New composite for extreme cold
Engineers at NASA's Goddard Space Flight Center have invented a new composite and new joining technologies in order to construct the frame of the Integrated Science Instrument Module for the James Webb Space Telescope
It is required to be able to survive the stresses of a rocket launch and then cool to 39°K without distorting or cracking. As a result of mathematical modeling, the design team discovered that by combining two composite materials, it could create a carbon fibre/cyanate ester resin system suitable for fabricating the structure's 75mm wide square tubes. To attach them, the team again used mathematical modeling to come up with a combination of nickel alloy fittings, clips and specially shaped composite plates joined using a novel adhesive process.
Lead mechanical engineer Jim Pontius observed that, "It is the first large, bonded composite spacecraft structure to be exposed to such a severe environment." Cyclic tests down to 27°K showed that the structure contracted by only 170µm against a design requirement of 500µm.
The telescope, which will have a 6.5m diameter mirror and work in the infra red part of the spectrum is scheduled for launch in 2014.
