Unfolding a space telescope

It took more than 50 individual steps and two weeks to set JWST up

25 December, 12:20 UT JWST launches from the Guiana Space Centre on an Ariane 5 rocket; after 27 minutes, it separates from the launcher’s upper stage to travel to L2 alone. 30–31 December Sunshield mid-booms are extended on either side, pulling the folded sunshield layers with them, to form the first part of its distinctive 21m x 14m kite shape. 25 December, 12:48 UT Deployment of JWST’s 6m, five-panel solar array, which delivers about 1Kw of power. The telescope can now switch from battery power to its own power. 3–4 January

The five Kapton layers of Webb’s sunshield are tensioned. While the Sun-facing side endures temperatures up to 90°C, the shielded side will be as cold as –230°C. 26 December Deployment of the high-gain communications antenna, which allows communication with Earth through NASA’s Deep Space Network. 5 January

JWST’s 74cm convex secondary mirror is deployed. The foldable structure supporting it has been dubbed “the world’s most sophisticated tripod”. 28 December

The Forward Unitized Pallet Structure (UPS), which supports and contains the five folded layers forming the front half of the sunshield, is lowered into place. 6 January Deployment of the 1.2m x 2.4m Aft Deployable Instrument Radiator (ADIR), which radiates heat from the space telescope’s science instruments into space. 29 December

The Deployable Tower Assembly (DTA) is raised by 1.2m for better thermal isolation and to give room for the sunshield to unfold in front and behind. 7–8 January Deployment of the two side panels forming JWST’s 6.5m primary mirror. Its 18 hexagonal segments are made of lightweight beryllium coated with pure gold.