
At NASA’s Kennedy Space Center, early on Monday morning, the Artemis 1 team got the “go” to begin tanking the rocket. First, they chilled down the umbilicals to cool the fuel, made of liquid oxygen and liquid hydrogen. Next, they pumped hundreds of thousands of gallons of it into Artemis 1. The simulated countdown began. Whatever happened next would be crucial in deciding whether the rocket was ready for the moon.