AstroMast

retract or extend

polygon

3

4

5

number of levels

15

bar

sphere

Bars are connected along the vertices of parallel polygons made of lines. When the polygons are rotated, the bars tilt and form helices, which extend or retract. This is the basic geometry of the

®

AstroMast

device, produced by Astro Aerospace, a business unit of Northrop Grumman Space Technology. It is used to deploy antennas in space.