Space Simulation Chamber Prepared for Testing Webb Telescope

This photo was captured from outside the enormous mouth of NASA's giant thermal vacuum chamber, called Chamber A, at Johnson Space Center in Houston. Previously used for manned spaceflight missions, this historic chamber is now filled with engineers and technicians preparing a lift system that will be used to hold the James Webb Space Telescope during testing. The James Webb Space Telescope is the scientific successor to NASA's Hubble Space Telescope. It will be the most powerful space telescope ever built. Webb is an international project led by NASA with its partners, the European Space Agency and the Canadian Space Agency. Credit: NASA/Goddard/Chris Gunn <a href="http://www.nasa.gov/audience/formedia/features/MP_Photo_Guidelines.html" rel="nofollow">NASA image use policy.</a> <a href="http://www.nasa.gov/centers/goddard/home/index.html" rel="nofollow">NASA Goddard Space Flight Center</a> 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. Follow us on <a href="http://twitter.com/NASAGoddardPix" rel="nofollow">Twitter</a> Like us on <a href="http://www.facebook.com/pages/Greenbelt-MD/NASA-Goddard/395013845897?ref=tsd" rel="nofollow">Facebook</a> Find us on <a href="http://instagrid.me/nasagoddard/?vm=grid" rel="nofollow">Instagram</a>

NASA's Webb Telescope "chilling out" in Houston for the summer

NASA’s James Webb Space Telescope was placed in Johnson Space Center’s historic Chamber A on June 20, 2017, to prepare for its final three months of testing in a cryogenic vacuum that mimics temperatures in space. Engineers will perform the test to prove that the telescope can operate in space at these temperatures. Chamber A will simulate an environment where the telescope will experience extreme cold -- around 37 Kelvin (minus 236 degrees Celsius or minus 393 degrees Fahrenheit). In space, the telescope must be kept extremely cold, in order to be able to detect the infrared light from very faint, distant objects. To protect the telescope from external sources of light and heat (like the sun, Earth, and moon), as well as from heat emitted by the observatory, a five-layer, tennis court-sized sunshield acts like a parasol that provides shade. The sunshield separates the observatory into a warm, sun-facing side (reaching temperatures close to 400 degrees Fahrenheit) and a cold side (185 degrees below zero). The sunshield blocks sunlight from interfering with the sensitive telescope instruments. Read more: <a href="https://go.nasa.gov/2sZAilS" rel="nofollow">go.nasa.gov/2sZAilS</a> <a href="http://www.nasa.gov/audience/formedia/features/MP_Photo_Guidelines.html" rel="nofollow">NASA image use policy.</a> <a href="http://www.nasa.gov/centers/goddard/home/index.html" rel="nofollow">NASA Goddard Space Flight Center</a> 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. Follow us on <a href="http://twitter.com/NASAGoddardPix" rel="nofollow">Twitter</a> Like us on <a href="http://www.facebook.com/pages/Greenbelt-MD/NASA-Goddard/395013845897?ref=tsd" rel="nofollow">Facebook</a> Find us on <a href="http://instagrid.me/nasagoddard/?vm=grid" rel="nofollow">Instagram</a>

The Webb Telescope's 'Golden Spider'

NASA image release August 23, 2012 What looks like a giant golden spider weaving a web of cables and cords, is actually ground support equipment, including the Optical Telescope Simulator (OSIM), for the James Webb Space Telescope. OSIM's job is to generate a beam of light just like the one that the real telescope optics will feed into the actual flight instruments. Because the real flight instruments will be used to test the real flight telescope, their alignment and performance first have to be verified by using the OSIM. Engineers are thoroughly checking out OSIM now in preparation for using it to test the flight science instruments later. This photo was taken from inside a large thermal-vacuum chamber called the Space Environment Simulator (SES), at NASA's Goddard Space Flight Center in Greenbelt, Md. Engineers have blanketed the structure of the OSIM with special insulating material to help control its temperature while it goes into the deep freeze testing that mimics the chill of space that Webb will ultimately experience in its operational orbit over 1 million miles from Earth. The golden-colored thermal blankets are made of aluminized kapton, a polymer film that remains stable over a wide range of temperatures. The structure that looks like a silver and black cube underneath the "spider" is a set of cold panels that surround OSIM's optics. During testing, OSIM's temperature will drop to 100 Kelvin (-280 F or -173 C) as liquid nitrogen flows through tubes welded to the chamber walls and through tubes along the silver panels surrounding OSIM's optics. These cold panels will keep the OSIM optics very cold, but the parts covered by the aluminized kapton blankets will stay warm. "Some blankets have silver facing out and gold facing in, or inverted, or silver on both sides, etc.," says Erin Wilson, a Goddard engineer. "Depending on which side of the blanket your hardware is looking at, the blankets can help it get colder or stay warmer, in an environmental test." Another reason for thermal blankets is to shield the cold OSIM optics from unwanted stray infrared light. When the OSIM is pointing its calibrated light beam at Webb's science instruments, engineers don't want any stray infrared light, such as "warm photons" from warm structures, leaking into the instruments' field of view. Too much of this stray light would raise the background too much for the instruments to "see" light from the OSIM—it would be like trying to photograph a lightning bug flying in front of car headlights. To get OSIM's optics cold, the inside of the chamber has to get cold, and to do that, all the air has to be pumped out to create a vacuum. Then liquid nitrogen has to be run though the plumbing along the inner walls of the chamber. Wilson notes that's why the blankets have to have vents in them: "That way, the air between all the layers can be evacuated as the chamber pressure drops, otherwise the blankets could pop," says Wilson. The most powerful space telescope ever built, Webb is the successor to NASA's Hubble Space Telescope. Webb's four instruments will reveal how the universe evolved from the Big Bang to the formation of our solar system. Webb is a joint project of NASA, the European Space Agency and the Canadian Space Agency. Credit: NASA/GSFC/Chris Gunn <a href="http://www.nasa.gov/audience/formedia/features/MP_Photo_Guidelines.html" rel="nofollow">NASA image use policy.</a> <a href="http://www.nasa.gov/centers/goddard/home/index.html" rel="nofollow">NASA Goddard Space Flight Center</a> 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. Follow us on <a href="http://twitter.com/NASA_GoddardPix" rel="nofollow">Twitter</a> Like us on <a href="http://www.facebook.com/pages/Greenbelt-MD/NASA-Goddard/395013845897?ref=tsd" rel="nofollow">Facebook</a> Find us on <a href="http://instagrid.me/nasagoddard/?vm=grid" rel="nofollow">Instagram</a>