From your article, they haven't even put fuel in the SLS core stage to see if it leaks. Their promised timeline is based on the expectation that there will be

From your article, they haven't even put fuel in the SLS core stage to see if it leaks. Their promised timeline is based on the expectation that there will be no major snags on the way to actually sending it into orbit. I'm not aware that any orbital rocket program has ever been that lucky. I'm therefore dubious that everything will go according to their plan. By comparison, a full-sized prototype of Starship managed to launch and land again a few weeks ago. (Though on one engine, and not on all 6 for the final model.) As of June, they still considered it possible that they would get to orbit this year. (See https://www.teslarati.com/spacex-starship-orbital-launch-debut-2020/ https://www.teslarati.com/spacex-starship-orbital-launch-deb... for confirmation.) I consider that unduly optimistic, but certainly would take an even money bet that they get into orbit in under a year.