The James Webb Space Telescope
Largest space telescope, observing the universe in infrared.
The James Webb Space Telescope (JWST) is a space telescope designed to conduct infrared astronomy. It is the largest telescope in space, equipped with high-resolution and high-sensitivity instruments, allowing it to view objects too old, distant, or faint for the Hubble Space Telescope. This enables investigations across many fields of astronomy and cosmology, such as observation of the first stars and the formation of the first galaxies, and detailed atmospheric characterization of potentially habitable exoplanets.
- Launch date
- 25 December 2021
- Destination
- Sun–Earth L2 Lagrange point, about 1.5 million km from Earth
- Primary mirror diameter
- 6.5 meters (21 ft)
- Observing wavelength range
- 0.6–28.5 μm (long-wavelength visible to mid-infrared)
- Total cost
- US$10 billion
Lore & Background
Two concept studies were commissioned in 1999, for a potential launch in 2007 and a US$1 billion budget. The program saw enormous cost overruns and delays. A significant redesign was carried out in 2005, with construction completed in 2016, followed by years of exhaustive testing, at a total cost of US$10 billion. The U.S. National Aeronautics and Space Administration (NASA) led Webb's design and development and partnered with the European Space Agency (ESA) and the Canadian Space Agency (CSA). The primary contractor for the project was Northrop Grumman.
Reader's Guide
The James Webb Space Telescope represents a major advancement in space-based astronomy, enabling observations of the earliest stars and galaxies, as well as detailed study of exoplanet atmospheres. Its location at the Sun–Earth L2 Lagrange point, combined with a five-layer sunshield that keeps it below 50 K, allows it to detect faint infrared signals without interference from its own heat. Webb's 6.5-meter gold-coated beryllium mirror provides over six times the light-collecting area of Hubble, yet it produces images of comparable resolution because it observes in longer-wavelength infrared. Webb's legacy lies in its ability to explore cosmic epochs and phenomena inaccessible to previous telescopes, fundamentally expanding humanity's understanding of the universe.
Did You Know?
- Webb's primary mirror consists of 18 hexagonal mirror segments made of gold-plated beryllium.
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