The scheduled launch of the Artemis II mission on February 8 has been postponed by at least a month due to a hydrogen leak detected by NASA during the tank fueling process. Similarly, the initial Artemis mission faced delays attributed to fuel leaks.
The unique properties of liquid hydrogen and liquid oxygen, the components of rocket fuel, make them prone to leakage despite being extremely cold substances. Liquid oxygen’s boiling point is -183 C, while liquid hydrogen is even colder at -253 C, just above absolute zero. The rocket fuel’s frigid temperatures can instantly freeze anything they contact, requiring specialized equipment to handle without freezing or cracking.
To maintain these cryogenic liquids in liquid form, insulation is crucial to counteract the ambient Florida air temperature during launch. The Space Launch System (SLS) rocket’s core stage is coated with insulating foam to protect the cold fuel from the warmth, necessitating pre-chilling of fuel lines and tanks. However, despite these precautions, the cryogenic fuel generates pressure due to ultra-cold temperatures and vaporization, leading to leaks.
The leaks are attributed to hydrogen’s ability to escape through tiny openings, with every pipeline, joint, and valve posing a potential leakage point. The fuels are transferred from nearby tanks to the rocket through a complex system of hoses and connectors, prone to leaks as seen during the recent wet dress rehearsal.
Efforts are underway to address the leaks at the launch pad to avoid extensive delays, with another rehearsal planned before the rescheduled launch no earlier than March 6. While hydrogen leaks have historically been a challenge for NASA, private companies like SpaceX have shifted to kerosene and methane fuels for easier handling.
Despite criticisms of the costly and disposable nature of the SLS rocket system, NASA continues to use liquid hydrogen and oxygen due to their high thrust-to-weight ratio and job creation across various states. The future of the SLS rocket hinges on resolving the hydrogen leak issues while balancing the cost considerations and job retention aspects.
