Major milestone caps off ‘amazing few weeks’ for JWST scientists

A technician inspects the gold-coated primary mirror of the James Webb Space Telescope ahead of its launch in December 2021. Credit: NASA/Chris Gunn

Leicester scientists have shared their excitement at the latest major milestone for the James Webb Space Telescope (JWST), the most advanced space observatory ever built.

Now in position at its new home around Lagrange point 2 (L2) – more than 930,000 miles from Earth – following a crucial orbit-insertion burn in January, engineers have started to test its complex instrumentation and align the telescope’s giant mirror assembly.

All of JWST’s instruments, including the Mid-Infrared Instrument (MIRI), constructed with Leicester expertise, have been powered up since its launch on Christmas Day 2021.

With its huge five-layer sunshade now fully deployed to protect the telescope from the intense radiation of the Sun, JWST continues to cool to its operating temperature below 50 Kelvin (-223° C).

Operators at the Space Telescope Science Institute (STScI) in Maryland, USA have now started to carefully align the 18 separate gold-plated segments which form JWST’s 6.5-metre primary mirror.

This early alignment image, with dots of starlight arranged in a pattern similar to the honeycomb shape of the James Webb Space Telescope's primary mirror, is called an 'image array.' Credit: NASA/STScI/J.DePasquale

Martin Barstow, Professor of Astrophysics and Space Science at the University of Leicester and Chair of the Space Telescope Institute Council which oversees STScI, said: “This stunning new image is a fantastic result from the dedication of the operations team, who have painstakingly adjusted the alignment of the mirror segments over the past few weeks. It shows that all the adjustment mechanisms are working well and that we can now begin the process of merging all these individual images into a single one at the centre of the field of view.

“This process, which has never been carried out on a telescope in space before, will be a huge technical achievement and is a really important milestone in the deployment of the James Webb Space Telescope.

“It has been an amazing few weeks since the launch on Christmas Day. Everything has gone as smoothly as we hoped, but dared not expect. The launch was perfect, preserving thruster gas and allowing a much longer lifetime at L2 than expected.

“Congratulations to all those involved and best wishes for these next critical steps in delivering a fully working telescope. I can’t wait to see the first science images.”

Once alignment of the primary, secondary and fine steering mirrors is complete, engineers can begin to calibrate the instruments carried onboard the spacecraft which will help space scientists ‘look back in time’ by observing some of the most distant objects as seen from Earth.

It is hoped that scientific data collected by JWST could help answer some of the most fundamental questions about our Universe.

Leicester engineers provided the mechanical engineering lead for the Mid-Infrared Instrument (MIRI) for the joint NASA, European Space Agency and Canadian Space Agency mission.

Piyal Samara-Ratna is part of the Leicester team which made major contributions to the design, build and test of MIRI. He said: “The fact that everything has gone so well is testament to the hard work of engineers and scientists around the world working together for many years. It was a real privilege for the University of Leicester to play its part in the design and build of this ground-breaking observatory.

“I’m incredibly excited to see what the observations made by MIRI and the other instruments on JWST can help us discover about our universe.”

Find out more about Leicester’s role in developing the most ambitious space telescope ever created at