Carrying out the James Webb Space Telescope’s (JWST) ground-breaking mission required powerful technological innovations in optics, detectors, mirrors and a multitude of other areas. JWST's unprecedented scientific power is partly a function of the size and extreme sensitivity of its primary mirror, which collects the images from space. The gold-plated mirror is 21 feet in diameter, giving a collecting area of 273 square feet.
At its fully deployed size, the mirror would have been too large to fit into the Ariane 5 rocket that launched it, so it was built in 18 hexagonal segments designed to unfold once the telescope was in space. These segments have to be minutely controlled to meld them into a single optical surface. JWST has 132 tiny electric motors dedicated to mirror control and each mirror segment requires seven small motors — six to change position and one central motor to adjust the radius of ...
