The mirror has a gold coating to provide infrared reflectivity and this is covered by a thin layer of glass for durability. This is over six times larger than the collecting area of Hubble's 2.4 m (7.9 ft) diameter mirror, which has a collecting area of 4.0 m 2 (43 sq ft). The mirror has a polished area of 26.3 m 2 (283 sq ft), of which 0.9 m 2 (9.7 sq ft) is obscured by the secondary support struts, giving a total collecting area of 25.4 m 2 (273 sq ft). Webb has a 6.5 m (21 ft)-diameter gold-coated beryllium primary mirror made up of 18 separate hexagonal mirrors. The mass of the James Webb Space Telescope is about half that of the Hubble Space Telescope.
In July 2023, astronomers reported that the first year of JWST operations were a considerable success. The high-stakes nature of the launch and the telescope's complexity were remarked upon by the media, scientists, and engineers.
The program was plagued with enormous cost overruns and delays a major redesign in 2005 led to the current approach, with construction completed in 2016 at a total cost of US$10 billion. Two concept studies were commissioned in 1999, for a potential launch in 2007 and a US$1 billion budget. Initial designs for the telescope, then named the Next Generation Space Telescope, began in 1996. It is deployed in a solar orbit near the Sun–Earth L 2 Lagrange point, about 1.5 million kilometers (930,000 mi) from Earth, where its five-layer sunshield protects it from warming by the Sun, Earth, and Moon. The telescope must be kept extremely cold, below 50 K (−223 ☌ −370 ☏), such that the infrared light emitted by the telescope itself does not interfere with the collected light. Unlike Hubble, which observes in the near ultraviolet and visible (0.1 to 0.8 μm), and near infrared (0.8–2.5 μm) spectra, Webb observes a lower frequency range, from long-wavelength visible light (red) through mid-infrared (0.6–28.3 μm). This gives Webb a light-collecting area of about 25 square meters, about six times that of Hubble. Webb's primary mirror consists of 18 hexagonal mirror segments made of gold-plated beryllium, which combined create a 6.5-meter-diameter (21 ft) mirror, compared with Hubble's 2.4 m (7 ft 10 in). The first Webb image was released to the public via a press conference on 11 July 2022. The James Webb Space Telescope was launched on 25 December 2021 on an Ariane 5 rocket from Kourou, French Guiana, and arrived at the Sun–Earth L 2 Lagrange point in January 2022. Webb, who was the administrator of NASA from 1961 to 1968 during the Mercury, Gemini, and Apollo programs.
The primary contractor for the project was Northrop Grumman. The NASA Goddard Space Flight Center (GSFC) in Maryland managed telescope development, while the Space Telescope Science Institute in Baltimore on the Homewood Campus of Johns Hopkins University currently operates Webb. National Aeronautics and Space Administration (NASA) led Webb's design and development and partnered with two main agencies: the European Space Agency (ESA) and the Canadian Space Agency (CSA). This enables investigations across many fields of astronomy and cosmology, such as observation of the first stars, the formation of the first galaxies, and detailed atmospheric characterization of potentially habitable exoplanets. Its high-resolution and high-sensitivity instruments allow it to view objects too old, distant, or faint for the Hubble Space Telescope. The James Webb Space Telescope ( JWST) is the largest space telescope, made to conduct infrared astronomy.
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