NASA’s Artemis II mission, originally scheduled for launch on Feb. 8, has been postponed by at least a month due to the discovery of a hydrogen leak during tank fueling. The mission’s predecessor, Artemis I, also encountered delays related to fuel leaks.
Liquid hydrogen and liquid oxygen, the primary components of rocket fuel, are notable for their ability to remain in liquid form at extremely low temperatures. These cryogenic liquids, with boiling points of -253 C for hydrogen and -183 C for oxygen, necessitate special handling to prevent freezing and leakage due to the significant temperature differential with the environment in Florida, where launches occur.
To safeguard the frigid fuels, the Space Launch System (SLS) rocket’s core stage is coated in insulating foam, and the fuel lines and tanks are pre-chilled before fueling. Despite these precautions, the cryogenic fuel’s vapor pressure can lead to leaks, particularly with hydrogen, the smallest molecule that can permeate tiny openings.
The recent delay in the Artemis II launch was caused by a leak at the connector between the launch tower hose and the rocket, a recurring issue that has required repairs and rollbacks to the Vehicle Assembly Building in the past. Engineers are working to address the leak at the launch pad to expedite the launch, now scheduled for no earlier than March 6.
NASA’s reliance on liquid hydrogen, despite its leak challenges, stems from its high thrust-to-weight ratio, ideal for heavy lift vehicles like the SLS rocket. However, critics argue that the SLS is costly and disposable, unlike reusable rockets employed by private companies like SpaceX, which opt for kerosene or methane fuels.
The future of the SLS rocket hinges on resolving hydrogen leak issues while addressing cost concerns to sustain the jobs tied to its production.