NASA’s Troubled $8-Billion Hubble Successor Is Back on Track [Slide Show]
The four science instruments for NASA's successor to the Hubble telescope have arrived at NASA Goddard Space Flight Center for testing and assembly
The first six of 18 JWST primary mirror segments are shown being prepped for testing in Goddard's cryogenic chamber. Credits: NASA/MSFC/David Higginbotham
SQUEAKY CLEAN: Here in the High Bay Clean Room at NASA's Goddard Space Flight Center in Greenbelt, Md., engineers will assemble the James Webb Space Telescope (JWST). Due to launch in 2018, the observatory will be the largest, most complex instrument ever sent to space.
ENTOURAGE: Members of the press toured Goddard in January 2014 to observe progress on James Webb, which passed its final design milestone—the critical design review—that month. All four science instruments for the telescope have been constructed and shipped to Goddard, where technicians will assemble them inside a giant clean room.
TOP MODEL: This model of the telescope, which greets visitors to Goddard in the lobby, shows the 18 golden mirror segments that will make up the observatory's primary mirror, and the metallic sunshade that will shield the scope from contaminating light from the sun, Earth and the moon.
COLD COMFORT: Goddard houses the world's second-largest thermal vacuum chamber, where the components of the JWST can be cooled down to the extreme temperatures they will be exposed to in space: below 50 kelvins (–370 degrees Fahrenheit, or –223 degrees Celsius). Inside the chamber the chilly climate is achieved by liquid nitrogen plus an extra cooling shell of liquid helium. The only larger chamber of this kind is at NASA Johnson Space Center in Houston, where the JWST will travel when it is fully assembled.
SHAKE IT OUT: The JWST will have to withstand intense vibrations when it launches on an Ariane 5 rocket provided by the European Space Agency in 2018. To simulate the rocky ride, the telescope's instruments are subjected to serious shaking in the Acoustic Test Chamber. To create the shaking, gigantic speakers inside the tall room blast out sound waves at 150 decibels—loud enough to rupture an eardrum.
BUNNY SUITS: Goddard's clean room is between 100 to 1,000 times cleaner than the outside environment, protecting the JWST's sensitive instruments from stray dust and microbes. To achieve this sterility, every person who enters must don hat, gown and booties, walk through an air shower and step on tape to pick up debris.
MAKING A MIRROR: The yellow scaffolding structure in Goddard's clean room was made specifically for the JWST and will enable engineers to attach all 18 of the telescope's mirror segments onto its shell-like back plane. A robotic arm on the structure will lift each hexagonal mirror segment separately and put it into place.
MIRROR PREP: The first six of 18 JWST primary mirror segments are shown being prepped for testing in Goddard's cryogenic chamber.
SAFE STORAGE: All 18 of James Webb's gold mirror segments are complete and have arrived at Goddard, where they are being stored inside separate stainless steel shock-absorbing canisters until it is time for mirror assembly.
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