Toward fulfilling the mission to observe the most distant objects in the universe, NASA's James Webb Space Telescope was newly dressed with giant mirrors coated with gold - a spectacularly new technology fit for its grand mission.

As a milestone for its development, engineers completed the coating process, covering a microscopically thin layer of gold over 21 hexagonal mirrors to reflect infrared light into the science instruments of NASA's flagship James Webb Space Telescope, world's most powerful space observatory awaiting its launch in 2018.

To make up a large 21.3-foot primary mirror, 21 mirrors are each 4.9 feet tall and coated with 0.12 ounces of gold. Beryllium was selected as the material for the mirror, for its stiffness, light weight and stability at cryogenic temperatures, according to NASA.

 

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The first six flight ready James Webb Space Telescope's primary mirror segments are prepped to begin final cryogenic testing at NASA's Marshall Space Flight Center in Huntsville, Ala. Credit: NASA/Chris Gunn

 

 

In the coating process, engineers heated gold to over 2,500 degrees Fahrenheit and evaporated it onto the beryllium panels.

Gold layer measure only 120 nanometers thick, 200 times thinner than a human hair.

Finishing all mirror coatings on schedule is another major success story for the Webb telescope mirrors, said Lee Feinberg, NASA Optical Telescope Element manager for the Webb telescope at the agency's Goddard Space Flight Center.

These coatings easily meet their specifications, ensuring even more scientific discovery potential for the Webb telescope. 

As successor to the Hubble Space Telescope, the Webb telescope is being built as the next-generation space observatory to provide images of the first galaxies ever formed, and explore planets around distant stars, says NASA. The project is joined by the European Space Agency and the Canadian Space Agency.

The telescope is now estimated to cost $8.7 billion.

On Sept. 14, the Webb telescope just survived a funding vote in the U.S. Senate as the Democratic-controlled Senate Commerce, Justice and Science Appropriations subcommittee allocated $530 million for the project out of a total NASA budget of $17.9 billion.