James Webb Space Telescope Artist Conception

Extended Description

Artist’s concept of the James Webb Space Telescope seen primarily from its top left (or port) side, angled roughly from top to bottom. This view primarily shows the top layer of the telescope’s multi-layered sunshield, which appears gray and is roughly shaped like an oblong hexagon. Below the top layer are the edges of three additional thin gray layers and the bottommost pink layer of the sunshield. They are in the same oblong hexagon shape as the top layer.

At the very back, or stern, edge of the telescope toward the top is a small gray square, but only a sliver appears in this view. This is the aft momentum flap, which helps steady the telescope against solar radiation pressure.

At the center, all of the telescope’s primary mirror is visible. Its height is about half the width of its pink and gray sunshield. 

The primary mirror is made up of 18 hexagonal segments that are coated in gold. Each are 1.32 meters (4.3 feet) in diameter, which, when properly phased together, act as a single mirror that is 6.6 meters (21.7 feet) in diameter. 

At the very center of the primary mirror is a gray hexagonal shape that is approximately the same size as each gold-plated mirror segment. A dark gray cone extends outward from this area. It is known as the aft optical subsystem, which contains the telescope’s tertiary mirror and fine steering mirror. It is only slightly longer than the diameter of each mirror segment. 

The 18 segments that make up the telescope’s primary mirror are outlined in medium gray. This gray area is known as the primary mirror backplane. 

In front of the primary mirror are three thin, medium gray poles, known as mirror support struts. They extend to the front, or bow, of the telescope, but do not go beyond its sunshield. They end in a point. At the end of the three struts, the gray back of the telescope’s secondary mirror is visible.

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Artist's concept of the James Webb Space Telescope, seen angled from top to bottom. This view shows part of the top of the telescope's multi-layered sunshield, its primary mirror, mirror support struts, and much more.