Caption: Hampton VA, May 30, 1957. May Follow Satellite--These spheres may be moons of the future if Project Vanguard succeeds in putting man's first satellite into space. The spheres are plastic bags covered with aluminum foil to be inflated by air bottle after reaching orbit. Smaller of the two being bounced by technician at laboratory at Langley Field here, is light enough to react quickly to air friction, permitting scientists to figure atmospheric density. Other is a "corner reflector" to reflect radar signals and has a 12-foot diameter. Both were developed by National Advisory Committee for Aeronautics.
The front and back of this photograph are pictured below:
