In this Let's-Read-and-Find-Out Science entry, Branley (see review, above) takes readers on a space shuttle mission, from blast-off to touchdown, but focusing mainly on life in orbit. As he points out, ``zero gravity'' is a misnomer—but only barely; so negligible is gravitational pull that astronauts temporarily grow an inch or so as their joints relax, are able to stand on the walls and ceiling, have to learn new ways to eat, sleep, and use the toilet, and must be very careful about stowing small objects before re-entry. In Kelley's cheerful watercolors, smiling space travelers—including one woman—bounce around the shuttle's cabin and suit up for extra vehicular tasks while back on Earth, a young girl eagerly tracks the flight on television. While in the claim that heavy equipment—even the 12-ton Hubble telescope—can be lifted in space, Branley oversimplifies the effects of inertia and momentum, his choice of detail about conditions in space will surprise and delight readers. (Picture book/nonfiction. 7-9)