English: The towering primary mirror of NASA’s James Webb Space Telescope stands inside a cleanroom at NASA’s Johnson Space Center in Houston, where it will undergo its last cryogenic test before it is launched into space in 2018. In preparation for testing, the “wings” of the mirror (which consist of the three segments on each side) were spread open. This photo shows one fully deployed wing, and one that is moments from being fully deployed. An engineer observes the move. The James Webb Space Telescope is the world’s most advanced space observatory. This engineering marvel is designed to unravel some of the greatest mysteries of the universe, from discovering the first stars and galaxies that formed after the big bang to studying the atmospheres of planets around other stars. It is a joint project of NASA, ESA (the European Space Agency) and the Canadian Space Agency.