Here is video of the “spin prime” test of Super Heavy booster #9 conducted on 2023-08-04. In a spin prime test, propellant flows through the engines as it would in a static firing or launch, but is not ignited. The mist that appears to originate around the launch mount prior to the test is the fire suppression water spray that was installed after the Booster 7 spin prime test explosion on 2022-07-12. The large white clouds from the engines are the propellant from the actual spin prime test.
