James Webb Space Telescope’s super-cold camera bounces back from glitch
The James Webb Space Telescope’s super-cold camera MIRI is back in full science mode after a technical problem with the grid wheel forced scientists to halt some observations.
The grid wheel on the Medium Resolution Spectrometer (MRS) of James Webb Space TelescopeThe Mid-Infrared Instrument (MIRI) allows astronomers to choose which wavelengths of light to observe the environment in universe. The wheel, which is only used in one of MIRI’s four sighting modes, began showing signs of friction in August, forcing the mission team to suspend sightings in that mode.
After weeks of remote research, engineers concluded that the problem was caused by “increased contact forces between the sub-components of the central wheel bearings under certain conditions,” the Space Telescope Science Institute (STScI) in Baltimore, which is responsible for Webb’s operations, said. in a pronunciation (opens in new tab).
The engineers have now given the green light for the affected spectroscopy mode to resume operations and are developing a series of recommendations on how to use the affected wheel safely, STScI said in the statement.
“A technical test demonstrating new operational parameters for the grid wheel mechanism was successfully conducted on Nov. 2, 2022,” STScI said in the statement. MIRI resumes MRS scientific observations, including taking advantage of a unique opportunity to observe Saturn’s polar regions. The JWST team will plan additional MRS scientific observations, initially at a highly orchestrated cadence with additional trend measurements to reflect the new operational regime of monitor the mechanism to prepare MIRI’s MRS mode for a return to full scientific planning.”
When working in MRS mode, MIRIA does not take pictures but light spectra, essentially light absorption fingerprints that reveal the chemical makeup of the observed objects.
MIRI’s other three observation modes — imaging, coronary imaging, and low-resolution spectroscopy — continued as usual during the MRS disruption. The super-cold camera has proven its worth with a series of stunning images, including a snapshot of the iconic Pillars of Creationrevealing the intricate dusty formation in terrifying detail.
MIRI, a specialist in detecting mid-infrared wavelengths, requires the coldest temperatures of any Webb instrument to operate accurately. While the other three instruments — NIRCam, NIRSpec, and FGS/NIRISS — rely on the telescope’s location and its giant sunshade to maintain temperatures of minus 369.4 degrees Fahrenheit (minus 223 degrees Celsius), MIRI needs additional cryocoolers to even colder temperature of minus 447 degrees F (minus 266 degrees C). That’s just 12 degrees F (7 degrees C) above absolute zero, the temperature at which atoms stop moving. Since MIRI detects infrared light, which is essentially heat, any additional heat would reduce the sensitivity of the measurements.
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