After a recent Monday-evening class, five-year-old Zang Siqi rushes toward her mother, eager to show off a white rocket she has made out of paper, a Snow White sticker in its nose cone.

Bathed in xenon spotlights, the white spaceship, attached to its twin solid rocket boosters and orange external fuel tank, crept 3.4 miles on the back of an enormous tractor called the Crawler.

The gleaming white Ares I-X, at its core, is a giant solid rocket booster.