With help from a cryocooler, Webb’s Mid-Infrared Instrument was dropped to as low as possible above the lowest possible temperature and was ready for calibration.
The James Webb Space Telescope will see the first steps taken after the Big Bang, but in order to do so its instruments will first need to be cold – real cold. On April 7, Webb’s Mid -Infrared Instrument (MIRI) – a joint development by ESA and NASA – reached its final working temperature of under 7 kelvins (minus 266 degrees Celsius).
“I’m happy after many years of hard work by the MIRI team now that the instrument is cool and ready for the next levels. The good performance of the trainer is important for the missionary, ”said Gillian Wright, senior European researcher for MIRI and Director of the UK Astronomy Technology Center (ATC).
Along with Webb’s three other instruments, the MIRI first cooled in the shade of Webb’s large tennis court, which dropped to about 90 kelvins (less than 183 C). But a reduction to less than 7 kelvins requires an electric cryocooler. Last week, the company went through a difficult event called the “pinch point,” when the instrument went from 15 kelvins (minus 258 C) to 6.4 kelvins (minus 267 C). .
“The MIRI design team has put a lot of effort into developing the process for the pinch point,” said Analyn Schneider, project manager for MIRI at NASA’s Jet Propulsion Laboratory in Southern California, USA. “The team was excited and excited about the hard work. In the end, it was the book’s execution of the process, and the performance was much better than expected.
Low temperatures are necessary because Webb’s four sensors detect infrared light – the wavelength is much longer than what human eyes can see. Distant stars, stars hidden in coconut fronds, and stars outside our Solar System emit infrared light. But so are the other heaters, including Webb’s own electrical equipment and optics. The cooling of the four sensors and the surrounding technologies eliminates those infrared emissions. MIRI detects infrared wavelengths that are longer than the other three instruments, which means they need to be cooler.
Another reason Webb’s detectors need to be cold is to detect something called darkness, or the lightning created by the vibrations of the powers in the detectors. themselves. Darkness is represented as a true signal to seers, giving the false impression that they have been struck by light from an external source. Such deceptive signals can eliminate the real signals that astronomers want to have. Because the higher the temperature of the vibration of the atoms in the eye, the lower the temperature, the less vibration, which means less vibration. the dark.
The ability of the MIRI to detect long infrared waves is much easier than the blackout, so it needs to be cooler than other devices to completely eliminate that effect. For every degree the temperature of the instrument rises, the black current rises by a factor of 10.
When the MIRI reached 6.4 kelvins dry, scientists began a series of tests to verify that the sensors were working as expected. Just as a doctor is looking for a symptom of a disease, the MIRI team looks at data that describes the health of the player, and then gives the player instructions to see if he or she can recover. perform tasks correctly.
This milestone is the result of the work of scientists and engineers in several studios with JPL, including Northrop Grumman, who built the cryocooler, and NASA’s Goddard Space Flight Center, which oversaw the integration. Measurement of MIRI and the pleasure of the rest of the observatory. .
“We spent years training for that time, running the orders and evaluations that we did at MIRI,” said Mike Ressler, project scientist for MIRI at JPL. “It’s like a movie: everything we do is written and edited. As the data went, I was happy to see that it was as expected and we found a healthy one.
The company faced many challenges before MIRI began its science career. Now that the instrument is at working temperature, team members will take test images of the stars and other sensors that can be used for calibration and observe the performance and performance. of the instrument. The company will lead these preparations with the calibration of the three instruments, releasing Webb’s first scientific photographs this summer.
“I am very proud to be part of this team of exciting, enthusiastic scientists and engineers drawn from Europe and America,” said Alistair Glasse, MIRI material scientist at ATC in Edinburgh, Scotland. “This is our‘ trial on fire ’but I understand that the personal commitment and respect for someone that has been built over the years is what we will have in the months to come. provides a useful tool to the global astronomy community.
MIRI is part of Europe’s donation to the James Webb Space Telescope (Webb) mission. It is an association between Europe and America; The main partners are ESA, a group of European funded companies, the Jet Propulsion Laboratory (JPL) and NASA’s Goddard Space Flight Center (GSFC).
Webb is a global partnership between NASA, ESA and the Canadian Space Agency (CSA).