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Official site of the design, build, test and launch of JWST.


JWST Science overview, future home of science data and images.


Overview of the spacecraft, mission and science of JWST.

JWST related content on the NASA HOME PAGE plus links to NASA’s other great activities and missions.


JWST related Missions.


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Vital Facts
  • FAQs:

  • Vital Facts

    Fact sheet on the JWST Mission.

  • FAQ Lite

    The most popular questions about JWST. (General Public)

  • FAQ Full

    All the major aspects of the JWST Mission are covered here. (General Public)

  • Technical FAQ

    Technical FAQ on a variety of mission issues, aspects and capabilities. (Science/Technical)

  • Solar System Observations FAQ

    Technical FAQ specifically on Solar System observations. (Science/Technical)

  • Q&A:

  • John Mather: "Ask Me Anything"

    Dr. John Mather (Nobel Laureate and James Webb Space Telescope project scientist) answering questions on Reddit. (General Public)

  • John Mather: JWST Q&A 1

    Dr. John Mather (Nobel Laureate and James Webb Space Telescope project scientist) captured on Twitter during our first Tweet Chat. (General Public)

  • John Mather: JWST Q&A 2

    Dr. John Mather (Nobel Laureate and James Webb Space Telescope project scientist) captured on Twitter during our second Tweet Chat. (General Public)

  • Mark Clampin: Exoplanets

    Dr. Mark Clampin (James Webb Space Telescope observatory project scientist) answers questions about JWST and exoplanets.

  • SXSW: Finding Life on Other Planets

    During SXSW 2014, we held a tweet-chat with some of the scientists on the"First Signs: Finding Life on Other Planets" panel.

  • Women of JWST Q&A

    Women with diverse jobs on the James Webb Space Telescope answered questions about the female experience working on a NASA flagship mission in the TwoXChromosomes subreddit.

  • Focus on XSTEM

    During the USA Science & Engineering Festival in April 2014 and focused on STEM (Science, Technology, Engineering, Math) topics.

  • Sara Seeger: Search for Life Part 1 | Part 2

    MIT's Dr. Sara Seager answered questions about exoplanets, the search for life, and the next technologies (like JWST!)

The James Webb Space Telescope (sometimes called JWST) is an orbiting infrared observatory that will complement and extend the discoveries of the Hubble Space Telescope, with longer wavelength coverage and greatly improved sensitivity. The longer wavelengths enable the Webb telescope to look much closer to the beginning of time and to hunt for the unobserved formation of the first galaxies, as well as to look inside dust clouds where stars and planetary systems are forming today.

Proposed Launch Date: The project is working to a 2018 launch date.
Launch Vehicle: Ariane 5 ECA
Mission Duration 5 - 10 years
Total payload mass: Approx 6200 kg, including observatory, on-orbit consumables and launch vehicle adaptor.
Diameter of primary Mirror: ~6.5 m (21.3 ft)
Clear aperture of primary Mirror: 25 m2
Primary mirror material: beryllium
Mass of primary mirror: 705 kg
Mass of a single primary mirror segment: 20.1 kg for a single beryllium mirror, 39.48 kg for one entire primary mirror segment assembly (PMSA).
Focal length: 131.4 meters
Number of primary mirror segments: 18
Optical resolution: ~0.1 arc-seconds
Wavelength coverage: 0.6 - 28 microns
Size of sun shield: 21.197 m x 14.162 m (69.5 ft x 46.5 ft)
Orbit: 1.5 million km from Earth at L2 Point
Operating Temperature: under 50 K (-370 °F)
Gold coating: Thickness of gold coating = 100 x 10-9 meters (1000 angstroms). Surface area = 25 m2. Using these numbers plus the density of gold at room temperature (19.3 x 10-6 g/m3), the coating is calculated to use 48.25g of gold, about equal to a golf ball. (A golf ball has a mass of 45.9 grams.)

Mission Goals

  • Search for the first galaxies or luminous objects formed after the Big Bang.
  • Determine how galaxies evolved from their formation until now
  • Observe the formation of stars from the first stages to the formation of planetary systems
  • Measure the physical and chemical properties of planetary systems and investigate the potential for life in those systems


  • Near Infrared Camera (NIRCam)
  • Near Infrared Spectrograph (NIRSpec)
  • Mid Infrared Instrument (MIRI)
  • Fine Guidance Sensors (FGS)

Major Innovations

  • Lightweight optics
  • Deployable sunshield
  • Folding segmented mirror
  • Improved Detectors
  • Cryogenic actuators & mirror control
  • Micro-shutters