Let's not wax sentimental about our space exploits thus far. The Apollo era was heroic, but beating the Soviets to the Moon never provided a compelling economic reason to return. (We didn't even get Teflon or Tang as spinoffs--both were invented before 1960.) The shuttle and the international space station continued this record of dismal return on investment. Small wonder, then, that most private-sector investors have focused instead on more earthly pursuits. Only one thing will prod us into the cold, hard vacuum of space, and that's the prospect of earning cold, hard cash.