Another Webb telescope instrument gets the ‘go for science’

The second of the four main science instruments on NASA’s James Webb Space Telescope, known as the Mid-Infrared Instrument (MIRI), has completed its post-launch preparations and is now ready for science.

The last MIRI mode to check off was the coronagraphic imaging function, which uses two different types of masks to intentionally block starlight from hitting its sensors while attempting to observe the planets orbiting the star. These custom masks allow scientists to instantly detect exoplanets and study dust discs around their guest stars in a way that has never been done before.

Together with Webb’s three other instruments, MIRI initially cooled in the shade of Webb’s tennis court-sized sunshade to about 90 Kelvin (minus 298 degrees Fahrenheit or minus 183 degrees Celsius). To carry out the intended science, it had to drop to less than 7 Kelvin — just a few degrees above the lowest temperature matter can reach — by using an electrically powered cryocooler. These extreme operating temperatures allow MIRI to deliver mid-infrared images and spectra with an unprecedented combination of sharpness and sensitivity.

“We are delighted that MIRI is now a functioning, state-of-the-art instrument with performance in all its capabilities that is better than expected. Our multinational commissioning team did a fantastic job getting MIRI ready in just a few weeks. Now we celebrate all people, scientists , engineers, managers, national agencies, ESA and NASA, who have made this instrument a reality as MIRI begins to explore the infrared universe in ways and to depths never before reached,” said Gillian Wright, MIRI European Principal Investigator at UK Astronomy Technology Center, and George Rieke, MIRI science lead at the University of Arizona. MIRI was developed as a collaboration between NASA and ESA (European Space Agency), with NASA’s Jet Propulsion Laboratory leading the US effort and a multinational consortium of European astronomical institutes contributing to ESA.

With NIRISS and MIRI’s post-launch commissioning activities completed, the Webb team will continue to focus on ticking off the remaining two modes on its other instruments. NASA’s James Webb Space Telescope, a partnership with ESA (European Space Agency) and CSA, will release its first color images and spectroscopic data on July 12, 2022.

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