James Webb Space Telescope faces sensor glitch in deep space

artist's impression of james webb space telescope in space next to earth. a planet is nearby the sun in the far right of the image
Artist's illustration of the James Webb Space Telescope. (Image credit: Kevin Gill)

A key instrument on the James Webb Space Telescope is facing sensor issues.

One mode of the Mid-Infrared Instrument (MIRI) on the James Webb Space Telescope (JWST or Webb) is receiving less sensor "throughput" — less than the expected amount of light — at the longest wavelengths. NASA officials are investigating the cause.

"No effect has been seen for MIRI imaging, and there is no risk to the instrument. All other observation modes — within MIRI and each of Webb's other scientific instruments — remain unaffected," NASA officials wrote in an update late Friday (April 21).

"NASA and its partners are developing a systematic plan to approach, analyze and then explore the issue. The Webb team will continue MIRI observations as planned," the update added.

Related: 12 amazing James Webb Space Telescope discoveries across the universe

MIRI has both a camera and a spectrograph (a device that can divide light into different wavelengths) to detect light from distant objects like galaxies, comets or young stars. It can also image faint objects in our own solar system, such as bodies in the Kuiper Belt, a donut-shaped ring beyond Neptune's orbit.

This isn't the first time that MIRI has faced down a glitch with the Medium Resolution Spectrometer. The instrument had a stuck grating wheel for a few months between August and November 2022, but MIRI was still able to observe in other modes.

While NASA continues to investigate what went wrong this time with MIRI, Friday's update suggests the Webb team may be able to get around the issue by "taking slightly longer exposures at the affected wavelengths" for clearer imaging, if necessary.

The $10 billion Webb has mostly been working well since launching on Dec. 25, 2021. It operates nearly 1 million miles (1.5 million kilometers) from Earth in a gravitationally stable location in space known as Lagrange point 2.

The telescope could operate for at least 20 years in space and has already collected a clutch of stunning images in its near-year of full science operations, including an incredible picture of Uranus just weeks ago.

Elizabeth Howell is the co-author of "Why Am I Taller?" (ECW Press, 2022; with Canadian astronaut Dave Williams), a book about space medicine. Follow her on Twitter @howellspace. Follow us on Twitter @Spacedotcom or Facebook.

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Elizabeth Howell
Staff Writer, Spaceflight

Elizabeth Howell (she/her), Ph.D., is a staff writer in the spaceflight channel since 2022 covering diversity, education and gaming as well. She was contributing writer for Space.com for 10 years before joining full-time. Elizabeth's reporting includes multiple exclusives with the White House and Office of the Vice-President of the United States, an exclusive conversation with aspiring space tourist (and NSYNC bassist) Lance Bass, speaking several times with the International Space Station, witnessing five human spaceflight launches on two continents, flying parabolic, working inside a spacesuit, and participating in a simulated Mars mission. Her latest book, "Why Am I Taller?", is co-written with astronaut Dave Williams. Elizabeth holds a Ph.D. and M.Sc. in Space Studies from the University of North Dakota, a Bachelor of Journalism from Canada's Carleton University and a Bachelor of History from Canada's Athabasca University. Elizabeth is also a post-secondary instructor in communications and science at several institutions since 2015; her experience includes developing and teaching an astronomy course at Canada's Algonquin College (with Indigenous content as well) to more than 1,000 students since 2020. Elizabeth first got interested in space after watching the movie Apollo 13 in 1996, and still wants to be an astronaut someday. Mastodon: https://qoto.org/@howellspace

  • Wind Angel
    Fascinating discovery. But I am dismayed that they are already trying to wedge this discovery into their chosen model, rather than reevaluating the Big Bang itself. I have trouble believing that something that should have taken billions of years to form could be there fully formed at such an early phase in our known universe. Why aren't they studying this without consideration of this faulty cosmology model?

    Furthermore, in this article, a halo of dark matter is being presented as fact. Dark matter hasn't been proven yet. I think dark matter might well exist, however until it is a proven fact, it should not be presented as such.

    I am not a Big Bang denier. I just have strong doubts it is the absolute beginning of all that exists. I see it as part of the equation, not the equation itself.

    Once again, I find myself wishing I had the money to fund my own private study of another phenomenon that professional scientists are trying to wedge into a predetermined model. Who do I complain to?