An artist’s conception shows the James Webb Space Telescope.
Credit: NASA

The James Webb Space Telescope was successfully launched into space atop an Ariane 5 rocket on Dec. 25, 2021. The James Webb Space Telescope, abbreviated JWST, is an observatory that will replace some capabilities of the Hubble Space Telescope. The Hubble Space Telescope is a powerful orbiting telescope that provides sharp images of heavenly bodies. Webb’s main mirror is 6.5 meters (21 feet) across. Webb will have about seven times larger light-collecting area than Hubble. However, Webb is designed to study infrared light, a type of light wave with longer wavelengths than those of visible light. Thus, Webb will not replace Hubble’s visible light capabilities.

The Ariane 5 rocket is used chiefly to launch commercial satellites. The rocket was developed by the European Space Agency and a European company known as Arianespace.
European Space Agency

Webb is a collaboration between the National Aeronautics and Space Administration (NASA), the European Space Agency (ESA), and the Canadian Space Agency (CSA). The Space Telescope Science Institute, which currently operates Hubble, is to manage Webb’s science operations, which are expected to begin in summer 2022. The telescope is named after James Webb, the former NASA administrator who conceived and directed the Apollo program for most of the 1960’s. Webb has been a work in progress since 1996 and its deployment was delayed many times over the years.

The Webb telescope will enable scientists to study the history of the universe, nearly all the way back to a cosmic explosion called the big bang. It will collect information on the first stars and galaxies that formed after the big bang, the formation of planetary systems, and the evolution of planets within the solar system.

Webb is equipped with several specialized cameras and spectrometers, instruments that spread out light into a band of wavelengths called a spectrum. Astronomers can study such a spectrum for signs of light given off by certain molecules or atoms. Webb also has a primary (main) mirror made of many segments, which was folded up to fit in the launch rocket. The mirror is to unfold and adjust to its proper shape before Webb reaches its permanent orbit. A large sun shield, about the size of a tennis court, will help prevent the infrared light from the sun, and the reflected sunlight from Earth and the moon, from interfering with observations. Webb is specifically designed to cool down its sensors to gather better data.

After launch, Webb is to travel to a Lagrange point, a special point in space where the gravitational pulls of the sun and Earth are in balance. Webb is to remain there, 930,000 miles (1.5 million kilometers) from Earth, observing the skies for up to 10 years. During its primary mission, Webb is designed to be the world’s premier space observatory, used by thousands of astronomers worldwide.