The James Webb Space Telescope (JWST, or Webb) is the biggest, most complex, and most expensive science mission that NASA has ever attempted. 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. Expected to launch in October 2018, the telescope will travel 1,000,000 miles in 30 days to its final orbital position. From there, it will turn its gaze on the cosmos.