But a simple capsule is gaining favor, according to Coats, because it's stable and forgiving when things run amok. In May, when U.S. astronauts rode a Soyuz down from the station, the capsule's guidance system broke down. The Soyuz tumbled, putting the crew through loads equal to eight times the force of gravity, and landed about 300 miles off target, but what impressed NASA was that the crew survived a major failure. Another issue is the life span of the vehicle. A winged vehicle is too complex to be thrown away, but some at NASA like the idea of a one-shot or short-lived vehicle, says Coats, because it's possible to incorporate improvements on the production line, rather than periodically grounding a mini-shuttle OSP for upgrades.