Live coverage of the countdown and launch of a Virgin Orbit LauncherOne rocket. The air-launched rocket will climb into orbit with seven small satellite payloads after release from a Boeing 747 carrier aircraft southwest of Los Angeles. Text updates will appear automatically below. Follow us on Twitter.
EDITOR’S NOTE: Virgin’s live webcast begins at 9:45 p.m. PDT (12:45 a.m. EDT; 0445 GMT).