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

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Mon, 19 Sep 2011 10:17:47 -0700 (PDT)
Message-ID: <201109191717.p8JHHli4005260_at_zagami.jpl.nasa.gov>

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
        
-end-
Received on Mon 19 Sep 2011 01:17:47 PM PDT