Meanwhile documents turned up that showed design work to fit a nuclear-weapon-sized object into the nose-cone of a Shahab missile—but Iran dismissed them as forgeries.

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.

The aerodynamically smooth nose cone will protect the spacecraft during launch.