This illustration shows the cold side of the Webb telescope, where mirrors and instruments are placed. Credit: Northrop Grumman
Recently, NIRISS, one of the four major scientific instruments in NASA’s James Webb Space Telescope, completed its post-launch preparations and declared itself ready for science. Now, a second of Webb’s four main scientific instruments, known as the mid-infrared instrument (MIRI), has also completed its post-launch preparations and is now ready for science.
“We are thrilled that MIRI is now a state-of-the-art instrument in operation with performance in all its capabilities better than expected.” – Gillian Wright and George Rieke
MIRI’s ability to coronary imaging, which uses two different styles of masks to intentionally block starlight from hitting its sensors when trying to make observations of planets in orbit of the star, was the latest mode. LOOK that it turned off. These custom masks allow scientists to directly detect exoplanets and study the dust disks around their host stars in a way never before done.
Along with Webb’s other three instruments, MIRI initially cooled in the shade of the parasol the size of a Webb tennis court up to about 90 kelvins (minus 298 degrees Fahrenheit, or minus 183 degrees Celsius). To carry out his predicted science meant going down to less than 7 kelvins, just a few degrees above the lowest temperature matter can reach, by using an electric cryorefrigerator. These extreme operating temperatures allow MIRI to offer images and mid-infrared spectra with an unprecedented combination of sharpness and sensitivity.
Spectroscopy animation Webb MIRI: The beam of light coming from the telescope is shown in deep blue entering the instrument through the capture mirror located at the top of the instrument and acting as a periscope. Then a series of mirrors redirect the light. towards the bottom of the instruments where there is a set of 4 spectroscopic modules. Once there, the light beam is divided by optical elements called dichroics into 4 beams corresponding to different parts of the middle infrared region. Each beam enters its own integral field unit; these components divide and reformat the light of the entire field of view, ready to be scattered in spectra. This requires light to fold, bounce, and split many times, making this probably one of Webb’s most complex light paths. To end this incredible journey, the light from each beam is scattered through grids, creating spectra that are then projected onto 2 MIRI detectors. (2 beams per detector). An amazing feat of engineering! Credit: ESA / ATG medialab
“We are delighted that MIRI is now a state-of-the-art instrument in operation with performance in all its capabilities better than expected. Our multinational commissioner team has done a fantastic job preparing MIRI in just a few weeks. We now celebrate all the people, scientists, engineers, managers, national agencies, the European Space Agency (ESA) and NASA, who have made this instrument a reality as MIRI begins to explore the infrared universe in ways and depths never achieved before . “said Gillian Wright, MIRI’s leading European researcher at the UK Astronomy Technology Center, and George Rieke, MIRI’s scientific director at the University of Arizona. MIRI was developed as a partnership between NASA and ESA (European Space Agency), with NASA’s Jet Propulsion Laboratory leading US efforts and a multinational consortium of European astronomical institutes contributing to ESA.
With the launch activities following the launch of NIRISS and MIRI, Webb’s team will continue to focus on marking the remaining two modes on their other instruments. NASA’s James Webb Space Telescope, a partnership with ESA (European Space Agency) and CSA, will release its first full-color images and spectroscopic data on July 12, 2022.