James Webb Space Telescope has gone cold, but that’s good

Nearly four months after launch, the James Webb Space Telescope has just taken a big step toward its first observations of deep space.

The $10 billion mission — a joint effort of NASA, the European Space Agency and the Canadian Space Agency — is looking to learn more about the origin of the universe while also looking for distant planets that may support life.

This week, NASA’s Jet Propulsion Laboratory (JPL) mission team confirmed that the Webb telescope had dropped to the temperature required for the observation work to begin.

A critical component of the telescope, the Mid-Infrared Instrument (MIRI), recently reached its final operating temperature below 7 kelvins (minus 447 degrees Fahrenheit or minus 266 degrees Celsius).

JPL said MIRI, along with the telescope’s other instruments, began to cool in the shadows of Webb’s large sunshade, to about 90 kelvins (minus 298 F or minus 183 C).

However, it was said that dropping to less than 7 Kelvin required an electrically powered “cryocooler” device to get it past the so-called “pinch point” when the instrument went from 15 Kelvin (minus 433 F or minus 258 C) to 6. ,4 goes. kelvin (minus 448 F or min 267 C).

“The MIRI cooler team has put a lot of effort into developing the bottleneck procedure,” Analyn Schneider, project manager for MIRI, said Wednesday. “The team was both excited and nervous going into the critical activity. In the end, it was a textbook implementation of the procedure, and the cooler performance is even better than expected.”

The low temperature is vital because Webb’s instruments detect infrared light, which “distant galaxies, stars hidden in cocoons of dust and planets beyond our solar system” all emit.

Parts of the Webb telescope, if they are too hot, would also emit infrared light, making it difficult for scientists to understand the collected data, so cooling them solves this problem.

Cooling the telescope also suppresses something called “dark current,” an electrical current created by the vibrations of atoms in the Webb detectors that can also confuse the telescope about where a light source is coming from.

“We practiced for years before that point, going through the commands and checks we did on MIRI,” said MIRI project scientist Mike Ressler. “It was like a movie script: everything we had to do was written down and rehearsed. When the test data came in, I was ecstatic to see that it looked exactly as expected and that we have a healthy instrument.”

The Webb team will now take test images of celestial bodies in deep space to calibrate the telescope’s instruments and make sure everything is working properly. Assuming everything goes according to plan, we should see the first images of the project this summer.

The James Webb telescope is the most powerful space-based observatory ever built, and its work will complement that of the Hubble telescope that has been exploring deep space for more than 30 years.

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