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dc.creatorSchweickart, Russell
dc.creatorFranck, Randy
dc.creatorPark, Sang
dc.date.accessioned2017-07-11T15:18:06Z
dc.date.available2017-07-11T15:18:06Z
dc.date.issued2017-07-16
dc.identifier.otherICES_2017_312
dc.identifier.urihttp://hdl.handle.net/2346/73084
dc.descriptionRussell Schweickart, Ball Aerospace, USA
dc.descriptionRandy Franck, Ball Aerospace, USA
dc.descriptionSang Park, Smithsonian Astrophysical Observatory, USA
dc.descriptionICES108: Thermal Control of Cryogenic Instruments and Optical Systems
dc.descriptionThe 47th International Conference on Environmental Systems was held in South Carolina, USA on 16 July 2017 through 20 July 2017.
dc.description.abstractThe James Webb Space Telescope (JWST), scheduled for launch in 2018, must be cooled to temperatures below 50 K as part of a rigorous set of ground tests to verify operational performance. Some of the components that drive the time required to cool down the assembly to this temperature are the beryllium optics. Two properties of these optics that determine their cool down time are mass and surface emissivity. The mass of these optics, including the primary comprised of 18 hexagonal segments, a secondary and a tertiary, have all been reduced by machining pockets into the back side of the substrates. One difficulty in predicting the time required to cool these optics is estimating how their pocketed back sides effects their emissivity. Component level tests of these optics at operational temperatures has allowed for verification of their cryogenic optical performance. These tests have also allowed for estimates of mirror back effective emissivities based on correlating thermal models of the tests. This paper will describe the subassembly tests and show correlated results for mirror back effective emissivities.
dc.format.mimetypeapplication/pdf
dc.language.isoeng
dc.publisher47th International Conference on Environmental Systems
dc.subjectspace optics thermal performance
dc.subjecteffective emissivity
dc.subjectcryogenic testing
dc.titleCorrelation of Effective Emissivity of Light-weighted Beryllium Mirrors during JWST Thermal Vacuum Testingen_US
dc.typePresentations


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