English: The primary mirror of NASA's James Webb Space Telescope consisting of 18 hexagonal mirrors looks like a giant puzzle piece standing in the massive clean room of NASA's Goddard Space Flight Center in Greenbelt, Maryland. Appropriately, combined with the rest of the observatory, the mirrors will help piece together puzzles scientists have been trying to solve throughout the cosmos.

Webb's primary mirror will collect light for the observatory in the scientific quest to better understand our solar system and beyond. Using these mirrors and Webb's infrared vision scientists will peer back over 13.5 billion years to see the first stars and galaxies forming out of the darkness of the early universe. Unprecedented infrared sensitivity will help astronomers to compare the faintest, earliest galaxies to today's grand spirals and ellipticals, helping us to understand how galaxies assemble over billions of years. Webb will see behind cosmic dust clouds to see where stars and planetary systems are being born. It will also help reveal information about atmospheres of planets outside our solar system, and perhaps even find signs of the building blocks of life elsewhere in the universe.

The Webb telescope was mounted upright after a "center of curvature" test conducted at Goddard. This initial center of curvature test ensures the integrity and accuracy, and test will be repeated later to verify those same properties after the structure undergoes launch environment testing. In the photo, two technicians stand before the giant primary mirror.

For information on the Webb's Center of Curvature test, visit: go.nasa.gov/2fidD9S

NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission.