James Webb has, again, a problem. Since last January 15, in fact, one of his main instruments, NIRISS (Near Infrared Imager and Slitless Spectrograph), is ‘offline’ due to an error in his internal communications that led him to disconnect. Among other things, NIRISS is in charge of studying the atmospheres of distant planets, so the failure will especially affect programs that have the objective of Look for signs of life on other worlds.
According to a NASA statement, “There are no indications of any danger to the hardware, and the observatory and other instruments are in good health. The affected scientific observations will be rescheduled.”
Under normal conditions, NIRISS is capable of operating in four different modes. In fact, it can work as a camera when the other telescope instruments are busy, but also, as has been said, analyze light signatures to study the atmospheres of small exoplanets, or make high-contrast images.
Finally, it has a mode specifically designed to find and analyze very distant galaxies.
not the first problem
But NIRISS isn’t the first Webb instrument to run into trouble. Last August, without going any further, a gear inside the observatory’s Mid-Infrared Instrument (MIRI) began to show signs of excessive friction. Fortunately, that wheel is used in only one of the instrument’s four observing modes, so the staff only had to stop those observations while MIRI work continued smoothly in the remaining modes. A few months later, in November, the engineers found a way to get the affected mode back to use, and everything was back to normal.
On top of that, in December, the space observatory spent two weeks affected by a bug that caused it to repeatedly go into ‘safe mode’, interrupting all scientific observations. But once again the engineers found the problem, which this time was in the telescope’s steering control system, and on December 20 everything was back to normal.
Now, it is not very clear when the NIRISS instrument will be able to be connected again, so the scientific programs that used it have had to be suspended. Due to the high demand for telescope airtime by scientists around the world, it is very likely that the failure will affect the rest of the planned observations as well.
Still, most of Webb’s work continues without a hitch. And the engineers are confident that they will soon be able to solve this new bug as well. These types of failures are practically inevitable in instruments of the complexity of the space telescope, in which hundreds of systems must work in unison to guarantee the success of scientific operations.