The James Webb Space Telescope (JWST) had many chances to fail. Launched on Christmas Day, Dec. 25, 2021, the telescope traveled almost a million miles (1.5 million km) through space. Then a sunshield the size of a tennis court was unfurled. Without this shield, the light and heat of the Sun and Earth would blind the telescope. The mirror, made of 18 gold-plated hexagons, unfolded to be 21.3 feet (6.5 m) across. Finally, the scientific instruments were cooled to -360 F (-218 C), turned on, and tested. The super-cold temperatures ensure heat from the telescope itself doesn’t interfere with signals coming from space. During this six-month process, at least 344 different things could have gone wrong that would have doomed the project. But they didn’t. Just months into a mission that is scheduled to last more than five years, the JWST is considered an overwhelming success.
The JWST has looked farther into space than any previous telescope. And since it takes a long time for light from distant stars and galaxies to reach Earth, the telescope is also looking back in time. The JWST is already teaching us about the universe’s earliest years. It is designed to peer through the gas and dust that surround very young stars. It can also capture detailed images of nearby objects, like planets that share our Sun. Another important part of its mission is studying exoplanets—planets beyond our
