SpaceX fully stacked Starship for the first time9. 8. 2021
Starship SN20 and SuperHeavy Booster 4 were mated together for the first time marking the fully integrated Starship stack milestone. Two vehicles were mated together just for a short while because this was a fit check. Both the Ship and the Booster still need to complete cryogenic proof test, static fires and will require some additional work mostly on the heat shielding. AlthoughSuperHeavy Boosters wont reach orbit, without a re-entry burn it still needs thermal protection for the engines and the bottom side of the vehicle.
As Elon mentioned, building the ground facilities (stage zero) is as hard as building the Starship rockets, so this is a very important milestone for SpaceX team in Stabase that is now successfully reached.
During this test all 29 Raptor engines on the Booster and 6 (3 sea level and 3 vacuum optimized) on the Ship were installed. Starship SN20 was later moved back to the High Bay for additional work and to remove all the engines allowing it to complete further tests in the future.