What was that in the skies above L.A. on Friday night that stopped traffic and sparked both alarm and curiosity?

It was a rocket.

SpaceX’s Falcon 9 rocket, launched from Vandenberg Air Force Base at 5:27 p.m., was carrying 10 satellites to low-Earth orbit. The satellites will be part of a constellation operated by Iridium Communications. All 10 satellites successfully deployed, with the last one deploying about 1 hour and 12 minutes after liftoff.

The rocket’s first stage was previously used during a mission in June.


Officials had warned the launch could be seen across Southern California and beyond. But on the day before the holiday weekend, the streaks of light against the blue sky were something to behold.

Many people pulled over their cars to take photos and videos of the sight.

The Los Angeles Fire Department put out an advisory saying the “mysterious lights in the sky” was from the Vandenberg launch.

Here's my video of tonight's @SpaceX launch as it shot over SoCal, compressed to 20 seconds. Such a great sight to see. #SpaceX pic.twitter.com/VHbNeMDT8N — Danny Sullivan (@dannysullivan) December 23, 2017


(Joe Mozingo / Los Angeles Times)

First-stage separation is seen at left, with the moon below, as SpaceX launches its Falcon 9 rocket, its final mission of the year, from Vandenburg Air Force Base in California. (Al Seib/ Los Angeles Times)

How cool. My friend Nick captured the #SpaceX #Falcon9 rocket 🚀 flying into space tonight!!! pic.twitter.com/CGcwzATd1P — Kacey Montoya (@kaceymontoya) December 23, 2017


This is SpaceX’s 18th launch of the year.

Here’s how it looked on social media:

Up in the sky over L.A. pic.twitter.com/5HzcEzHySF — Hector Becerra (@hbecerraLATimes) December 23, 2017

What the hell is this? pic.twitter.com/8tGK4GQ5ks — Joe Mozingo (@joemozingo) December 23, 2017


I think this is my favorite shot of the @SpaceX launch. What a year. Saw the eclipse & now this, fantastic! #SpaceX pic.twitter.com/FQOFFrP57k — Danny Sullivan (@dannysullivan) December 23, 2017

gary.robbins@utsandiego.com

Twitter: @grobbins


joe.mozingo@latimes.com

Twitter: @joemozingo

samantha.masunaga@latimes.com

Twitter: @smasunaga


UPDATES:

6:40 p.m.: This article was updated with more details about the launch.

6 p.m.: This article was updated with more details and reaction.

This article was originally posted at 5:30 p.m.