Are you as prepared for hydrogen leaks as NASA was?
Liquid hydrogen fuel storage prepared for Artemis II mission.
Artemis II Is a Great Example of Why Hydrogen Safety Engineering Matters
As NASA prepares to launch four astronauts around the Moon on Artemis II, the world is watching. During launch, more than 700,000 gallons of liquid hydrogen and liquid oxygen must be delivered from the SLS core stage tanks to the four RS-25 engines. This must be done at a consistent temperature and pressure. Managing those conditions from loading through lift-off is an extraordinary feat of safety engineering. It is precisely why the Artemis team takes even minor leak events seriously enough to delay a mission.
During a wet dress rehearsal in early February 2026, NASA’s Artemis II mission was delayed after a liquid hydrogen leak occurred during a simulated countdown. It wasn’t a catastrophic failure and no one was hurt. NASA engineers caught the hydrogen leaks because they were ready for them. They were aware of the potential for leakage and were prepared with processes in place to prevent and address leaks.
How is Hydrogen Unique, and What Can Be Done to Manage Hydrogen Safely?
Hydrogen is the smallest and lightest molecule in existence. Very small hydrogen releases do not pose safety hazards as long as the hydrogen does not accumulate enough to pose a flammable hazard – this is where process safety engineering comes into play to manage leaks and releases and reduce risks to people and property. Below is a table comparing some of hydrogen’s unique properties with common safety mitigation measures, and examples of process safety management to reduce risk on an ongoing basis:
| Hydrogen Property | Hazard | Common Mitigation Technique | Example of Process Safety Management |
|---|---|---|---|
| Small Molecule Size | Tendency to permeate through materials that are airtight to other gases, as well as cause embrittlement (metal fatigue, cracking, and loss of ductility) | Use of hydrogen-compatible materials and regular maintenance processes. | Process safety review of materials; mechanical integrity review of design, fabrication, maintenance, and inspection; and management of change processes to verify materials compatibility checks. |
| Wide Flammability Range in Air | 4% – 75% by volume | Use of leak detection and prevention processes and systems to reduce occurrence of leaks. | Development of calibration processes, equipment use, and maintenance for detection systems. |
| High Buoyancy | Hydrogen gas rises quickly and may accumulate under ceilings and overhangs, forming an invisible, highly flammable mixture that may ignite with low energy | Design considerations to allow ventilation and reduce confined areas. | Hazard identification and risk analysis, compliance with codes and standards. |
| Invisible Flame & Low Radiant Heat | Hard to detect in daylight | Use of flame detection systems. | Responding to alarms according to standard operating procedures (SOP). |
| Low Ignition Energy | Easy to ignite in air | Use of properly rated electrical equipment. | Quantitative risk assessment (QRA) and consequence modeling to address release dispersion and ignition probabilities. |
In addition to addressing the above hazards inherent to gaseous hydrogen, liquid hydrogen safety must also include safe handling procedures, processes, and equipment associated with the use of a cryogenic fuel. By committing to safety, understanding hazards and risks, managing risk, and learning from experience, hydrogen can be safely managed, whether gaseous or liquid, and at all scales from laboratory to the launchpad.
Liquid hydrogen tank in use for Artemis II Mission at NASA Kennedy Space Center.
The Bottom Line
NASA made headlines across the world when a hydrogen leak postponed a crewed lunar mission. Your facility may never make those headlines, but the consequences of an uncontrolled hydrogen release are no less serious for the people working on your site or living in your community.
The hydrogen economy is scaling rapidly. Hydrogen holds important promise as a source of clean energy, but for hydrogen to be an effective alternative energy source, it must be produced cleanly and used safely. That requires rigorous engineering, systematic hazard analysis, and specialized expertise.
If your organization is expanding hydrogen operations, evaluating hydrogen risk, or building out a hydrogen program, contact AcuTech for a hydrogen safety assessment. We bring the process safety rigor that complex projects need to be ready for hydrogen.