In the long process of getting ready to take its first scientific observations this summer, the James Webb Space Telescope now has three out of its four instruments aligned to its mirrors. The fourth instrument, the mid-infrared instrument, will take a little longer because it uses a different type of sensor which needs to be kept at an extremely low temperature. NASA shared an update on the process of getting MIRI ready for operations.
The three other instruments are operating at temperatures of 34 to 39 kelvins, but MIRI needs to go all the way down to 7 kelvins. The instrument has a special cryocooler that will help cool it to 15 kelvins. The circulating helium gas will be forced through a flow restriction by operating the cryocooler. When the gas expands, it becomes cold and can bring the MIRI detectors to a cool operating temperature.
The pinch point is where the instrument has to make it through before it can reach operating temperature. Engineers have to perform a series of complex and rapid adjustments based on the cooler's temperature and flow rate when it is at its cooling limit. The most difficult part of the operation is the critical point, so technicians have been practicing it here on Earth. MIRI will be ready to start taking readings once this tricky operation is over.
The imager will reveal targets ranging from nearby nebulae to distant interacting galaxies. The planets will shine the most in mid-IR light.
All Rights Reserved © 2024
