NASA is once again struggling with a hydrogen leak as it works to fuel its massive Space Launch System rocket. Early this morning, the NASA launch director called a “go” for propellant loading, and NASA engineers were able to successfully start running liquid oxygen from storage tanks on the ground into the rocket’s fuel tanks.
They also started loading the liquid hydrogen, but at about 7:15 a.m. Eastern, engineers noticed there was a leak. They paused fueling the liquid hydrogen, which is kept at minus 423 degrees Fahrenheit, and attempted to warm the lines, a fix that they hoped would strengthen the seal. But when they started to reflow the hydrogen, they noticed another leak. This time, they used helium to pressurize the line, but this did not work either.
