THE FIRST OF 18 SEGMENTS that will form NASA’s James Webb Space Telescope’s primary mirror for space observations, have completed final cryogenic testing.
The ten-week test series included two tests cycles where the mirrors were chilled down to -228 degrees Celsius, then back to ambient temperature to ensure the mirrors respond as expected to the extreme temperatures of space.
A second set of six mirror assemblies will arrive at Marshall in late July to begin testing, and the final set of six will arrive in the later in 2011.
The X-ray and Cryogenic Facility at NASA’s Marshall Space Flight Centre in Huntsville, Alabama, provides the space-like environment to help engineers measure how well the telescope will image infrared sources once in orbit.
Each mirror segment measures approximately 1.3 metres in diameter to form the 6.5 metres, hexagonal telescope mirror assembly critical for infrared observations. Each of the 18 hexagonal-shaped mirror assemblies weighs approximately 40 kilograms.
The mirrors are made of a light and strong metal called beryllium, and covered with a microscopically thin coating of gold to enabling the mirror to efficiently collect infrared light.
The NASA’s James Webb Space Telescope is expected to be launched in 2017 or 2018. Placed over 1 million kilometres from Earth, it will observe primarily the infrared light from faint and very distant objects.
It will be the premier observatory of the next decade, serving thousands of astronomers worldwide. It will study every phase in the history of our Universe, ranging from the first luminous glows after the Big Bang, to the formation of planetary systems capable of supporting life on planets like Earth, to the evolution of our own Solar System.
The telescope is a combined project of NASA, the European Space Agency and the Canadian Space Agency. Northrop Grumman is the prime contractor under NASA’s Goddard Space Flight Centre. Ball Aerospace & Technologies Corp. in Boulder, Colorado, is responsible for mirror development. L-3- Tinsley Laboratories Inc. in Richmond, California is responsible for mirror grinding and polishing.
Adapted from information issued by NASA / Emmett Given.
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