Northrop Grumman James Webb Space Telescope
Northrop Grumman · Space Telescope / L2 Orbit Observatory / Infrared Astronomy / Deep Universe Observation · USA / International · Digital Age (2010–present)
The James Webb Space Telescope (JWST) is the largest and most powerful space observatory ever launched, a $10 billion international flagship mission built by Northrop Grumman for NASA with contributions from the European Space Agency and Canadian Space Agency. Launched on an Ariane 5 rocket from Kourou on 25 December 2021, Webb reached its operational station at the Sun-Earth Lagrange 2 point — 1.5 million km from Earth — by January 2022, and released its first full-colour science images on 12 July 2022.
Webb weighs 14,300 lb at launch and carries a 6.5-metre (21.3 ft) segmented primary mirror composed of 18 hexagonal beryllium segments coated in gold, each polished to nanometre precision. No rocket fairing could accommodate this mirror fully unfolded; the telescope stowed within the Ariane 5 payload volume and executed a 29-day automated deployment sequence — 344 single-point-failure steps — after launch. The observatory observes from 0.6 to 28 microns, spanning near-IR through mid-IR wavelengths. Infrared observation allows Webb to see through dust clouds that block visible light and to detect the redshifted light of galaxies formed within 300 million years of the Big Bang.
Webb's instruments include the Near-IR Camera (NIRCam), Near-IR Spectrograph (NIRSpec), Mid-IR Instrument (MIRI), and Fine Guidance Sensor/Near-IR Imager and Slitless Spectrograph (FGS/NIRISS). NIRSpec, contributed by ESA, can simultaneously measure spectra from 100 individual objects in a single pointing using programmable micro-shutter arrays — a capability that enabled early confirmation of galaxy candidates beyond redshift z=13, corresponding to a universe age of under 320 million years. MIRI, jointly built by ESA and NASA's Jet Propulsion Laboratory, must be cooled to 6.7 Kelvin (−447°F) by a dedicated cryocooler.
Five sun-shield layers made of aluminised Kapton film, each the thickness of a human hair, passively cool the mirror and instruments to below 50 Kelvin (−370°F) by blocking sunlight. The telescope's on-station orbital cost includes no servicing margin — Webb is too far from Earth for crewed repair unlike Hubble. Propellant remaining after the precision Ariane 5 injection trajectory gave Webb an estimated lifespan of over 20 years rather than the design life of 10, pending optics and instrument longevity. Within its first year of science operations, Webb confirmed exoplanet atmospheric carbon dioxide detection, imaged the deepest long-wavelength field ever recorded, and produced the first direct mid-infrared images of an exoplanet.
For Kids — a shorter, friendlier version
The James Webb Space Telescope is the most powerful space telescope ever built. Scientists use it to see galaxies that formed just after the Big Bang. It launched on Christmas Day 2021. It was named after James Webb, who led NASA in the 1960s.
Webb's mirror is about six and a half metres wide. That makes it larger than any mirror ever sent into space before. It was too big to fit inside a rocket in one piece. So it folded up like origami for launch and then unfolded itself in space.
Webb looks at infrared light rather than normal visible light. This lets it see through dust clouds where new stars are born. It also studies the air around planets orbiting other stars. Webb sits one and a half million kilometres from Earth. A sunshield as wide as a tennis court keeps it cold enough to work.
Webb's first pictures showed thousands of galaxies in a patch of sky smaller than a grain of sand. Scientists expect it to keep making new discoveries for at least twenty years.
Fun Facts
- Webb launched on Christmas Day 2021 on an Ariane 5 rocket from French Guiana.
- Its gold mirror is about six and a half metres wide — built from 18 hexagonal pieces.
- The telescope was folded up like origami for launch and unfolded itself in space.
- Webb orbits one and a half million kilometres from Earth — about four times farther than the Moon.
- A sunshield the size of a tennis court keeps Webb cold enough to detect faint heat signals.
- Webb sees infrared light, letting it look through dust clouds where new stars are forming.
- Its first released photos showed thousands of galaxies in a patch of sky smaller than a grain of sand held at arm's length.
Kids’ Questions
Why does Webb look at infrared light instead of regular light?
All objects give off heat, and heat is infrared light that our eyes cannot see. Very distant galaxies have their light stretched to infrared wavelengths by the expansion of the universe, so a telescope sensitive to infrared can see much farther back in time. Infrared also passes through clouds of dust that block ordinary light, letting Webb peer inside the dusty nurseries where new stars and planets are forming. No telescope before Webb could do all of this from space.
How far away is the James Webb Space Telescope?
Webb sits at a point in space called the second Lagrange point, or L2, which is one and a half million kilometres from Earth. That is about four times farther than the Moon. At L2, Earth and the Sun line up behind the telescope, so Webb's giant sunshield can block the heat and light from both at the same time. This keeps the telescope cold enough to detect the incredibly faint heat signals coming from the most distant galaxies in the universe.
Variants
- James Webb Space Telescope (nominal)
- Single spacecraft; no variants. MIRI, NIRCam, NIRSpec, and FGS/NIRISS instruments cover 0.6–28 micron wavelengths. Designed lifespan a decade; propellant margins support 20+ years of operations.
Notable Operators
- NASA (Space Telescope Science Institute operations)
- Primary mission authority. STScI in Baltimore manages science operations, observation scheduling, and data archiving under contract to NASA Goddard Space Flight Center.
- European Space Agency
- Contributed NIRSpec, MIRI (co-built with JPL), and the Ariane 5 launch vehicle. Receives 15% of Webb observing time in return.
- Canadian Space Agency
- Contributed the FGS/NIRISS instrument. Receives 5% of observing time in return.
Frequently Asked Questions
How far away is the James Webb Space Telescope?
Webb orbits the Sun-Earth Lagrange 2 (L2) point 1.5 million km from Earth — four times the distance to the Moon. This location keeps the Sun, Earth, and Moon consistently on one side of the spacecraft, allowing Webb's sunshield to passively cool the optics to below 50 Kelvin without active refrigeration of the primary mirror.
What can Webb see that Hubble cannot?
Webb observes primarily at infrared wavelengths (0.6–28 microns) rather than visible light, enabling three capabilities beyond Hubble: (1) seeing through dust clouds opaque to visible light, revealing star-forming regions and galaxy cores; (2) detecting redshifted light from the earliest galaxies — objects Hubble could not resolve; and (3) characterising exoplanet atmospheres via transmission spectroscopy of molecules including water, carbon dioxide, and methane.
How much did the James Webb Space Telescope cost?
The total mission cost reached approximately $10 billion across development, launch, and five years of operations (per NASA). The original 1996 estimate was $0.5 billion; multiple descopes and redesigns over 25 development years drove the final cost up by a factor of 20. The launch on an Ariane 5 rocket was provided by ESA as part of the partnership contribution.
How long will Webb operate?
Webb was designed for a 10-year science mission, but the precision of the Ariane 5 insertion trajectory left enough onboard propellant for over 20 years of station-keeping at L2 — a forecast NASA confirmed in January 2022. Instrument longevity is the main unknown; MIRI's cryocooler and detector aging set the practical lifespan ceiling.
What were Webb's first discoveries?
Within its first year of full science operations (July 2022 – July 2023), Webb: confirmed carbon dioxide in the atmosphere of exoplanet WASP-39b; detected galaxy candidates at redshift z>13 (universe age under 320 million years); produced the deepest long-wavelength field image ever recorded; directly imaged planet HIP 65426b in mid-infrared; and resolved star-forming clumps in the Cosmic Cliffs region of the Carina Nebula.
Can Webb be serviced like Hubble?
No. Webb operates 1.5 million km from Earth at L2, far beyond the reach of any crewed vehicle. Hubble was serviceable because it orbited at 547 km altitude within Space Shuttle range. Webb was designed for maximum reliability rather than servicability; all instruments have redundant electronics, but a physical failure of the primary mirror or sunshield could not be repaired.
Sources
See Also
- Hubble Space Telescope — Predecessor observatory Webb was designed to succeed
- Spitzer Space Telescope — IR-band predecessor operating in a similar wavelength regime
- Chandra X-ray Observatory — X-ray sibling in NASA's Great Observatories programme
- SpaceX Starship — Launch vehicle candidate for future large space telescopes
- SpaceX Dragon 2 — Current crewed spacecraft — cannot reach Webb's L2 station but provides context for NASA's deep-space architecture