The launch in the setting sun created a shining, billowing streak that was widely seen throughout Southern California and as far away as Phoenix.
The object is reported to be the Falcon 9 rocket, which launched out of Vandenberg Air Force Base.
Calls came in to TV stations as far afield as San Diego, more than 200 miles south of the launch site.
Many people pulled their cars over to take photos and videos of the sight. The normal nighttime sky was overcome with bright lights and sounds many people quickly associated with UFOs.
Los Angeles Fire Department had to issue an alert explaining the "mysterious light in the sky" was the rocket launch. "It was very cool". All 10 satellites successfully deployed, with the last one deploying about one hour and 12 minutes after liftoff.
This is the fourth Iridium mission consisting of 10 satellites on a SpaceX Falcon 9 rocket. SpaceX has made four launches and expects to make several more to complete the job by mid-2018.
The residents of Los Angeles were in for a spectacle on 22 February after SpaceX launched it's Falcon 9 rocket from the Vandenberg Air Force Base at 5.27 pm (local time) for delivering 10 satellites to lower earth orbit.
The Falcon 9 SpaceX rocket as seen over Menifee.
The Falcon 9 rocket carrying the satellites launched at about 5:30 p.m. from Vandenberg. It carried the latest batch of satellites for Iridium Communications. The array will also include the Aireon aircraft tracking and surveillance system.