Skip to main content

One of James Webb’s four instruments is offline following error

The James Webb Space Telescope is experiencing an issue with one of its instruments, the Near Infrared Imager and Slitless Spectrograph, or NIRISS. The instrument is currently offline with no indication of when it will be back online, but engineers are working to address the issue and the telescope hardware remains safe.

As alarming as that might sound, it is not uncommon for such issues to crop up, especially in space telescopes. As performing physical maintenance on space telescopes is extremely difficult, software troubleshooting is done in a slow and careful way to prevent any damage from occurring. That’s why you’ll see instruments on space telescopes like Hubble or the Swift Observatory going into safe mode to protect themselves whenever an issue arises.

In the case of James Webb, the problem with the NIRISS instrument was due to a communication delay. “On Sunday, Jan. 15, the James Webb Space Telescope’s Near Infrared Imager and Slitless Spectrograph (NIRISS) experienced a communications delay within the instrument, causing its flight software to time out,” NASA wrote in a statement. “The instrument is currently unavailable for science observations while NASA and the Canadian Space Agency (CSA) work together to determine and correct the root cause of the delay.”

NIRISS sits alongside a sensor called the Fine Guidance Sensor or FGS which allows the telescope to point at its targets accurately. NIRISS can work as both a camera and a spectrograph and has a special feature called an aperture mask which allows it to block out light from particularly bright sources to better see dimmer sources around them. The instrument is used for tasks like detecting and examining exoplanets and for looking at distant galaxies.

The planned scientific observations which were scheduled to use NIRISS will now be rescheduled, according to NASA.

This comes on the heels of another issue with Webb which occurred in December 2022. A software issue in the attitude control system caused some instruments to enter safe mode on December 7, with science observations being paused. That was fixed by December 20, when all science operations resumed.

Georgina Torbet
Georgina is the Digital Trends space writer, covering human space exploration, planetary science, and cosmology. She…
Voyager 1 probe has nine lives, is operating its four instruments once again
An artist’s concept of the Voyager spacecraft.

An artist’s concept of the Voyager spacecraft. NASA/JPL-Caltech

Having suffered through a tricky glitch, the incredible Voyager 1 spacecraft is now operational once again, with data coming in from all four of its current scientific instruments. The spacecraft is nearly 50 years old, having launched in 1977, and has long since traveled beyond the orbit of Pluto and out into interstellar space.

Read more
Well-known star turns out to be not one star, but twins
This artist’s concept shows two young stars nearing the end of their formation. Encircling the stars are disks of leftover gas and dust from which planets may form. Jets of gas shoot away from the stars’ north and south poles.

This artist’s concept shows two young stars nearing the end of their formation. Encircling the stars are disks of leftover gas and dust from which planets may form. Jets of gas shoot away from the stars’ north and south poles. U.S. NSF/NSF NRAO/B. Saxton

There are some regions and objects that become favorite targets for astronomers -- often because they are nearby (and so easier to observe) and because they are a well-known example of an object like a stellar nursery or a black hole. But occasionally, even these well-known objects turn out to be hiding surprises. This was the case recently, when observations from the James Webb Space Telescope revealed that a particular star, WL 20S, in the frequently observed WL20 region, turned out not to be a single star at all, but actually a pair.

Read more
James Webb discovers the most distant galaxy ever observed
JADES (NIRCam Image with Pullout). The NIRCam data was used to determine which galaxies to study further with spectroscopic observations. One such galaxy, JADES-GS-z14-0 (shown in the pullout), was determined to be at a redshift of 14.32 (+0.08/-0.20), making it the current record-holder for the most distant known galaxy. This corresponds to a time less than 300 million years after the big bang.

JADES (NIRCam Image with Pullout). The NIRCam data was used to determine which galaxies to study further with spectroscopic observations. One such galaxy, JADES-GS-z14-0 (shown in the pullout), was determined to be at a redshift of 14.32 (+0.08/-0.20), making it the current record-holder for the most distant known galaxy. This corresponds to a time less than 300 million years after the big bang. Credit: NASA, ESA, CSA, STScI, B. Robertson (UC Santa Cruz), B. Johnson (CfA), S. Tacchella (Cambridge), P. Cargile (CfA). NASA

Researchers using the James Webb Space Telescope have discovered the most distant known galaxy to date, one that is so far away that it existed just a few hundred million years after the Big Bang. Since Webb began its science operations in 2022, astronomers have used it to look for very distant, very ancient galaxies and have been surprised by what they found. Not only have they found many of these distant galaxies, but the galaxies are also brighter and more massive than they expected -- suggesting that galaxies evolved into large sizes faster than anyone imagined.

Read more