Inside the Cleanroom of NASA’s James Webb Space Telescope


Technicians Ensure James Webb Space Telescope Sunshield Survives Stresses Experienced During Liftoff

The sound associated with a rocket launch creates extreme vibrations that can adversely affect any satellite or observatory, so engineers put spacecraft through simulations to ensure they will remain operational. In this photo, technicians delicately inspect stowed sunshield membranes of NASA’s James Webb Space Telescope on the forward side of the spacecraft. Acoustic testing exposes the spacecraft to similar forces and stress experienced during liftoff, allowing engineers to better prepare it for the rigors of spaceflight.

The sunshield separates the observatory into a hot, sun-facing side (reaching temperatures close to 230 degrees Fahrenheit), and a cold side (approximately minus 400 degrees Fahrenheit) where the sunlight is blocked from interfering with the sensitive space telescope instruments.

The James Webb Space Telescope will be the world’s premier space science observatory. Webb will solve mysteries of our solar system, look beyond to distant worlds around other stars, and probe the mysterious structures and origins of our universe and our place in it. Webb is an international project led by NASA with its partners, the European Space Agency (ESA) and the Canadian Space Agency (CSA).

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​Image credit: Northrop Grumman

By Thaddeus Cesari
​NASA’s Goddard Space Flight Center

More About the James Webb Space Telescope

Space Telescope

The James Webb Space Telescope will observe primarily the infrared light from faint and very distant objects. In order to be able to detect those faint heat signals, the telescope itself must be kept extremely cold. To protect the telescope from external sources of light and heat (like the Sun, Earth, and Moon) as well as from heat emitted by the observatory itself, Webb has a 5-layer, tennis court-sized sunshield that acts like a parasol providing shade. [Actual dimensions: 21.197 m x 14.162 m (69.5 ft x 46.5 ft)]

This sunshield will always be between the Sun/Earth/Moon and the telescope. It’s able to be positioned this way because JWST will be orbiting the Sun 1.5 million kilometers away from (but approximately in line with) the Earth.

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