There's a lot riding on the debut flight of SpaceX's Starship V3 megarocket — not the least of which are NASA's Artemis moon landing ambitions.

Elon Musk's SpaceX has postponed a launch of its massive Starship rocket and said it plans to make another attempt at the highly-anticipated test flight on Friday.

“For those who think this is simply another repeat test flight, the engineering changes under the rocket ‘hood’ are substantial,” Joseph Gonzalez, an associate professor of practice in aerospace engin...