The spiritual successor to the Hubble space telescope has reached a “hugely significant milestone”, according to the team putting it together.

Due for launch in 2014, the James Webb Space Telescope aims to be the ‘premier observatory of the next decade’.

Yesterday NASA announced that the first segment of its primary mirror had been successfully ‘cryo-polished’. This process is designed to ensure that even when cooled to the very, very, very, very cold temperatures at which it will operate, the mirror retains the shape it needs to observe the stars.

“Many predicted it would take us multiple iterations to successfully polish these mirror segments to achieve the correct optical prescription at the telescope’s operating temperatures, but we did it on our first try,” says Scott Willoughby, the telescope’s programme manager at contractor Northrop Grumman Aerospace Systems (press release).

Lee Feinberg, NASA’s Webb Optical Telescope Element Manager, adds, “The completion of cryogenic polishing of the engineering development unit primary mirror segment is a hugely significant milestone for the Webb telescope project.”

Image: NASA/MSFC/Emmett Givens