SpaceX succeeded in its sixth launch of 2018, putting the fifth batch of Iridium NEXT satellites into orbit using a previously-flown Falcon 9 rocket.



Launched Friday from the central coast of California, Elon Musk's rocket company has now put up 50 satellites for a next-generation communications system.



Friday's launch was part of a larger contract to deliver 75 satellites to low-earth orbit for Iridium, a satellite communications provider.



When completed, this "constellation" of low-earth-orbit satellites could revolutionize air traffic control, allowing planes to fly shorter and more direct routes.

SpaceX failed, however, to catch the nose cone on top of the rocket, called the fairing, using a high speed boat known as "Mr. Steven."



Musk tweet



It was the second failed attempt by SpaceX to catch the nose cone. After the Feb. 22 launch from Vandenberg, Musk tweeted that the boat missed catching the fairing "by a few hundreds meters," adding that the fairing slowed down enough to land "intact" in the Pacific Ocean.

Photos of Feb. 22 SpaceX Elon Musk's Instagram.



The boat has a net strung up behind it to capture the fairing and Musk said SpaceX "should be able catch it with slightly bigger chutes to slow down" its descent. SpaceX did not respond to a CNBC request for comment regarding whether Friday's launch attempt would see new fairing recovery technologies deployed.

Musk has noted that the fairing returns to Earth "at about eight times the speed of sound."

"It has onboard thrusters and a guidance system to bring it through the atmosphere intact, then releases a parafoil and our ship with basically a giant catcher's mitt welded on tries to catch it," Musk said, sharing a photo of the boat.



SpaceX announced before Friday's launch it would "not attempt to recover" the Falcon 9's first stage, as it did with the Iridium-3 mission the booster previously launched. As SpaceX brings about a new variation of the Falcon 9 booster, known as "Block 5," older models are being discarded through expendable missions. SpaceX is using ocean landings to test more booster recovery options. Reports before Iridium-5 showed a SpaceX boat stationed in the Pacific Ocean, presumably to retrieve data after an ocean landing attempt.

Originally scheduled to launch in December, the Iridium 5 mission had been pushed back multiple times to Thursday. With the launch two days away, Iridium CEO Matt Desch said in a tweet Tuesday the company was "having an issue" with one of the 10 satellites being prepared, pushing the attempt to Saturday.

@IridiumBoss: We are having an issue with 1 of the 10 satellites in prep for #Iridium5. Our supplier and launch team is resetting for NET 3/31, with potential to shift into next week, if not resolved quickly. Launch success is priority #1! Will provide more info as available.

Desch quickly followed up Tuesday evening, saying in a tweet "there has been a technical resolution" to the problem and the launch was now be set for Friday. He clarified in following tweets that it was not an issue with the Falcon 9 rocket or the Iridium satellites but rather "an obscure problem with communication harnesses used for testing on the ground."

"Kudos to combined teams for working round the clock to resolve," Desch said.