Uh oh, There’s a Problem With one of Webb’s Science Instruments

James Webb is currently experiencing problems with its MIRI instrument. The problem is due to increased friction in one of MIRI’s mechanisms in the Medium-Resolution Spectroscopy (MRS) mode. The observatory is otherwise healthy, but the team decided to stop observations using MRS mode until they find a solution.

JWST’s Mid-Infrared Instrument (MIRI) is one of the most important instruments onboard. It allows the telescope to see in the wavelength range from 5 to 27 micrometers. The instrument has 4 modes: imaging, medium-resolution spectroscopy, low-resolution spectroscopy, and coronagraphy.

On August 24 during preparation for observations using MIRI’s medium-resolution spectroscopy mode (MRS) the team detected a problem with a grating wheel. Its function is to select between short, medium and longer wavelengths. During the setup process leading to scientific observation, the telescope detected increased friction in the mechanism, which caused the issue.

Here’s an inside view of the MIRI instrument in spectroscopy mode:

Following preliminary health checks, an anomaly review board was convened on September 6 to assess the best path forward. As a result, JWST paused observations in the MRS mode using MIRI until an adequate solution is found. Three remaining modes of MIRI are still working properly. Other instruments aren’t affected either.

Previous Problems with James Webb

It’s not the first time that James Webb experiences issues since its launch in December 2021. Previously a larger-than-expected micrometeoroid hit one of JWST’s mirror segments. There was enough damage to be detected by the team, but the quality of observations is still exceeding original expectations.

We covered this situation in this episode of Space Bites:

Despite the current issues, we should still expect new images to come. So, recent releases of the Tarantula Nebula and the Orion Nebula definitely won’t be last. There are many other modes the observatory can use for now. Besides, there are a lot of things that James Webb already observed but did not release to the public yet. Like the images of the TRAPPIST-1 system, which it took during the first month of scientific operation.

Hopefully, the team will be able to find the solution to the current issue and return the telescope into fully functioning mode.

Source: NASA