James Webb Space Telescope nears awakening as 3 out of 4 instruments completely aligned

In a key update, Engineers handling the James Webb Space Telescope have completely aligned three out of the four science instruments with the golden mirrors. According to the latest developments, NASA stated that this has completed six of the total seven alignment phases and the telescope is now even closer to producing the most focused and accurate images of the universe. “Previous alignment efforts were so accurate that the team concluded no additional adjustments are necessary for Webb's secondary mirror until the seventh stage”, NASA mentioned in a tweet. As for the final stage, the mission team would align the Mid-Infrared Instrument or MIRI once it completely cools down. 

A challenging seventh phase awaits scientists

The seventh and final phase of the alignment process, which involves the MIRI, would be challenging as the instrument needs to be cooled down to -266°C while preventing ice formation. While the formation of ice in space sounds bizarre, NASA claims that this does happen and might jeopardise Webb’s functioning. 

Elaborating on how ice formation takes place in space, NASA noted that when Webb was launched on December 25 last year, the telescope’s sunshields and other components trapped water vapour from the Earth’s atmosphere. Although most of it escaped 200 seconds post launch, some of the moisture was left behind and was carried into space. And since water behaves differently in space, water molecules contacting surfaces colder than -133 degrees celsius stick as ice and never come off. 

“Once Webb’s sunshield deployed, Webb began to cool quickly. Our team carefully managed the rate of this cooldown and the order in which different components cooled using electric strip heaters. This allowed water to escape to space rather than freeze onto sensitive components”, NASA said. It further revealed that MIRI, which is equipped with a refrigerator or cryocooler, uses helium gas to carry heat out to the warm side of Webb’s sunshield. 

“To ensure that the cryocooler could work & MIRI could cool to its ultimate temperature, all water had to be either eliminated or purposely contained in designated areas”, the agency added. Once all the instruments are aligned with Webb's primary mirror, each of the instruments would be individually calibrated before the telescope beams back its first images later this year. 

Image: @ESA_Webb/Twitter