- Oct. 26, 2017
-- In preparation for the Webb telescope's cryogenic testing, engineers at Johnson have suspended it from the ceiling of the center's Chamber A. This "hammock" (really, six support rods attached to Minus K Technology's Negative-Stiffness vibration isolators) is not for relaxation; it's meant to isolate the telescope from the vibrations Chamber A could produce once the door closes and testing begins, as well as from disturbances that might occur outside the chamber. The telescope needs an arrangement that holds it and its test equipment (an interferometer, auto-collimating flat mirrors, and a system of photogrammetry 'precision surveying' cameras already used for tests with a surrogate 'pathfinder' telescope) in precise relative alignment inside the chamber while isolated from any sources of vibration, such as the flow of nitrogen and helium inside the shroud plumbing and the rhythmic pulsing of vacuum pumps.
"Remember that the system is designed to work in space, where the disturbances are highly controlled and only come from the spacecraft,"
said Gary Matthews, an integration and testing engineer at NASA's Goddard Space Flight Center in Greenbelt, Maryland, who is testing the Webb telescope while it is at Johnson. "On Earth, we have to deal with all the ground-based disturbances, such as the pumps and motors, and even traffic driving by."
With the telescope suspended, engineers conducted a "push test," where they gave it a very slight nudge and observed how it reacted to ensure the suspension system was functioning the best it could, said Matthews.
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, ESA (European Space Agency) and the Canadian Space Agency.https://www.minusk.com/content/in-the-news_vibration_cont...
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