Above is Webb in space.
Webb is the biggest, most complex, and most expensive science mission that NASA has ever attempted, and expectations among astronomers and the public are huge. Webb will have 100 times the sensitivity of the Hubble Space Telescope. It will be able to look into the universe's infancy, when the very first galaxies were forming; study the birth of stars and their planetary systems; and analyze the atmospheres of exoplanets, perhaps even detecting signs of life.
Some of the James Webb Space Telescope team are shown here in front of the Webb full-scale model at the Goddard Space Flight Center in Greenbelt, Maryland. Webb has over 1200 skilled scientists, engineers and technicians from 14 countries building it. Assembly and testing of the mirror and instruments occurred at NASA Goddard.
The catch phrase in NASA at the time, championed by agency chief Daniel Goldin, was "faster, better, cheaper." Goldin challenged NASA engineers and the astronomical community to come up with a follow-on that was cheaper than Hubble but bigger, with a mirror 8 meters across. He received a standing ovation when he described the plans to the American Astronomical Society in 1996. Whereas Hubble covered the whole range of visible light, plus a smidgen of ultraviolet and infrared, the Next Generation Space Telescope (as it was then known) would be a dedicated infrared observatory.
Beginning in 2001, concerns about the swelling cost of the telescope forced NASA to shrink the mirror from 8 meters to 6.5 meters, reducing the number of mirror segments from 36 to 18 and its light-collecting area from 50 square meters to 25. But review panels decided that Webb could still achieve its scientific goals. The change would make Webb less sharp at near-infrared wavelengths between 1 and 2 micrometers—no great loss. NASA's James Webb Space Telescope finally launched on Dec 25, 2021, from ESA's launch site at Kourou in French Guiana, at 7:20 a.m. EST, aboard an Arianespace Ariane 5 rocket. It is the largest and most powerful space telescope to date.