Humankind is looking deeper and deeper into the cosmos and seeing incredible things that were totally unknown just a few years ago. In the past three decades, astronomers have described the nature of gamma ray bursts, proved that the expansion of the universe is accelerating, and helped land rovers on Mars. And yet, while our telescopes can see Earthlike planets more than 20 light-years into the intergalactic abyss, we humans can’t seem to get past the moon, a sterile rock orbiting just 238,000 miles from Houston. What’s taking so long?