Eighteen mirror segments and a parking spot 1.5 million km out: the James Webb Space Telescope

Background

The James Webb Space Telescope is the great space observatory that follows Hubble, and it was built to look further back towards our origins than any instrument before it. Its science runs from how stars and planets take shape to the first galaxies that lit up the young universe, and it works in infrared light. It is not one country's project: it is a partnership between the American, European and Canadian space agencies. The telescope lifted off on an Ariane 5 rocket from Europe's Spaceport in French Guiana on 25 December 2021. It does not circle the Earth. It works from Lagrange point 2, about 1.5 million kilometres away, where it can keep the Sun, the Earth and the Moon all behind it. Its main mirror is 6.5 metres across and is made of 18 separate segments that were folded for launch and unfolded in space. A sunshield of five layers keeps sunlight off the instruments so they stay cold enough to see infrared light, and the telescope carries four science instruments.