April 30, 2024

Webb Glitch: Issue With Space Telescope’s Mid-Infrared Instrument (MIRI)

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 components called dichroics in 4 beams corresponding to different parts of the mid-infrared region. This needs the light to be folded, bounced and split many times, making this probably one of Webbs most complicated light paths.To surface this amazing voyage, the light of each beam is dispersed by gratings, producing spectra that then predicts on 2 MIRI detectors (2 beams per detector).

The beam coming from the telescope is then displayed in deep blue entering the instrument through the pick-off mirror located at the top of the instrument and imitating a periscope.Then, a series of mirrors reroute the light towards the bottom of the instruments where a set of 4 spectroscopic modules are located. Once there, the beam is divided by optical aspects called dichroics in 4 beams corresponding to various parts of the mid-infrared area. Each beam enters its own integral field unit; these components split and reformat the light from the whole field of vision, all set to be dispersed into spectra. This requires the light to be folded, bounced and split numerous times, making this most likely among Webbs most intricate light paths.To finish this incredible voyage, the light of each beam is distributed by gratings, creating spectra that then projects on 2 MIRI detectors (2 beams per detector). An amazing feat of engineering! Credit: ESA/ATG medialab
An inconsistency was discovered in the James Webb Space Telescopes MIRI Medium Resolution Spectroscopy mode, with lowered throughput at the longest wavelengths. NASA and partners are exploring and investigating the problem mitigation methods, while continuing MIRI observations.
All 17 observing modes of the James Webb Space Telescope undergo regular efficiency monitoring and calibration. This month, while performing calibration by comparing the brightness of basic stars that have actually been well-cataloged by other observatories to what Webbs Mid-Infrared Instrument (MIRI) was getting, employee noticed a disparity in the information.
More analysis of MIRIs Medium Resolution Spectroscopy (MRS) mode exposed that at the longest wavelengths, the throughput, or the quantity of light that is ultimately signed up by MIRIs sensing units, has reduced since commissioning last year. No result has actually been seen for MIRI imaging, and there is no risk to the instrument. All other observation modes– within MIRI and each of Webbs other clinical instruments– stay untouched.

The Webb group will continue MIRI observations as prepared. More test observations will be taken to completely characterize the nature of the issue using this particular mode of observation. Next, a plan for long term-monitoring will be enacted, while the team continues to examine the cause, determine dangers, and check out mitigations that would potentially enhance performance.