Table of Contents

Satellites

James Webb Space Telescope, Successor to Hubble

How the telescope works

Shielded from the Sun and Earth by a large deployable sun shade, the entire telescope assembly will be passively cooled to about 35 degrees Kelvin (35 degrees above absolute zero, or -223 degrees Celsius). This gives JWST exceptional performance in the near-infrared and mid-infrared wavebands. The wavelength range for the instrumentation is 0.6 to 27 microns, and the telescope will be diffraction-limited above two microns.

The sensitivity of the telescope will be limited only by the natural zodiacal background, and should exceed that of ground-based and other space-based observatories by factors of 10 to 100,000, depending on the wavelength and type of observation. The JWST observatory will have a 5- to 10-year lifetime and will not be serviceable by astronauts (as is Hubble), since it will be too far away.

Designed to block solar light, the sunshield will enable the Webb Telescope's infrared sensors to see distant galaxies, stars, and planetary systems. (Source: NASA)