Space telescope sunshade tested

GREENBELT, Md., Sept. 20 (UPI) -- NASA says it's testing the sunscreen that will protect the James Webb Space Telescope during its mission to probe the distant universe.

The sunshield, five tennis court-sized layers of polymer-based film and supporting structure, will allow the Webb telescope, successor to the Hubble instrument, to cool to its cryogenic operating temperature of minus 387.7 degrees Fahrenheit, a NASA release said Tuesday.

Testing began this month in Huntsville, Ala., using a test sunshield layer made of Kapton, a very thin, high-performance plastic with a reflective metallic coating, similar to Mylar familiarly used in birthday balloons, the agency said.

"The conclusion of testing on this full size layer will be the final step of the sunshield's development program and provides the confidence and experience to manufacture the five flight layers," Keith Parrish, sunshield manager at NASA's Goddard Space Flight Center in Greenbelt, Md., said.

The Webb telescope is a joint project of NASA, the European Space Agency and the Canadian Space Agency.