The flight backplane of the James Webb Space Telescope has been delivered to Nasa for mirror assembly ahead of the 2018 launch.
The flight backplane, one of the most crucial components of the telescope, which will replace the iconic Hubble telescope, will hold its 18 hexagonal mirrors and instruments steady while the telescope is looking into deep space.
Engineers at Nasa’s Goddard Space Flight Center in Maryland unpacked the backplane and checked it didn’t sustain any damage during transportation and that it works as designed.
"The delivery of the backplane to Goddard represents another significant step in the evolution of Webb," said Bill Ochs, James Webb Space Telescope project manager. "Final assembly of the telescope can now begin this fall leading to integration of the telescope and science instruments in late spring of 2016."
The flight backplane, built by Northrop Grumman Aerospace Systems in Redondo Beach, California, will be hoisted onto an assembly stand in a large clean room in Goddard where the telescope’s 18 flight mirrors will be mounted onto the backplane with a robotic arm.
These 18 mirrors will make up Webb’s primary mirror, which together with the secondary, tertiary and fine steering mirrors will help scientists observe the formation of the first stars and galaxies more than 13.5 billion years ago. Once completed, James Webb, a joint project between Nasa, the European Space Agency and the Canadian Space Agency, will be the most powerful space telescope ever built.
"The telescope's beryllium mirrors are held together nearly motionlessly in space by the backplane, which also acts as a stable platform during ground test operations and launch," said Scott Texter, telescope manager at Northrop Grumman Aerospace Systems. "The stability of this hardware contributes to the Webb telescope's ability to provide an unprecedented look at our own solar system as well as discover exoplanets well beyond this solar system."
The backplane will have to meet the most stringent thermal stability requirements of any space-based telescope to minimise thermal distortion. Webb undergoes extreme temperature changes in the time between its construction and its final home in deep space. While its components are being built at room temperature, the telescope will eventually operate in extreme cold with temperatures as low as minus 234 ºC.
Once in space, the telescope will be subject to extreme temperature changes based on its position relative to the Sun. These changes will put extreme pressure on the telescope’s structural components. Despite the expansion and shrinking induced by the thermal jumps, the backplane is not allowed to expand by more than a thousandth of the diameter of a human hair.
James Webb Space Telescope backplane arrives for assembly. Watch a video: