The mirror alignment process is a task due to be completed in time for the revolutionary eye in the sky to peer into the cosmos by early summer.

Mission control engineers at Nasa’s Goddard Space Flight Center in Greenbelt, Maryland, began by sending their initial commands to tiny motors called actuators that slowly position and fine-tune the telescope’s principal mirror.

Comprising 18 hexagonal segments of gold-plated beryllium metal, the primary mirror measures 6.5m in diameter – a much larger light-collecting surface than Webb’s predecessor, the Hubble Space Telescope.

The 18 segments, which had been folded together to fit inside the cargo bay of the rocket that carried the telescope to space, were unfurled with the rest of its structural components during a two-week period following Webb’s launch on 25 December 2021.

Those segments must now be detached from fasteners that held them in place for the launch and then moved forward half an inch from their...

Robert Heaton