgrade” in space.

Eighty-one satellites are being manufactured and tested in partnership with Thales Alenia Space, and SpaceX is launching 75 of them in batches of as many as 10 satellites at a time. The first three launches were completely successful, and those 30 satellites are undergoing system checks.
The new constellation will open the way for new services from Iridium, including a next-generation Certus satellite communications platform for the Internet of Things as well as other aviation, maritime, terrestrial and governmental applications.

Another service is the Aireon system for aircraft tracking and surveillance. This system will provide air traffic control centers and aircraft operators with real-time, global visibility of aircraft that are equipped with ADS-B equipment.

Just a minute before SpaceX’s launch, on the other side of the Pacific, a Japanese H-2A rocket sent two research satellites into orbit. The spacecraft, known as Shikisai and Tsubame, will study Earth’s carbon cycle and test a thruster technology aimed at keeping satellites stable in super-low-altitude orbits.

Source:AFP