The Space Launch System that will carry Artemis II astronauts around the Moon and back has now taken on its most precious cargo yet: hundreds of thousands of gallons of supercold propellant. With the rocket fully fueled in a high stakes rehearsal at Kennedy Space Center,

As NASA completes final preparations for the Artemis II mission, including a critical 'wet dress rehearsal,' former astronaut Leroy Chiao spoke with NBC News' Brian Cheung about the anticipated missio...