On Monday, Feb. 12, two astronauts stepped outside the International Space Station (ISS), 220 miles (322 kilometers) above Earth, to continue assembly of the fledgling orbital habitat. At nearly the same moment, nearly 200 million miles (322 million kilometers) away, a small robotic probe called NEAR Shoemaker made a breathtaking, historic landing on the surface of an asteroid. The dueling space events added fresh zip to the oldest question in spaceflight: As we expand our cosmic horizons, do we send humans or robots?