The James Webb Space Telescope is doing something astronomers dreamed about for decades: peering into our universe’s early past, a period known as cosmic dawn. A new NASA documentary—also called Cosmic Dawn—chronicles the inside story of Webb’s design, construction, and launch. John Mather, who won the 2006 Nobel Prize for Physics, proposed the telescope and led its science team for decades. In this interview, Mather talks about his life, his research, and the pre-dawn phone call telling him he had won the Nobel Prize.

Find more at nasa.gov/cosmicdawn