NASA and its partners have made huge strides since the Apollo program, as demonstrated by the success of the International Space Station. Humans have continuously lived and worked aboard the ISS for two decades. The ISS, however, is just 250 miles above Earth. The moon, by contrast, is 250,000 miles away, while Mars is 140 million miles away. If humans want to establish a longer-term presence beyond low Earth orbit (where the ISS is located), returning to the moon is the next logical step. "There are many reasons to go back, or as you may have heard me say, go forward to the moon," then-NASA Administrator Jim Bridenstine wrote in 2019. "With Artemis, we're going to explore more of the moon than ever before, and we're planning to stay this time. We are traveling 250,000 miles to the moon to demonstrate new technologies, capabilities and business approaches needed for future exploration of Mars, which can be as far as 250 million miles away from home."