During Artemis II, four astronauts will see the lunar surface as few humans have—and possibly, parts of the Moon’s far side that no one has seen before. Learn what lunar science questions NASA hopes to answer through the astronauts’ eyes with lunar geologist Kelsey Young. And those astronauts will also be subjects of science. Jancy McPhee, associate chief scientist of NASA’s Human Research Program, explains how studying human health on Artemis II will prepare us for exploration deeper into space than ever before.