SpaceX: "The third flight test aims to build on what we’ve learned from previous flights while attempting a number of ambitious objectives, including the successful ascent burn of both stages, opening and closing Starship’s payload door, a propellant transfer demonstration during the upper stage’s coast phase, the first ever re-light of a Raptor engine while in space, and a controlled reentry of Starship. It will also fly a new trajectory, with Starship targeted to splashdown in the Indian Ocean."
SpaceX livestream of the launch: