MIRI Anomoly

James Webb Space Telescope MIRI Spectroscopy Animation: The beam of light coming from the telescope is then shown in deep blue entering the instrument through the pick-off mirror located at the top of the instrument and acting like a periscope.Then, a series of mirrors redirect the light toward the bottom of the instruments where a set of 4 spectroscopic modules are located. Once there, the beam of light is divided by optical elements called dichroics in 4 beams corresponding to different parts of the mid-infrared region. Each beam enters its own integral field unit; these components split and reformat the light from the whole field of view, ready to be dispersed into spectra. This requires the light to be folded, bounced, and split many times, making this probably one of Webb’s most complex light paths.  To finish this amazing voyage, the light of each beam is dispersed by gratings, creating spectra that then projects on 2 MIRI detectors (2 beams per detector). An amazing feat of engineering! Credit: ESA/ATG medialab

Mid-Infrared Instrument Operations Update
The 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.  READ MORE...