James Webb Space Telescope’s coolest instrument captures first star

The UK’s main contribution to the James Webb Space Telescope (JWST), the Mid-Infrared Instrument (MIRI), has now opened its eye to the sky.

And Leicester scientists and engineers – many of whom involved with the most complex space observatory ever built from the very start – have reacted to the first MIRI images released by NASA.

Engineers have confirmed that the telescope’s alignment is complete using the measurements from all four of the science instruments meaning MIRI is now receiving focused light from the telescope and taking astronomical images for the first time.

The James Webb Space Telescope is the largest most powerful telescope ever launched into space and MIRI is one of four scientific instruments on board. Leicester engineers provided the mechanical engineering lead for the instrument which serves as the UK’s contribution to the multi-national collaboration.

MIRI was the last instrument to become functional on Webb as it operates at lower temperatures than the other instruments, so had to be carefully cooled to 7 Kelvin (-266°C). 

After confirming that the instrument systems were functional at this extremely cold temperature the MIRI cover was opened and the first data obtained.

Professor Martin Barstow confessed the image, which represents the culmination of more than two decades’ work from scientists and engineers both in Leicester and across the world, “brought a tear to my eye”.

Leicester colleague Dr John Pye described the astonishing image as “well worth the more than 20-year wait”.

These first MIRI observations were the first step to incorporating MIRI into the multi-instrument multi-field alignment (MIMF) process. MIRI has no internal adjustments for focus or alignment and relies on the incredible accuracy of the Webb optical alignment. Although it is an engineering image for the telescope alignment, these first measurements have also provided the MIRI team with some preliminary information about the flight instrument. 

Leigh Fletcher, Professor of Planetary Science at the University of Leicester, will lead a series of observations in the telescope’s first year of operation. Professor Fletcher added: “This is a key moment that astronomers have been waiting for – this image shows just how incredible the mid-infrared observations are going to be, probing low-temperature phenomena both near and far.

“It really whets the appetite for the amazing infrared science to come when JWST starts looking at our science targets this summer.”

Professor Mark Thomson, STFC Executive Chair, said: “This is a remarkable achievement for the hardworking scientists and engineers who have worked tirelessly to get to this point. MIRI is an incredible feat of engineering. 

“Watching MIRI come to life is inspiring, and is a testament to the talent of the UK teams involved.”

This is a key milestone in Webb’s science mission as it means that all the instruments, including MIRI, are now able to take super sharp, sensitive astronomical images and spectra.

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