NASA is testing an element of the sunshield that will protect the James Webb Space Telescope's mirrors and instruments during its mission to observe the most distant objects in the universe.
The sunshield will consist of five tennis court-sized layers to allow the Webb telescope to cool to its cryogenic operating temperature of minus 387.7 degrees Fahrenheit (40 Kelvin).
Testing began early this month at ManTech International Corp.'s Nexolve facility in Huntsville, Ala., using flight-like material for the sunshield, 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 is less than half the thickness of a sheet of paper. It is stitched together like a quilt from more than 52 individual pieces because manufacturers do not make Kapton sheets as big as a tennis court.