NASA attempted to launch the Artemis I mission for a second time over the weekend but was unable to do so due to a propellant leak of super-cold liquid hydrogen (LH2).

The "quick disconnect," which connects the SLS core stage with a propellant line coming from the massive rocket's mobile launch tower, is where the leak happened. The Artemis 1 crew has opted to repair the seal on the problematic quick disconnect after considering the problem for a few days, agency representatives revealed in an update on Tuesday night (Sept. 6).

An unmanned Orion spacecraft will be sent into lunar orbit and returned using NASA's new Space Launch System (SLS) megarocket.

"Performing the work at the pad requires technicians to set up an enclosure around the work area to protect the hardware from the weather and other environmental conditions but enables engineers to test the repair under cryogenic, or supercold, conditions," NASA officials wrote in the Tuesday update.

This operation will be carried out at Kennedy Space Center's (KSC) Pad 39B in Florida, where the Artemis 1 stack has been stationed for the past three weeks.

"Teams may return the rocket to the Vehicle Assembly Building (VAB) to perform additional work that does not require use of the cryogenic facilities available only at the pad," they added.

And whether or not the team intends to undertake more repairs at the VAB, a rollback may be required. For only a 25-day period, the US Space Force has validated Artemis 1's flight termination system (FTS), which would destroy the rocket if it veered off track during liftoff.

That deadline will have passed by the time the next Artemis 1 launch window begins on Sept. 19.

Recertification necessitates testing the FTS, which can only take place at the VAB. NASA officials have stated that they may seek another waiver to extend the certification period, allowing Artemis 1 to remain on the pad for longer, although it is uncertain whether they would do so.

One such extension, from 20 to 25, was granted to Artemis 1 already.

For Artemis 1, Saturday's scrub was the second. One of the four engines on the SLS core stage wasn't cooling down to the required prelaunch temperature, which led to the first failure, which happened on Aug. 29.

The Artemis 1 crew chose to move on with a Saturday attempt after immediately deducing that the reading was brought on by a malfunctioning temperature sensor.