What to know about 1st test flight of SpaceX's big Starship

Elon Musk’s SpaceX is about to take its most daring leap yet with a round-the-world test flight of its mammoth Starship.

Monday's launch attempt was called off because of a stuck valve in the first-stage booster and there could be another try this week from South Texas. Musk's company got the OK from the Federal Aviation Administration on Friday.

It will be the first launch with Starship's two sections together. No one will be on on board. Early versions of the sci-fi-looking upper stage rocketed several miles into the stratosphere a few years back, crashing four times before finally landing upright in 2021. The towering first-stage rocket booster, dubbed Super Heavy, will soar for the first time.