NASA created the James Webb Space Telescope with support from the European Space Agency and the Canadian Space Agency. The telescope is named after James E. Webb, who served as NASA administrator from 1961 to 1968 and was instrumental in the Apollo program.
JWST’s primary mirror, the Optical Telescope Element, consists of 18 hexagonal mirror segments made of gold-plated beryllium which combine to create a 6.5 meter (21 ft 4 inch) diameter mirror.
Construction was finished in late 2016, after which a thorough testing phase commenced. JWST was launched by an Ariane 5 launch vehicle from Kourou, French Guiana, at 12:20 UTC on December 25, 2021, and was released from the upper stage 27 minutes later.
It is expected to be NASA’s flagship project in astrophysics, succeeding the Hubble Space Telescope. JWST was launched on Ariane flight VA256 on December 25, 2021.
It is intended to provide improved infrared resolution and sensitivity over Hubble, viewing objects up to 100 times fainter, and will enable a wide range of investigations in astronomy and cosmology, including observations up to redshift z20 of some of the Universe’s most distant events and objects, such as the formation of the first galaxies, and detailed atmospheric characterization of potentially habitable exoplanets.
This gives Webb’s telescope a light collecting area about 5.6 times larger than Hubble’s 2.4 m (7.9 ft) mirror (25.37 m2 collecting area to Hubble’s 4.525 m2).
Unlike Hubble, which observes in the near ultraviolet, visible, and near infrared (0.1–1.0 μm) spectra, JWST will observe in a lower frequency range, from long-wavelength visible light (red) through mid-infrared (0.6–28.3 μm). This will enable it to observe high-redshift objects that are too old and too distant for Hubble.
The telescope must be kept below 50 K (−223 °C; −370 °F) to observe faint signals in the infrared without interference from any other sources of warmth, so it will be deployed in space near the Sun–Earth L2 Lagrange point, a point in space about 1.5 million kilometers (930,000 mi) from Earth, where its 5 layer kite-shaped sunshield can protect it from warming by the Sun, Earth and Moon at the same time.
The high-stakes nature of the launch, which is the planned backbone of the next generation of research in its fields, and the telescope’s required complexity, was remarked upon by the media, and commented on by scientists and engineers.
JWST is overseen by NASA’s Goddard Space Flight Center (GSFC) in Maryland, and it is operated by the Space Telescope Science Institute. Northrop Grumman was the primary contractor. Development began in 1996 for a launch planned for 2007 with a US$500 million budget.
There were many delays and cost overruns, including a major redesign in 2005, a ripped sunshield during a practice deployment, a recommendation from an independent review board, the COVID-19 pandemic, issues with the Ariane 5 rocket and the telescope itself, and communications issues between the telescope and the launch vehicle.
As of January 2022, the telescope is being gradually tested and unfolded to its operational configuration, while traveling to its target destination. It will slow down as it travels, in order to arrive at L2 with only the velocity needed to enter its orbit there.