New
Scientist: The
James Webb Space Telescope is suffering yet another
setback—a team at the University of Arizona in Tucson
found in December that about 2% of pixels in a detector
destined for
JWST’s Near Infrared Camera were transmitting
signals although no light was hitting them. That's four times
as many "hot pixels" as there were when the detector was
analyzed in 2008. The researchers later found that the problem
affects four of the camera’s five long-wavelength
detector arrays. NASA allows no more than 5% of a detector's
pixels to be hot by the end of the telescope's five-year space
mission. At this rate, the detectors may exceed this limit
before the telescope even leaves the ground.
