[meteorite-list] Tests Under Way On The Sunshield For NASA'S Webb Telescope

[Ron Baalke]

Sept. 19, 2011

Trent J. Perrotto 
Headquarters, Washington 
202-358-0321 
trent.j.perrotto at nasa.gov 

Mary Blake 
Northrop Grumman, Redondo Beach, Calif. 
310-812-6291 
mary.blake at ngc.com   


RELEASE: 11-311

TESTS UNDER WAY ON THE SUNSHIELD FOR NASA'S WEBB TELESCOPE

WASHINGTON -- 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. 

The tests are expected to be completed in two weeks. 

"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," 
said Keith Parrish, Webb Sunshield manager at NASA's Goddard Space 
Flight Center in Greenbelt, Md. 

During testing, engineers use a high-precision laser radar to measure 
the layer every few inches at room temperature and pressure, creating 
a 3D map of the material surface, which is curved in multiple 
directions. The map will be compared to computer models to see if the 
material behaved as predicted, and whether critical clearances with 
adjacent hardware are achieved. 

The test will be done on all five layers to give engineers a precise 
idea of how the entire sunshield will behave once in orbit. Last 
year, a one-third-scale model of the sunshield was tested in a 
chamber that simulated the extreme temperatures it will experience in 
space. The test confirmed the sunshield will allow the telescope to 
cool to its operating temperature. 

After the full-size sunshield layers complete testing and model 
analysis, they will be sent to Northrop Grumman in Redondo Beach 
Calif., where engineers verify the process of how the layers will 
unfurl in space. There the sunshield layers will be folded, much like 
a parachute, so they can be safely stowed for launch. 

The Webb is the world's next-generation space observatory and 
successor to the Hubble Space Telescope. The most powerful space 
telescope ever built, Webb will provide images of the very first 
galaxies ever formed, and explore planets around distant stars. The 
Webb is a joint project of NASA, the European Space Agency and the 
Canadian Space Agency. 

For more information and related images, visit: 

http://www.nasa.gov/topics/technology/features/sunshield-test.html   

For more information about the James Webb Space Telescope, visit: 

http://www.jwst.nasa.gov   
	
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