Ball Aerospace & Technologies Corp. started building the first flight primary mirror segment for NASA‘s James Webb Space Telescope, the company announced June 14.

Ball Aerospace is the main optical subcontractor for the program and will construct the telescope’s mirror out of 18 6.5-meter segments. The remaining segments will be delivered throughout the next four years.

The Webb Telescope, scheduled to be launched in 2013, will be able to detect objects 20 times fainter than the Hubble Space Telescope and will be used to observe the earliest formation of galaxy clusters that followed the Big Bang.