Mission Overview

The James Webb Space Telescope will be the next great space science observatory, designed to answer outstanding questions about the Universe and to make breakthrough discoveries in all fields of astronomy. It is a once-in-a-generation mission.

Webb is designed and built to offer scientists the capabilities needed to push the frontiers of knowledge of our own Solar System, of the formation of stars and planets including planets outside our Solar System (exoplanets), and of how galaxies are created and evolve, in ways never before possible. Webb will observe the Universe at wavelengths longer than visible light, namely in the near-infrared and mid-infrared. Its data will be made available to the scientific community worldwide.

Webb carries a suite of state-of-the-art astronomical instruments capable of addressing a very broad range of outstanding questions in astrophysics. The instrument complement includes powerful cameras, coronagraphs, and spectrographs that will provide scientists with the data they need to analyse the materials that make up stars, nebulae, galaxies and the atmospheres of planets.

The James Webb Space Telescope is named after NASA’s second administrator, James E. Webb, who headed the agency from February 1961 to October 1968 and directed the Apollo programme.

Fact Sheet

Launch date 25 December 2021
Mission duration Nominal duration is 5 years; goal is 10 years
Launch vehicle Ariane 5
Launch mass 6200 kg, including fuel and launch vehicle adaptor
Orbit Sun-Earth L2 halo orbit, approximately 1.5 million km from Earth
Folded dimensions 10.66 m high x 4.47 m wide 6.5 m diameter,
Primary mirror 18 mirror segments of gold-coated beryllium
Sunshield 22 x 12 metres, 5 layers
Wavelength range About 0.6 μm to 28 μm (visible to mid-infrared)
Operating temperature Telescope at -233°C MIRI instrument at -266°C
Operations centre Space Telescope Science Institute in Baltimore, USA

Webb's orbit at L2

Days since launch:

Diagram not to scale
Earth and Moon positions are indicative only for visualization purposes

What's New

Space Sparks video
Webb’s Science Goals: Space Sparks Episode 1

Watch this special Space Sparks episode to learn about the science goals of the NASA/ESA/CSA James Webb Space Telescope.

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ESA/Hubble/JWST Science Newsletter
Passing the Baton

This has been a good week! In spite of the resurgence of COVID and its fast-moving Omicron variant, as we approach the Holiday season we have many reasons to celebrate.

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ESA/Webb News
ESA/Webb Early Release Observations Unveiling Solicitation Call

The NASA/ESA/CSA James Webb Space Telescope (JWST) Early Release Observations (ERO) will be among the first spectacular images and spectra taken following the commissioning of the observatory. This release will represent Webb’s debut to the world by showcasing the observatory’s capabilities and is intended to have immediate and dramatic appeal for a broad audience.

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ESA/Webb, ESA Office, Space Telescope Science Institute, 3700 San Martin Dr, D-21218 Baltimore, United States

Content Credit: ESA/Webb

Telescope Model Credit: NASA, ATG

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