James Webb - regarded as the successor to Hubble - is due to launch in 2018. The Mid-Infrared Instrument (Miri) will gather key data as the $9bn (£5.5bn) observatory seeks to identify the first starlight in the Universe. It will carry a 6.5m primary mirror (more than double the width of Hubble's main mirror), and a shield the size of a tennis court to guard its sensitive vision from the heat and strong light of our Sun.