A successor to the Hubble Space Telescope three decades in the making, the James Webb Space Telescope (JWST) is a project NASA had pursued through years of delays and cost overruns that more than doubled its original price tag. Astronomers and the space agency pressed on, seeing the telescope as the only way to observe conditions in the early universe that telescopes on Earth could never see. The discovery of planets orbiting nearby stars also gave a boost to the telescope, which promises to reveal the chemistry of some of these worlds.
An earlier version of a photo annotation misstated the age of the galaxies pictured. This version has been corrected.
Thanks to Lillian Barkley for copy editing this article.