Webb Space Telescope Sunshield Gets Full Size Test
Tests on five tennis-court sized sunshield layers designed to protect NASA's James Webb Space Telescope mirrors and instruments from the heat of the sun will tell Northrop Grumman Corp. (Falls Church, Va.) engineers how the full-size sunshield layers will behave in orbit. The sunshield allows the Webb telescope to cool to its 40 K cryogenic operating temperature, necessary to image faint infrared objects in the early universe.
"Testing the full-size sunshield in a fully simulated flight configuration and comparing test results to our computer models is a very significant step forward in validating the sunshield's predicted performance," says Jim Flynn, Webb telescope Sunshield manager, Northrop Grumman Aerospace Systems. "The size of the sunshield mandates the use of computer models to verify performance, and this test represents the next level of analysis on a full-size membrane."
Testing began in early September at ManTech International Corp.'s Nexolve facility in Huntsville, Ala., using flight-like material for the sunshield, and a full-scale test frame and hardware attachments. The test sunshield layer is made of Kapton, a very thin, high-performance plastic with a reflective metallic coating, similar to a Mylar balloon. Each sunshield layer thickness is less than half the thickness of a sheet of paper and is stitched together from over 52 individual pieces.
Test engineers used a high-precision laser radar tool to measure the layer every few inches at room temperature and pressure, creating a 3D map or picture of the material surface, which is curved in multiple directions. The map made during the test will be compared to computer models to see if the material behaved as the model predicted, and whether critical clearances with adjacent hardware are achieved.
Successor to the Hubble Space Telescope, the James Webb Space Telescope is the world's next-generation space observatory. It will be the most powerful space telescope ever built and now has more than 75% of its hardware either completed, in production, or undergoing testing.
Northrop Grumman Corp., www.northropgrumman.com