What is the name of the largest space telescope ever launched, placed in orbit in December 2021?

The James Webb Space Telescope is the largest space telescope ever launched, entering space in December 2021.

NASA launched Webb on December 25, 2021, aboard an Ariane 5 rocket from French Guiana. Its segmented primary mirror is 6.5 meters wide, far larger than Hubble’s 2.4-meter mirror, and is made from 18 gold-coated beryllium segments.

Webb observes primarily infrared light, allowing it to study cool objects, dust-shrouded regions, exoplanet atmospheres, and some of the earliest galaxies. Its five-layer sunshield protects the telescope from heat and helps it operate near the Sun–Earth L2 point.

Webb is often called the successor to Hubble, but it does not simply replace it. Hubble remains especially valuable for ultraviolet and visible-light observations, while Webb extends astronomy into longer infrared wavelengths.