The problem was discovered on the James Webb Space Telescope

MIRI spectroscopy of the James Webb Space Telescope: The light beam from the telescope is then displayed in dark blue as it enters the device through the pickup mirror on the top of the device and behaves like binoculars.
Then a series of mirrors directs the light towards the bottom of the instruments, where there is a set of 4 spectral units. Once there, the light beam is split by optical elements called dichroism into 4 beams corresponding to different parts of the mid-infrared region. Each ray enters its own integrated field unit; These components divide and reformat the light from the entire field of view, ready to be diffused into the spectra. This requires bending, bouncing and splitting the light multiple times, making this arguably one of Webb’s most complex light paths.
To complete this fantastic journey, the light from each ray is scattered by grids, creating spectra which are then projected onto two MIRI detectors (two beams per detector). Incredible technical result! Credit: ESA / ATG multimedia laboratory

–

Update for mid-infrared device operations

Of[{” attribute=””>James Webb Space Telescope’s Mid-Infrared Instrument (MIRI) has four observing modes. During setup for a science observation on August 24, a mechanism that supports one of these modes, known as medium-resolution spectroscopy (MRS), exhibited what appears to be increased friction. This mechanism is a grating wheel that allows astronomers to select between short, medium, and longer wavelengths when making observations using the MRS mode. Following preliminary health checks and investigations into the issue, an anomaly review board was convened on September 6 to assess the best path forward.

The Webb team suspended planning notes using this monitoring mode while continuing to analyze their behavior. They are also currently developing strategies for filming MRS sightings as soon as possible. The observatory is healthy and the other three MIRI monitoring modalities – imaging, low-resolution spectroscopy, and coronograph – are functioning normally and remain available for scientific observations.

The James Webb Space Telescope (MIRI) instrument sees light in the mid-infrared region of the electromagnetic spectrum, with wavelengths longer than what our eyes can see.

MIRI allows scientists to use multiple observation techniques – imaging, spectroscopy and chromography to support the full range of Webb’s scientific goals, from observing our solar system and other planetary systems to studying the early universe.

To encapsulate all of these modes in a single instrument, the engineers designed a complex optical system in which light from the Webb telescope follows a complex 3D path before finally reaching the MIRI detectors.

This artist’s rendering shows the path to MIRI’s acquisition mode, which offers both photocopy and chorography capabilities. It also includes a simple spectrophotometer. We first look at the mechanical structure with three prominent pairs of carbon fiber trusses that will be attached to the Webb instrument compartment at the rear of the telescope.

The pickup mirror, which behaves like binoculars, receives the light from the telescope, shown in dark blue, and sends it to the MIRI’s image processing unit. Inside the device, a mirror system reconfigures and redirects the light beam until it reaches the filter wheel where the desired range of mid-infrared wavelengths is selected from a set of 18 different filters, each with its own function (the ray turns blue in the animation).

Finally, another series of mirrors captures the ray of light coming out of the filter wheel and reconstructs the image of the sky on the MIRI detectors.

Credit: ESA / ATG medialab

–