The SLS launch was canceled due to engine problems

NASA has canceled the launch of the super-heavy SLS rocket scheduled for August 29. This was due to problems with one of the carrier’s first stage engines. The next SLS launch attempt will take place no earlier than September 2.
The SLS rocket on the launch pad. Source: NASA-J. Kowlsky

At first, preparation for the SLS launch took place routinely. NASA engineers began fueling the rocket with fuel components. At some point, a hydrogen leak was detected, but the specialists managed to cope with this problem and the fueling of the rocket was continued.

However, another problem soon arose. Before starting, the RS-25 engines installed in the first stage are fed with some fuel. This is necessary in order to bring them to the desired temperature. However, the hydrogen venting system on one of the SLS power units failed and the engine was not cooled. An attempt to eliminate the malfunction was not successful. Because of this, the flight director had to cancel the launch.

All fuel will now be drained from the SLS, after which specialists will inspect the problematic power unit. Depending on the severity of the situation, it will either be repaired on site or the rocket will be returned to the Vertical Assembly Building for repair. The closest launch windows for the SLS launch will be open on September 2nd and 5th. If the rocket fails to launch on those dates, the next launch windows for a flight to the Moon will be open between September 20 and October 4 and October 17 and October 31.

You can learn more about SLS, as well as the main goals and objectives of the Artemis I mission from our articles.