NASA’s next big space observatory came one step closer to completion last week, as engineers placed the final segment of the James Webb Space Telescope’s primary mirror.
The careful construction of the segmented mirror began in November 2015 at the Goddard Space Flight Center in Greenbelt, Maryland. Each hexagonal segment is 4.2 feet (1.3 meters) across, coated with gold and beryllium, and weighs 88 pounds. There are 18 mirror segments in all. Now fully assembled, the primary mirror is 21.3 feet (6.5 meters) in diameter, making JWST the largest telescope ever fielded in space.
Often touted as the Hubble Space Telescope’s successor, the James Webb Space Telescope (JWST) will actually work at longer wavelengths than its famous cousin: from the long-wavelength end of the visual spectrum into the infrared regime. In that sense, it’s more of a follow-on to the Spitzer Space Telescope. JWST’s primary is also much larger than Hubble’s, which spanned only 2.4 meters, yet JWST’s overall observatory is actually lighter in mass.
Picture Credit : Google
