[meteorite-list] NASA Completes Mirror Polishing For James Webb Space Telescope

[Ron Baalke]

June 30, 2011

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

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


RELEASE: 11-210

NASA COMPLETES MIRROR POLISHING FOR JAMES WEBB SPACE TELESCOPE

WASHINGTON -- Mirrors are a critical part of a telescope. The quality 
is crucial, so completion of mirror polishing represents a major 
milestone. All of the mirrors that will fly aboard NASA's James Webb 
Space Telescope have been polished so the observatory can see objects 
as far away as the first galaxies in the universe. 

The Webb telescope is comprised of four types of mirrors. The primary 
one has an area of approximately 25 square meters (29.9 square 
yards), which will enable scientists to capture light from faint, 
distant objects in the universe faster than any previous space 
observatory. The mirrors are made of Beryllium and will work together 
to relay images of the sky to the telescope's science cameras. 

"Webb's mirror polishing always was considered the most challenging 
and important technological milestone in the manufacture of the 
telescope, so this is a hugely significant accomplishment," said Lee 
Feinberg, Webb Optical Telescope manager at NASA's Goddard Space 
Flight Center in Greenbelt, Md. 

The mirrors were polished at the L3 Integrated Optical Systems - 
Tinsley in Richmond, Calif. to accuracies of less than one millionth 
of an inch. That accuracy is important for forming the sharpest 
images when the mirrors cool to -400°F (-240°C) in the cold of space. 

"The completion of the mirror polishing shows that the strategy of 
doing the hardest things first has really paid off," said Nobel Prize 
Winner John C. Mather, Webb's senior project scientist at Goddard. 
"Some astronomers doubted we could make these mirrors." 

After polishing, the mirrors are being coated with a microscopically 
thin layer of gold to enable them to efficiently reflect infrared 
light. NASA has completed coating 13 of 18 primary mirror segments 
and will complete the rest by early next year. The 18 segments fit 
together to make one large mirror 21.3 feet (6.5 meters) across. 

"This milestone is the culmination of a decade-long process," said 
Scott Willoughby, vice president and Webb Telescope Program manager 
for Northrop Grumman Aerospace Systems. "We had to invent an entire 
new mirror technology to give Webb the ability to see back in time." 

Northrop Grumman Corp. in Redondo Beach, Calif. is the telescope's 
prime contractor. 

As the successor to the Hubble Space Telescope, the Webb telescope is 
the world's next-generation space observatory. It is the most 
powerful space telescope ever built. More than 75 percent of its 
hardware is either in production or undergoing testing. The telescope 
will observe the most distant objects in the universe, provide images 
of the first galaxies ever formed and study planets around distant 
stars. NASA, the European Space Agency and the Canadian Space Agency 
are collaborating on this project. 

For related images and more information about the mirrors, visit: 

http://www.nasa.gov/topics/universe/features/webb-mirrors-done.html 

To view the "Behind the Webb: Wax on, Wax Off" video explaining the 
mirror polishing process, visit: 

http://webbtelescope.org/webb_telescope/behind_the_webb/10 

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

http://www.jwst.nasa.gov   
	
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