The James Webb Space Telescope, now under construction, will peer deeper into space.
If the mirror were assembled completely and fully opened on the ground, there would be no way to fit it into a rocket. The telescope's 18 mirror segments will be assembled when the telescope is in space.
At nearly twenty two feet in diameter, the assembled mirrors will be almost seven times the size of the primary mirror in Hubble. When launched in 2013, scientists hope to use the telescope to see the first stars following the Big Bang.