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James Webb Space Telescope Passes Its Eye Exam
The design for NASA's James Webb Space Telescope's "eye" is in perfect working order. That's the word from scientists and engineers who checked the design of all the systems in what is called the "Optical Telescope Element" on the space telescope.

Labeled diagram of JWST components The Optical Telescope Element (OTE) is the eye of the James Webb Space Telescope. The OTE gathers as much light as possible coming from space and provides it to the science instruments, labeled in this diagram. Click image for enlargement. Credit: NASA
The Optical Telescope Element is the "eye" of the Webb observatory. The telescope consists of a 21.3 foot (6.5-meter) primary mirror which is made up of 18 small mirrors; a second, a third and fine steering mirrors; and supporting structures, a tower and electronics that control these parts.

The "eye" of the James Webb Space Telescope is the key to the telescope being able to see a time when galaxies were young. The "eye" will see galaxies billions of light-years away, further away than any other telescope has observed. It's like having the world's most far-sighted telescope, so far-sighted that it can even look back in time.

Northrop Grumman is NASA’s prime contactor for the Webb Telescope. Northrop Grumman's engineers are leading the design and development effort under a contract with NASA Goddard.

"The successful completion of the Optical Telescope Element Preliminary Design Review is an important milestone in the development of the telescope," said Lee Feinberg, James Webb Space Telescope Optical Telescope Element Manager at NASA's Goddard Space Flight Center, Greenbelt, Md. The passing of this test means that the telescope's "eye" will work properly, so now the team can move on to final, detailed designs. The testing also ensures that the telescope will survive launch. This is the purpose of the vibration and acoustic tests.

Labeled diagram of JWST mirrors So that the segments work together as a single large mirror, the 18 mirror segments have been divided into 3 groups of six mirrors, each group having a slightly different shape. Click image for enlargement. Credit: NASA
In January 2007, in front of a team of experts assembled by NASA, the Northrop Grumman the telescope team showed that the "eye" technology is ready to move into a detailed engineering phase. All critical telescope components or prototypes had been successfully tested in a thermal vacuum chamber. The thermal vacuum simulates the very cold temperatures and vacuum of space. At the review, the team also presented a plan for the final assembly and testing that the actual instruments on the telescope function correctly. The team also presented a plan to test the instruments in an environment that simulates the temperature changes in space. That will be done at NASA's Johnson Space Center in Houston, Texas.

The Webb Telescope will be launched in 2013 and will be the premier space observatory of the next decade, serving thousands of astronomers worldwide. It will study every phase in the history of our universe, from the first galaxies assembled in the universe, to the formation of solar systems potentially capable of supporting life, to the evolution of our own Solar System.

Related links:

> Read the press release for more detail and an animation
> The James Webb Space Telescope mission page

Rob Gutro
NASA's Goddard Space Flight Center

Richard Bent
Northrop Grumman Corp., Redondo Beach, Calif.