Nasa will not attempt to launch its space launch system in the coming days, the agency announced today. The announcement comes after two launch attempts of the massive rocket, and will likely result in a delay of several weeks.

The launch attempt was supposed to be the debut launch of the space launch system. Engineers noticed an issue with the temperature of one of the rocket’s four engines. Today, a second attempt was foiled by a persistent hydrogen leak.

The rocket was set to launch an uncrewed capsule called Orion on a mission called Artemis I. The mission is designed to serve as a test flight, paving the way for future missions which will carry astronauts to the moon.

Nasa has n’t announced when its next launch attempt of Artemis I will be. Engineers are focused on part of the fueling system that helps send liquid hydrogen fuel into the rocket.

Nasa could replace and test the parts inside the vehicle assembly building (vab). If they went back into the pad, the building itself would act as an environmental enclosure. But NASA can only do it at ambient temperature – not cryogenic.

If the SLS rolls back into the vab, the next attempt would likely happen in mid to late October. The process of rolling the megarocket back to the vab takes several hours.

Nasa had 20 days in which to launch the rocket before it would have to be rolled back to test the batteries in the rocket’s flight termination system. Nasa got approval to extend that to 25 days, but that time is almost up.