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James Webb Space Telescope suffers another hitch: Instrument down

Second system to be knocked offline

The Near Infrared Imager and Slitless Spectrograph (NIRISS) on NASA's James Webb Space Telescope is currently offline, and all science observations using the instrument will have to be rescheduled as engineers try to repair the thing.

"On Sunday, January 15, the James Webb Space Telescope's NIRISS experienced a communications delay within the instrument, causing its flight software to time out," NASA confirmed in a statement this week.

"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. There is no indication of any danger to the hardware, and the observatory and other instruments are all in good health."

Together with the Fine Guidance Sensor, the NIRISS allows the telescope to point its cameras and instruments precisely to capture light from objects deep in space. The spectrograph operates at near-infrared wavelengths, and is a specialized instrument that can resolve light from individual objects that otherwise appear quite close together. 

Astronomers use the NIRISS to detect exoplanets as well as capture wide-field images to study populations of stars and galaxies. But boffins who were in the middle of using the telescope's instrument or planning to will have to wait until it comes back online. The glitch, unfortunately, will mean precious observation times allotted to astronomers will have to be adjusted.

NIRISS was built by the Canadian Space Agency, and is sensitive enough to study the atmospheres of exoplanets. The first set of images taken by the JWST, revealed by NASA back in July last year, showed it had managed to detect water and hazy clouds on the hot gas giant WASP-96b. 

Launched on Christmas Day in 2021, the years-late, multi-billion-dollar JWST is the most expensive and powerful space telescope built yet. But the machine has suffered a few glitches less than a year into its operations, including a grating wheel issue that temporarily took down its Mid-Infrared Instrument, as well as a software fault that impacted its attitude control system and forced it to enter safe mode for a few weeks.

Unlike Hubble, the JWST isn't repairable as it orbits the Sun a million miles from Earth at the second Lagrange point. The instrument has already been pelted with space debris, such as micrometeoroids. The eggheads think this latest gremlin is repairable from our home world. ®

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